GOST 21729-76

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  ГОСТ 21729-76

GOST 21729−76 structural Pipes, cold and warm from carbon and alloy steels. Specifications (with Amendments No. 1, 2)

GOST 21729−76

Group B62

INTERSTATE STANDARD

STRUCTURAL PIPES, COLD-DRAWN
AND WARM CARBON
AND ALLOY STEELS

Specifications

Cold-deformed and hot-deformed structural carbon
and alloyed steel tubes. Specifications

ISS 23.040.10
VCG OKP 13 4−40 0 135 100

Date of introduction 1978−01−01

INFORMATION DATA

1. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 22.04.76 N 893

2. INTRODUCED FOR THE FIRST TIME

3. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

4. The expiration time limit is removed by the Resolution of Gosstandart from 18.08.92 N 984

5. EDITION with Amendments No. 1, 2 approved in June 1980 and June 1987 (IUS 9−80, 10−87)


This standard applies to seamless cold-drawn and cold-rolled toplokatie tubes of carbon and alloy steels.

Indicators of technical level established by this standard are intended for the highest quality.

(Changed edition, Rev. N 2).

1. ASSORTMENT

1.1. The size, curvature and maximum deflection of pipe shall conform to the requirements of GOST and GOST 8734 9567. At the customer’s request pipes are made from a unilateral marginal deviations.

The value of unilateral marginal deviations shall not exceed the amount of the deviation according to GOST and GOST 8734 9567.

Examples of symbols:

Pipe an outer diameter of 56 mm, a wall thickness of 2.0 mm, a length that is a multiple of 1250 mm, regular accuracy of manufacturing, of steel grade 30HGSA, group A:

Pipe A-56х2х1250 cu. — 30KHGSA GOST 21729−76

The same manufacturing high precision in outside diameter, lengths of 6000 mm:

Pipe A-56пх2х6000 — 30KHGSA GOST 21729−76

Same internal diameter 30 mm, wall thickness of 3.0 mm, B group, regular accuracy of manufacturing, off-gage length of steel grade 30HGSA vacuum-arc remelting:

Pipe B-VN 30x3 — 30KHGSA-VD GOST 21729−76

2. TECHNICAL REQUIREMENTS

2.1. Pipe shall be manufactured from steel grades: 20A, 45, 10G2, 38KHA, 30KHGSA, 30KHGSN2A (30ХГСНА), 30KHGSNMA and 38H2MYUA, ordinary melted or vacuum-arc method. Method of smelting is specified in the order. The pipes from steel grades 12KHN3A and 12KH2NVFA (EI 712) are made of metal conventional smelting.

2.2. Chemical composition of steel must comply with:

carbon grade 45 — GOST 1050;

alloy brands 38KHA, 30KHGSA, 30KHGSN2A, 12KHN3A, 38H2MYUA, GOST 4543;

alloy brand 12KH2NVFA (EI 712) — GOST 11268;

grades of alloy steel 30KHGSA-VD, 30KHGSN2A-VD, 30KHGSNMA-VD produced, net charge — GOST 4543 and table.1, respectively, except the sulfur content shall not exceed 0,011% phosphorus, which should not exceed 0,015%, and the total content of sulfur and phosphorus, which shall not exceed 0,022%. For steel grades 30KHGSN2A-30KHGSNMA VD and-VD, the manganese content should be 1.0% to 1.2% with extreme deviation %, steel grades 20A, 10G2, 30KHGSNMA chemical composition must comply with the specified in table.1.

Table 1

Note. By agreement with consumer it is allowed manufacture of pipes of steel grade 20A with a carbon content of 0.16 percent — 0.24 percent.

2.1, 2.2. (Changed edition, Rev. N 1).

2.2.1. The content of residual copper should not be more than 0.20% and in the metal, smelted scrap-process or copper ore, permitted residual content of copper not more than 0.25%.

2.3. Limit deviations of chemical composition for all carbon steel — GOST 1050, for alloyed steel — GOST 4543, GOST 11268 for steel grade 12KH2NVFA.

2.4. Depending on the quality requirements of the surface of the pipe are divided into groups A and B.

To the group And include pipes according to GOST and GOST 8734 9567 with the dimensions listed in table.1A.

Table 1A

Group B includes the rest of the pipe sizes in the range of the standards.

(Changed edition, Rev. N 1).

2.5. The outer and inner surfaces of the tubes of group A must be smooth and clean, without dross, captivity, cracks, wooloowin, cavities, tears, laps, dents and Pererva.

Corrections of defects under the condition that the thickness of the wall in places Stripping will not go beyond the minimum size.

