GOST R ISO 14284-2009
GOST R ISO 14284−2009 Steel and cast iron. Selection and preparation of samples for the determination of chemical composition
GOST R ISO 14284−2009
Group B39
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
STEEL AND CAST IRON
Selection and preparation of samples for the determination of chemical composition
Steel and iron. Sampling and preparation of samples for determination of chemical composition
OKS 77.080.10
AXTU 0709
Date of introduction 2011−01−01
Preface
The purpose and principles of standardization in the Russian Federation established by the Federal law of 27 December 2002 N 184-FZ «On technical regulation», and rules for the application of national standards of the Russian Federation — GOST R 1.0−2004 «Standardization in the Russian Federation. The main provisions"
Data on standard
1 PREPARED AND SUBMITTED by the Technical Committee for standardization TC 145 «monitoring Methods of steel products» based on the authentic translation of the standard referred to in paragraph 3, which is FSUE «STANDARTINFORM"
2 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of December 11, 2009 N 730 St
3 this standard is identical with ISO 14284:1996 «Steel and cast iron. Selection and preparation of samples for the determination of chemical composition» (ISO 14284:1996 «Steel and iron — Sampling and preparation of samples for determination of chemical composition»).
In applying this standard it is recommended to use instead of the referenced international standards corresponding national standards of the Russian Federation, details of which are given in the Appendix With
4 INTRODUCED FOR THE FIRST TIME
Information about the changes to this standard is published in the annually issued reference index «National standards», and the text changes and amendments — in monthly indexes published information «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet
1 Scope
This standard establishes the methods of sampling and preparation of samples for determination of chemical composition of cast iron ingots, cast iron and steel. Methods apply to the sampling of liquid and solid metals.
2 Normative references
This standard uses the regulatory references to the following international standards:
ISO 377:1997 Steel and steel products. Location and preparation of samples for mechanical tests
ISO 9147:1987 Cast iron. Definition and classification
3 Terms and definitions
This standard applies the following terms with respective definitions:
3.1 chemical analysis method (chemical method of analysis): determination of the chemical composition, in which the sample (sample) start a chemical reaction.
3.2 physical analysis method (physical method of analysis): a Method of determining chemical composition at which the sample does not enter into chemical reaction, such as the optical emission spectral analysis or x-ray fluorescence spectroscopy.
3.3 thermal analysis method (thermal method of analysis): a Method of determining chemical composition at which the sample is subjected to heating, burning or melting.
3.4 the melt (melt): molten metal, from which is taken the sample.
3.5 selection of sample (sample) spoon (spoon sampling): Selection of the sample from the melt or during casting melting with a long spoon or ladle, followed by pouring the melt in a small form.
3.6 sample selected by the spoonful (spoon sample): Sample taken from the melt with a spoon and filled in a small form.
3.7 selection of sample the sampling probe (probe) (probe sampling): Selection of the sample from the melt of commercially available probe sampler.
3.8 immersion sampling (immersion sampling): sampling Method in which the probe is immersed in the melt and the sample chamber is filled under the action of ferrostatic pressure or gravity.
3.9 selection of the sample suction (suction sampling): a Method of selecting a sample in which the probe is immersed in the melt to fill the chamber by suction of the melt.
3.10 the selection of the sample in the stream (stream sampling): Method of selecting sample, wherein the probe is substituted for the flow of liquid metal to fill the chamber under the pressure of this stream.
3.11 sample (sample), selected probe (probe sample): Sample taken from the melt of commercially available probe.
3.12 casting (cast product): cast Iron or steel billet is not subjected to deformation, such as ingot or semi-finished product obtained by continuous casting or a shaped.
3.13 forging (wrought product): Steel billet is subjected to deformation by rolling, drawing, forging or any other method, such as long products, billet, sheet, strip, pipe of small diameter, wire.
3.14 the original sample (sample product): Special cast-iron or steel item selected from a production batch as the original sample (specimen).
3.15 intermediate sample (preliminary sample): a Sufficient amount of metal selected from the original sample in order to obtain one or more samples (samples) for analysis.
3.16 a sample for analysis (sample for analysis): part of the original sample or the intermediate portion of the sample selected from the original sample or the sample taken from the melt that has been prepared for analysis. A sample for analysis may consist of the initial sample or from the sample from the melt.
Note 1 — the following categories of sample for analysis:
the sample in the form of a solid mass (monolith);
the sample is subjected to remelting;
the sample in the form of chips obtained when machining on the lathe;
the sample in the form of granules (pieces) obtained by crushing;
the sample in powder form obtained by grinding.
3.17 the working sample (test portion): the portion of the sample for analysis, or samples taken from the melt, which is directly analyzed. In some cases, working sample is taken from the original sample.
Note 2 — there are the following special types of work samples in the form of a monolith obtained from the sample by the sampler:
a working sample is in the form of a small disk, typically a piece of metal of irregular shape, obtained by cutting from a sheet;
a working sample is in the form of small nodules, called «the tide»;
a working sample is in the form of a rod of small diameter, called «hairpin», obtained by cutting.
Note 3 — When the sample for analysis is presented in the form of chips or powder or if the sample is in the form of a monolithic mass analyzed thermal method, working sample (a sample) is prepared by weighing. If using a physical method of analysis, then analyze the part is actually only a small part of the sample for analysis. In optical emission spectral analysis the mass of metal consumed in an electric discharge, ranging from 0.5 to 1 mg. In the case of x-ray fluorescence spectroscopy of the characteristic radiation is generated in a very thin surface layer of the sample.
3.18 grinding (grinding): Preparation of metal sample for analysis by a physical method, wherein the surface portion is polished with an abrasive.
3.19 sharpening (finishing): Preparation of metal sample for analysis by a physical method, wherein the surface portion is polished during processing of the flexible rotating disk or continuous tape with an abrasive coating.
3.20 milling (milling): get sample in the form of chips or surface preparation of the sample for analysis by a physical method, a surface treatment of a rotating cutter with multiple cutting blades.
3.21 party (consignment): Metal supply at a time.
3.22 point-sample (increment): Metal, taken in a single sample of the consignment.
4 Selection and preparation of samples
4.1 General provisions
This section addresses General requirements for samples, selection and preparation of samples of iron and steel. Special requirements apply to each category of liquid and solid metal. These requirements are discussed in the relevant sections. The sequence of selecting and preparing samples of liquid iron and steel casting of iron and steel products is shown in figure 1. Special attention is paid to the selection and preparation of samples of iron ingots (section 8).
Figure 1 — Sequence of sampling and preparation of sample
| and Liquid iron and steel | b — Casting of iron and steel products |
Figure 1 — Sequence of sampling and preparation of sample
4.2 Sample (sample)
4.2.1 Quality
Technology selection must ensure that the analysis sample, representative for the average chemical composition of the melt or the original sample. A sample for analysis must be sufficiently homogeneous in chemical composition to a small heterogeneity does not affect the discrepancy between the results of a particular analysis method. However, for samples taken from the melt, some scatter of the results of the analysis within one sample and between different samples is inevitable. In this case, the divergence of the results will be an integral part of the values of repeatability and reproducibility of the analysis.
The sample for analysis shall not have surface coatings, moisture, dirt or other contaminants. The sample for analysis should not have holes, cracks and pores, as well as scoring, sunsets or other surface defects. In the selection and preparation of sample for analysis, special attention is required in those cases where it is expected that the sample taken from the melt is nonuniform or in any way contaminated. The sample taken from the melt must cool so that the chemical composition and the metal structure of the sample was varied from trial to trial. It is important to understand that the results of the analysis of some physical methods can affect the structure of the metal. This is particularly true of cast iron with a white or gray structure, as well as steel in a state directly after casting or deformation.
4.2.2 Dimensions
The size of the intermediate pattern in the form of a solid monolith should be sufficient to ensure the selection of samples for re-analysis using an alternative method.
Should be prepared a sample of sufficient mass, allowing for any necessary re-analysis. A weight of 100 g is sufficient for the sample in the form of chips or powder.
The size requirements of the sample for analysis in the form of a monolith depend on the chosen method. In the case of optical emission spectral analysis method and method x-ray fluorescence spectroscopy the shape and size of the sample will determine the dimensions of the chamber (table/magazine) for the sample. Sample sizes for the analysis given in this standard should be considered only as illustrative.
4.2.3 Identification
The sample for analysis must be assigned to one of a kind identification, which determines the number of melting metal of the original sample from which the sample for analysis. If necessary, you should also know the process conditions of melting metal or location on the original sample, from which was selected the intermediate sample or a sample for analysis. The sample for analysis of cast iron in pigs must be assigned to one of a kind identification information in order to establish a political party or part of the cargo, as well as isolated metal sample, which sample taken for analysis. To the initial and intermediate samples must be attached to tag (label) or used equivalent method of marking, to ensure identity communication with the sample for analysis. Identification, status and condition of the sample should be registered to avoid confusion in product identification, which includes records and results of analysis.
4.2.4 Storage
You must have a special room for sampling and storage of samples for analysis. During and after preparation of the sample for analysis shall be provided with such storage, which prevents its contamination or change in chemical composition. Allowed storage of an intermediate sample in the form of a monolith, which may be, if necessary, the prepared sample for analysis. A sample or intermediate sample in the form of a solid mass (monolith) should be stored for sufficient period of time to protect the reputation of the analytical laboratory.
4.2.5 Arbitration
In the case that the sample is intended to resolve contentious issues, the sample for analysis should be selected and prepared in the presence of the supplier and the customer or their representatives. Methods of sample preparation for analysis should be documented (Protocol). Containers with samples for analysis that are destined for arbitration, should be sealed by both parties or their representatives. Otherwise by arrangement, these containers needs to store representatives of each party responsible for the preparation of samples.
4.3 Selection of the sample
4.3.1 the Sample from the melt
Samples of the molten metal are taken at different stages of production to the current production monitoring and process control. Samples can be selected during casting of the melt to check the chemical composition in accordance with the technical conditions of casting process. If the molten metal is intended for the production of castings, the sample for analysis may be selected from rods or blocks specially molded from the same material for mechanical testing in accordance with product standard. Must be the developed technologies for sampling from melts during a specific production process including quality requirements that must be met for the samples (4.2.1). The sample obtained from the melt, is typically a small ingot, a cylindrical or rectangular block, chilled cast disc or a combination disc with one or more pins (runner). In some cases, the sample disc has a small thickening.
Note 4 Devices (probes) for sampling of iron and steel in the liquid state can be purchased from a number of suppliers. In applications and the characteristics of the different types of samplers (probes), including reference information about the sizes.
