GOST R 51381-99
GOST R 51381−99 Billet of corrosion-resistant alloys based on cobalt for prosthetic dentistry. General specifications
GOST R 51381−99
Group В31
STATE STANDARD OF THE RUSSIAN FEDERATION
PROCUREMENT OF CORROSION-RESISTANT ALLOYS BASED ON COBALT FOR PROSTHETIC DENTISTRY
General specifications
Corrosion-resistant cobalt-base alloy billets for orthopedic stomatology. General specifications
OKS 77.190.20*
OKP 09 6300, 17 3130
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* In the index «National standards», 2008
OKS
Date of introduction 2000−07−01
Preface
1 DEVELOPED AND SUBMITTED by the Technical committees on standardization TC 375 «steel Products from ferrous metals and alloys» and TC 279 «Dental business"
2 ADOPTED AND put INTO EFFECT by the Resolution of Gosstandart of Russia from November 30, 1999 No. 473-St
The Standard 3 meets in part the requirements for the chemical composition, mechanical properties, and determining corrosion resistance of international standard ISO 6871−1-94 «Dental casting alloys on metal base. Part 1. Alloys based on cobalt"
4 INTRODUCED FOR THE FIRST TIME
1 Scope
This standard establishes requirements for the procurement of corrosion-resistant alloys based on cobalt, intended for the manufacture of cast dentures (crowns, solid bridges and partial skeletons).
The standard does not apply to alloys intended for the manufacture of metal-ceramic prostheses.
2 Normative references
The present standard features references to the following standards:
GOST 1497−84 Metals. Test methods tensile
GOST 2999−75 Metals and alloys. Method of measurement of hardness by Vickers
GOST 3916.1−96 General purpose Plywood with outer layers of hardwood veneer. Specifications
GOST 3916.2−96 General purpose Plywood with outer layers of veneer of softwood. Specifications
GOST 7376−89* corrugated Cardboard. General specifications
________________
* On the territory of the Russian Federation GOST R 52901−2007, here and hereafter. — Note the manufacturer’s database.
GOST 7565−81 Iron, steel and alloys. Method of sampling for chemical composition
GOST 7566−94 metal Products. Acceptance, marking, packing, transportation and storage
GOST 10354−82 polyethylene Film. Specifications
GOST 10459−87 base Paper for an adhesive tape. Specifications
GOST 15150−69 Machines, instruments and other technical products. Performance for different climatic regions. Categories, conditions of use, storage and transportation of the impact of climatic factors of the external environment
GOST 16337−77 high-pressure Polyethylene. Specifications
GOST 18251−87 adhesive Tape on a paper basis. Specifications
GOST 25281−82 powder metallurgy. The method of determining the density of the moldings
GOST R 15.013−94 System development and production statement on manufacture. Medical products
GOST R 50444−92 Instruments, apparatus and medical equipment. General specifications
3 Definitions
In this standard use the following terms with respective definitions:
3.1 the corrosion-resistant dental alloys cobalt-based:Metallic materials, the main component of which is a cobalt with the necessary technological physical, mechanical and corrosion properties as well as Toxicological and sanitary-chemical indicators, allows them to be used for dental prosthesis without harmful effects to the human body.
3.2 fluidity: the Ability of liquid metal to fill the mold.
3.3 linear casting shrinkage: the Property of liquid metal during cooling and solidification to reduce their linear dimensions.
4 Classification, basic parameters and dimensions
4.1 procurement type (manufacturing method):
cast;
— forged;
— HR.
4.2 the condition of the material — without heat treatment.
4.3 the Kind of customization and purpose indicated in the order.
4.4 Workpiece produce a mass of 5−30 g with maximum deviation of weight is ±10%.
By agreement between the consumer and the manufacturer is allowed to produce workpieces of a different mass.
4.5 Maximum linear dimension of the workpiece is not more than 20 mm. In agreement with the consumer allowed other linear dimensions of the workpiece.
Examples of symbols
Billet is cast from corrosion-resistant dental alloy based on cobalt (symbol stamps), weighing 20 g:
Cast billet — marking stamps — 20 GOST R 51381−99
Billet forged from corrosion-resistant dental alloy based on cobalt (symbol stamps), weight 10 g:
Billet forged — the designation of mark 10 GOST R 51381−99
5 Technical requirements
5.1 Alloys should be smelted with the use of clean charge materials. The production methods chosen by the manufacturer. Allowed the use of waste of its own production.
