GOST 8733-74
Seamless COLD AND WARM DEFORMED pipes. Specification
This standard is applied to seamless cold and warm deformed steel pipes of general purpose of carbon and alloy steel.
1.1. Pipes are to produce in accordance with requirements of present standard conforming with technological process in accordance with established procedure.
1.2. Depending on quality pipes are to be produced by the following groups:
Б – with chemical composition regulation of finished steel conforming with GOST 1050, GOST 14959, GOST 4543, GOST 19281;
B – with mechanical properties regulation mentioned in table 1 and chemical composition regulation of steel grade conforming with GOST 1050, GOST 14959, GOST 4543, GOST 19281;
Г – with mechanical properties regulation controlled on heat treatment examples and chemical composition regulation of steel grade conforming with GOST 1050, GOST 14959, GOST4543, GOST 19281. Mechanical properties are to conform with requirements of steel grades;
Д – without mechanical properties and chemical composition regulation but with test hydraulic pressure;
Е – after special heat treatment. Steel grade, heat treatment mode and mechanical properties are established by documents in accordance with established procedure.
Table 1
Steel grade | Tensile strength, σв, MPa (kgs/mm) | Yield strength, σт, MPa, (kgs/mm) | Elongation, δs, % | Brinell hardness (provided wall thickness over 10 mm) | |
Min | Diameter impression, mm, min | Hardness number HB, max | |||
10 (St 37.00) |
343 (35) |
206 (21) |
24 |
5,1 |
137 |
20 (St 44.00) | 412 (42) | 245 (25) | 21 | 4,8 | 156 |
35
| 510 (52) | 294 (30) | 17 | 4,4 | 187 |
45
| 589 (60) | 323 (33) | 14 | 4,2 | 207 |
10G2
| 422 (43) | 245 (25) | 22 | 4,3 | 197 |
15Х
| 412 (42) | - | 19 | 4,5 | 179 |
20Х
| 431 (44) | - | 17 | 4,5 | 179 |
40Х
| 618 (63) | - | 14 | 4,1 | 217 |
30ХGCА
| 491 (50) | - | 18 | 4,0 | 229 |
15ХМ
| 431 (44) | 226 (23) | 21 | - | - |
Notes: Mechanical properties of steel grade not mentioned in the above table 1 as well as impact strength and contraction for all steel grades are set under the agreement between producer and customer.
1.3. Pipes are to be heat treated. Pipes with OD/ WT ratio amounted 50 and more are to be produced without heat treatment. Mechanical properties are set by additional agreement if pipes are produced without heat treatment.
1.4. Surface pipes are not allowed cracks, skins, tears, holes and collar marks. Separate minor nick, drossings, which are not prevent surveying , pinchers, flattering and machining traces and defect trimming are not allowed if they do not exceed max deviations.
1.5. As per customer request drossings are to be removed from surface of pipes.
1.6. Edges pipes are to be cut orthogonally and smoothed out wire-edge. Facing can be allowed while smoothing out wire-edge.
1.7. As per customer request edge pipes are to be welded with WT 5 mm and more edging have to be on-the-mitre 30-40° to the pipe edge. At that end ring with width 1-3 m are to be.
1.8. All pipes range applied under pressure (working conditions are mentioned in request), are to withstand testing hydraulic pressure (P1) in MPa (kgf/cm²), calculated by formula acc GOST 3845, where R - working stress = 40% of tensile strength for a certain steel grade, in N/mm² (kgf/mm²).
Hydraulic pressure capability of pipes are provided by production technology.
1.8.a. Per customer request pipes are to withstand hydraulic pressure, calculated by formula in GOST 3845, but not over 20 MPa (200 kgf/cm²).
Per customer and producer agreement it can be testing under pressure over 20 MPa (200 kgf/cm²).
Instead of hydraulic pressure it can be done eddy current test guaranteeing that pipes are accord to hydraulic pressure requirements (P1) per formula in GOST 3845.
1.9. By customer request heat treated pipes of steel grades 10, 20 and 15XM depending on application and operating conditions are to withstand one or several technological tests mentioned in paragraph 1.10-1.13.
1.10. Pipes are to withstand bending test.
1.11. Pipes with OD less 160 mm and WT less 8 mm have to withstand expansion testing on nipple with obliquity 1:10 till OD expansion indicated in table 2.
Steel grade | OD expansion of pipe, %, WT, mm | |
Up 4 | Over 4 | |
10 | 10 | 6 |
20, 15XM | 8 | 5 |
1.12. Pipes with OD 22 mm and more and WT less 10 mm are to withstand flattering test until getting distance (H) between flattered surfaces in mm calculated as follows:
H= ___1.08 * WT__ ,
0.08 + WT/ OD
WT – nominal wall thickness, mm,
OD – nominal outside diameter of pipe, mm.
1.13. Lipping test are to be applied to pipes with OD min 25 mm and max 160 mm with WT:
Max 10% of OD – for OD pipes up 60 mm
Max 8% of OD - for OD pipes from 60 up 108 mm
Max 6% of OD - for OD pipes from 108 up 140 mm
Max 5% of OD - for OD pipes from 140 up 160 mm
Width of bending side measured from internal pipe surface are to be min 12% of inside diameter and min 1.5 of WT.
Bending angel are to be:
90° - for pipes of steel 10
60° - for pipes of steel 20 and 15XM.
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2.7. Yield strength and ball hardness are to be tested periodically by producer per customer request.
