GOST 23338-91

• gost-23338-91.pdf (615.28 KiB)
  ГОСТ 23338-91

GOST 23338−91 welding of metals. Methods for determination of diffusion hydrogen in the deposited metal and the weld metal

GOST 23338−91

Group B09

STATE STANDARD OF THE USSR

WELDING OF METALS

Calculation of the diffusion
hydrogen in the deposited metal and the weld metal

Welding of metals.
Methods for determination of diffusible hydrogen
in deposited weld metal and fused metal

AXTU 0809

Date of introduction 1992−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Academy of Sciences of the Ukrainian SSR

DEVELOPERS

L. M. Lobanov, member.-cor. USSR; by I. K. pokhodnya (leader theme); I. R. Avdoshin, PhD. tech. Sciences; A. P. Balcewicz, PhD. tech. Sciences; J. M. Usikov, PhD. tech. Sciences; V. I. Petrukhin; A. T. Vasilyev, A. N. Troshchenkov; B. B. ESCOs; R. I. Sherbakov; G. L. Petrov; A. M. Levchenko

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 04.06.91 N 783

3. REPLACE GOST 23338−78

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard establishes, chromatographic and vacuum methods for the determination of the content of diffusion hydrogen in the deposited metal and the weld metal and applies to covered electrodes, cored wires, steel welding wire for welding low carbon and low alloy steels.

Chromatographic method is designed to determine the level of hydrogen in the samples of welds made with coated electrodes, powder and steel wires.

The vacuum method is for the determination of hydrogen in samples of welds made with coated electrodes from diameter 3 to 6 mm.

When welding with electrodes with a diameter of 4 mm the measurement range of the mass fraction of the hydrogen from 0.25 to 13.5 million — in the weld metal, 0.4 to 22 millionin the deposited metal or from 0.3 to 15 cm/100 g in the weld metal, from 0.5 to 25 cm/100 g in the deposited metal.

Measurement of the content of diffusion hydrogen in the deposited metal and the weld metal used for classification and quality control of batches of welding materials and research purposes.

For classification and control of batches of welding materials of welding seam conditions specified in the standard.

1. EQUIPMENT AND MATERIALS

1.1. The essence of the chromatographic method (method 1)

1.1.1. The method is based on the collection evolved from the sample weld of hydrogen in the cell and then measure its volume by gas chromatography.

For acceleration analysis, the sample is outgassed at a temperature of (150±5) °C.

The diagram is shown in hell. 1. Emitted from the sample 1, the hydrogen is collected in a metal chamber 2, connected to the chromatograph 7 through the electromagnetic switch the direction of gas flow 5. Control of the switch 5 is performed by the control unit 6.

Damn.1. Diagram of the device for chromatographic method of analysis (method 1)

1 — sample; 2 — reaction chamber; 3 — cover of the reaction chamber; 4 — furnace for heating the sample chamber; 5 — solenoid switch the direction of gas flow; 6 — control unit of the electromagnetic switch the direction of gas flow; 7 — chromatograph; 8 — preparation unit gas chromatograph; 9 — the block of preparation of the detector for thermal conductivity; 10 — block temperature controller; 11 — potentiometer KSP-4; 12 — integrator-And-02 (I-05); 13 — a tank of argon

Damn. 1

Period of time, the camera 2 is connected to the carrier gas flow of argon to flush emitted from the sample hydrogen (or chamber cleaning of air after insertion of the sample), the selection cycle hydrogen or chamber cleaning. Period of time, the camera 2 is disconnected from the flow of the carrier gas argon in hydrogen storage, the cycle of accumulation of hydrogen.

During accumulation of hydrogen in the chamber 2 a carrier gas of argon passes through the chromatograph 7, bypassing the chamber 2. To measure the volume of evolved hydrogen gas, the carrier gas using a switch 5 is directed through the chamber 2 into the chromatograph 7, which is detected.

The output signal is registered by the potentiometer 11, and the area measured by the integrator 12. Work 7 chromatograph and detector for thermal conductivity is controlled respectively by the blocks 10 and 9. The flow rate of the carrier gas in the two lines of the chromatograph is set by using the preparation unit gas chromatograph 8. To accelerate the analysis of sample 1 with the camera 2 is heated by a resistance furnace 4.