5.2 Mass fraction of the main chemical elements of the alloy should meet the following requirements:
cobalt — based;
chrome — not less than 25%;
molybdenum: not less than 4%;
cobalt+Nickel+chromium no less than 85%.
Notes
1 Chemical composition of the alloy (symbol mark) is agreed when ordering.
2 allowed for different mass fraction of main alloying elements and their correlation, subject to the fulfilment of the other requirements of this standard.
5.2.1 the Permissible deviations of the mass fraction of chemical elements in the alloy must be not more than 1% for those elements, the mass fraction of which in the alloy is from 2 to 20%, and not more than 2% for elements, mass fraction of which in the alloy is more than 20%.
5.3 Hardness and mechanical properties of samples molded from corrosion resistant alloys cobalt-based, must meet the requirements of table 1.
Table 1 — Hardness and mechanical properties of samples molded from corrosion resistant alloys based on cobalt at room temperature
Hardness, HV |
Mechanical properties | |
Yield strength |
Elongation | |
| 260−450 |
500 |
3 |
| Notes 1 the Rules of temporary resistance established by agreement between manufacturer and consumer. 2 Standards hardness optional before 01.01.2005. | ||
5.4 the Surface of the workpieces of the alloys should be clean, without foreign inclusions.
5.5 Density for each particular brand of alloy is set by the manufacturer. The deviation of the density determined by the consumer, should not exceed 2%.
5.6 the Casting properties of alloys
5.6.1 the fluidity of the alloy must ensure that the casting of thin-walled products.
5.6.2 Linear casting shrinkage for each particular brand of alloy is set by the manufacturer. The deviation of linear casting shrinkage of the consumer should not exceed 5%.
5.6.3 Temperature and melting range of alloys is defined by the manufacturer and specified in the instrument of quality.
5.7 Billets should be non-toxic.
5.8 Billets are manufactured with the guarantee of resistance against corrosion.
5.9 Billets must be resistant to climatic influences during transport and storage for products of group 5 GOST 15150.
5.10 Billets must be resistant to mechanical stress, for products of group 2 according to GOST R 50444.
5.11 completeness
5.11.1 each package includes:
— one pack of blanks of the same alloy with a weight of 100−1000 g;
— one label.
5.12 Packaging
5.12.1 Billet alloy packaged in a plastic package according to GOST 10354 or GOST 16337, or other method as agreed of manufacturer with the consumer. The label should be enclosed in the package (package) or be placed directly on the packaging.
5.12.2 When sending to the consumer packaging blanks are placed in boxes made of plywood churchyard or GOST 3916.1 3916.2 or boxes made of corrugated cardboard according to GOST 7376. By agreement between the consumer and the manufacturer are permitted, other methods of packaging.
5.12.3 Each drawer should be covered with tape on paper according to GOST 18251 or paper according to GOST 10459. Lots of pieces in the box must not exceed 11 kg.
5.12.4 In each box or carton must be invested packing list indicating the number of packaging products.
5.13 Marking
5.13.1 At the request of the consumer for alloy identification is allowed marking of the workpieces.
5.13.2 the label in the package with the pieces of alloys, should be specified:
— the name and address of the manufacturer;
— the designation of the brand of alloy (trade name);
— the scope of the alloy;
— the main components of the alloy and their mass fraction in percent;
— the batch number;
— the weight of one workpiece;
— number of blanks.
6 acceptance Rules
6.1 the Products shall be made by the parties, consisting of billets of one melting.
Each production batch must be accompanied by a quality document, which must be specified:
— the designation of the alloy and batch number;
— density, g/cm;
— the yield stress at a residual strain of 0.2%, N/mm;
— elongation, %;
hardness Vickers (HV);
linear casting shrinkage;
— temperature range of melting.
