1. Specification Breakdown

2. Chinese Equivalent Standard and Material

Direct equivalent material: 30CrMnSiA (GB/T 3077 – Alloy structural steel)

They are fully equivalent and can be considered the same material. Chemical composition comparison:

Reference mechanical properties:
Tensile strength: ≥ 420 MPa
Yield strength: ≥ 235 MPa
Elongation: ≥ 24%
Impact toughness: ≥ 35 J/cm²
Hardness: ≤ 207 HB

3. Standard Interpretation

GOST 8732-78

Dimension range: OD 32 – 426 mm, wall thickness 2.5 – 75 mm (some sources indicate up to 75 mm)

Length: Usually 4.0 – 12.5 m

Applicable steel grades: Both carbon and alloy steels (e.g., alloy steel 12Kh1MF, etc.)

GOST 8731-74

Scope: General‑purpose hot‑deformed seamless steel pipes of carbon and alloy steels

Key content: Chemical composition, mechanical properties, test methods, inspection rules, heat treatment requirements, etc. Must be used together with GOST 8732-78

4. Key Production Considerations

This material is a medium‑carbon alloy steel requiring strict process control. Pay special attention to:

4.1 Raw Material Control

Billets must be made of alloy steel round blooms. Strictly inspect chemical composition to meet standard requirements (low S & P to avoid cracks).

Choose billets from large mills with alloy steel experience (e.g., Baosteel, Valin Steel, Hengyang) ensuring internal quality (low gas content, few inclusions).

4.2 Heating Temperature Control

Heating temperature of billets: 1150 – 1250 °C; ensure uniform temperature from core to surface to avoid overheating or underheating.

Strictly control heating time and atmosphere to prevent surface decarburisation (affects surface hardness and strength).

4.3 Deformation & Forming Control

Control wall thickness uniformity to ensure OD and wall thickness tolerances meet standard requirements.

For the piercing process, use a relatively small reduction before the plug to avoid internal defects such as laps or cracks.

4.4 Heat Treatment (Critical!)

30KhGSA is a medium‑carbon quenched and tempered steel – it must undergo quenching + tempering to achieve required properties. After quenching and tempering, it exhibits high strength and sufficient toughness. Typical heat treatment specification: quenching at 880 °C, oil cooling; tempering at 540 °C, water or oil cooling. Mechanical properties after heat treatment must be strictly tested according to the standard.

4.5 Quality Inspection

Non‑destructive testing: According to requirements, each pipe shall be examined by ultrasonic (UT) or eddy current (ET) testing.

Mechanical property testing: Samples shall be taken per batch for tensile, impact, flattening / bending tests.

Dimensional & visual inspection: Each pipe checked for OD, wall thickness, length, surface quality, end bevel, etc.

5. Applications & Export Requirements

Seamless pipes of this material are mainly used in aerospace, military manufacturing, mechanical engineering (high‑strength applications), as well as heavy‑load shafts, gears, compressor blades, etc.

When exporting to Russia, compliance with Eurasian Customs Union Technical Regulation TR CU 032/2013 (Safety of Pressure Equipment) is required. It is recommended to confirm EAC certification requirements with the customer in advance and include relevant technical support in the quotation.

If the customer provides only the steel grade and standard without specifying OD, wall thickness, length and quantity, request this information first before quoting to avoid subsequent performance risks.

When replying, proactively mention critical notes such as poor weldability and EAC certification to demonstrate professionalism.