The number of cycles of hydrogen accumulation and selection of hydrogen is determined by the intensity of hydrogen release from the sample. The amount of released hydrogen of sample is equal to the sum of the areas of the peaks of hydrogen multiplied by the conversion function of the device.

1.2. The essence of the vacuum method (method 2)

1.2.1. The method is based on the collection of hydrogen from the sample in the vacuumed container connected to a manometer. The volume of the evolved hydrogen is determined based on the volume of the container and changes in this pressure due to the evolved hydrogen gas. Degassing of the sample is performed at room temperature.

The design of the device for measuring the diffusion volume of hydrogen given on features. 2. The hydrogen released from the sample, placed in a flask 7, increases the pressure of the detected liquid pressure gauge 6.

Damn.2. Device for vacuum method of analysis (method 2)

1, 2, 3, 4 — vacuum valves; 5 — a lamp of vacuum; 6 — manometer; 7 — flask

Damn. 2

1.3. To measure the volume of hydrogen used appliances, fixtures and materials:

1.3.1. Method 1

1.3.1.1. The device is ON or ABOUT 2456 2144, which includes a chromatograph lxm-8МД or lxm-80 with thermal conductivity detectors (or other brands chromatographs with thermal conductivity detectors). Are the instruments made according to normative-technical documentation. The device is ABOUT 2456 is designed for the simultaneous analysis of three samples, the device is ABOUT 2144 for the same sample.

It is allowed to use other devices based on the principles mathographics gas analysis, providing identical results, made by other normative-technical documentation.

1.3.2. Method 2

1.3.2.1. Vacuum device (Fig. 2), which is given in Appendix 2.

1.3.2.2. A device for welding (Fig. 3, 4).

Damn.3. Fixture for welding samples according to the methods 1 and 2

1, 2 — copper water-cooled sponge; 3 vise with manual transmission

Damn. 3

Damn.4. Fixture for welding samples according to the method 2

1 — M12; 2, 4 — clamps copper; 3 — blank sample; 5 — M12 nut; 6 — dimensional Planck

Damn. 4

1.3.2.3. Universal photographic enlarger «Belarus-2» at the NTD.

1.3.2.4. Thermometer according to GOST 28498−90.

1.3.2.5. WLDP analytical scale 200 g, 2 CL. in NTD.

1.3.2.6. Reagents: acetone according to GOST 2603; technical ethyl alcohol according to GOST 18300; toluene according to GOST 5789; silica gel according to GOST 8984; argon according to GOST 10157; ether — NTD.

2. PREPARING FOR THE TEST

2.1. Samples for test

2.1.1. The sample is a plate with the weld roller. Roller, apply to the workpiece, consisting of plates assembled together with lead strips in accordance with the devil.5.

Damn.5. Workpiece composite samples for surfacing roller

1 — plate; 2, 3 — pin strips; unspecified tolerances H12

Damn. 5

2.1.2. The material of the lead plates and straps: for classification of welding consumables steel grades БСт3сп, Stzsp according to GOST 380; for other assignments allowed the use of low carbon and low alloy steels, for welding which are the subjects of welding materials.

Blanks for the manufacture of lead plates and straps shall be subjected to annealing at a temperature of 650−670 °C for at least 2 hours.

2.1.3. Plate is marked on the lower surface (with respect to the weld bead).

2.1.4. Plate and lead strips after the filing of the burrs and sharp edges shall be washed: for method 1, in acetone and ethyl alcohol, technical; for method 2 in toluene, then in acetone and ethyl alcohol technical.

2.1.5. Plate before welding roller must be weighed with an accuracy of ±0.01 g.

2.1.6. Plate and strap lead to the surfacing of the roller should be stored in a desiccator with silica gel. Silica gel should be regenerated at a temperature of 150−300 °C for 3 h, at least once in three months.

2.1.7. Procurement type I is designed to test electrodes with a diameter of 3−4 mm according to method 1, preparation of type II is designed to test rods with diameter more than 4 mm wires and cored wires, steel welding by the method 1, preparation of type III is designed to test electrodes with a diameter of 3−6 mm by the method 2 (Fig. 5).