6.2 To check the quality of the workpieces from alloys taken from the party:
— for chemical analysis — 1 sample from the melt;
— to control the masses — 2−3 samples of the same weight and the melt;
to control density — 1−2 sample from the melt;
— to check the surface quality and size all the blanks from the party;
— to control the hardness of 3 samples from the melt;
to control fluidity — 2−3 sample from the melt;
— to control the linear mold shrinkage 2−3 sample from the melt;
for tensile tests at room temperature 3−6 samples from melting.
6.3 Billets shall be subject to the following types of tests:
— acceptance;
— acceptance;
— periodicals.
6.4 Acceptance testing
6.4.1 Acceptance testing is carried out at the production of the alloy for mass production.
6.5 acceptance tests
6.5.1 acceptance testing each batch of workpieces from alloys to confirm compliance with the requirements of this standard and the chemical composition of the alloy, the surface quality of workpieces, completeness, marking and packing.
6.5.2 If during the process of acceptance testing will be mismatched billets from alloys of at least one requirement of the standard, the test is repeated on twice the number of samples. In case of unsatisfactory re-test batch is rejected.
6.6 Periodic testing
6.6.1 Periodic test carried out at least once a year to confirm the compliance of the produced alloy, passed acceptance tests, all requirements of the standard, except density, castability and linear casting shrinkage of the alloy resistance to mechanical and climatic influences.
Listed in 6.6.1 6.6.2 properties are checked only once at the installation party.
6.6.3 Periodic tests are made mandatory in case of change of the technological mode of production of blanks for the confirmation of conformity is made of alloy all requirements of the standard.
Note — it is allowed to conduct a number of tests 6.6.1, as acceptance tests at the discretion of the manufacturer or at the customer’s request.
7 test Methods
7.1 Chemical composition of alloys determined by methods providing the required accuracy. Sampling for the determination of chemical composition — GOST 7565.
7.2 the Test mass blanks from alloys is carried out on scales with divisions of not more than 0.1 g.
7.3 blanks Hardness Vickers (HV) determined according to GOST 2999.
7.4 the Density of the alloys determined according to GOST 25281.
7.5 the Length of the workpiece measured by the measuring ruler with a scale division of 1 mm.
7.6 Evaluation of fluidity was carried out after filling with liquid metal forms at the visual fidelity of detail in the casting (figure 1); shells and underfilling are not allowed.
Figure 1 — a Sample casting for the determination of castability
Dimensions in mm |
Scale: 5:1 |
Figure 1 — a Sample casting for the determination of castability
7.7 Linear casting shrinkage of alloys is determined by the following method: in the standard test block made of wax samples (standards), which length cause risks. Distance between risks is measured using a measuring microscope accurate to 0.001 mm. Wax samples were molded in refractory ceramic mass, which is then calcined at 900 °C.
Fill the resulting shape alloy produced by centrifugal casting.
After measuring the distance between risks on the resulting casting foundry linear shrinkage is calculated by the formula
where — the distance between the marks on the standard, mm.
— distance between risks on the resulting casting alloy, mm.
7.8 surface Quality of workpieces evaluated visually at an illumination of not less than 300 Lux.
7.9 Assessment of toxicity (sanitary-chemical and Toxicological studies) alloys produced according to methods approved by the Ministry of health of the Russian Federation in the prescribed manner.
7.10 General requirements of sampling for mechanical tests
7.10.1 Samples for mechanical tests are made using the casting method for lost wax investment casting.
7.10.2 the Samples must be cleanly separated from the sprues and profits are exempt from edges, seams and surface impurities and then subjected to sandblasting. Allowed additional surface treatment (grinding). All samples with visible defects shall not apply.
7.10.3 Types of specimens for mechanical testing are shown in figures 2 and 3.
Figure 2 — Sample with short head
Figure 2 — Sample with short head
Figure 3 — Sample with extended head
Figure 3 — Sample with extended head
7.10.4 the proposed foundry model for producing samples for mechanical tests is presented in figure 4.
Figure 4 — Sample with the recommended Gating system
Figure 4 — Sample with the recommended Gating system
Allowed to use other Gating system to ensure the absence of casting flaws in the working area of the samples (inversions, blockages, sinks, etc.).
7.11 tensile Test is carried out according to GOST 1497.
