GOST 9941-81

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  ГОСТ 9941-81

The Tubes GOST 9941−81 seamless cold — and warm from corrosion-resistant steel. Technical specifications (with Changes 1−5 N, adjusted)

GOST 9941−81

Group В62

INTERSTATE STANDARD

TUBES SEAMLESS COLD — AND WARM
FROM CORROSION-RESISTANT STEEL

Specifications

Seamless cold — and warm-deformed tubes of corrosion-resistant steel.
Specifications

ISS 23.040.10
OKP 13 6700

Date of introduction 1983−01−01

INFORMATION DATA

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

DEVELOPERS

V. P. Sokurenko (supervisor), L. G. Kovalev, V. M. Rovenskaya, G. A. Gorovenko

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 19.11.81 N 5037

Change No. 5 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 18 dated 18.10.2000)

The adoption voted:

3. REPLACE GOST 9941−72

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)

6. EDITION Changes N 1, 2, 3, 4, 5, approved in August 1983, June 1987, June 1988, August 1988, June 2001 (IUS 11−83, 11−87, 9−88, 12−88, 9−2001), Amendment (IUS N 6−2002)


AMENDED, published in the IUS N 9, 2011

An amendment made by the manufacturer of the database

This standard applies to seamless cold — and warm-deformed tubes of corrosion-resistant steel for General purposes.

(Changed edition, Rev. N 2).

1. ASSORTMENT

1.1. Pipe manufactured by outside diameter and wall thickness dimensions that are listed in the table.1.

Table 1

Notes:

1. Requirements for thin-walled pipes with the ratio of 40 in terms of technical characteristics and extreme deviations in the sizes established by the normative-technical documentation.

2. The pipes from steel grades 12X17, 08KH17T, 15KH25T produce an outer diameter of not less than 21 mm; of the alloy 06HN28MDT — outer diameter 14−85 mm and a wall thickness of 1−5 mm.

3. The mass of one meter length is calculated in kilograms by the formula

,

where is the nominal outside diameter, mm;

 — nominal wall thickness, mm;

 — density of metal, g/cm, depending on the steel grade in accordance with table.3.

1.2. The length of the pipe manufacture:

measuring length within off-gage, but not less than indicated in the table.1 with maximum deviation in length +15 mm, in agreement with the consumer allowed the manufacture of pipes measuring in length less than indicated in the table.1;

dimensional length, measuring, with an allowance for each cut to 5 mm and a maximum deviation over the entire length +15 mm Minimum fold length of 300 mm;

random length, with wall thickness up to 0.5 mm, from 0.75 m to the value specified in table.1;

with a wall thickness of from 0.5 to 1 mm, from 1.0 m to the value specified in table.1;

with a wall thickness of 1.0 mm and more — from 1,5 to 12,5 m;

by agreement with the consumer allowed production of tubes with a length of over 12.5 m.

In coordination with the consumer pipes up to 25 mm are made with a length of 16 m.

(Changed edition, Rev. N 2).

1.3. The party of pipes of random length may be no more than 6% of the pipes length:

from 0.5 to 0.75 m — wall thickness up to 0.5 mm;

from 0.75 to 1 m with a wall thickness of from 0.5 to 1 mm;

from 0.75 to 1.5 m with a wall thickness of 1 mm or more.

(Changed edition, Rev. N 1).

1.4. Limit deviations for outer diameter and wall thickness of pipes shall not exceed that specified in table.2.

Table 2

Extension table 2

At the customer’s request pipes are made with combined limit deviation for diameter and wall thickness.

1.5. At the customer’s request pipes are made at the inner diameter and wall thickness. Tolerances for the inner diameter established by agreement between manufacturer and consumer.

1.6. The ovality of pipes shall display a pipe diameter limit deviations for outer diameter.

1.7. The pipe curvature of any segment with a length of 1 m must not exceed:

1 mm — for pipes with a diameter of 5 mm and over with wall thickness of 0.5 mm or more;

2 mm — for pipes with diameter more than 15 mm, with wall thickness less than 0.5 mm.

For pipe diameters less than 15 mm, with wall thickness less than 0.5 mm the norm of the curvature is not regulated, these pipes must not have sharp bends.

1.8. The pipe ends should be square-cut and cleaned of burrs; allowed the formation of the chamfer and roughness when they are deleted. At the request of the consumer at the ends of the pipes with wall thickness more than 5 mm should be beveled for welding.