4.3.2 Sample from the products
Intermediate sample or a sample for analysis can be cut from the original sample in the location specified in the specifications for the selection of material for mechanical testing, if available. In the case of testing cast iron a sample for analysis chemical composition may be cut from a block or unit that retains the properties of the casting. In the case of forging, the sample for analysis to determine the chemical composition can be selected from the source material, which is made from a forging or cut from the straight section of the forging or wrought additional blanks. Requirements for the selection and preparation of the specimen may be missing in the product standard or specification when placing the order. In this case, the supplier and the customer may agree on the selection of the sample for determining the chemical composition of the sample for mechanical testing or directly from the original sample. Intermediate sample or a sample for analysis can be obtained from the original sample by mechanical means, using a cutting torch. Cases of sampling to determine the content of certain elements are subject to special consideration.
4.4 sample Preparation
4.4.1 intermediate training
If any part of the specimen (sample) is not strictly representative in chemical composition, for example due to oxidation, after study of the nature and extent of any changes in the composition, it is possible to negotiate the removal of those parts of the sample, the chemical composition of which has changed. After this operation the sample must be protected from changes in its chemical composition. If you want on the surface of metal machining does not have any coatings, any coating applied during the manufacturing process, it is necessary to remove any way. If necessary, the metal surface must be degreased with a suitable solvent, with a degreasing solvent should not affect the accuracy of the analysis.
4.4.2 Sample for analysis in the form of chips
A sample for analysis must be from chip of conventional size and shape. This can be achieved by drilling, crushing, grinding or «IOS». The chips should be part of the sample, which was exposed to the heat of the cutting torch. Tools, machines and containers used during sample preparation must be clean to prevent any contamination of the sample. Machining should be performed so that the chip is not subjected to overheating as evidenced by discoloration (blue appearance and black colors). The inevitable staining of the chips obtained from certain types of alloy steels, and austenitic manganese for example, may be minimized by selection of appropriate cutting tools and cutting speeds. You may need heat treatment to reduce the hardness of the sample material prior to machining. The use of coolant emulsions during machining is allowed only in exceptional cases. Chips after this treatment should be cleaned with a suitable solvent that does not leave any traces. The chips should be thoroughly mixed before weighing the sample taken for analysis. For most analyses, it is sufficient to mix the chips by jiggle and/or easy rotation of the container on a flat surface.
4.4.3 a Sample for analysis in the form of powder or granules
In the case where it is difficult to carry out the drilling of the sample to obtain chips to be cut or cut into pieces. Then these pieces need to be crushed in a percussion mortar or fibroidsmiracle, also known as a disk or ring mill to obtain a sample for analysis in the form of powder wholly passing through a sieve with a predetermined opening size of the cell. In some cases, the determination of carbon by combustion the sample is crushed in a percussion mortar to obtain particles of size approximately 1 to 2 mm. Equipment used for crushing should be made of a material that does not change the chemical composition of the sample. May require special testing to verify that application equipment does not affect the composition of the sample for analysis. Crushing it should not be used for sample preparation of ferrous metal with inclusions of graphite. The sieving operation must be performed with the use of all necessary measures of protection against contamination or loss of material. For the screening of solid materials requires caution in handling the sieve, so as not to damage his canvas. The sample for analysis should be averaged before weighing the analyzed sample. The powders can be homogenized by shaking.
Note 5 — the subdivision of the metals into particles with a size of about 150 microns can create a fire hazard. The crushing, you must use adequate ventilation.
4.4.4 a Sample for analysis in the form of a monolith
4.4.4.1 Selection of sample for analysis
A sample shall be cut from the original sample or intermediate sample piece, size and shape shall meet the requirements of a particular method of analysis. Samples are cut with a saw or abrasive wheel by cutting or punching. If the product standard does not indicate the method of analysis, the analysis of the physical method needs to be performed on the part of the sample, which corresponds to the cross section of the product provided that the product is made of material of adequate thickness.
4.4.4.2 Preparing the sample surface for analysis
A sample for analysis must have an open surface suitable for analysis by a given method. You should not prepare for the analysis of the surface area of the sample that was in the heat affected zone of the cutting torch. Equipment used for sample preparation shall, at its constructive solution to ensure minimal heating of the sample and, if possible, have the cooling system. Use any of the four basic types of equipment for surface preparation of the sample:
a) a milling machine capable of removing the metal layer a predetermined depth in repeat mode with samples which by their hardness are appropriate for milling. The equipment should be such that it could handle the hot sample taken from the melt;
b) grinding machine with a stationary rotating or vibrating head, is able to remove the metal layer a predetermined depth in the repeat mode;
c) surface grinding machine with abrasive discs or grinding machine with a circular tape coated with abrasive material, capable of processing the surface of the sample for analysis with varying degrees of finishing;
d) machine blasting with sand, gravel or metal shot, suitable for special cleaning of the sample surface for analysis or work samples. After preparing the surface of the sample to be analyzed must be flat and free of defects that affect the accuracy of the analysis. Cutting and surface preparation can be performed manually or automatically. In the case of a sample taken from the melt, it is possible to use commercially available systems which automatically carry out every stage of preparation. Such systems for the automatic surface preparation of samples double thickness selected by the sampler (A. 2.3, Appendix a), and for knocking out pieces of metal when obtaining work samples before analysis may include means of sandblasting and heat treatment for softening of the specimen before its perforation. Abrasives used in the final stage of preparation of the sample for analysis should be selected so as to exclude the possibility of contamination of the surface chemical elements are identified in the analysis process. The grain size of the abrasive must match the required for a particular method of analysis the purity of the surface treatment. When using the method of optical emission spectral analysis for surface preparation suitable abrasive material having the grain size of the class from 60 to 120. For the method x-ray fluorescent spectroscopy, it is important to choose the method of surface preparation which provides the degree of finishing, reproducible from sample to sample. You should also protect the sample surface from contamination (clogging). The influence of the abrasive material depends on the analytical method. When using the method of optical emission spectral analysis a preliminary uzyskiwania cleans the surface of the analytical sample, as this removes any contaminants after grinding. However, this requires special attention to avoid contamination of the surface when applying a new abrasive disc. For x-ray fluorescence spectroscopy all stages of surface preparation should be checked for the potential effect of surface contamination. The sample for analysis shall be subject to visual inspection after preparation to verify the absence on the surface of fine particles and surface defects. In case of detection of defects on the sample surface is re-treated or the sample discarded. The sample must be dry. You should also protect the prepared surface from contamination.
4.4.5 sample Preparation for analysis by remelting
The sample in the form of small pieces or shavings or part of the original sample can be melted in argon atmosphere, using commercially available fusion equipment. The sample is transformed into disc with a diameter from 40 mm to 30 mm and a thickness of 6 mm, which is suitable for the analysis of the physical method. Some types of melting equipment have a device for centrifugal casting of the disk. As experience shows, possible partial loss of some elements during the melting process. It is important to control for any sample loss to evaporation or segregation of the elements or any other change in composition during melting was quantitatively evaluated and had no significant effect on the results of the analysis. Should conduct appropriate tests to ensure that any changes in composition are insignificant and reproducible. The equipment used and the method for melting should be selected or developed taking into account the exclusion or minimizing of changes in the composition and to ensure the reproducibility of any changes. When melting, you should use a deoxidizer, such as Zirconia with a mass fraction of 0.1% (m/m). The method used for calibration of analytical measurement must take into account any changes. Not all ferrous metals can be re-melted in this way. This method cannot be applied for sample preparation to determine the content of the element during remelting is prone to significant and irreversible changes of the contents in the chemical composition of the sample.
4.5 safety Rules
4.5.1 personal protection
To minimize the risk of trauma during selection and preparation of samples must be provided personal protective equipment. Precautions when sampling molten metal should include the use of protective clothing, protection of hands and face that is resistant to spatter. Precautions for the selection and preparation of samples of solid metal should include personal protective equipment (overalls, gloves, goggles, etc.) and respirators when required.
4.5.2 Mechanical equipment
The use of mechanical equipment for sampling and preparation of samples should comply with regulations. Grinding operation, used for surface preparation can be performed in the framework of national legislation for labor protection and safety.
4.5.3 Hazardous substances
Observe the relevant rules for the treatment of solvents used for cleaning, and precautions for drying of samples and working samples for analysis.
5 Liquid iron for steelmaking and cast iron ingots
5.1 General provisions
The following methods applicable to sampling of liquid pig iron for steel production, commonly called liquid metal, casting pig iron. Samples of liquid iron is taken, usually from the groove to release the iron from the blast furnace by pouring of a melt into the ladle, cigar-shaped or chugunovsky buckets, or during the secondary technological processes ladle refining cast iron, or pouring the melt into ingots. Chemical composition of cast iron varies in the production process of the blast furnace. Should select two or more samples from the melt at certain intervals of time and determine the average chemical composition. In the application of physical methods for analysis should develop a method of sampling with the cooling of liquid metal in a way that ensures the preservation of metal structure meeting the requirements of the selected method of analysis.
5.2 Sampling spoon
5.2.1 selection Methods
To select sample from the melt to the preheated steel is dipped a spoon into the melt and fills it with liquid cast iron. Remove the spoon and remove the slag from the surface of liquid iron in the spoon. For sampling from streams of metal preheated steel spoon brings to the jet from the ladle and fill it with liquid cast iron. Liquid iron is poured from a spoon without delay in a metal mold (mold), as quickly as possible to cool the iron. Remove the sample from the mold and break off from the profit of the casting (Salvini). It is important to pour liquid iron into the cold to provide adequate cooling. If necessary, the form should be cooled before use in a stream of cold air. The form must not contain moisture. The sample in the form of a disc, commonly called a coin (a Nickel), can be obtained by using a steel mould in two parts. This produces a typical sample with a diameter of 35 to 40 mm and a thickness of 6 to 12 mm. the Form consists of two parts which are held together by a clamp during use. One part is a flat cooling plate, and the second part in the form of a block with a recess for the gate forms a cavity forms. Edge of the mold cavity may be beveled on the cone size from 38 to 32 mm to facilitate the excavation of the specimen from the mold. Casting of a sample coin into a mold carried vertically or horizontally. Coin-a sample with one or more sprues may be made in the mold of the combined type. The pins break off the drive. If necessary, they are used as work samples for analysis by thermal method (mold combined type used for liquid metal intended for the production of iron casting, shown in figure 2). A thin sample in the form of a slab with rounded edges can be manufactured in cast iron or steel composite form, in which usually get a sample size 70х35 mm and a thickness of 4 mm. the Two halves of the forms have a bevel the upper edge for the formation of a «profit» and when you use a connected clip. This type of mold is preferred, if the molten cast iron has a high percentage of carbon.