Allowed grinding of the outer surface of the pipe along the entire length, provided that the quality of sanded surface shall be 20 microns (purity class not less than 5) churchyard 2789.

2.6. On the outer and inner surfaces of the tubes of group A are allowed without Stripping: rabiza, color tint, roughness, specific risks, shallow dents, if their depth does not exceed half the minus tolerances for wall thickness and does not display wall thickness beyond the minimum size.

Allowed light sooty coating and a thin oxide film that do not impede the inspection of pipes and amenable to removal by Stripping sandpaper grit 16−20 5009 churchyard, and traces of changes, not deducing the diameter of the pipes beyond a minimum size.

2.7. On the outer and inner surfaces of the tubes of group B are allowed: rabiza, needlewoman scale, do not interfere with the inspection of risks, some dents and signs of repair defects, if they do not take wall thickness beyond the minimum size.

On the outer and inner surfaces of the tubes of group B should not be captured, pinches, cracks, wooloowin, rips, dings and Pererva.

2.7.1. In the manufacture of the group And of thick-walled pipes and isobutylester requirements to the surface quality set by agreement with the consumer.

(Changed edition, Rev. N 2).

2.8. The pipe ends should be square-cut and cleaned of burrs.

2.9. Pipe is supplied in heat treated condition. The pipe group And is subjected to heat treatment in gas cylinders or stoves basicsliderui atmosphere.

Notes:

1. Tubes in which the ratio of outer diameter to wall thickness equal to 50 and more are supplied without heat treatment and mechanical properties control.

2. Pipe with a diameter of 22.0 mm and a wall thickness of about 2.2−6.0 mm belong to the group B, but subjected to balloon to annealing or heat treatment in furnaces with basicsliderui atmosphere.
(Changed edition, Rev. N 1).

2.10. The mechanical properties of the pipes in thermally treated condition shall be as specified in table.2.

Table 2

(Changed edition, Rev. N 2).

2.11. Tubes shall withstand hydraulic pressure (a) in accordance with the requirements of GOST 3845. The value shall be equal to 40% strength for a given steel grade.

The ability of pipe to withstand hydraulic pressure is provided by the production technology.

At the customer’s request pipes are subjected to hydraulic pressure test in accordance with the requirements of GOST 3845, but not more than 20 MPa (200 kgf/cm).

By agreement with the consumer allowed to test the pipes under pressure higher than 200 kgf/cm(20 MPa).

2.12. On demand of the consumer steel pipe 20A, an outer diameter of 120 mm and a wall thickness of not more than 8 mm shall be tested on the hand before the diameter increases by 10%.

2.13. The pipes from steel grades 30KHGSA, 12KH2NVFA (EI 712), 30KHGSN2A (30ХГСНА), 30KHGSNMA, 38KHA, 38H2MYUA, 12KHN3A check for the presence of surface decarburization.

Pipe group A value bezoperatsionnogo layer of pure ferrite is allowed to a depth of not more than 2%, group B — not more than 3% of the wall thickness on each side.

2.11−2.13. (Changed edition, Rev. N 1, 2).

2.14. The macrostructure of the pipes must not have delamination, cracks, and nonmetallic inclusions.

2.15. The quality of the metal of alloyed steel grades for foloowing determined on the finished parts and shall conform to the standards given in table.3.

Table 3

Notes:

1. For every subsequent 200 cmcontrolled surface of parts made from metal smelting open, and 500 cmcontrolled surfaces, made of metal vacuum-arc remelting, the area of which exceeds 1000 cm, additionally allowed no more than one volosovichi length up to 5 mm.

2. Volosovichi located in one line, are considered continuous if the interval between them is less than 2 mm.

3. On the details area of 200 cmor more, made of an open metal smelting, are not permitted the accumulation of more than five wooloowin on separate sites of a surface area of 10 cm, the metal parts of the vacuum-arc remelting — no more than three wooloowin on separate sites of a surface area of 10 cm.

4. Standards at the point of inclusion with a length of less than 0.5 mm, if necessary, established by agreement between manufacturer and consumer.

(Changed edition, Rev. N 1, 2).

2.16. At the customer’s request pipes are subjected to non-destructive types of quality control.

(Changed edition, Rev. N 2).

3. ACCEPTANCE RULES

3.1. The party should consist of pipes of the same nominal diameter, same wall thickness, the same steel grade and smelting and one mode of heat treatment and be accompanied by a document of quality in accordance with GOST 10692.

The number of pipes in the lot shall be not more than:

400 PCs — for pipes with a diameter less than 76 mm and wall thickness not exceeding 2.5 mm;

200 pieces for pipes of other diameters.

