S355 Seamless Hollow Section

Tianjin Brisk Metalwork Co., Ltd. is one of the leading manufacturers and suppliers of s355 seamless hollow section in China. We have world-leading production equipment and strong manufacturing capabilities. Please feel free to buy bulk durable s355 seamless hollow section from our factory.

Our Product

Tianjin Brisk Steel focus on produce and supply hollow section and steel pipe

The letters after S355 are not decoration. They tell us which impact test temperature and energy level to build into the production lot:

• S355J0H - Charpy tested at 0 degC. Our standard grade for indoor frames, machine bases, and warm-climate steelwork.
• S355J2H - Charpy tested at -20 degC. The grade most buyers order; it covers outdoor structures, bridges, and export projects into cold-season regions.
• S355K2H - higher impact energy at -20 degC. We recommend it for dynamically loaded nodes, crane structures, and offshore-adjacent steelwork.

Tell us the lowest service temperature and the load type, and we will confirm the sub-grade before we roll. Impact properties cannot be added after production; they are built into the heat, so we settle this at quotation, not after shipment.

1. Billet selection - S355 round billet from qualified steelmakers, each heat traced by number.
2. Heating - billets are heated in a rotary hearth furnace to rolling temperature.
3. Piercing - a mandrel pierces the solid billet into a hollow shell; this is where the seamless structure is created.
4. Elongating and rolling - the shell is rolled over a mandrel to the target wall thickness.
5. Sizing / reshaping - a sizing mill sets the final OD; for square and rectangular sections, the round tube is hot-reshaped in the forming stand.
6. Cooling and straightening - controlled cooling, then hot straightening to keep straightness within the delivery tolerance.
7. Heat treatment (+N on request) - normalizing for orders that require refined grain and uniform properties.
8. Testing and marking - dimensional check on every tube, mechanical tests per lot, NDT as specified, then paint marking of grade, size, heat number, and standard.

• Round (CHS) - our core seamless product, from small-bore truss members to 406.4 mm columns and piles.
• Square and rectangular (SHS / RHS) - reshaped from seamless round, so the finished section keeps continuous grain flow and a uniform wall around all four corners, with no seam to position or inspect.

Heavy-wall capability is where our seamless line separates from welded supply: wall thickness up to 50 mm at diameters where welded CHS becomes uneconomical or difficult to inspect.

• Chemical analysis - per heat, reported on the MTC.
• Tensile test - per lot, longitudinal or transverse as ordered.
• Charpy impact test - at the temperature matching your sub-grade.
• Flattening or flaring test - for ductility of the wall.
• Hydrostatic or eddy current test - leak-tightness / wall integrity check.
• Ultrasonic testing - 100% wall UT available for critical-service orders.
• Documents - EN 10204 3.1 certificates as standard; 3.2 with SGS, BV, TUV, or your nominated inspector, who is welcome to visit the mill.

• Direct manufacturer - no trading layer between your specification and the mill floor.
• Grade, size, and test data confirmed before production - we send a written offer sheet stating the sub-grade, delivery condition, and testing scope.
• Lot-based traceability - heat number on the tube, on the MTC, and on the packing list.
• Export packing - bundled with steel strapping and waterproof wrap, end caps for exposed ends, and container or breakbulk loading planned by length.
• Flexible quantities - from 25 tonnes per size for mill-standard sections.

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