Figure 2 is a Vertical form of the combined type, which is used for sampling of liquid iron in iron foundries
Note — Flat cooling plate has the same dimensions.
Figure 2 is a Vertical form of the combined type, which is used for sampling of liquid iron in iron foundries
5.2.2 Maintenance of equipment
It is important to keep spoons for sampling and metal molds are clean and dry. After use, remove the slag and nastily, clean the mould surface with a wire brush. Forms should be re-machine the worn interior surfaces. Thus eliminate the phase of additional treatment of the sample in the machine during the preparation of the surfaces.
5.3 Sampling with special devices
5.3.1 General provisions
Describe the different types of devices (probes) used to sample pig iron, is given in Appendix A. These devices should be used to obtain samples in the form of a disc with structure in white cast iron, deep enough to meet the requirements of the physical method chosen for analysis. The sampling is influenced by such factors as the angle and depth immersion of the probe into the melt. The time of immersion may vary depending on the temperature of the liquid iron. These factors establish the specific process of iron smelting, and then they must be strictly controlled to maintain quality standard of sample for analysis.
5.3.2 Methods
To take samples of the melt are immersed a suitable device into the melt at an angle as close as possible to the vertical plane. When sampling from the chutes of blast furnace choose the position of immersion of the probe in sufficient depth of liquid metal. A depth of approximately 200 mm fits most types of samplers. For sampling from the jet of liquid cast iron insert suitable suction device into the stream of metal flowing from the ladle at an angle of about 45° relative to the vertical plane and as close as possible to the spout of the bucket. Remove the sampler from the melt after a predetermined time interval, to separate its parts from each other and allow the sample to cool in air.
5.4 Preparation of sample for analysis
5.4.1 Preliminary preparation
From the sample taken from the melt, remove any surface oxides, which can contaminate the sample for analysis during subsequent training.
5.4.2 Sample for analysis by chemical method
Break sample into small pieces and ground the pieces, using a percussion mortar or vibrating mill to obtain a sufficient mass of sample for analysis of particle size not more than 150 µm. You can get chips by drilling sample for analysis with low speed,
5.4.3 model for analysis of thermal method
The broken-off stub of the specimen cast in the form of a disk, broken into pieces of a suitable mass to use them as work samples for analysis. Perform the determination of the chemical composition of a representative number of working samples to get the average value. Alternative ground pin or protrusions probe the sample in a percussion mortar to obtain a sufficient mass of sample for analysis in the form of particles with a size of about 1−2 mm. is Not allowed too strong grinding material. When working with a sample in the form of slab (plate) break it into small pieces and pulverized them in a similar way.
5.4.4 Sample for analysis by a physical method
In the case of the sample in the form of a disk and remove the tabs or the pins and then grind the surface until bleached to the structure of cast iron, which is a representative for this sample. The amount of material removed in this way must be established for each grade of cast iron with a specific chemical composition and for sampling. The thickness of the removed layer is 0.5−1 mm (A. 6). If the sample is presented in the form of a slab, it is divided into two parts to obtain a sample of suitable size. Prepare the surface of the sample by the method of Stripping and sanding. The grinding is performed using a coolant to avoid over heating the sample, but the final finishing must be carried out by dry grinding. Alternative cool the sample after grinding by immersion in water, and then perform finishing of the surface with a dry polishing. Special attention is required during preparation of the sample surface. During the operations of grinding and Stripping, the specimen shall be held by the Chuck of special design.
6 Molten metal for iron production
6.1 General
For sampling of liquid iron from blast and electric furnaces, ovens duplex transfer processes, as well as ladles and converters processing used the following methods. Liquid iron is intended for the production of iron castings, can be heterogeneous. It is necessary to pay special attention to the development of methods for sampling, to match the requirements of a particular production process. For example, in holding furnaces is a process of layers of liquid iron, so the samples should provide a representativeness of the melt as a whole. In the case of periodic technological processes two or more samples should be collected from the smelting furnaces at a time when one or two third part of the melt is already released. For these samples determine the average chemical composition of the metal. In continuous processes samples are taken at regular intervals of time. Usually develop sampling techniques that allow fast cooling liquid metal sample poured from a spoon, to obtain a metal structure of white cast iron free from graphite. The structure of white cast iron sample, obtained by casting in the mold, is generally required for analysis by physical methods. You can also use non-refrigerated samples. In this case, samples to be analyzed can be specially cast in the selection of liquid metal spoon or selected from blocks or flat blocks for mechanical testing. Bars and blocks for testing are cast separately from the same metal used for the production of castings or cast goods. In agreement with the customer in the production of large castings or castings should be selected two or more samples. Special consideration is given to sampling and sample preparation of liquid cast iron for the determination of oxygen, nitrogen, and hydrogen (6.5).
6.2 Sampling spoon
6.2.1 General provisions
Samples are taken prior to adding in the melt-modifying additives. Alternative — waiting a sufficient period of time to complete the action process the newly added additives. Then, the melt should be thoroughly mixed prior to sampling. Failure to comply with requirements of exposure before sampling may impair the representativeness of the sampling. It is especially difficult to make a selection of samples of ductile cast iron because of the possibility of contamination of its dross in the production process. In this case, a representative sample can be obtained by filtration of cast iron using ceramic disk.
Note 6 — note that when sampling before adding modifying additives, the resulting sample may not be representative of the chemical composition of the cast product.
6.2.2 Methods
Graphite or steel spoon, covered with refractory material with high content of silica, can be used in one of the following methods:
a) remove the slag from the melt surface, immerse the pre-heated spoon to melt and fill the liquid iron;
b) introducing the pre-heated spoon into the stream of metal during pouring and filling with liquid cast iron.
6.2.3 Refrigerated sample
Liquid iron is quickly poured from the spoon in a split mold made of graphite, hematite iron or copper, to obtain a sample in the form of small flat plate with a thickness of 4 to 8 mm. Remove the sample from the mold once it has hardened, to avoid overheating of the shape and breaking of the sample. Then cut off the profit casting. The sample, called the coin can be round, rectangular or square with a diameter of 35 to 40 mm or 50х27 and 50x50 mm, respectively. As a rule, disk specimens are cast vertically, and rectangular and square — horizontal. The form consists of two parts that clamp together. Flat plate cooling, and the other part in the form of a block forms a cavity forms. The edge of the mold cavity can be bevelled to facilitate the excavation of the specimen from the mold. A round sample with one or more pins can be cast in the form of combined type. The pins break off of the disc, to the extent necessary, to use them as work samples for analysis by the thermal method. Vertical this type is commonly known as owner. Its made of gray cast iron with low phosphorous content and a high content of carbon, graphite or copper. This can be a form of copper with water cooling (figure 2). The sample in the form of a disk with a diameter of 35 to 40 mm and thickness 4 to 6 mm has three pins with a diameter of 5 mm each. The temperature of the liquid iron in the spoon needs to be as high as possible depending on the material form. The form must be cold to provide adequate cooling in the manufacture of the sample for analysis having a structure of white cast iron. If necessary, cooling form air prior to its intended use. The form should not be moisture. For the process with frequent samples should have multiple cold forms. Thermal stress from overheating in the form can be the cause of the fracture of the sample, therefore, such voltage is unacceptable.
6.2.4 non-refrigerated sample
Liquid iron is quickly poured from the ladle of a spoon in the sand the form to get a sample in the form of a cylinder with a diameter of approximately 50 mm and a height of 40 to 50 mm. the Sample for analysis can be selected from bars or blocks for mechanical testing. These bars and blocks cast from liquid iron taken from the ladle ladle a spoon or a small hand bucket. The standard Board has a 30 mm diameter, 150 mm in length and can be cast vertically or horizontally in the sand mold. It is necessary to ensure complete cooling of the sample before removing it from the form.
6.2.5 maintenance of the equipment
Spoon for sampling and metal forms shall be kept clean and dry. After use remove the slag and nastily, clean the mould surface with a wire brush. Moulds should be re-processed on the machine in case of wear of the internal surfaces. Then it will not require additional sample processing during the preparation of the surface.
6.3 Sampling with special devices (probes)
Sampling of special devices — samplers for iron foundries limited. If necessary, the samplers should be designed for sampling from the melt so that the sample in quality and the metal structure met the requirements necessary to conduct a certain analysis method.
6.4 Preparation of sample for analysis
6.4.1 Pre-training
The sand adhering to the surface of the sample cast in sand form, remove with a scraper-brush or sandblasting. Oxides from the surface is removed by grinding. Prepare the sample in accordance with one of the procedures described in 6.4.2, 6.4.3 or 6.4.4, depending on the method chosen for analysis.
6.4.2 Sample analysis by chemical method
6.4.2.1 above General provisions
The machining of the piece to get the shavings is carried out by drilling or turning on a lathe at a speed of 100−150 rpm using a cutter tool with tungsten carbide, so adjusting the speed and flow, to have chips of the same size without fine particles. Shavings must be solid and compact mass, is approximately 10 mg (100 pieces/g) to prevent spalling, and loss of graphite. The chips are not washed with solvent and not treated by magnetic separation because of the risk of changes in the distribution of metal and graphite (segregation). Drill diameter 10 mm suitable for the production of chips by drilling. To determine the total carbon content of the cooked chips of 1 to 2 mm. If machining is impractical, the sample is broken into pieces, which are then milled in a mortar drum or on a vibrating mill to obtain a sufficient mass of sample for analysis with a particle size of not more than 150 µm. This method is used only in cases where it can be shown that the grinding does not lead to contamination of the sample.
6.4.2.2 Methods
To prepare hardened samples of used drilling, if feasible, discarding the waste shavings removed from the surface. If you cook the untempered sample, is presented in the form of a cylindrical block, then drill a cross hole in the point located at one third of the length of that block. Then drilled another hole on the opposite side. Shavings obtained from drilling to one third of the radial depth from two directions, do not use. Continue drilling through the center of the block to obtain a sample for analysis. If the submitted sample in the stick, then use one of the following methods:
a) grind two planes of the opposite sides of the bar; drilled from one side to the other in position one third of the length of the bar;
b) grind the bar on a lathe with the maximum depth of cut of 0.25 mm. the cutting fluid is not used. Perform a radial cut from the edge to the center or front facing in the plane of the cross section of the bar, not limiting turning processing only the surface of the bar. The chips obtained with the whetstone surface, do not use. If the sample is not machinable, then break off pieces or cut a layer with a thickness of 3 mm or disc from the plane of the cross section near the bottom of the test bar. Grind these pieces in a mortar drum or on a vibrating mill to obtain a sufficient mass of sample for analysis with a particle size of not more than 150 µm.