(Changed edition, Rev. N 2).

3.2. Chemical composition of steel pipes take the document about the quality of the manufacturer of the workpiece. The carbon content is controlled on the finished pipes.

The differences in the assessment of the quality of the chemical composition to check take two pipes from the party.

3.3. To control the quality from batches of finished tubes are taken:

two tubes for chemical analysis of carbon content;

two tubes — tensile and distribution;

two pipes — to control the macrostructure;

2% of the pipes, but not less than two pipe — to decarburization.

3.2, 3.3. (Changed edition, Rev. N 1).

3.4. Checking the external and internal surfaces and sizes, as well as a test of the hydraulic pressure is subjected to each pipe of the party.

(Changed edition, Rev. N 1, 2).

3.5. With the continuous quality control of pipes non-destructive methods the manufacturer is allowed not to conduct hydraulic tests.

3.6. The manufacturer carries out control of the macrostructure of pipe with a wall thickness of 12 mm or more.

(Changed edition, Rev. N 1).

3.7. If unsatisfactory test results of at least one of the indicators it is carried out re-tests on twice the number of samples taken from the same batch of tubes.

The results of repeated tests apply to the entire party.

4. TEST METHODS

4.1. For testing of mechanical properties, chemical composition, tests for the distribution and control of the macrostructure of each selected for the test pipe cut off one sample.

4.2. Check the external and internal surfaces and dimensions of the pipes involves visual inspection and measurement.

The length of the pipe measure tape according to GOST 7502. The curvature of the pipe is measured with a straight edge according to GOST 8026 probe on the other 2−034−225.

Diameter and ovality check with a micrometer smooth MK-type according to GOST 6507, staples sheet according to GOST 18360, 18365 GOST.

Pipes with a ratio of outer diameter to thickness equal to 40 or more perimeter check gauges-rings according to GOST 24851. Allowed check with a micrometer.

The wall thickness of the pipe is controlled by micrometer type MT according to GOST 6507.

Allowed to control the surface quality by nondestructive methods churchyard 17410.

(Changed edition, Rev. N 2).

4.3. Pipes are subject to control by steeloscope, spark method or other method for determining the steel grade.

(Changed edition, Rev. N 1).

4.4. Chemical analysis of steel pipe is carried out according to GOST 22536.0 to GOST 12344−12365 GOST, GOST 28473. Samples for determining the chemical composition of the steel pipes are selected according to GOST 7565.

(Changed edition, Rev. N 2).

4.5. The tensile test shall be carried out according to GOST 10006 on the longitudinal short samples.

Test speed up to yield strength should be not more than 10 mm/min, yield point is not more than 40 mm/min.

Allowed to control the mechanical properties of pipes non-destructive methods.

In case of disagreement in the evaluation of test results carried out according to GOST 10006.

(Changed edition, Rev. N 1, 2).

4.6. Hydraulic testing of pipes must be carried out according to GOST 3845 with aging pipes under pressure of not less than 10 s.

4.7. Test decarbonization should be carried out according to GOST 1763.

4.8. Test pipes for the distribution is carried out according to GOST 8694 on the mandrel with a taper of 1:10.

4.9. Control of macrostructure is carried out on the etched cross ring samples with subsequent visual inspection. Preparing and etching samples according to GOST 10243.

(Changed edition, Rev. N 1).

4.10. The control metal on volosovichi carried out according to the technical documentation.

(Changed edition, Rev. N 1, 2).

4.11. The quality control of pipes non-destructive methods the methodology of control, the amount and valid for the rule of defects are established by normative-technical documentation.

(Changed edition, Rev. N 2).

5. LABELING, PACKAGING AND TRANSPORTATION

5.1. Marking, packing, transport and documentation — according to GOST 10692 with the following additions.

5.1.1. Marking pipes is made by coating on one of the pipe ends annular color band of width not less than 30 mm:

for pipes of steel grade 45 red color;

for pipes of steel grade 20A — white + blue;

for pipes of steel grade 30HGSA — green + yellow;

for pipes of steel grade 10G2 blue;

for pipes of steel grade 12KH2NVFA (EI 712) — yellow + red;

for pipes of steel grade 30KHGSN2A (30ХГСНА) — green + blue;

for pipes of steel grade 30KHGSNMA green + blue;

for pipes of steel grade 38KHA — green + red colors;

for pipes of steel grade 12KHN3A — yellow + black;

for pipes of steel grade 38H2MYUA — aluminum color.

Pipe steel produced by vacuum arc method, additionally marked with the letters VD, for example: 30KHGSA-VD.

(Changed edition, Rev. N 1).