Examples of symbols

Pipe outer diameter 25 mm, wall thickness 2 mm, regular accuracy of manufacturing, off-gage length of steel 12KH18N10T:

Pipe 25x2 — 12X18H10T GOST 9941−81

The same, high precision manufacturing (in), lengths of multiples of (cu) 1000 mm:

Pipe 25вх2вх1000кр — 12X18H10T GOST 9941−81

The same, regular accuracy of manufacturing, measuring length (m) 3000 mm:

Pipe 25х2х3000 m — 12X18H10T GOST 9941−81

The same high manufacturing precision (p), length (m) 3000 mm:

Pipe 25пх2пх3000 m — 12X18H10T GOST 9941−81

The same, high-precision manufacturing (V) length (m) 3000 mm, manufactured at the inner diameter (EXT) and wall thickness:

Pipe EXT 25вх2вх3000 m — 12X18H10T GOST 9941−81

(Changed edition, Rev. N 2, 5; The Amendment).

2. TECHNICAL REQUIREMENTS

2.1. Pipe manufactured in accordance with the requirements of this standard for technological regulations approved in the prescribed manner.

(Changed edition, Rev. N 2).

2.2. Tubes manufactured from the steel grades listed in table.3, with the chemical composition according to GOST 5632.

Table 3

Allowed to manufacture pipes with micro rare earth metals.

The sulfur content of the steel for the pipes to be welded, as specified in the order, shall not exceed 0,02%.

(Changed edition, Rev. N 3, 5).

2.3. Pipes must be thermally processed. At the customer’s request pipes are made without heat treatment and the lightness of the surface. Norms of mechanical properties and curvature of pipes without heat treatment are established by agreement between manufacturer and consumer.

2.4. Mechanical properties of pipes shall be as specified in table.3.

The yield strength for pipes made of steel 12X18H10T must be at least 216 MPa (22 kgf/mm). The norm of yield strength for pipes of steel grades 12Х18Н12Т, 10X17H13M2T and 08KH18N10T determined by agreement between manufacturer and consumer.

Determination of the yield stress of tubes of steel grades 12X18H10T, 12Х18Н12Т, 10X17H13M2T and 08KH18N10T carried out at the request of the consumer.

(Changed edition, Rev. N 3, 4, 5).

2.5. At the request of the consumer pipe shall withstand a tensile test at 350 °C.

Rules of temporary rupture strength and the yield strength determined by agreement between manufacturer and consumer.

(Changed edition, Rev. N 4).

2.6. The outer and inner surfaces of the pipes must be free of captivity, flaws, laps, cracks. Remove defects by local sweep, continuous or local sanding, boring and turning, provided that the amount of boring, turning, solid grinding does not output the diameter and wall thickness for the negative limit deviation, and the local cleaning and polishing — thickness of the wall for the negative limit deviation specified in table.2.

Without Stripping the unit allowed slivers, risks, rabiza, scratches and dents, provided that they do not take wall thickness for the negative maximum deviations.

At the request of the consumer individual slivers must be stripped.

(Changed edition, Rev. N 3).

2.7. Surface of the pipe should be light. Allowed matte surface with a gray tint, due to the production method and steel grade.

Allowed to manufacture pipes without subsequent etching after the heat treatment in protective atmosphere or vacuum with the colors of a tint on the surface.

2.8. At the customer’s request pipes of steel grades 12X18H10T, 12Х18Н12Т, 12H18N9, 17H18N9, 04KH18N10, 08KH20N14S2, 10X17H13M2T, 08KH18N12B, 10Х23Н18, 08KH18N10T, 08X18H10, 08KH18N12T, 08KH17N15M3T, 06HN28MDT must withstand flattening to obtain sludinajumi between surfaces distance () in mm, calculated by the formula

,

where is the nominal wall thickness, mm;

 — nominal external diameter, mm,

or distribution to increase the outer diameter by 10% a mandrel with the taper angle 30°; it is possible to use a mandrel with a taper angle of 6° and 12°.

2.9. At customer’s request, tubes shall withstand hydraulic pressure in accordance with the requirements of GOST 3845 with allowable stress equal to 40% of the temporary tear resistance for this grade of steel. The ability of pipe to withstand hydraulic pressure is provided by the production technology.