2.2. Surfacing roller on the workpiece

2.2.1. Roller for surfacing the workpiece is clamped in the fixture for welding. The temperature devices must be in the range from ambient temperature to the temperature of its dew point.

2.2.2. The electrodes and wire with powder before applying the roller needs to be dried in accordance with the requirements of normative-technical documentation for their production.

If in the normative and technical documentation there are no instructions on the modes of drying, they shall be set by agreement between manufacturer and consumer of welding material on the basis of the type of coating or core flux-cored wire.

2.2.3. The kind and polarity of the current in surfacing cushion must meet the requirements of the operational documentation of the manufacturer of welding material, average current should be 90% of its maximum value for electrodes and 80% for powder and steel welding wires.

2.2.4. When welding with covered electrodes of a roller linear speed of welding should be set from the conditions of melting of from 12 to 13 cm length of the electrode while welding a 10 cm length of the cushion.

Note. When using electrodes containing iron powder coating, the length of the molten part of the electrode per unit length of a filler cushion should be reduced proportionately in accordance with the output of the weld metal to test the electrode.

2.2.5. In surfacing cushion powder and steel welding wires the welding conditions should set out the conditions for obtaining a cushion, width 22 mm, height 6 mm, heat input when welding, not more than 3 kJ/mm.

2.2.6. In surfacing cushion its beginning and end should be performed on the output rails.

2.2.7. The transverse vibrations of the end of the electrode or wire during welding are not allowed.

2.2.8. Welding of multiple parts of samples of one of the electrodes is not allowed.

2.2.9. Surfacing roller should be at an absolute humidity of 10−15 g/m(relative air humidity 60 to 90% at 20 °C).

2.3. Processing of the samples after welding

2.3.1. Method 1

2.3.1.1. After overlaying the platen to remove the workpiece from the fixture for welding, submerge in water with a temperature not exceeding 10 °C. the Volume of water must be at least 8 DM. After cooling in water of not more than 3 with the workpiece placed in alcohol or acetone, mixed with solid carbon dioxide or liquid nitrogen.

2.3.1.2. To separate lead strips after cooling of the workpiece in coolant for at least 5 min. to Remove slag, splatter, clean the surface of the sample on all sides with a wire brush. The residence time of the sample out of the coolant to perform these operations shall not exceed 15 s. To continue processing the sample to immerse it in coolant for at least 2 min. Cleaned sample stored in the coolant to the analysis: not more than 3 months in liquid nitrogen, other fluids no more than 3 days.

2.3.2. Method 2

2.3.2.1. After overlaying the platen to remove the workpiece from the fixture for welding, submerge in water with a temperature not exceeding 10 °C. the Volume of water must be at least 8 DM.

2.3.2.2. To separate lead strips. To remove slag, splatter, clean the surface of the sample on all sides with a wire brush. Brush when cleaning should be to dip into the water.

2.3.2.3. After cleaning the specimen should take the tongs and sequentially rinsed in ethyl technical alcohol, acetone and in ether 8−10 S.

When washing with alcohol, the sample should be wiped with coarse calico. Consumption of each of the liquids is less than 100 cmon four samples.

2.3.2.4. The washed sample is needed from all sides to drain of residual solvents in a stream of hot air over the unit capacity of not less than 1 kW with a closed spiral at a distance of 10−15 mm from the surface of the tiles.

2.3.2.5. The sequence of the processing operations of the samples after welding and their execution time are given in the table.

2.3.2.6. Samples made with the breakage of the arc when welding roller, and also have cracks, fistulas, pores, slag inclusions and shell not be accepted for analysis by methods 1 and 2.

2.3.2.7. The samples processed with the timed operations will not be accepted for analysis by methods 1 and 2.

3. ANALYSIS

3.1. Method 1

Description of device ABOUT 2144, which uses a chromatograph lxm-80 with one camera (damn. 1).

3.1.1. The gearing on the cylinder 13 to adjust the pressure of the argon at the inlet of the device from 0.49 to 0.68 MPa (5−7 kg/cm).

3.1.2. Apply power to the device and set on the temperature controller unit 10: the temperature detector of the thermal conductivity at 40 °C, the temperature of the chromatographic column 50 °C;

set on the treatment unit of the detector of the thermal conductivity of 9 current detector 60 mA;

apply power to the potentiometer 11 and the integrator 12;

apply power to the kiln 4 from the camera 2 and to install a heating temperature of 150 °C.

