GOST 21945-76

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  ГОСТ 21945-76

GOST 21945−76 seamless hot-rolled Tubes from alloys based on titanium. Specifications (with Amendments No. 1, 2, 3)

GOST 21945−76

Group В62

INTERSTATE STANDARD

SEAMLESS HOT-ROLLED TUBES FROM ALLOYS BASED ON TITANIUM

Specifications

Seamless hot-rolled tubes of alloys based on titanium. Specifications

ISS 23.040.10
GST 18 2558

Date of introduction 1978−01−01

INFORMATION DATA

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

DEVELOPERS

V. P. Sokurenko, PhD. tech. Sciences (head of subject); Yu. M. Mironov, Cand. tech. Sciences; E. I. Kosygina

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 21.06.76 N 1484

3. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

4. The expiration time limit is removed by the Resolution of Gosstandart from 12.08.92 N 951

5. EDITION with Amendments No. 1, 2, 3 approved in December 1981, April 1983, June 1987 (IUS 2−82, 7 to 83, 11−87)


This standard applies to seamless hot-rolled tubes of alloys based on titanium, used for parts and structures.

Indicators of technical level established by this standard for pipe bands And higher precision on the diameter and wall thickness, provide for the highest quality pipe and tube group* General precision on the diameter and wall thickness for the first category of quality.
________________
* The text matches the original. — Note the CODE.

(Changed edition, Rev. N 3).

1. ASSORTMENT

1.1. The pipe dimensions shall be as specified in table.1.

(Changed edition, Rev. N 3).

Table 1

Extension table 1

Extension table 1

Extension table 1

Notes:

1. At the request of the consumer pipe diameters of 83, 89, 95 mm with a wall thickness of 6 and 7 mm and pipe diameters of more than 325 mm manufactured machined.

2. Pipe group B are made with a wall thickness of 10 mm or more.

1.2. The length of the pipe shall be made:

random length:

when 83−325 mm diameter — from 1.5 to 6 m,

when 351−480 mm diameter — from 2 to 4.5 m;

length — not less than indicated in the table.1. The pipe lengths are produced on customer requirement;

multiple gauge length — in the range of measuring with an allowance for each cut on 10 mm. the Minimum magnification is 300 mm.

Maximum deviations along the length of the tubes (dimensional and dimensional) +25 mm.

1.2.1. In each batch of pipes of random length may be no more than 15% of the pipe length not less than 0.75 m.

1.2.2. In each batch of pipes of standard length may be no more than 10% of tubes of random length, but not shorter than 1.5 m.

1.2.3. By agreement with the consumer it is allowed manufacture of pipes beyond the limits mentioned in point 1.2.

(Changed edition, Rev. N 2)

1.3. Tolerances for pipe sizes shall be as specified in table.2 and 2A.

Table 2

Table 2A

(Changed edition, Rev. N 1).

1.4. At the request of the consumer pipe shall be made with a combination of extreme deviations. For example: the diameter deviations of usual precision and thickness with deviations of high accuracy or Vice versa.

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

2.5 mm — wall thickness of pipe up to 20 mm;

4.0 mm — wall thickness of pipe over 20 mm.

1.6. (Deleted, Rev. N 3).

1.7. Theoretical weight of 1 m of pipe () in kilograms is calculated by the formula

,

where  — outside diameter of pipe, mm;

 — wall thickness, mm.

The density of the alloy is taken equal to 4.5 g/cm.

Examples of symbols

Hot-rolled pipe with an outside diameter of 89 mm and a wall thickness of 10 mm from alloy grade PT-7M, non-standard length, regular accuracy of manufacturing:

89х10 pipe PT-7M GOST 21945−76

The same random length, manufacturing high precision on diameter and wall thickness and high surface quality (group a):

Tube 89X10PT-7M AND GOST 21945−76

The same length that are multiples of 1500 mm, regular accuracy of manufacturing by diameter and manufacturing high precision wall thickness:

Tube 89X10X1500 PT-7M GOST 21945−76

The same dimensional length equal to 4000 mm, regular accuracy of manufacturing:

Tube 89х10х4000 PT-7M GOST 21945−76

The same, high manufacturing precision, measuring length equal to 4000 mm, with the usual surface quality (group B):

Tube 89X10X4000 PT-7M B GOST 21945−76

2. Technical requirements

2.1. Pipe shall be manufactured in accordance with the requirements of this standard alloy grades VT1−0, PT-1M, PT-7M, PT-3V, VT14, OT4, OT4−1, AT3 and TC5 with the chemical composition specified in normative and technical documentation for procurement, duly approved.

Pipes made of alloys AT3 and TC5, and the pipe diameter of 351 mm from alloys of all brands are made by agreement between manufacturer and consumer.

Mass fraction of hydrogen in the pipes of the group And must not exceed:

Of 0.005% of the alloy grades VT1−0, PT-7M;

0,006% grades PT-1M, PT-3V;

0,010% brand alloys OT4−1,

the norms established in the technical documentation for billets of all other alloys listed in clause 2.1.