2.10. At the request of the consumer that is specified in the order, pipe from steel grades 10X17H13M2T, 08KH17N15M3T, 08KH22N6T, 04KH18N10, 08H18N10, 08CR18NI10TI, 12CR18NI10TI 08KH18N12T, 12Х18Н12Т, 12H18N9, 08KH18N12B and alloy 06HN28MDT should be resistant against intergranular corrosion.

(Changed edition, Rev. N 5).

2.11. At the request of the consumer pipe should be monitored by ultrasound. The size of artificial defect is determined by agreement between manufacturer and consumer.

3. ACCEPTANCE RULES

3.1. Pipes take by the parties.

The party should consist of pipes of the same size in diameter and wall thickness, the same grade of steel and one form of heat treatment, as customer’s request — one of melting and to be issued a single document on quality according to GOST 10692 with the addition of: chemical composition in accordance with the document of quality pipe billets, as well as information on heat treating.

The number of pipes in the lot shall be no more than 300.

3.2. Control surfaces, dimensions, hydraulic pressure, ultrasound is subjected to control each pipe.

3.3. For quality control from the party taken:

tensile twin pipe;

the flattening or the distribution — one pipe;

on the intergranular corrosion of two pipes.

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

The results of repeated tests apply to the entire party.

(Changed edition, Rev. N 5).

3.4. (Deleted, Rev. N 5).

4. TEST METHODS

4.1. For quality control of each selected pipe cut one sample for each test.

4.2. Inspection of the pipe surface is carried out visually.

4.3. The length of the tubes test tape according to GOST 7502.

4.4. The curvature of the pipes checked straightedge according to GOST 8026 probe on the other 2−034−225.

(Changed edition, Rev. N 4).

4.5. Diameter and ovality of pipes controlled by a micrometer smooth MK-type according to GOST 6507, staples sheet according to GOST 18360, 18365 GOST.

The thickness of the wall of the test tube micrometer type MT according to GOST 6507.

4.6. The tensile test is carried out according to GOST 10006, GOST 19040 (at 350 °C). The speed of the movable grip — not more than 10 mm in 1 m. allowed to exceed the test speed to 40 mm in 1 min after reaching the yield stress.

Allowed control of mechanical properties to carry out the method of hardness according to normative-technical documentation.

The differences in the evaluation of the results of test carried out according to GOST 10006, GOST 19040.

4.7. Test distribution is carried out on pipes with diameter up to 150 mm inclusive wall thickness of not more than 10 mm according to GOST 8694.

4.8. Pipes are produced without heat treatment, not subjected to a flattening and distributing and checking on susceptibility to intercrystalline corrosion.

4.9. Test flattening is carried out on pipes with a wall thickness of not more than 10 mm in the churchyard 8695.

At the request of the consumer test flattening is carried out on pipes with a wall thickness of not more than 15% of the outer diameter.

When detected at clusively samples of small defects resulting from external defects permitted without Stripping, is permitted to conduct a second test sample taken from the same tube, with pre-cleaning the surface to a depth of half of the extreme deviations, but not more than 0,2 mm from the side on which the detected defects.

(Changed edition, Rev. N 1).

4.10. The hydraulic pressure test is carried out according to GOST 3845 with aging pipes under pressure of not less than 10 s.

4.10.1. Instead of the hydraulic pressure test is allowed to carry out inspection of each pipe by nondestructive methods according to GOST 17410 and normative-technical documentation 01.01.90.

(Added, Rev. N 2).

4.11. Ultrasonic testing is carried out according to GOST 17410 and normative-technical documentation.

4.12. Test the resistance against intergranular corrosion of steels of all grades, except 06XH28MDT, spend methods AM or AMU, and the alloy 06HN28MDT — WU method according to GOST 6032. In case of disagreement in evaluation of the results of the test steels of all grades, except 06XH28MDT, carried out by AM.

By agreement between manufacturer and user test the resistance against intergranular corrosion of steels 08KH18N10T and 12KH18N10T grades may be performed by the method of PT according to GOST 9.914. In case of disagreement in evaluation of the results of the test carried out by AM according to GOST 6032.

(Changed edition, Rev. N 2, 5).

5. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

5.1. Marking, packaging, transportation and storage is carried out according to GOST 10692.