6.4.3 Sample monolithic form for analysis by thermal method
When presented with a sample of chilled, break off the pin and break or cut it into pieces to use them as work samples for analysis. Alternative — crushed pin in a percussion mortar to prepare a sample for analysis in the form of particles with a size of about 1 to 2 mm. are Not allowed very fine grinding of material. In the case, when presented with a non-refrigerated sample, cut off saw disc or layer 3 mm in the plane of the cross section of a cylindrical block or block and cut into pieces of suitable weight to use them as test portions for analysis. Analyze a representative number of batches to obtain the average value. The mass of the slice, chosen as the sample should not be less than 0.3 G.
6.4.4 Sample for analysis by a physical method
When presented with a sample of chilled, break off the pins, then use a grinder with fixed grinding head to open the structure of white cast iron, which is characteristic for this sample. The amount of material removed in this way must be set to cast a specific chemical composition and the conditions of sampling. The thickness of the removed layer is usually not less than 1 mm. During the grinding it is recommended that air cooling. It is possible to carry out wet grinding to avoid excessive overheating of the sample, but the final treatment should be dry and be held by friction or grinding. Excessive grinding can lead to errors in the analysis when it comes to chilled section of the sample. Chilled samples should be periodically investigated in daily practice to confirm the suitability of the structure of metal samples prepared for this method of analysis. When presented with non-refrigerated sample, use the sanding or the abrasion of friction for removal of sample surface layer with a thickness of approximately 1 mm. During the grinding it is recommended that air cooling. Coolants should not be used. For cast iron, which is prone to segregation, such as engineering cast iron with high phosphorus content or ductile iron with high silicon content, or malleable cast iron, cooking surface, both sides of the sample for analysis to obtain the average value. It is necessary to avoid overheating of the sample during the preparation of the surface. Otherwise it will lead to the formation of surface cracks, which will affect the correctness of the analysis results. Caution is required when preparing the sample surface in the form of a thin coin. Must be designed in a special cartridge to securely hold the sample during grinding operations.
Note 7 — Grinding machine with fixed grinding head is preferable to the pendulum grinding machine for surface preparation. Pendulum grinder produces a flat surface of the sample for analysis.
6.5 Selection and preparation of samples for the determination of oxygen, nitrogen and hydrogen
6.5.1 General provisions
Determination of oxygen, nitrogen and hydrogen in the process of production of castings is required only to a limited extent. Using methods of sample selection and preparation should be to a minimum to reduce the loss of hydrogen and to prevent contamination of the sample with oxygen, nitrogen or hydrogen (7.5 and 7.6).
6.5.2 Methods
Rapid cooling of the sample is an important factor for determining the hydrogen content. Take out the specimen from the mold immediately after curing and cooled without delay. Suitable for cooling a mixture of acetone and solid carbon dioxide in the form of slurry. Store sample in a cooler. For this purpose it is immersed in liquid nitrogen or a slurry from a mixture of acetone and solid carbon dioxide. For the determination of oxygen and nitrogen as the sample is usually suitable pins, broken off from the sample, molded. For this samples can be collected with a spoon from the melt. Then the liquid cast iron is poured according to 6.2 in book form of the combined type, in order to obtain samples with pins with a diameter of 6 to 8 mm. With this purpose, change the design of the form shown in figure 2, by extending the three cavities for the manufacture of pins of the required diameter.
6.5.3 Preparation of working samples
From the pins and remove all traces of surface oxidation, using a lathe with the cutter of the alloy tungsten carbide. Use a separate cutter to get a clean working sample of suitable weight for analysis. Avoid overheating the pin during the preparation of samples for determination of hydrogen content. Cool a working sample at short intervals of time, using a milled solid carbon dioxide. To ensure continuity between the preparation of the working sample and conduct a specific analysis.
7 Liquid steel for the production of steel products
7.1 General provisions
The following methods are applicable for sampling molten steel from furnaces, ladles and other containers, as well as of casting equipment and ingot during the melting, secondary treatment and casting. Special conditions are created in the selection and preparation of samples of liquid steel for the determination of oxygen (7.5) and hydrogen (7.6).
7.2 Sampling with a spoon
7.2.1 Methods
For sampling of the melt is lowered the spoon through the slag into the melt and fills it with liquid steel. First, the spoon is immersed in the slag layer and cover it with slag to reduce cooling and prevent adhesion of the metal pattern to the spoon. Remove the spoon, remove the slag from the steel in the spoon. When sampling from a stream fills the spoon under the stream of water from bucket and fill it with liquid steel. Then the spoon is withdrawn from the jet. Appropriate caution when entering the spoon under the stream of water, as the spoon the force of gravity the liquid metal flowing from the nozzle. You may need to decrease the speed of metal flow during sampling. If necessary, add a certain amount of deoxidizer in the molten steel in the spoon. When the molten steel will settle down (approximately 10 seconds), it poured without interruption in a monolithic steel shape, which ensures the production of wedge-shaped cylindrical sample. The sample should have the following dimensions: diameter — approx 25−40 mm in the upper part and 20 to 35 mm at the base and the height is from 40 to 75 mm. Remove the sample from the mold and cooled in a manner to prevent the formation of cracks. Cool the sample slowly enough to allow for easy mechanical machining. When sampling, the stainless steel can be used as a fire ring, put on the cast iron plate. The wall thickness of this ring may be from 10 to 12 mm. the Sample is removed from the mold by fracture of the refractory ring.
Note 8 — Aluminum wire is often used as deoxidizer, when a sample is taken with a spoon, provided that the aluminum does not interfere with the analysis method and do not need to install the aluminum content in the melt. The amount of aluminum added is usually from 0.1 to 0.2 mole percent (m/m). Other deoxidizers, such as titanium or zirconium, can be applied with similar restrictions.
7.2.2 the Maintenance of equipment
It is important to keep the ladle of the spoon and the metal mold is clean and dry. After use remove the slag and nastily, clean the mould surface with a wire brush. Molds are re-processed on the machine in case of wear of their internal surfaces. In this case, does not require additional mechanical treatment of the sample by cutting during the preparation of the surface.
7.3 Sampling with special devices
7.3.1 General provisions
Characteristics of the main properties of different types of commercially available sampling devices for liquid steel is given in Appendix A. the sampling is influenced by such factors as the angle and depth immersion of the probe in the melt and during his stay in the melt. It is important to establish these factors for certain of the compositions and temperature of the steel and then strictly manage to maintain the standard of quality required for analysis. You should apply precautionary measures, ensuring the operation of sampling without contamination of the sample molten steel, particularly when sampling for the determination of elements in small quantities. The materials used in the sampling device, head design and intake system, and method of deoxidation should be given to minimize the risk of contamination of the sample (from sources other than the reducing agent).
7.3.2 Methods
When sampling from deep tanks, such as melting furnaces and ladles suitable quickly immerse the sampler through the slag layer into the melt as close as possible to the center of the melt and at an angle close to 90°. When sampling from shallow containers, such as filling device on top of the mould insert of a suitable inlet pipe of the suction sampler in the melt through the slag layer or covering of powder. Create a partial vacuum in the sampler for a period of time approximately 2 to fill the mold inside the unit. Some filling device may contain a melt of sufficient depth that allows you to take samples using dip sampler. If a sample is taken from a stream, then enter the appropriate device into the stream of metal flowing from the ladle, at a 45° angle and in a place that is located closest to the neck are identified. Care must be taken with the introduction of the probe into the stream of metal. To ensure security, you can decrease the speed of metal flow from the ladle at the time of sampling. The sampler is withdrawn from the melt flow through a predetermined time interval and separate demountable part. Give the sample of the metal to cool in the air until dull red, then quickly cool in water in a manner that does not cause cracking. In some cases, samplers transportyou to the lab in a hot condition.
7.4 Preparation of sample for analysis
7.4.1 Preliminary preparation
Remove any surface oxides from the sample taken from the melt, if this can contaminate the sample for analysis in the subsequent training.
7.4.2 a Sample for analysis by chemical method
In the case when used with a sample obtained using the spoon, drilled the resulting metal cylinder at a point located at a distance of one third of its lower edge, through the middle of this cylinder, discarding the waste chips obtained from the surface layer of the sample. Alternative — cut on the machine one third of the lower part of the cylindrical sample and milled across the exposed surface of the remaining part. May require heat treatment of the sample tempered to alleviate the mechanical cutting. When using a sample drawn from the melt, taken by the sampler, prepare the chips from disk section of the sample by drilling or milling according
7.4.3 Sample for thermal analysis methods
In the case of the sample with the pins that were cast from the melt, taken by the probe, break off one of the pins, to prepare a working sample for the analysis of a thermal method. In the case of using a sample of double thickness, made of melt selected by the sampler, emboss a piece of perforation of thin sections of the disc to prepare a working sample for the analysis of a thermal method. May require heat treatment such sample to the extent to facilitate the operation of punching, if the hardness of the metal sample is greater than 25 units on a scale From Rockwell. If of metal, selected by the sampler, the sample is made in the form of a disk with pins, then cut off from the pins a working sample of suitable weight for analysis. If a cylindrical specimen, prepared the chips in a drilling or milling of the cylinder. Particular caution is required when working with samples intended for the determination of carbon in low carbon steels to prevent pollution at the stage of preparation of the working sample. Use tweezers for all procedures, treatment of samples.
7.4.4 a Sample for analysis by physical methods
In the case of a cylindrical sample is cut off the base of the cylinder, using an abrasive cutting wheel or a cutting tool to prepare the sample for analysis, typically with a thickness of 20−30 mm. the surface of the cutoff abrasive wheel must be aligned, shear cutting tool can be aligned before analysis. If you use the sample from the melt selected by the sampler, then separate the bosses or pins, if necessary, and then milled or wear the surface of the disc until you get the surface of the sample quality. The amount of material to be removed in this way must be set to black metal a specific chemical composition depends on the conditions of sampling. The thickness of the removed layer — 1−2 mm (A. 6, Annex A). In the case of a sample of twice the thickness of the melt selected by the sampler, prepare a thick section of the disc. When using the specimens of steels containing lead, equipment for surface preparation should be fenced off, and the place of work is equipped with a dust collector (exhaust fan).
Warning — Small shavings rising during surface preparation of steel, lead, and dust from the filter system of the dust collector must be collected and placed in a safe place in accordance with the safety regulations prescribed for lead-containing wastes.