In the tubes of group A with a diameter of 351 mm and more and in the tubes of group B the hydrogen content is not defined.

(Changed edition, Rev. N 1, 2).

2.2. Pipes must be thermally processed. Heat treatment of pipe bands And alloy grades VT1−0, PT-1M and PT-7M with a diameter of 325 mm and less is made in a vacuum.

Mechanical properties of metal of pipes shall be as specified in table.3, the mechanical properties of pipes with a wall thickness of 20 mm or more from alloy grade PT-3V shall be as specified in table.4.

Table 3

Table 4

At the request of the customer can be manufactured tubes without heat treatment. Norms of mechanical properties of pipe metal, manufactured without heat processing, and metal tubes made of alloys AT3 and TC5 are set by agreement between manufacturer and consumer.

(Changed edition, Rev. N 1, 3).

2.3. Tubes of alloys given in table.3, are made with a high quality external surfaces (group a) and normal (group B).

Tubes of group A are made internal bored and honed or polished on the outer surface. The depth of the removed layer from the surface of the pipe when machining must be at least 1 mm. the surface roughness of the pipe needs to be 40 µm according to GOST 2789.

Pipe group B are shipped after hot rolling without pickling and machining.

The surface quality of the pipes (group a or B) is specified in the order.

2.4. On the outer and inner surfaces of the finished pipe bands And should not be alteromonas layer.

2.5. The outer and inner surfaces of the tubes of group A should not be captured, flaws, laps, cracks, deep and sharp scratches, scale residues, dents and rough traces of the stripper.

Remove defects by local slope Stripping or grinding, provided the depth of local Stripping or sanding does not display wall thickness beyond the minimum size.

Without cleaning the surface of pipes allowed: rabiza, shallow indentations, traces of waviness, arranged in a spiral, the local sticking of the metal during machining, dents, traces of the cold Stripping, if they don’t bring the wall thickness beyond the minimum size.

2.6. On the outer and inner surfaces of the tubes of group B are permitted: scale, risk, cuts, traces of the imprint of scale, traces of waviness, arranged in a spiral, gently deepening, the local sweep of the defects, the depth of which does not go beyond the negative limit deviation for wall thickness.

On the outer and inner surfaces of the tubes of group B allowed the presence of gas-saturated layer.

2.7. The pipe ends should be square-cut and cleaned of burrs. Pipe group B allowed the trim ends with the presence of burrs. On the inner surface of pipes with a diameter of 351 mm and more allowed the chamfer to 10 mm.

2.8. Pipe band And alloy grades VT1−0, PT-1M and PT-7M and tested for flattening in the cold state to receive between the compression planes of distance () in mm, calculated by the formula

,

where is the nominal wall thickness, mm;

 — nominal outside diameter of pipe, mm;

 — the stiffness coefficient is equal to 0.05.

When discovering a tapered specimens cracks or tears tubes are rejected.

Test flattening of pipes of different grades of alloys as well as standards for testing established by agreement between manufacturer and consumer.

(Changed edition, Rev. N 1, 2).

2.8.1. Pipes manufactured by piligrimage installations, flattening tests; not exposed.

2.9. At customer’s request, each pipe must test by hydraulic pressure GOST 3845, at the same allowable stress shall be equal to 40% of the temporary rupture strength for the alloys, calculated at the lower limit.

Maximum test pressure is set to 40 MPa (400 kgf/cm).

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

By agreement with the consumer allowed to test the pipes under pressure up to 40 MPa (400 kgf/cm).

The hydraulic pressure test may be replaced by NDT methods. The type and amount of testing shall be established in consultation with the consumer.

(Changed edition, Rev. N 1, 2, 3).

3. Acceptance rules

3.1. The pipes are accepted by the parties. The party should consist of pipes of the same brand of alloy, one size, subjected to heat treatment under the same conditions, and be accompanied by a document about quality that contains:

trademark or name of the manufacturer and trademark;

the size of the pipes and grades;

the number of tubes, batch number, and numbers of heats that are part of it, and the quality group of the surface.

the number of pipes;

the results of all testing;

the designation of this standard;

the image of the national Mark of quality for pipes of the highest quality.

The number of tubes in a batch must not exceed 75.

Allowed to complete a batch of pipes from several heats of metals. Picked party is assigned a conventional number of melting, has the highest hydrogen content.

(Changed edition, Rev. N 2).

3.2. Checking of external and internal surfaces and dimensions must be subjected to each pipe of the party.

3.3. For inspection of pipe bands And the tensile, impact strength, flattening and defining the content of hydrogen is taken via the two pipes from the party.

If the party is assembled from pipes of different bottoms, take on two tubes from each heat.

3.4. The chemical composition of the alloy take the document about the quality of the manufacturer of the workpiece.

The hydrogen content in the tubes of the group And controlled by the manufacturer of the pipes.

For pipes with diameter of 351 mm and pipes group B the hydrogen content is taken on the document about the quality of the manufacturer of the workpiece.