3.1.3. After warming up of the device and the furnace chamber during the 50−60 min to remove the camera cover 3.

3.1.4. Remove the sample from the coolant. Rinse the sample in alcohol with an initial temperature of from 20 °to 35 ° C (volume of alcohol of 180−200 cm, from the condition of a flow rate of 5 cmof alcohol per one sample) with the use of a tampon from calico, wipe dry with a cloth, placed in the chamber 2, to close the camera cover 3.

3.1.5. Immediately after the closing of the cover 3 flush with the carrier gas argon of the chamber 2 with the sample from the air, including by means of the control unit 6 electromagnetic switch gas 5 for 25−30 pages.

3.1.6. In the process of degassing the sample, the sampling gas should occur after 5−20 min (the cycle of accumulation of hydrogen) for 25−30 s (selection cycle hydrogen), controlling the operation of the gas switch 5 with the control unit 6 in manual or automatic mode.

The integrator measures the peak areas in mV·with proportional samples of hydrogen produced in each cycle of accumulation and selection of hydrogen gives the result on backlit display and records on paper tape using tsifropechatayuschee device.

3.1.7. The duration of analysis of samples of type I is 1.0−2.5 h, the duration of analysis of samples of type II is 2.0−2.5 hours

The end of the analysis is established on the magnitude of the output signal. The peak area at the last sampling gas from the chamber, collected within 15 min shall be not more than 2% of the sum of squares of the previous peaks.

3.1.8. After analysis is complete, disable automatic operation of the electromagnetic switch 5 gas. To open the camera cover 3, remove the sample 1.

3.1.9. Weigh the sample after cooling to room temperature with an accuracy of ±0.01 g.

3.2. Method 2

3.2.1. To prepare the device (Fig. 2) to check its tightness, which is necessary to create a vacuum in the device, equal to 0.8−1.0 PA [(6−8)·10mm Hg.St.] with open valves 4, 3, 2 and 1 the valve is closed (Fig. 2). Close tap 2 and open tap 1. Remove the lower portion of the bulb 7.

3.2.2. Place the sample in the lower part of the flask and connect it to the device. Vacuum device with the sample up to a pressure of not more than 2.7 PA (2 x 10mm Hg.St.) with open valves 4, 3, 2 and 1 the valve is closed during 60−70 C. Upon reaching the set vacuum to simultaneously close the valves 4 and 3, and then tap 2. To withstand the instrument with the sample in an evacuated condition within 5 days at room temperature.

3.2.3. After 5 days of exposure to record the difference between the liquid levels in the manometer of the device with an accuracy of ±0.5 mm When the metering gauge should be measured the temperature of the air in the room at a distance of not more than 1.0 m from the measuring devices with an accuracy of ±0.5 °C. Open valves 4, 3, 1, remove the lower portion of the bulb, remove the sample, close the faucet 1. Install the lower portion of the bulb to the device, open the valve 2 and vacuum device to the pressure not more than 1.0 PA (8·10mm Hg.St.), to close the valve 2.

The instrument without the sample should be kept in a vacuumed state.

3.2.4. Determine the mass of sample () with an error of ±0.01 g.

3.3. The determination of the proportion of deposited and molten metal in cross section of the sample (methods 1 and 2)

3.3.1. Manufacture and etched thin section of the cross section of the sample to determine the boundaries of the welded seam. Or photographically reproducing the outlines of the specimen and weld on tracing paper to obtain an image of the cross section of the sample with a linear magnification of at least 4. In accordance with the devil. 6 to apply a line that separates the image of the weld and the welded metal. Cut and determine the mass of a paper representing the area of the weld metal and the weld metal . Weighing on an analytical balance to perform with an accuracy of ±0.001 g.

Damn.6. Cross section of the specimen

 — the area of the deposited metal;  — the area of welded metal;
 — the area of the seam; the line between the weld and the welded metal

Damn. 6

3.3.2. To determine the mass and in each of the three sections for the sample types I, III (fracture surface samples and outlet strips and middle of the sample; the two cross sections for sample type II — fracture surface of the samples and lead strips).