7.5 Selection and preparation of samples for the determination of oxygen
7.5.1 sampling Methods
Methods of sampling of liquid steel for the determination of oxygen is based on the use of commercially available sampling devices — samplers. The main properties of different types of commercially available sampling devices are outlined in Appendix A. Methods of use of these devices must ensure that the operations of sampling, which do not affect the equilibrium content of carbon and oxygen in the melt. It is important to prevent contamination of the sample and remove any surface oxides at each stage of sample preparation. Small tides on the samples made from the melt sampled by a sampler, such as the pin diameter less than 5 mm or the protrusion, is usually not suitable for preparation of the working sample, free from surface oxidation. However, fit can be a piece of metal, embossed stamp from a sample of double thickness. In some cases it is preferable to have a sample of a larger mass produced from the melt selected by the sampler, which is filled under the action of gravity.
7.5.2 Preparation of working samples
Remove oxidation products from the surface of the sample obtained by the sampler through the abrasive processing in a manner that does not cause overheating of the sample. Cut off a piece of the disc sample and cut from it a working sample in the form of a cube with a mass suitable for analysis. Place the working sample in a headlock or some other holding device for abrasive machining of every surface using the velvet file. Use tweezers for all procedures, with a working sample. Working immerse the sample in acetone or ethanol, then dried in air or in low vacuum. Analyze without delay between the training samples and analysis.
7.6 Sampling and sample preparation for the determination of hydrogen content
7.6.1 General provisions
Methods of sampling of liquid steel for the determination of hydrogen content based on the use of commercially available samplers. The main characteristics of different types of commercially available sampling devices are given in Appendix B. sampling Methods develop subject to minimize and control the fast diffusion of hydrogen from the sample. The diffusion process occurs during the selection of the melt sampler storage made of sample and preparation of the working sample for analysis. Loss on the diffusion can be large at ambient temperatures, particularly for samples of small diameter. On the sample from the melt selected by the sampler, there should not be cracks, pores on the surface and moisture, in particular water detained. The condition of the working sample can strongly influence the analytical measurement. Methods of analysis may differ in their sensitivity due to the presence of water. If sampling has been used a suction sampler, then the development of a method of operation of the sampling is necessary to exclude the risk of moisture in the sample. The choice of method of sampling depends on the temperature of the melt, method of analysis and the required analytical accuracy. These relationships need to explore to choose a suitable method for a particular steel manufacturing technology, to obtain samples of the required quality. It is necessary to strictly follow the procedures to ensure the constant quality of the analysis. It is important to keep the sample made from a melt of the selected sampler, and the working sample at the temperature, the lowest at all stages of processing after sampling and during storage of the sample. The sample should be stored in the refrigerant. As the cooler you can apply liquid nitrogen or a mixture of acetone and solid carbon dioxide.
Note 9 — This storage method is very important for ferritic steels. Diffusion of hydrogen in austenitic steels occurs slowly, but for any particular material, in the absence of experimental data, you should use the suggested cooling method during storage.
The sample from the melt selected by the sampler, and a working sample, you need to keep cool during the cutting of the sample and during the preparation of the working sample for analysis. Cooling may be carried out by immersion of the sample in ice water or preferably in a cooler. Any moisture remaining on the surface of the working sample, after cooling, should be removed. The working sample is immersed in acetone, and then dried for a few seconds at low vacuum. Samples that were not adequately refrigerated or saved, marriage. Surface preparation of the working samples by abrasive machining can be applied to a minimum extent, only when needed for the elimination of oxidation products and surface defects. A working sample is analyzed immediately after preparation.
7.6.2 sampling Methods
There are a number of commercially available samplers, designed to provide samples in the form of a pin or rod of different diameters (Appendix B). The selected device for sampling is used in accordance with manufacturer’s instructions. It is important to quickly cool the sample selected by the sampler in cold water, which should be vigorously and continuously stirred while cooling. There should be no delay, begin cooling the sample within 10 s after sampling. Silicon shell is used as a form for the sample, should be quickly removed to ensure rapid cooling. Sufficient cooling, the sample is immersed in a cooler for storage and transportation to the laboratory. If the sampler is designed for retention of diffusible hydrogen, it should be promptly and energetically cooling, so it will be easier to work in very cold condition.
7.6.3 Preparation of working samples
A working sample of a suitable mass cut off from the Central sections of the sample obtained from the melt selected by the sampler. Cutting should be accomplished with minimal heating of the sample. Apply a generous flow of coolant in the cutting process or cool the sample through frequent intervals, or use a combination of both cooling methods. The surface of the working sample is prepared by grinding with a file, by shot peening or slight grinding. If you use a velvet rasp, abrasive processing is carried out manually, with the shot blasting machine should be used only for this purpose to avoid contamination of the working samples from the fractions. In the case of grinding the working sample is cooled through frequent time intervals. A working sample is degreased by immersion in acetone, dried at low vacuum and analyze without any delay. The alternative — working sample can be prepared for analysis by immersion in isopropyl alcohol (2-propanol) and subsequent drying diethyl ether.
8 pig Iron
8.1 General provisions
The following methods apply to the sampling of pig iron, which is poured into ingots in the form of a double diamond or other similar forms. Different types of pigs classified in ISO 9147. Other types of cast iron can be obtained in the manufacture of cast iron, for example cast iron produced in cupola furnace or electric furnace. Require special precautions in the selection of the representative sample for iron ingots.
8.2 the Selection of point samples, depending on the lot size
8.2.1 Number of samples
The number of pigs, sampled must be representative for the party is made or prepared for shipment products. If the shipment deliver in bulk (in the absence of agreement between the supplier and the customer) the minimum number of pigs to be shipped away from the party, must conform to ISO 9147 (table 1).
Table 1 — Minimum number of pigs, which are selected as samples of the ship of the party
| Weight of the consignment, t |
The number of pigs | |
| To 10 |
9 | |
| From 10 to 20 |
11 | |
| «20» 40 |
12 | |
| «40» 80 |
14 | |
| «80» 160 |
16 | |
| «160» 300 |
18 | |
| «300» 600 |
21 | |
| «600 |
24 | |
8.2.2 Methods
During loading and unloading operations or any other movement of the consignment is taken of the samples at the specified intervals of time or mass that is roughly equivalent. In the case of consignments shipped in cars or trucks, designated for sampling should be distributed in a certain order. For example, five positions, i.e., in the center of the car, at one-sixth of the distance from the corners of the car two diagonals. If pigs are lying in bulk in a warehouse, then throw on a bunch of rope with a certain number of nodes and selected the pig, which relate those nodes. Repeat this operation until until you get a sufficient number of pigs. In the case where it is impossible to get access to the entire surface of the pile or such access is a dangerous thing, then sampling should be distributed in a certain order on the surface of the heap. Alternative — use a mechanical shovel to take samples of subgroups of the places in the lot selected at random. Then choose at random one pig from each group.
8.2.3 consignment of mixed pigs
The party sent pigs may contain pigs from different production sources. If ingots of different sizes and shapes can be distinguished in the consignment, then you should make a visual assessment of the quantitative ratio of each type of pigs available. Should be samples of each type of pigs in the consignment to be a separate sub-group of pigs to obtain a weighted average of the result of the analysis for party sent products.
8.3 sample Preparation for analysis
8.3.1 General provisions
If pig, sampled, contain residual magnetism as a result of their loading/unloading a magnetic gripper, it should be demagnetize using a demagnetizing coil, to prevent separation of fine and coarse particles during drilling. Sample processing cut to obtain chips perform drilling at a low speed (100 to 150 rpm). Use well-sharpened drill bit, adjusting speed and feed to get the chips of the same size with a minimum amount of fine particles. A drill with a diameter of 12−14 mm is suitable for the production of such chips. The drill must be periodically sharpened at certain intervals of time. Also take precautions to prevent overheating of the sample and instrument. For some types of cast iron, for example obtained by the oxygen-Converter method, you may need a drill with a tip made of tungsten carbide. Chips need, to be solid and compact in order to prevent crumbling and loss of graphite. The particle size of the chips, designed for determination of carbon, should be kept in the range of approximately 1 to 2 mm. Crushing is not used due to a high share of fine particles. The prepared sample should not be rinsed with solvent or treated by magnetic separation, because there is a risk of change in the distribution of metal and graphite.
8.3.2 Samples for chemical analysis
Preparation each of the samples ingots is carried out in one of the following methods:
a) for the analysis of iron, amenable to mechanical treatment, clean one front surface of the ingots by grinding for half the distance along the length and width to open the portion of the metal surface with a minimum diameter of 50 mm. Drill a hole in the plane of the cross section of a pig. Stop drilling at a point located approximately 5 mm from opposite face. If necessary, drill another hole parallel to the first (figure 3a, b, with, d);
b) for iron are not amenable to machining, split a pig in half, separate the pieces from the broken surface, they are crushed to a particle size of about 5 mm, then treated on a vibrating setting to a particle size of not more than 150 µm. Mix equal amounts of material obtained from each pig. From this mixture take a sample of sufficient mass for analysis through the formation of a cone and divide into four parts. Alternative — conduct analysis of material collected separately from each pig to obtain the average value of the consignment.
Figure 3 — Locations of samples for analysis of cast iron ingots
Figure 3 — Locations of samples for analysis of cast iron ingots
8.3.3 Samples for analysis by thermal method
8.3.3.1 General provisions
Apply the method of preparing each of the samples ingots in accordance with
8.3.3.2 Sample in the form of chips or granules
For the analysis of iron, amenable to machining, drill the hole with diameter of 12 to 14 mm in the center of each pig and on the opposite sides. Remove mill scale and any other inclusions around each hole on both sides of the pig. Then drill another hole, coaxially with the first diameter from 20 to 34 mm in order to obtain chips with a size of approximately 1−2 mm. For analysis of cast iron, not amenable to machining, you get small pieces from the ingots as described in 8.3.2, the enumeration of b) and then ground those pieces in a percussion mortar to obtain particles with a size of about 1 to 2 mm. Mix equal amounts of material obtained from each pig. From this mixture take a sample of sufficient mass for analysis through the formation of a cone and divide into four parts. Alternative — conduct analysis of material collected separately from each pig to obtain the average value of the results for the consignment.
8.3.3.3 solid sample
Cut a layer full cross-section ingots with a thickness of about 3 mm in half the distance along its length. Clean the edges by grinding. From this piece cut out the pieces in the positions shown in figure 3, e and fto obtain the mass of the working samples suitable for analysis. Alternative — sawn or split a pig in half the distance along its length. Drill hole drilling, make 3 or 5 holes in the locations shown in figure 3, e and fto receive studs having a diameter of approximately 3 mm. Break these heels to pieces to get working samples with a mass appropriate for the analysis.
