GOST 19040-81

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  ГОСТ 19040-81

GOST 19040−81 Pipe metal. Method of tensile tests at elevated temperatures (Change No. 1)

GOST 19040−81

Group В69

INTERSTATE STANDARD

PIPE METAL

Method of tensile tests at elevated temperatures

Metal tubes. Method of tension test at high temperatures

ISS 23.040.10
AXTU 1709

Date of introduction 1983−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of ferrous metallurgy of the USSR

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 15.06.81 N 2941

3. REPLACE GOST 19040−73

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken on the Protocol, the Interstate Council for standardization, Metrology and certification (ICS 2−93)

6. EDITION (September 2010) with amendment No. 1, approved in October 1987 (ICS 1−88)

This standard establishes the method of static tensile testing of metallic seamless welded pipe with a wall thickness of at least 0.2 mm for the characterization of mechanical properties at temperatures above 35 to 1200 °C:

— yield point (physical);

— yield strength (conditional);

— temporary resistance;

— the elongation after rupture;

the relative constriction after rupture.

Terms and definitions — according to GOST 10006, GOST 9651.

(Changed edition, Rev. N 1).

1. SAMPLING METHODS

1.1. Longitudinal samples produce three forms.

1.1.1. A section of pipe of total cross section without restriction of the outer diameter (Fig.1, 2).

Damn.1

Damn.2

1.1.2. Bands of pipes with wall thickness up to 12.0 mm, cut along the axis of the tube (segment) with width of the working part specified in the table.1.

Table 1

mm

Segmented samples are made without heads (Fig.3) and heads (damn.4 and 5).

Damn.3

Damn.4

Damn.5

1.1.3. A cylindrical sample (Fig.6).

Damn.6

Cylindrical specimens taken from pipes with a wall thickness of 8.0 mm and more. The diameter of the working part of the cylindrical sample set:

Dimensions, mm

5.0 mm — wall thickness of more than 7.0 to 12.0 mm, inclusive;

8.0 mm — wall thickness in excess of 12.0 to 16.0 mm, inclusive;

10.0 mm — wall thickness in excess of 16.0 mm. wall Thickness nominal. Sample requirements in accordance with GOST 9651.

Notes:

1. By agreement with the consumer allowed to produce samples with a diameter of 3.0 mm and the wall thickness from 5.0 to 7.0 mm inclusive.

2. On the heads of specimens with symmetrical thread allowed the flats due to the size of the wall of the pipe.

(Changed edition, Rev. N 1).

1.1.4. If there are indications in the normative-technical documentation for steel allowed the use of proportional samples of other types and sizes in accordance with GOST 1497.

(Added, Rev. N 1).

1.2. Longitudinal cylindrical samples and samples in the form of strips of welded pipes are manufactured from billets cut from a location at an angle of 90° relative to the position of the weld.

1.3. Form of the applicable sample is specified in the normative-technical documentation on the pipe. In the absence of such instructions, the form of the sample set by the manufacturer.

In case of disagreement in the assessment of the quality of pipes according to test results segmented samples used samples in the form of a segment head.

1.4. The initial gauge length of the specimen () — GOST 9651.

If the result of calculating the estimated length of samples capillary or thin-walled pipes will be less than 20 mm, taken to be 20 mm.

1.5. The initial gauge length of the specimen is set with an accuracy of up to 1% of its value and is limited to shallow cores or in other ways that do not cause destruction on a road marking lines.

The initial calculated length is rounded up: for your samples to the nearest multiple of 5; for long samples up to the nearest multiple of 10.

1.6. Working length of samples () should be:

— for pipes — ;

for segments with a wall thickness less than 3.0 mm from to ;

for segments with a thickness of 3.0 mm or more from to the ;

— for cylindrical specimens — from to .

In cases of disagreement in assessing the quality of tubes working length of samples should be the greatest.

For the samples given on features.1, 2 and 3, the total length of samples (), depending on the size of the working space of the heating device used must be .

(Changed edition, Rev. N 1).

1.7. Limit deviations for dimensions of the working part of the specimens shall be as specified in table.2.

Table 2

mm

1.8. Place tenderloin pieces and the orientation of the longitudinal axis are specified in the normative-technical documentation for pipe.

1.9. Longitudinal samples in the form of tubes and bands should maintain the surface layers untouched. Burrs on the edges of the samples should be removed easy zapilovku.

1.10. Transverse samples are made of cylindrical proportional cut from the pipe, perpendicular to its longitudinal axis with the dimensions listed in table.3.

