GOST 23870-79

• gost-23870-79.pdf (277.00 KiB)
  ГОСТ 23870-79

GOST 23870−79 Weldability of steels. A method of assessing the influence of fusion welding on the base metal

GOST 23870−79

Group B09

STATE STANDARD OF THE USSR

WELDABILITY OF STEELS

A method of assessing the influence of fusion welding on the base metal

Weldability of steels.
Test method for evalution of fusion welding effect on parent metal

Valid from 01.01.81
prior to 01.01.86*
______________________________
* Expiration removed
Protocol 5−94 N Interstate Council
for standardization, Metrology and certification.
(IUS N 11−12 1994). -
Note the manufacturer’s database.

Promulgated by the Decree of the USSR State Committee for standards, dated October 30, 1979 N 4140

REPRINTING. October 1981


This standard specifies a method of assessing the influence of fusion welding on the base metal in the HAZ, in which the thermal influence on the metal is carried out without welding.

The test results set based on the temporary resistance, relative elongation after rupture, the relative narrowing after the break, long-term strength, toughness, hardness, grain size and content of the structural components from the cooling rate.

The standard applies to research and experimental work.

The terms and definitions given in the reference Appendix 1.

1. THE SHAPE, SIZE AND SAMPLES

1.1. Samples must be made of metal taken from the head portion of the ingot from the side adjacent to the profitable part of it, or rolled (sheet, profile, etc.).

1.2. The shape and dimensions of the working part of the samples must comply with those in hell.1−3 and types I, VIII and XI according to GOST 6996−66.

Parameter Ra of the roughness of surfaces of the working part of the samples by the devil.1−3 should not exceed 1,25 µm.

1.3. Samples for God.2 and types VIII and XI according to GOST 6996−66 should be made of the samples by the devil.1, subjected to thermal effects in the setup to simulate the thermal effects of welding.

The samples for God.2 should be restricted to marks the initial estimated length of 6 mm in a way that ensures their preservation after the test.

Samples of type I according to GOST 6996−66 should be made of the samples by the devil.3, subjected to thermal effects in the setup to simulate the thermal effects of welding.

In the manufacture of the samples by the devil.2 and of types I, VIII and XI according to GOST 6996−66 should not be offset transverse and longitudinal axes of symmetry from its initial position by more than 0.2 mm.

1.4. The form and sizes of heads for samples features.1−3 and the transitional part from the heads to the working part are determined by the adopted method of mounting the specimen in the grips of the testing machine.

The mate of the head of the sample with its working parts must be smooth.

Damn.1−3, the Shape and size of heads samples

Damn.1

Damn.2

Damn.3

1.5. The sample surface should be smooth, free from oxide films burrs, scratches and damage.

1.6. When testing metal cold rolled with the thickness of 3 mm or less should be applied to the samples by the devil.1 and 2, and types VIII and XI according to GOST 6996−66 thickness equal to the thickness of the hire, maintaining the surface roughness corresponding to the rolled delivery condition.

Samples of different shapes and sizes give comparable test results.

1.7. For samples in hell.1−3 flatness of all surfaces and non-parallelism of opposite surfaces of the working part shall not exceed 0.05 mm in length 60 mm.

1.8. The marking must be applied outside of the working part of the specimen so that it remained after the test.

2. APPARATUS, MATERIALS AND REAGENTS

2.1. Setting to simulate the heat effects of welding should ensure:

adjustable heating and cooling of the test sample according to the thermal cycles of the HAZ. The range and step of the regulation shall be as given in the table.

The control deviation of the temperature should not exceed 1%, heating rates and cooling — 5%.

During heating and cooling of the test sample of tensile deformation (compression) must not exceed 2%, the camber — 0.01 mm, angle of twist — 1;

uniform heating of the middle section of the sample. The difference in temperatures in this area should not exceed 2% of the highest in the given time;

the temperature at the boundaries of the working part of the specimen throughout the testing process is not higher than 50 °C;

continuous measurement and recording of the temperature of the middle of the working part of the sample, time of heating and cooling. Measurement error and the record should not exceed 0.5%;

protect the sample from oxidation in a manner not affecting the properties of the material under test.

Structural diagram of an apparatus to simulate the heat effects of welding is given in recommended Appendix 2.