Analyze a representative number of working samples to get the average value of the results for each pig.
8.3.4 Samples for analysis by physical methods
Samples obtained from cast ingots, are usually not subjected to analysis by physical methods. If you intend to use physical methods of analysis, the process of sample preparation must take into account the structure of cast iron. For this to be developed method of surface preparation of the sample for such analysis. Alternative — prepare a sample of a suitable form by melting small pieces of the sample (4.4.5).
9 Products cast iron
9.1 General provisions
The place and method of selection of interim sample or sample for analysis of cast iron products should be agreed between supplier and customer. These methods are described in 9.2.2, 9.2.3
9.2 Sampling and preparation of samples
9.2.1 General provisions
The selection and preparation samples should be conducted in accordance with the brand of cast iron and casting type, as well as the method chosen for analysis. The source or intermediate sample clean scraper, wire brush, sanding, or bead-blasted to remove adhering sand particles and open areas of the metal surface. It is also necessary to clean the outer and inner surface of molded hollow articles.
9.2.2 Samples for chemical analysis
9.2.2.1 General provisions
Chips get mechanically on a drill or a lathe at low speed (100 to 150 rpm) using a tool with a cutting end made of tungsten carbide and adjusting speed and feed, in order, the chips were of equal size with a minimum amount of fine particles. It is necessary to avoid overheating of the sample and instrument. There is a risk of tool breakage when using a drill with a cutting head made of tungsten carbide. In this case, the chips must be deemed unfit for use as a sample. Crushing of the sample is not applicable due to a high share of fine particles. The chips should be done solid and compact, having a weight of approximately 10 mg (100 units/g), to prevent crumbling and loss of graphite. The chips should not be cleaned with solvent or treated by magnetic separation, because there is a risk of change in the distribution of metal and graphite. Drill size of 10 mm diameter is suitable for obtaining chips way of drilling. The particle size of the chips, intended for the determination of carbon or nitrogen should be approximately 1 to 2 mm When machining to obtain a chip is impractical, the sample may be broken into pieces, which are then crushed in a percussion mortar or on a vibrating mill to obtain a sufficient mass of sample for analysis of particle size not more than 150 µm. This method should only be used in cases where it can be shown that grinding does not lead to contamination of the sample.
9.2.2.2 Methods
Method of sampling and preparation of sample should match the type of cast iron, as shown below:
a) to analyze grades of grey cast iron to get the chips from the Central part of the casting, i.e. from the region, which is one third of the total cross section of the casting. Chips obtained from the surface of the cast sample, is used to determine chemical composition. Possible and depending on the shape of the casting to get the shavings by drilling in the casting in several positions. The thus obtained chips are mixed to average sample for analysis. For casting large cross-section can be impractical drilling through the casting. In this case the drill for half the distance in the plane of the cross section. Hollow casting, such as pipe, drill entirely through the wall of the pipe at each end and in the middle when the spacing of the axes of the three holes drilled at 120° relative to each other. For large castings get the intermediate sample with a diameter of 3 to 5 mm with the use of a tool for hole drilling. Break sample into small pieces and pulverized them in a mortar drum or on a vibrating mill to obtain a sufficient mass of sample for analysis of particle size smaller than 150 microns;
b) for ductile iron sample for analysis should produce (if possible) before its thermal treatment by annealing. Annealing is the main reason for the segregation elements, and it is important that the sample taken from annealed castings, presented a full cross section of the casting. Particular attention is required in the selection of the sample of the casting with variable thickness cross section. If the annealed material is subject to analysis, then mechanically cut a layer full cross-section, broken into chunks and ground in a mortar drum or disc cutter. Separate coarse and fine fractions using a sieve with a mesh size of 150 µm, and determine the mass of each fraction. Thoroughly mix each of the fractions separately, weigh a proportional amount to obtain a representative combined sample for analysis;
c) to analyze brands white and alloyed cast iron, you can obtain a sample for analysis by drilling, as described in the listing). If drilling is not practical, then cut off thin layers of preferably the total cross section from the source or intermediate sample, using a saw or, if necessary, abrasive cutting circle. In the case of abrasive cutting circle and remove the areas of thermal influence. Break the pieces into smaller pieces and pulverized them in a mortar drum or on a vibrating mill to obtain a sufficient mass of sample for analysis of particle size not more than 150 µm.
Note 10 — Wrought iron products are particularly prone to segregation of manganese sulphide in the case where the ratio of manganese and sulfur exceed 2:1.
9.2.3 Sample solid samples for analysis by thermal methods
Cut off a thin layer from the source or an intermediate sample, as set out
9.2.4 Samples for analysis by physical methods
Use a saw or abrasive cutting circle to cut a sample of appropriate size from the source or intermediate sample. Prepare the cut surface by grinding on a machine with fixed head or the abrasion of the friction, or a combination of both methods. To avoid overheating of the sample, it is recommended that air cooling. Liquid coolers do not apply. Alternatively the sample can be prepared for analysis by melting (4.4.5). Beat off pieces of the full cross section of the intermediate sample. Melted a representative number of these pieces in order to obtain a sample for analysis. The method selected for remelting, must ensure the production in a mold of a sample with the structure of white cast iron. Special attention should be paid to the requirements in 4.4.5, which relate to the partial loss of elements.
Note 11 — Grinding machine with fixed head preferably a rotary grinding wheel for surface preparation. Rotary grinding may not provide a flat sample surface for analysis.
Note 12 — Specimens obtained from the cast iron products that contain free graphite may not be suitable for quality determination of chemical composition by optical emission spectral analysis or x-ray fluorescence spectroscopy. In such cases it is preferable to use other methods of analysis set forth in 9.2.2 and
10 Steel products
10.1 General provisions
The place and method of selection of interim sample or the analysis sample from the initial sample should be agreed between the supplier and the customer. These methods are described in 10.2 and 10.3. Intermediate sample or a sample for analysis can be selected from the original sample in the location specified in the standard for the selection of material for mechanical testing, or as stated in ISO 377, as well
10.2 Selection of interim sample or the analysis sample from the ingot
From the ingot of large cross-section selected sample for analysis in the form of chips, which can be obtained by drilling parallel to the axis at a location at half distance between the outer edge and the center section. If this is impractical, then get a sample for analysis by drilling from the side of the section plane and select chips, which is obtained from the cross section located at half the distance between the outer edge and center. Alternative — if the sample required in the solid samples, an intermediate sample cut from the ingot mechanical or gas cutter at a location on the half or quarter section.
10.3 Selection of interim sample or the analysis sample of rolled products
10.3.1 General provisions
For rolled products the process of selecting intermediate sample should be conducted in the context of the product perpendicular to the direction of rolling and at one end of the product. Methods of obtaining a sample for analysis in the form of solid masses or filings set forth in 10.3.2 in respect of products with different cross sections.
10.3.2 steel bars
Cut intermediate sample across the axis of the original products in the form of a thin layer. To obtain a sample for analysis in the form of a monolithic piece, cut from the intermediate sample piece of a suitable size for a particular method of analysis. To obtain a sample for analysis in the form of chips, milled the entire cross-sectional area of the intermediate sample. In the case where milling is not practical, you can apply drilling, but this method is not recommended for boiling steel. The most convenient position of the point of the drill depends on the configuration of the cross section as follows:
a) for a symmetric section, such as bars, round profile, slab, get shavings by drilling the front surface of the slice cross section in the direction parallel to the longitudinal axis, at points located at half distance between center and edges (figure 4a, b);
b) for sections with a complicated configuration, such as angle, T-profile, channel, I-beam, get the shavings the drill at the points shown in figure 4with a-g, leaving a clearance of at least 1 mm around the drill;
c) to get a shaving rail drilling the rail head, holes with a diameter of 20−25 mm, which is midway between the middle line and the edge of the rail (figure 4h, i). In the case when drilling at the end or front surface of the cross section is impractical, the chip can be obtained by drilling inwards from the surface, perpendicular to the major axis.
Figure 4 — Positions of the samples for analysis in the section steel products
Figure 4 — Positions of the samples for analysis in the section steel products
10.3.3 Thick sheets or slabs
Cut intermediate sample of a suitable size to prepare a sample for analysis in the form of a monolithic piece or shavings, from the point at half distance between the middle line and the outer edge of the plate. Figure 4j illustrates an intermediate sample of 50 mm width. if this is uncomfortable, a sample should be selected at a location agreed between the supplier and the customer so that it was representative chemical composition of the plate.
10.3.4 small-section profiles, bars, rods, sheets, strips and wire
When the source sample has a sufficient cross-sectional area, cut off a thin layer in the transverse direction to obtain intermediate sample and a sample for analysis, as described
10.3.5 Pipes small and large diameters
Sampling is carried out in one of the following ways:
a) intermediate sample cut off in a position 90° from the weld of the product;
b) cut the sample across the pipe and processed on a lathe or milling machine the cut surface to obtain a sample for analysis in the form of chips (pipes with a small cross section can be flatten prior to milling);
c) the pipe wall of the small or large diameter drilled at several locations on its circumference for receiving a sample for analysis in the form of chips.
10.4 preparation of a sample for analysis
10.4.1 General provisions
Methods sample preparation steelwork must meet the General requirements given in 4.4. Special requirements take into account in the following cases.
10.4.2 the Sample for analysis in the form of chips
Shavings obtained by a mechanical process, must be sufficiently small to avoid or minimize the need for subsequent grinding in the process of preparing the sample for analysis. Chips should be of a size such that the mass of the individual chips was approximately 10 mg (100/y) for alloy and low alloy steels, and about 2.5 mg (400 pieces/g) for high alloy steels. If the chips are small enough for analysis, then it is crushed in a percussion mortar. Mechanical machining by cutting should be done in such a way to avoid getting very small particles of material. In the case of selection of the sample for analysis containing fine powder in the form of particles smaller than 50 microns (or 500 µm for the determination of carbon in form of graphite, sulphur and other elements prone to segregation, depending on the chip size), separating large particles from small and determine the mass fraction of each size. Weighed proportional part of each fraction to obtain a representative sample for analysis. In the selection of the sample for analysis to determine nitrogen contamination of atmospheric nitrogen fine particles of chips obtained by mechanical cutting. Prepare the sample for analysis by mechanically cutting the intermediate sample so that to avoid (if possible) a particle chip size of less than 50 microns. In addition, it is preferable to conduct this operation in an argon atmosphere. Store the chips in a sealed container. The selection of the sample for analysis, which will be used for the determination of carbon, when present in very small quantities, could be contaminated with chips of carbonaceous materials present in the atmosphere, or from other sources. Chips should be stored in a sealed container or, preferably, under conditions of inert atmosphere. It is desirable to remove the surface carbon, for example, by pre-heating immediately before the definition of its contents, or you can separately set the content of surface and inner carbon, for example, by using the differentiated signals. Alternative — you can select the working sample is in solid form, for example as the piece of metal obtained by punching.