Table 3

mm

Note. Samples with a diameter of 3 mm are made by agreement between manufacturer and consumer.

1.11. Pipe with a diameter of 426 mm and over are allowed to test according to GOST 9651 flat on the transverse samples.

1.12. When testing samples in the form of a strip is allowed to straighten the ends for clamping grips of the machine. Straightening the ends is carried out outside of the working length of the specimen.

1.13. Samples it is recommended to process on machine tools. The surface roughness of the cylindrical specimen should not be more than 0.63 microns, segment  — not more than 20 µm according to GOST 2789.

1.14. Measurement of flanges and segments before the test is carried out according to GOST 10006, cylindrical samples according to GOST 9651.

1.15. (Deleted, Rev. N 1).

1.16. Labeling of samples is carried out outside the working part.

2. EQUIPMENT

2.1. Test machines and test conditions should correspond to requirements of GOST 10006.

2.2. The heating device must provide a uniform heating of the sample by its working part to a predetermined test temperature and maintain this temperature taking into account permissible deviations specified in paragraph 3.5 throughout the test.

2.3. Requirements for regulating and measuring devices, primary thermoelectric converters (thermocouples) according to GOST 9651.

(Changed edition, Rev. N 1).

3. TESTING

3.1. Testing of samples is carried out according to GOST 10006.

Samples in the form of segments and nozzles experience to a temperature of 900 °C. the test procedure is segmented samples with the heads (hell.5) is given in Appendix 1.

3.2. To measure the temperature of the test thermocouple samples set:

— when 100 mm — two thermocouples (at the boundaries of the estimated length of the specimen).

It is allowed to install one thermocouple in the middle of the estimated length when the length calculated of the sample to 50 mm When there is disagreement in the assessment of the quality of the pipes temperature control for these samples is carried out by two thermocouples;

— when 100 mm or three of the thermocouples (on the borders and in the middle of the estimated length of the specimen).

3.3. The working end of the primary thermocouple (thermocouple) must have reliable contact with the sample surface and be isolated from the radiant heating.

Permitted to measure the sample temperature thermocouple touch subject to compliance with the limit deviations of the temperature of the sample to the requirements of section 3.5.

3.4. The heating time to a predetermined test temperature and soaking time at this temperature point in the normative-technical documentation for pipe.

In the absence of instruction, the duration of heating to the test temperature shall be not more than 1 h, holding time at this temperature is 20−30 min.

Allowed to apply pre-heating of the samples to the desired temperature in the auxiliary furnace with the subsequent transfer them to the test in the furnace, installed directly on the machine.

The exposure time after the transfer at a given temperature should be equivalent to the time spent on migration:

— at the time of transfer 1 with the holding time shall be not less than 1 min;

— at the time of transfer of 2 — 2 min etc.

Samples of welded austenitic pipes (wall thickness 0,5 mm and less) shall be tested in furnaces that are installed on the machine, i.e. without pre-heating. The duration of exposure when reaching the preset temperature should be at least 5 min.

3.5. Maximum deviations from the established test temperature at the measurement points along the length of the design portion of the sample without taking into account the errors of temperature measurement caused by the thermoelectric Converter and the secondary devices must not exceed:

The differences in the assessment of the quality of the metal limits the temperature deviation from the set when tested at any point the calculated length of a specimen should be below 2 °C.

3.6. Allowed to conduct tests in a protective atmosphere or in vacuum, which is noted in the test report.

3.7. The test results do not take into account:

— at break of the sample cores or beyond the estimated length at break of the specimen in the clamps of the testing machine or production defects, if any mechanical feature its size does not meet the requirements;

— the formation of two or more pins and two or more of the tear;

— when rupture of the tube spiral, if the calculated length is formed of two or more of the spiral loop.

In these cases, the tensile test should be repeated on Brasco taken from the same melting or party.

The number of samples must match the number of invalid tests.

3.3−3.7. (Changed edition, Rev. N 1).

4. PROCESSING OF THE RESULTS

4.1. The measurement of specimens after test and calculation results carried out according to GOST 10006, GOST 9651.

4.2. To specify the test temperature to the determined marking characteristics of the mechanical properties add the corresponding numeric index.

Example: , , , — the yield strength conditional with the tolerance on the amount of residual deformation of 0.2%, tensile strength, elongation after rupture of the sample , the relative narrowing of the cross section after rupture, defined at test temperature 450 °C.

(Changed edition, Rev. N 1).

ANNEX 1 (reference). The scheme of the test samples with segment heads

ANNEX 1*
Reference

________________
* ANNEX 2. (Deleted, Rev. N 1).