The values of yield stress corresponding to the residual strain equal to 0.2%, and elongation, calculated as the arithmetic means of four, five or six specimens, shall conform to the requirements of table 1. If the requirements of table 1 correspond to the arithmetic means of at least four samples, prepared another set of samples and repeat tests are carried out. When you re-test in case of discrepancy between the values of table 1 arithmetic mean values of at least four samples of the alloy is rejected.
7.12 the stability of the workpieces from alloys to climatic influences during transport and storage is determined by exposure of the packaging blanks from alloys in the camera of heat and cold at temperatures respectively of 50 °C and minus 50 °C for 4 h, followed by aging in a humidity chamber for four days in a cyclic mode according to GOST R 50444. After testing the integrity of the packaging should be retained on the surface of the workpieces should be free of corrosion.
7.13 the Resistance of the workpieces from alloys to mechanical stress is determined on the stands, simulating the vibratory loads and shock loads on GOST R 50444 for product group 2.
After testing the integrity of the packaging should be retained on the surface of the workpieces should not be rough damage.
7.14 the Reliability (persistence) of the workpieces of the alloys is determined by laying the samples on storage for a period of not less than 5 years with further tests of mechanical and physical properties in accordance with [1].
7.15 a completeness Check, labeling and packing is carried out by visual inspection and comparison with the documentation.
7.16 Acceptance testing is carried out according to GOST R 15.013.
7.17 the recommended method of determining the corrosion resistance of workpieces from alloys of the type and quantity of metal ions, leached (released) from the alloy by static immersion tests, is presented in Appendix A.
8 Transportation and storage
8.1 Billets transporterowych all kinds of covered vehicles in accordance with GOST 7566 transportation of goods, operating in the corresponding mode of transport, and conditions of loading and fastening of cargoes.
8.2 Billets should be stored in packaging manufacturer in the conditions of storage 2 according to GOST 15150.
9 manufacturer’s Warranty
9.1 the Manufacturer guarantees the conformity of workpieces from alloys of the requirements of this standard when complying with the storage conditions.
9.2 the Warranty period of storage — 5 years from date of manufacture.
Annex a (recommended). The method of statistical trials by immersion to determine the corrosion resistance
APPENDIX A
(recommended)
A. 1 Samples
Samples (two sets of three samples from melting) for testing are prepared by casting in lost wax investment casting size 32х10х1,5 mm.
Samples must be cleanly separated from the sprues and profits are exempt from edges, seams and surface impurities, subjected to sand-blasting, then wet polishing using standard metallographic techniques.
Remove not less than 0.1 mm from all sides. All traces of abrasive must be cleaned.
In the presence of visible defects on the last samples to be replaced.
A. 2 Reagents
Lactic acid WithN
On
analytical purity.
NaCI sodium chloride of analytical purity.
Ethyl alcoholN
IT.
Water.
A. 3 Methodology
Prepare the surface of test specimens A. 1 and measure the surface area of the samples to the nearest 0.1 cm. Purified samples from the abrasive, oil or grease. Washed in ethanol and dried.
Divide the samples into two sets of three samples with a total surface area of each set 20 cm. Prepare an aqueous solution comprising: 0.1 mol/l
lactic acid and 0.1 mol/DM
sodium chloride.
Each set of three samples are hung in a separate sealed vessel (incubator) for 7 days at a temperature of (37±1) °C so that the samples were fully closed test solution, not in contact with each other and with the walls or bottom of the thermostat. Thermostats are selected such as to avoid absorption of trace elements on their surface, and the solution volume should be about 1.3 cmper square centimeter of surface area of test specimens. The thermostat is sealed to prevent evaporation.
Explore test each solution separately against the elements, the mass fraction of which in the alloy exceeds 2%, using a quantitative analytical method of appropriate sensitivity: atomic absorption spectrometry (AAS) and optical emission spectrometry (OES).
Determine the total content of all elements, detected in each solution and record the mean value of both tests (µg·cm).
Annex B (reference). Bibliography
APPENDIX B
(reference)
[1] RD 50−701−91 guidance. Medical equipment products. The requirements for reliability. Rules and methods of control of reliability indicators
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* Probably a mistake of the original. Should read RD 50−707−91. — Note the manufacturer’s database.
The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: IPK Publishing house of standards, 2000