10.4.3 Sample for analysis in the form of a monolithic piece
In the case of determining the chemical composition of products of thin cross section, such as strips or sheets, work samples to analyze the thermal methods can be made by biting small pieces from the edge of the product. Alternative pieces of metal thickness from 4 to 6 mm can be obtained by the perforation of the sheet or strip. In the case of the initial sample with the thickness of about 1.5 mm or less is necessary to reduce the local heating that occurs when an electrical discharge that occurs when using the method of optical emission spectral analysis. For example, the edge of the sample for analysis can be electrically welded to a small steel blocks or the sample may be embedded, for example, in tinplate, with one open surface.
10.5 samples of steel containing lead
To minimize the appearance of dust particles during the operations of sample selection and preparation should be taken precautions. Intermediate sample cut from the original sample and a saw for cutting metal. Chips obtained by milling the sample at low speed, to avoid overheating and dust formation. The equipment used for surface preparation of the sample for analysis by a physical method must be fenced and equipped (with ventilation) dust collector.
Warning — Small chips generated during surface preparation of steels that contain lead, and the dust from the filter system and exhaust ventilation must be collected and placed in a safe place in accordance with the factory rules of utilization of wastes containing lead.
10.6 Sampling and sample preparation for the determination of oxygen
10.6.1 General provisions
It is important to prevent contamination of the sample and to remove oxides from its surface at each stage of selection and preparation of samples. In all operations with the work breakdown using tweezers, the touch of your fingers is not allowed. In the case of the analysis of steels with very low oxygen content of machining of the working samples performed under protection of an inert gas.
10.6.2 Methods of selection of sample
Samples selected in accordance with one of the following methods:
a) cut a suitable shape of the intermediate sample mechanical saw. The sample can be, for example, in the form of a small plate or disc. Using a handsaw, cut off from this sample, working sample, the mass of which is sufficient for analysis;
b) an intermediate sample cut in the shape of the piece thickness from 3 to 4 mm. Treated the sample surface with emery paper on the basis of silicon carbide with 60 grit, then cleaned using a small cutter, i.e. a rotary rasp with cutting teeth, at a speed of 30000 Rev/min sample Surface after preparation must be smooth, with a metallic luster and without defects. Emboss a piece of metal of suitable weight of the sample for analysis to obtain a working sample using a punch with a diameter of 4−6 mm. Operation knockout performed in such a way that the working sample fall in a glass container which is blown with argon or nitrogen and can be closed with a cap or stopper;
c) cut out the intermediate pattern in the shape of a rectangle approximately the size of a 10h100 mm. the Sample will be turned on a lathe at a speed of approximately 1000 rpm, to obtain a sample having a diameter of approximately 7 mm. Continue turning at a controlled feed rate of the cutter from 0.1 to 0.15 mm per revolution at speeds from 800 to 1000 rpm to reduce the diameter of the specimen to 6 mm. of the sample Surface after preparation must be smooth, with a metallic luster and without defects. Coolants should not be used in the final stage of the process of mechanical machining. Hand saw cut from clean sample working sample of weight suitable for analysis.
10.6.3 Preparation of working samples
In the case of applying the method on 10.6.2, enum b), and if the working sample and the intermediate sample is not oxidized, the working sample can be used immediately after its knockout punch (after a brief storage in a glass container). In the case of application of methods for 10.6.2, enum a) and C), the cylindrical surface of the working sample is prepared smooth enough to do without additional processing of the file. However, each of the two end surfaces should be prepared with a file. Working immerse the sample in acetone and then dried in air or under low vacuum. The analysis is carried out immediately. Should not be a delay between the preparation of the working sample and analysis.
10.7 Sampling and sample preparation for the determination of hydrogen content
10.7.1 General provisions
Methods of sampling and sample preparation to ensure minimal diffusion of hydrogen and the control over the speed of diffusion that occurs during the time of sampling, sample storage and preparation of the working sample. The sample should be choose free from cracks, surface porosity and moisture. The condition of the working sample can strongly influence the results of the analytical measurement; methods of analysis can differ in their sensitivity to the presence of water. Procedural niceties should be strictly performed in order to obtain reproducible quality analysis. Loss of hydrogen with the sample by diffusion can be large at ambient temperature, especially from samples with thin cross section. It is important to preserve the intermediate sample, sample and the working sample at a temperature which is low as possible at all stages of selection, storage and sample preparation. The sample for analysis should be stored in the cooler. For this purpose is liquid nitrogen or a mixture of acetone and solid carbon dioxide in the form of slurry. Sample and the working sample should be kept cool during the cutting of the sample and during the preparation of the working sample. Sample and the working sample is cooled by an abundant flow of coolant during machining operations by cutting or cool short intervals of time, or use a combination of both methods. The sample was cooled by immersing it in ice water or preferably in a cooler. Samples of large cross section should be Packed with solid carbon dioxide so that a good thermal contact with the sample. During intervals between machined pieces rough cut should be returned to storage in the cooler. Any moisture present on the surface of the sample after cooling should be removed. The working sample is immersed in acetone and then dried for several* seconds at low vacuum. Samples that are improperly cooled or stored, is rejected. Surface preparation of the working sample sweep is used to a minimum extent, only to remove oxides and surface defects. A working sample is analyzed immediately after preparation.
________________
* The text matches the original. — Note the manufacturer’s database.
10.7.2 sampling Methods
In accordance with the geometric shape of a single piece of material or products, apply the appropriate machining tools to prepare the initial sample for analysis by turning, milling, sawing, slicing when cutting round blanks, etc. From castings or forgings select a sample of suitable size from the median part, where the density of hydrogen content above. From a long forged products are cut intermediate the sample saw or abrasive cutting circle at a location at half distance between the Central line of the product and the edge, and the distance from the edge equal to at least half of the cross section. From the intermediate sample cut piece sizes, suitable for turning on a lathe, to obtain a sample for analysis. A sample for analysis is stored in the cooler.
10.7.3 Preparation of working samples
From the sample for analysis is cut off a working sample of a suitable mass in such a way to minimize heating of the sample. Cool the sample in cutting short intervals of time. Prepare the surface of the working samples the turning of a file, by shot peening or slight grinding. In the case of the turning process of the surface manually velvet with a file. When bead blasting using suitable machine used for preparation of the working sample to avoid contamination from spray. When using grinding cool the working sample for short intervals of time. A working sample is degreased by immersing it in acetone, then dried for a few seconds under the influence of low vacuum. The alternative — working sample can be prepared for analysis by degreasing in isopropyl alcohol (2-propanol) and subsequent drying using diethyl ether.
Annex a (informative). Device for sampling liquid samples of iron and steel
Appendix A
(reference)
A. 1 General provisions
Disposable device for sampling of liquid iron and steel is composed of a small pressed steel molds, ceramic or quartz tube, which is mounted in a thick-walled protective cardboard tube. Commercially released a number of samplers of different types. Characterization of their main properties is given in A. 2 to A. 4 with examples shown in figures A. 1-A. 6. Dimensions given in this Annex are for information only.
A. 2 Immersion samplers
A. 2.1 Device for sampling submerged type can be introduced into the melt manually or by mechanical means using steel mould, inserted into a cardboard tube or attached directly to the node of the probe. Dive time varies depending on the design of the probe and the conditions of sampling, in particular, the temperature of the melt, but usually it is from 3 to 8 s shape Design is such that provides easy release of air from the mold cavity and gases released during the combustion of cardboard. Manual rod allows you to control the lance during the immersion and withdrawal from the melt. Sampling of ladles and converters secondary treatment can use a mechanical system for raising and lowering the spear. Some types of samplers have a thermocouple to measure the temperature, which is installed in the quartz tube near the camera for the sample. When in the oxygen Converter has an additional measuring lance, the mold Assembly can be combined with the measuring sensors to obtain samples for laboratory analysis.
A. 2.2 Device in which the chamber for the sample filled with the melt under the action of ferrostatic pressure. It consists of a steel split form, held in a cardboard tube with a ring of refractory material. Form has the below input a quartz tube with a fine steel protective cap to prevent slag or any other contamination. Cardboard tube length from 200 to 1500 mm or more may be partially covered with refractory material to reduce spattering during the dive. This type of sampler used mainly for sampling of liquid steel in furnaces and ladles. Two different designs are shown in figure A. 1.
and the Deoxidizer in the chamber for the sample
1 — cover; 2 — quartz tube; 3 — reducing agent; 4 — cap; 5 — adhesive; 6 — sand; 7 — chamber for sample; 8 — outer sleeve; 9 — sleeve; 10 — bracket; 11 — protective tube
b — reducing agent in a separate mixing chamber
1 — cardboard tube; 2 — plug; 3 — sandy holder; 4 — quartz tube; 5 — deoxidizer with cameras for mixing; 6 — slag cap
Figure A. 1 — Examples of immersion samplers filled under the action of pressure ferrostatic
A. 2.3 Samples obtained using immersion devices, fill firestations under the action of pressure, may vary in configuration. There are the following three main types:
a) samples in the form of a disk with a pin shown as an example in figure A. 2and. Drive suitable for analysis by a physical method, and the pin can be used to analyze the thermal method. The disc can be oval, round or other similar shape;
| and — basic design | b — Drive double thickness |
with Disk, showing the stratification layers
Figure A. 2 — Examples of specimens in the form of a disk with a pin
b) samples in the form of a disk with pins and a number of flushes to the disk. Tides have a mass of 0.5−1 g. They easily break off from disk to use as work samples in thermal methods of analysis;
c) samples with a double thickness is shown as an example in figure A. 2b. In this sample portion of the disc is reduced in thickness. It is suitable for punching, to obtain pieces of metal with a diameter of from 4 to 6 mm, which are used as working sample in a thermal analysis methods. A thicker section of the disc sample with double thickness used for analysis of the physical method. For sample received from the sampler and having a hardness of 25 on a scale From Rockwell, may require heat treatment before perforation.