4. PROCESSING OF MEASUREMENT RESULTS

4.1. The mass of deposited metal (), g, is calculated by the formula

(1)

where  — weight of plate after welding, g;

 — weight plate,

4.2. Determination of the volume of evolved hydrogen gas

4.2.1. Method 1

The volume of the evolved hydrogen (), cm, is calculated by the formula

(2)

where  — the sum of the areas of the peaks µv·s;

 — function conversion, cm/V·s, determined in accordance with Annex 1.

The obtained value of the leave to three significant figures.

4.2.2. Method 2

The volume of the evolved hydrogen (), cm, is calculated by the formula

(3)

where  — the temperature of the air in the room at the time of reading of pressure gauge, °C;

 — the volume of the bulb, cm;

 — the volume of the sample after welding, cm, according to the formula

(4)

where 7,85 — density low carbon steel, g/cm;

 — the difference between the liquid levels in the manometer, cm;

 — idle speed correction device.

and determined for each specific device according to claim 3.2.3 of Annex 2,

in the calculation with a positive sign.

4.3. Hydrogen, referred to 100 g of weld metal , cm, is calculated by the formula

. (5)

4.4. Hydrogen, referred to 100 g of weld metal , cm, to calculate according to the formula

(6)

where is the arithmetic mean of the ratio of the mass of weld metal and weld metal in the cross section of the analyzed sample determined by the formula

, (7)

where is the number of sections.

4.5. The translation of the content of diffusion hydrogen of cm/100 g to the mass concentration of mnis performed by the formula

(8)

4.6. To test the same batch of welding material must be performed according to method 1 three parallel experience, according to the method of 2 — four parallel experience.

4.7. Measurement of the content of diffusion hydrogen in the deposited metal (weld metal) according to the method 1 is executed with a relative error of 7%, at confidence probability P=0.95 is in the range of measured values.

4.8. Measurement of the content of diffusion hydrogen in the deposited metal (weld metal) by the method 2 is executed with a relative error of ±5% in the range of measured values.

4.9. Control of accuracy of analysis results is carried out periodic calibration of devices for measuring the volume of evolved hydrogen gas in accordance with annexes 1 and 2.

4.10. The result of measurement of hydrogen content present in the following form

(9)

where is the arithmetic mean of parallel experiences;

 — relative standard deviation, determined in accordance with Annex 3;

is the number of parallel experiments.

ANNEX 1 (mandatory). THE DEFINITION OF THE TRANSFORMATION FUNCTION OF THE INSTRUMENT ABOUT 2144, 2456 TO MEASURE THE RATE OF DIFFUSION OF HYDROGEN BY THE METHOD 1

ANNEX 1
Mandatory

1. Measuring tools, accessories and materials necessary for calibration of the instrument:

calibration gas mixture (CGM) of argon and hydrogen according to normative-technical documentation with the volume fraction of hydrogen of 10 to 25%;

a syringe for a set of samples of PGS and typing in the camera (damn. 7);

Damn.7. The syringe and diagram of the set of samples of PGS with different volume

1 — the glass part of the syringe — burette-type 6−2-2 GOST 20292; 2 — head of the syringe;
3 — epoxy glue; 4 — the piston

Damn. 7

laboratory scales WLTP-200 in the NTD;

syringe («Record»), with a capacity of 1.5 ml according to normative-technical documentation;

needle injection 04х25 according to GOST 25377;

rubber tube 6−10 mm;

capacity glass 200−400 cm;

glycerin according to GOST 6259;

stopwatch SOS пр2б-2 in NTD;

barometer BAMM-1 in NTD;

thermometer according to GOST 28498−90;

the rectified spirit according to GOST 5962, at 20 °C =0,79 mg/mm.

2. The definition of the function transform () is to establish a relationship between the volume of hydrogen measured in cm(mm) and brought to 0 °C and pressure of 101.3 kPa (760 mm Hg.St.) and peak area . For this sample of PGS given volume, containing a known proportion of hydrogen, with a syringe injected into the chamber, then the carrier gas, the sample is washed away and transported into the chromatograph, where the detection of hydrogen. Measurement of peak area is performed by the integrator.

