GOST 8731-74 Seamless Hot-Deformed Steel Pipe for Industrial Service

Material

GOST 8731-74 covers seamless hot-deformed (hot-finished) steel pipes for general industrial use, manufactured from carbon and alloy steels. Pipe dimensions and tolerances are applied per the referenced size/tolerance standards (notably GOST 8732 and GOST 9567), and pipes can be ordered by quality group (A/B/V/G/D) depending on whether mechanical properties, chemistry, or test pressure is prioritized.

Specifications

• Manufacturing process: seamless, hot-deformed / hot-finished.

• Dimensional basis: OD & WT per GOST 8732 (assortment) and accuracy/tolerance options per GOST 9567.

• Length options (GOST 8732):

  • Random length: 4 to 12.5 m

  • Fixed length: within random-length limits

  • Multiple (of fixed): within random-length limits (with cutting allowance)

• Typical tolerance framework (GOST 8732): OD tolerance depends on diameter band; wall tolerance depends on thickness band and accuracy class.

• End preparation (when specified): for thicker-wall pipes, bevels are specified at 35–40° with a small land left on the end face.

• Documentation / traceability: supplied by batches with a quality document per GOST requirements; chemistry can be tied to the billet/heat documentation.

Key Features

• Quality groups to match project needs (GOST 8731):

  • Group A: mechanical properties guaranteed (Table 1)

  • Group B: chemical composition guaranteed

  • Group V: both mechanical properties (Table 2) and chemical composition guaranteed

  • Group G: chemistry guaranteed with mechanical testing on heat-treated samples per steel standards

  • Group D: no guaranteed chemistry/mechanics, but test pressure is specified

• Pressure integrity options: pipes intended for pressure service must meet calculated hydrostatic test pressure (per GOST 3845 methodology); NDT on every pipe may be used instead of hydrotest when agreed.

• Surface quality requirement: cracks, laps, folds and similar severe defects are not permitted; minor marks may be acceptable if they do not take the wall below minus tolerance.

Our Advantages (Top 3 buyer concerns—answered)

1. “Can you provide complete traceability and a certificate buyers recognize?”
   Yes. We supply batch traceability with heat/billet linkage and can provide inspection documentation aligned with common international purchasing practice (e.g., EN 10204 Type 3.1 / 3.2 when requested by the PO/ITP).

2. “Hydrostatic test or NDT—what will you deliver?”
   For pressure applications, we support hydrostatic testing per the GOST approach; where projects prefer 100% NDT in lieu of hydrotest, we can arrange full-length automated UT based on widely used tube-testing practice (e.g., ISO 10893 ultrasonic testing frameworks) to verify integrity.

3. “Will the pipe meet dimensional tolerances and end requirements for fabrication?”
   We manufacture to OD/WT and length rules per GOST 8732, and can select accuracy/tolerance classes as required. Where weld prep is needed, we can provide beveled ends in the angles specified by the GOST requirement, supporting faster fit-up and more consistent weld quality.

Chemical Composition

Note: Grades 10/20/35/45 are listed in GOST 1050-88; Grade 40Х (40Kh) chemistry is per GOST 4543-71. Limits for P/S and residual Ni/Cu are shown as specified for the grade family.

Mechanical Properties

Execution Standard

• GOST: GOST 8731-74 (technical requirements); GOST 8732-78 (size range); GOST 9567-75 (high-accuracy tolerances)

• ASTM (typical equivalents by use): ASTM A106 (high-temp service), ASTM A53 (general service), ASTM A519 (mechanical tubing)

• EN: EN 10216-1 / EN 10216-2 (seamless pressure tubes, non-alloy/alloy)

• JIS: JIS G3454 (pressure service), JIS G3455 (high pressure), JIS G3441 (machine structural)

• GB: GB/T 8163 (fluid transport), GB/T 8162 (structural), GB/T 5310 (high-pressure boiler), GB/T 3087 (low/medium-pressure boiler)

Application Fields

• Industrial piping & pressure lines: process pipelines, steam/water lines, compressed-air headers (hydrotest or NDT options support pressure duty).

• Mechanical engineering & machining parts: sleeves, shafts, cylinders, and turned components (surface quality rules help ensure defect-free machining stock).

• Energy, petrochemical, general fabrication: structural and equipment tubing where a seamless product with predictable properties and tolerances is required.