A. 2.4 In devices for sampling related to the type shown in figure A. 3, the sample chamber is filled under gravity. This device consists of two or four cylindrical steel forms, which are placed in the refractory Assembly and attached to a cardboard tube. The form has a side inlet that is protected from the ingress of slag. A node may have refractory protection to reduce spattering during the dive. The total length of the Assembly and the cardboard tube is 400−800 mm. the dive Time is usually two or three seconds. This type of probe is used in situations where a sample of the type of the disk with the pin does not satisfy the requirements of the analysis. It is usually used for sampling of liquid iron and steel from ladles and liquid steel from the ingot, and continuous casting through an intermediate device. The sample obtained from this sampler typically has a diameter of 30 mm and a length of 70 mm.
1 — steel; 2 — reducing agent; 3 — a cover to protect against splashes
Figure A. 3 — Example of an immersion probe, is filled under the action of gravity
A. 2.5 Device for sampling, developed on a special project. They are used for sampling of liquid iron in the sprue of the blast furnace, from the ladle cigar-shaped on the truck and the gear of the bucket. These samplers have built-in cooling plates of different thickness to ensure rapid cooling of the samples of liquid iron. Characteristics of two such devices of different types is given below:
a) version of the sampler, which is filled under the action of ferrostatic pressure (A. 2.2). It implements a constructive solution based on the use of steel split form with thick walls or steel cooling plates to get a sample in the form of a disk with pins and a number of flushes to the disk. This type of sampler is shown in figure A. 4. The disk sample may be of different thickness in the range of 8 to 12 mm. the Pin typically is a cylinder with a diameter of 4 mm. the Time of immersion from 5 to 9 depending on the application;
1 — outer protective cardboard sleeve; may have a coating material that protects from splashes; 2 — steel form of rapid cooling (6 mm) to form the structure of white cast iron; 3 — intake tube samples; 4 — metal cover
Figure A. 4 — Example of an immersion device for taking samples of liquid iron from blast furnace
b) the probe design which eliminates the risk of percolation of liquid iron sampling of very fluid melts. Form with a lateral entrance opening has one or more cooling plates. It is held in the body of the sand associated with the cardboard tube. This type of probe may include single or associated form for casting rod. The resulting sample usually has a diameter of 35 mm with thickness variable from 4 to 12 mm depending on the required structure of the metal. The variant of the core sample with a diameter of 6 mm and a length of 45 mm.
A. 2.6 the Device of special design is used for sampling of liquid metal in vacuum induction furnace.
An example is the mechanism of selection of the sample tube of refractory material, which is located in the loading system of the furnace. The sampler is suspended on a rope, to provide vertical access of the melt under the action of gravity. In this case, get a sample in the form of a cylinder with a diameter of 35 mm.
A. 2.7 components of the measuring sensors used in an additional lance of a oxygen Converter for steel production, can enable mold for sampling molten steel. These forms are of the type specified in A. 2.2, can be applied in the case of the use of additional tuyeres during oxygen supply (operation blast) and in the period when oxygen is not fed (the end of the operation of the blast). During this operation, you can use the form of different construction, to obtain a sample of rectangular shape with a size of 40x30 mm and thickness 20 mm Typical Assembly is shown in figure A. 5, incorporates sensors for the measurement of the spot liquidus, temperature, oxygen potential and includes a rectangular shape with a side entrance, which is used to obtain the sample during the measurement process.
1 — protective caps; 2 — oxygen cell; 3 — thermocouple stop the liquidus; 4 — cardboard tube; 5 — reducing agent; 6 — the lateral accumulation; 7 — thermocouple; 8 — iron contact electrode; 9 — metal plate cooling; 10 — sample chamber; 11 — sand body; 12 — carton pipe; 13 — gas; 14 — connection
Figure A. 5 — Example of node tuyere with the probe showing the camera for sample
A. 3 the Device of sampling in the stream
Samplers of the type shown in figure A. 6andconsist of steel of a split form with a protruding input quartz tube held by the sleeve in a cardboard tube with a length of from 100 to 225 mm. Of these devices are examples of the type of the disk with the pin. For sampling of liquid iron are used form different designs. The peaks of the devices for sampling from a stream is designed in such a way that the probe may be positioned in the flow of metal at an angle of 45°. This can be provided some means of support — peaks. The sampling time is typically 2 s. This type of sampler is used for obtaining samples of molten iron and steel pouring from ladle.
| a Device for sampling in the stream | b — suction Device samples |
1 — quartz tube; 2 — plug; 3 — cardboard; 4 — cap
Figure A. 6 — Examples of devices for sampling in the stream and suction
A. 4 the Device of sampling suction
Samplers of the type shown in figure A. 6.b, consist of a metal split form, held in position by a sleeve in a cardboard tube with a length of from 100 to 225 mm. the Form has an open front quartz tube with a protective cap to prevent the ingress of slag or casting powder. The air is removed from the mold to create a partial vacuum using a manual or pneumatic Venturi pump that runs on compressed air. The sampling time is typically 2 s. This type of sampler is used for sampling of liquid steel in small furnaces, molds, continuous casting into molds and the filling devices. In this case you get the samples of disc type with a pin.
A. 5 system of deoxidation of devices for sampling
Devices used for sampling of liquid steel and the oxidized pornocopia contain a deoxidizer usually in the form of wire or tablets inserted into the probe so that the deoxidizer is uniformly distributed in the liquid steel. For the introduction of the reducing agent to the probe used different methods, for example:
the deoxidizer is placed in the camera for the sample, as shown in figures A. 1and A. 3;
the deoxidizer is placed in the inlet tube chamber for sample;
the deoxidizer is placed in a separate chamber;
— reducing agent and the molten steel is thoroughly mixed before entering the chamber for the sample, as shown in figure A. 1b; some samplers have a second mixing chamber. Aluminium, zirconium and titanium is usually used as a deoxidizer, depending on the steel grade and analytical requirements.
A. 6 sample Quality
A. 6.1 Surface layers of the sample can be subjected to segregation, and the Central portion may be porous and subject to shrinkage or other thermal effect (figure A. 2with), regardless of the presence of defects and oxides on the surface of the disk. Therefore, you must be particularly careful to comply with the procedures for preparing a disk surface for physical analysis methods. During the preparation of the sample surface it is necessary to open the metal layer that are representative of chemical composition.
Usually you must remove a metal layer from 1 to 2 mm from the surface of the disk obtained from samples of the liquid steel to open the part of the sample, which is suitable for a physical analysis method.
A. 6.2 the Amount of material removed from the surface of chilled samples taken from the sample liquid iron is determined by the metal structure of the sample, which may vary according to the thickness of the disk. The type of sampler used and the method of preparation of the disk sample should be chosen in such a way as to obtain the surface structure white or grey cast iron in accordance with the requirements of the method of analysis. If the sample disc obtained from liquid iron, it is usually necessary to remove the surface layer with a thickness of approximately 0.5 to 1 mm.
A. 6.3 In everyday practice, the device for sampling should be periodically inspected to assess the suitability of the sample for a particular method of analysis.
Annex b (informative). Device for sampling liquid steel for the determination of hydrogen content
The App
(reference)
B. 1 General provisions
One-time samplers for sampling of liquid steel with the purpose of determination of hydrogen content usually consist of pressed steel shapes or quartz tube mounted in a thick-walled protective cardboard tube. These devices for sampling molten steel from the ladles, molds, forms, and continuous casting is designed to obtain samples in the form of a pin or rod with a diameter of 7−12 mm and a length of from 75 to 150 mm. Several types of samplers are mass-produced, characteristics of their main properties is given in B. 2 and B. 3 examples listed in figure B. 1. In the present application are only recommended sizes.
| a Submerged probe 1 — cardboard tube; 2 — coverage spray; 3 — quartz tube |
b — Immerse sampler 1 — aluminium foil 2 — cardboard tube; 3 — quartz tube; 4 — aluminum foil |
| with the Vacuum sampler 1 — hole; 2 — steel housing; 3 — iron; 4 — seal; 5 — flexible cap |
d — Suction sampler 1 — metal cap; 2 — quartz tube; 3 — cardboard tube; 4 — pressed steel detachable form |
Figure V. 1 — Examples of samplers used for sampling molten steel with the purpose of determination of hydrogen content
B. 2 Immersion sampling probes
There are two types of devices for sampling by immersion in the melt:
a) samplers of the type shown in figure V. 1andconsist of a quartz tube inner diameter of 7−9 mm, placed in a protective cardboard tube. The upper end of the tube is open, and the bottom is provided with a cap with aluminum foil to prevent contamination. Cardboard tube length of 250 or 400 mm, depending on the application, has a refractory coating as protection from splashes or surges. This type of sampler is used for sampling of liquid steel at a temperature close to the liquidus;
b) samplers of the type shown in figure V. 1b, consist of protruding quartz tube inner diameter of 10−12 mm, held in a cardboard tube. The upper end of the tube is open and can be closed with aluminum foil. The tube has a side inlet, a closed aluminum foil. It can contain aluminum wire as deoxidizer usually weighing about 0.1 g. the Sampler of this type are widely used for sampling of liquid steel.
B. 3 Suction samplers
There are two types of devices for sampling by suction of the melt:
a) a vacuum probe of the type specified in figure V. 1with, consists of a steel sleeve and camera for sample, made of iron of high purity, internal diameter 4 mm. the Probe is mounted in a cardboard tube, protected by a refractory material, and may have a cap that protects from falling slag. When immersed in the melt cap is melted, the liquid steel is sucked into vakuumirovannoj camera for the sample, which then closes as the solidification of the metal, tightly closing the sampler. The hydrogen which diffuses from the sample enters into the outer vacuum chamber and is measured when the probe is inserted into analytical instrument special design, pierced. The content of residual hydrogen in the sample can be measured separately after extraction of the sample with the camera. Samplers of the type shown in figure V. 1brepresent a vacuum pipe (<10Torr) of borosilicate glass. The advantage of the device for sampling of this type is that the inner side of the probe protected from contamination prior to filling;
b) samplers of the type shown in figure B. 1,d, consists of molded steel split form inner diameter of 7−9 mm and a length of 75 mm with a quartz inlet tube. Keep the form in a cardboard tube with rim. The air removed from the chamber by the air pump Venturi to create a partial vacuum.
Application (reference). Data on compliance with national standards of the Russian Federation the reference to international standards
Application
(reference)
Table C. 1
| Marking the reference international standard |
Designation and name of the relevant national standard |
| ISO 377:1997 |
* |
| ISO 9147:1987 |
* |
| * The corresponding national standard is missing. Prior to its adoption, it is recommended to use the translation into Russian language of this international standard. The translation of this international standard is the Federal information Fund of technical regulations and standards. | |