3. Calibration of the syringe for a set of samples of PGS and enter it into the chamber (syringe)

3.1. To enter to lock the plunger into the syringe and weigh the syringe with the needle five times for 30 min.

3.2. To combine the specified portion of the piston (arrow on the devil. 7) with the nearest division on the glass part of the syringe by pulling the plunger of the syringe, and determine the mass of the syringe with alcohol at this setting piston. To fill the syringe with alcohol to remove (if worn) with the needle head of the syringe, medical syringe to collect glass containers of ethyl alcohol, alcohol to enter separately into the syringe and removed the needle, and then put on the head of the syringe without allowing air bubbles within the filled volume. To remove drops of ethanol from the surface of the syringe and weigh the syringe.

3.3. Similar to weighing the syringe with alcohol to produce by sliding the piston of 0.2 ml, 0.4 ml, 0.6 ml, 0.8 ml, 1.0 ml relative to the position of the piston according to claim 3.2.

3.4. Every experience at PP.3.2 and 3.3 to perform the five times, re-filling a syringe and a needle with rubbing alcohol.

Weighing to carry on the scales WLTP-200 with accuracy of at least ±0.001 g.

3.5. To determine the arithmetic average of the dry weight of the syringe and the syringe with alcohol in each position of the piston — ,,, , .

3.6. To determine the capacity of the syringe (,,,,) cm, according to the formula

,

where room capacity (1, 2, 3, 4, 5);

 — arithmetic mean value of the mass of the syringe with alcohol;

 — the arithmetic average of the dry weight of the alcohol.

The obtained values are rounded to two significant digits.

4. The performance of experiments to determine the transformation function

4.1. Turn the unit on and set the operating parameters in accordance with sub.3.1.1, 3.1.2 of this standard, not including a furnace for heating the chamber. The device is ready to perform the experiments after 1 h.

4.2. With the help of the gear apply the calibration gas from a cylinder through a rubber tube into a beaker with a capacity of 200−400 cmfilled with glycerol to a height of 20−50 mm (Fig. 8). To set the flow rate of PGS 1−2 l/h and pass at least 1 h before conducting experiments.

Damn.8. Diagram of the device for a set of PGS in a syringe

1 — rubber tube; 2 — glass bowl; 3 — glycerin

Damn. 8

4.3. Invest in the chamber is degassed sample (a sample obtained in accordance with the requirements of the PP.2.1, 2.2, and 2.3.1 of this standard, excluding the storage of the sample in the coolant, and kept at room temperature for more than seven days). To close the camera lid with a rubber membrane, designed for injection of gas into the chamber with a syringe.

4.4. Rinse the sample chamber with the carrier gas within 30−40 °C. Repeat this operation three times, to monitor the removal of air from the chamber to reduce the peaks of oxygen and nitrogen of air on the potentiometer.

4.5. For a set of samples of PGS in the syringe should enter the piston all the way into the syringe to pierce the rubber tube through which the PGS is supplied smoothly to gain 200−300 mmPGS and gently push. Repeat this operation without removing the syringe needle from the puncture 3−4 times. Dial 100 mmPGS pre-planned more volume, gently remove the syringe.

4.6. No more than 15 with a sample of calibration gas to enter the inside of the reaction chamber. It is necessary to push the excess part of PGS, to pierce the diaphragm in the chamber cover 3 and to smoothly push out the sample of PGS in the cell. Without removing the syringe to gain 100−200 mmgas out of the camera and push the camera. This operation was repeated 3−4 times. To remove the syringe.

4.7. Rinse the cell with introduced the breakout of the PGS a carrier gas. The potentiometer will register a peak of the hydrogen, the integrator area.

4.8. In accordance with the PP.4.5, 4.6, 4.7 to measure the areas of peaks in the input samples PGS syringe volumes , , , , and register the corresponding area , , , , . Measurements for each value of the capacity to repeat five

time.

4.9. To measure the temperature of the environment with the error not more than ±0.5 °C and pressure environment with accuracy up to ±0.2 hPa.

5. The calculation of the transformation function for the detector

5.1. To determine the amount of hydrogen cm, reduced to 0 °C and 101.3 kPa, for each of the capacity of the syringe according to the formula

5.2. To determine the arithmetic mean of the peak area µv·s according to the formula

where is the room capacity;

 — room measurement.

