ere are some common specifications for seamless steel pipes (outer diameter × wall thickness, mm):

Hot-rolled pipe: Outer diameter: >38～630; Wall thickness: 3～80; Common specifications: 42×4, 50×5, 89×6, 108×4.5, 133×7, 159×6, 219×6, 273×8, 325×8.5

Cold-drawn (cold-rolled) pipe: Outer diameter: 6～720; Wall thickness: 0.25～120; Common specifications: 22×2.5, 25×2.5, 32×3, 38×4, 45×3

Common standards and materials:

Standards: GB/T 8162 (for structural use), GB/T 8163 (for fluid transport);

Materials: 10#, 20#, 35#, 45#, 16Mn, etc.

When purchasing, the following must be specified: the applicable standard, the intended use, the outer diameter, the wall thickness, and the tolerances.

Time：06/11/2026 16:03:14

1. Small-diameter seamless steel pipes

Outer diameter range: 6 mm~108 mm

Common outer diameter specifications: 6, 8, 10, 12, 14, 16, 18, 20, 25, 32, 38, 42, 45, 48, 51, 57, 60, 76, 89, 108mm

Wall thickness range: 1 mm~12 mm

Applications: Primarily used for conveying fluids (such as water, gas), mechanical structural parts (such as automotive drive shafts), instrument conduits, etc.

2. Medium-diameter seamless steel pipes

Outer diameter range: 114 mm~325 mm

Common outer diameter specifications: 114, 133, 140, 159, 168, 180, 219, 273, 325mm

Wall thickness range: 4 mm~25 mm

Application scenarios: Mainly used for oil pipelines, natural gas transportation, heat pipelines, and large mechanical structure support, etc.

3. Large-diameter seamless steel pipes

Outer diameter range: 351mm and above

Common outer diameter specifications: 351, 402, 426, 450, 508, 610mm, etc.

Wall thickness range: 6 mm- 50 mm (some special applications can be thicker)

Application scenarios: Suitable for high-pressure pipelines (such as power plant steam pipelines), pressure vessels, marine engineering, bridge construction, etc.

Time：06/11/2026 13:21:09

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