3.5. The impact strength and relative contraction are determined on pipes with wall thickness from 7 mm or more.

Pipe with wall thickness less than 7 mm, and the tubes of group B on the impact strength and relative contraction of do not.

3.6. If unsatisfactory results of the analysis to the hydrogen pipe is subjected to continuous control during heat treatment in vacuum.

3.7. If unsatisfactory test results of at least one of the indicators (except for control on the hydrogen content) it is carried out re-tests on twice the number of pipes, taken from those not undergoing testing. If unsatisfactory results of the repeated test is a continuous test of pipes of the party.

4. Test methods

4.1. From each selected pipe cut:

for tensile tests at room and elevated temperatures, two sample;

for the impact test, two sample;

to test the relative narrowing of two of the sample;

testing flattening — two samples;

for the control of hydrogen content — the two samples.

Samples taken from both ends of the pipe.

4.2. Check outer surface of the pipe is produced visually, and internal — through the periscope.

Control of the outer diameter, conduct a caliper type SHC according to GOST 166, micrometer smooth MK-type according to GOST 6507, staples sheet according to GOST 18360, 18365 GOST.

Control of the wall thickness of the pipe is carried out with a micrometer type MT according to GOST 6507.

Control the length of the pipes is carried out measuring tape according to GOST 7502.

Control the curvature of the pipes is carried out with a straight edge according to GOST 8026 probe on the other 2−034−225.

Allowed to control the geometric dimensions of other devices according to normative-technical documentation.

4.1, 4.2 (Revised edition, Edit. N 3).

4.3. The tensile test is carried out on a short longitudinal samples according to GOST 10006, at elevated temperature — according to GOST 19040.

Test speed 10 mm/min to yield 40 mm/min for yield strength. For pipes with diameter of 351 mm and a test speed of 3−2 mm/min.

4.4. Test for impact strength is carried out according to GOST 9454:

on samples with a cross section of 10x10 mm and the wall thickness of the pipes 12 mm and more;

on the samples cross section 5x10 mm (sample type 3 according to GOST 9454) with a wall thickness of from 7 to 12 mm.

4.3, 4.4. (Changed edition, Rev. N 1).

4.5. The relative narrowing of the point determined on cylindrical samples according to GOST 1497.

4.6. Test flattening is carried out according to GOST 8695.

4.7. Hydraulic testing of the pipes is carried out according to GOST 3845 with endurance under pressure for the time required for inspection.

4.8. Ultrasonic inspection of pipe bands And are produced according to GOST 17410 and instructions of the manufacturer when setting the sensitivity of the flaw detector according to the risk incurred on the test sample, to a depth of not more than 5% of the nominal wall thickness.

4.9. In the pipe groups A diameter of less than 351 mm, the determination of hydrogen produced according to normative-technical documentation approved in the established order.

5. Marking, packaging, transportation and storage

5.1. Each tube group A distance no more than 50 mm from one end or at one end of the marks must be applied: the mark of the technical control Department of the manufacturer, grade, pipe, and batch number. The tubes of group B with paint grade and batch number.

5.2. Pipe group A must be Packed weighing up to 500 kg wooden crates type VI-2 according to GOST 2991 or other similar boxes, the quality is not inferior indicated, and securely fastened inside of the packaging spacers from the free movement of their transportation. When transporting pipes in covered wagons the weight of packages should not be more than 1.2 T.

Pipe group B are delivered in integrated packages at the normative-technical document, weighing from 1 to 5 tons.

Packages firmly linked the length of not less than three places, and in the transverse direction — not less than two turns. Linking packages should be made of wire of diameter not less than 5 mm according to GOST 3282 or steel tape with a cross-section of 1.2−1. 8x30 mm 3560 churchyard. Binding material is not a device for zastroyki.

(Changed edition, Rev. N 2).

5.2.1. Each package or wooden crate, which is Packed in tubes must be plywood, metal or plastics label that contains:

the designation of the standard;

the size of the pipes;

grade;

and at the request of the consumer:

the room melt;

batch number;

the mass or length of pipe in meters;

trademark or name of the manufacturer and trademark.

5.2.2. Packaging tubes supplied in the far North regions and equated areas, must comply with GOST 15846, group 132 (a).

5.2.3. Transport marking of goods, place of application and method of execution must comply with GOST 14192.

5.2.1.-5.2.3. (Added, Rev. N 2).

5.3. (Deleted, Rev. N 2).

5.4. Pipe should be stored indoors, sorted into sizes and grades.

5.5. Pipes are transported by all kinds of transport in accordance with the rules of cargo transportation applicable to transportation of each type.

Railway transportation of pipes up to a length of 3 m made in covered wagons, over 3 m — select rolling stock produced in accordance with the shipping rules, approved by Ministry of USSR. Stowage and securing of cargo is made in accordance with the technical conditions of loading and fastening of goods* approved by the Ministry of Railways of the USSR.
________________
* Probably, the error of the original. Should read: «Technical conditions of loading and fastening cargoes». — Note the manufacturer’s database.

(Changed edition, Rev. N 2).

5.6. (Deleted, Rev. N 2).