5.3. Using the least squares method to determine the transformation function with the dimension cm/V·s according to the formula

.

The value obtained rounded to two significant digits.

ANNEX 2 (mandatory). DEVICE PREPARATION AND CALIBRATION OF THE INSTRUMENT TO MEASURE THE VOLUME DIFFUSION OF HYDROGEN ACCORDING TO THE METHOD 2

ANNEX 2
Mandatory

1. The device

1.1. The device (see the devil. 2) must be made of molybdenum glass. The recommended thickness of the device is about 2 mm.

1.2. The volume of the measuring flask and tubes from tap 3 to the capillary of the pressure gauge should be 150−160 cm.

1.3. The device only apply a vacuum taps.

1.4. The vacuum seal should be applied with grease Ramsay. If necessary, the grease must be removed with carbon tetrachloride according to GOST 20288, and ether.

1.5. The vacuum level should be measured thermorenovation a vacuum gauge.

1.6. The manometer of the device it is necessary to fill 2−3 cm ofvacuum oil-dibutyl phthalate according to GOST with 8,728. The pressure gauge shall be fitted with a scale with divisions 1 mm. scale Length should be 400−500 mm.

1.7. The vacuum in the device, you should create a backing pump, which should have a capacity of at least 50 DM/min.

2. Preparing the appliance for use

2.1. The inner surface of the device and the capillary pressure gauge shall be thoroughly washed with ethyl alcohol according to GOST 18300.

Consumption of ethyl alcohol shall not be less than 100 cmon four device.

2.2. The device should be checked for vacuum density in the following sequence:

create a vacuum, equal to 0.8−1.0 PA [(6−8)·10mm Hg.St.] with open valves 4, 3, 2 and 1 the valve is closed;

to sequentially close valves 2 and 3 and leave the device under vacuum for 5 days.

The device is considered a vacuum-tight, ready to work, if after aging for 5 days the pressure in the device when you open the tap 3 is not more than 13 PA (1·10mm Hg.St.).

2.3. The device shown in operating condition, must be kept under vacuum (valves 3, 1 and 2 closed, valve 4 open).

2.4. Preparing the appliance for use after a long (over 2 months) the break should be in accordance with the requirements of the PP.2.1, 2.2.

3. Calibration of the instrument

3.1. The volume of the measuring flask and tubes from tap 3 to the capillaries of the manometer should be measured by filling with distilled water with an accuracy of ±0.2 cm.

3.2. The definition of idle speed correction device

3.2.1. The device shown in operating condition must be defined for a single amendment. Measurement blank corrections should be carried out by exposure of the device under vacuum for 5 hours inside a device ballast with a volume of 20−25 cmof glass or stainless steel, simulating the sample.

3.2.2. The volume of ballast before laying the instrument should be thoroughly washed with ethyl alcohol according to GOST 18300 and vacuum in the device during 5 h at a negative pressure equal to 0.8−1.0 PA [(6−8)·10mm Hg.St.], taps 2, 4, 3 open, valve 1 closed, the roughing pump should run continuously.

3.2.3. After pumping the device for 5 h, the device should prepare to measure the idle of the amendment:

close valve 2, open valve 1 (valves 4 and 3 are open) and stand in this state for 60 seconds.

close valve 1, open valve 2 (taps 4 and 3 are open). Evacuate the device within 60 seconds.

to close the valves 4, 3, 2 successively;

to sustain the unit for up to 5 days, to register a change of pressure which has a negative value.

APPENDIX 3 (obligatory). THE DEFINITION OF THE STANDARD DEVIATION OF THE MEASUREMENT RESULT THE LEVEL OF HYDROGEN WHEN INSPECTING WELDED MATERIAL (METHODS 1 AND 2)

APPENDIX 3
Mandatory

1. For the existing technology of production of welding material to perform concurrent measurements of the level of hydrogen.

2. Determine the magnitude of the standard deviation () by the formula

where is the number of measurements;

 — the result of an individual measurement;

 — the arithmetic mean of the measurement result determined by the formula

3. To determine the value of the relative deviation () of measurement in percentage according to the formula

The value obtained rounded to two significant digits.

4. If you change the technology of production of welding material to determine the amount of relative deviation of measurement of hydrogen content in accordance with the PP.2, 3.