2.2. The rest of equipment, materials and reagents must meet:

for testing static stretching — GOST 1497−73 or GOST 11150−75 or GOST 9651−73;

for long-term strength testing — GOST 10145−62;

for testing the impact strength GOST 9454−78;

for measuring the hardness — GOST 2999−75 or GOST 9013−59;

to identify and determine the grain — GOST 5639−65;

to determine the content of the structural components — GOST 8233−56.

3. TESTING

3.1. Tests should be subjected to the samples by the devil.1. The number of samples should be:

for the determination of temporary resistance, relative elongation after rupture, the relative narrowing after the break not less than three;

to determine the long-term strength — not less than three;

to determine the impact toughness of at least three;

for measuring the hardness of one or more;

for the detection and determination of grain size is one or more;

to determine the content of structural components is one or more.

For the determination of temporary resistance, relative elongation after rupture and the relative constriction after rupture is allowed to use the samples for God.3.

3.2. Test samples should be heated and cooled in the setup to simulate the heat effects of welding in the following thermal cycles of the HAZ: the highest heating temperature should be equal to 0,9±0,02 of the melting temperature, the average in the range of 700−900 °C, the heating rate of 250±12,5 °C/s, the average in the range of 600−500 °C cooling rate -0,1±0,01; 1,0±0,1; 10±1,0; 100±10 and 600±60 °C/s.

Permitted to conduct additional tests at other speeds heating and cooling.

3.3. For the determination of temporary resistance, relative elongation after rupture and the relative constriction after rupture of the samples by the devil.2 or type I according to GOST 6996−66 should be tested according to GOST 1497−73 or GOST 11150−65 or GOST 9551−61.

3.4. To determine the long-term strength of the samples by the devil.2 should be tested according to GOST 10145−62.

3.5. To determine impact viscosity of the samples of a type VIII or XI according to GOST 6996−66 should be tested according to GOST 9454−78.

3.6. Hardness, grain size and content of the structural components should be determined in the middle part of the samples for God.1.

Hardness should be determined according to GOST 2999−75 or GOST 9013−59, the amount of grain according to GOST 5639−65, the content of structural components according to GOST 8233−56.

4. PROCESSING OF THE RESULTS

4.1. Calculate the values should be:

temporary resistance, relative elongation after rupture, the relative narrowing after a break up — according to GOST 1497−73 or GOST 11150−75 or GOST 9651−73;

the long-term strength — according to GOST 10145−62;

impact strength — according to GOST 9454−78;

hardness — GOST 2999−75 or GOST 9013−59;

the value of grain according to GOST 5639−65;

the contents of the structural elements — according to GOST 8233−56.

4.2. For values of temporary resistance, relative elongation after rupture, the relative narrowing after the break, long-term strength and toughness at a given average in the range of 600−500°C cooling rate should take the arithmetic mean of the results of relevant tests obtained at the same cooling rate.

4.3. Tests are considered invalid in cases specified 1497−73 GOST, GOST 11150−75, 9651−73 GOST, GOST and GOST 10145−62 9454−78.

In such cases the test should be repeated on samples made from the same melting or party. The number of samples for re-testing should not be less than the number of invalid test results.

4.4. According to test results, you should build a schedule based on the received parameters from the average in the range of 600−500 °C cooling rate in the coordinates: ordinate — values to a uniform scale, abcissa — the average cooling rate on a logarithmic scale.

If the average in the range of 700−900 °C, the heating rate is different from that adopted in this standard, it should be shown on the chart.

An example plot is given in the recommended attachment 3.

ANNEX 1 (reference). TERMS AND DEFINITIONS

ANNEX 1
Reference

1. Koloshina area-the area of the HAZ, heated above the temperature of beginning of intensive growth of grain.

2. The average area of sample — area of the working part of the specimen, with a length of from 12 to 20 mm, located symmetrically relative to the transverse axis of the sample.

APPENDIX 2 (recommended). STRUCTURAL DIAGRAM OF AN APPARATUS TO SIMULATE THE THERMAL EFFECTS OF WELDING

ANNEX 2
Recommended

Appendix 3 (recommended). The graphs

Appendix 3
Recommended

Graph of temporary resistance, relative elongation after rupture, the relative constriction after rupture, hardness, toughness and points of grain at room temperature on the speed of cooling for steel 35

Graph of temporary resistance , relative elongation after rupture , the relative constriction after rupture , hardness , toughness and points of grain at room temperature on the speed of cooling for steel 35

A graph of the percentage of structural components at room temperature (f — ferrite, P-pearlite, B — beynit, M — martensite) from the cooling rate for steel 35