Heavy Wall 200x200x12mm Stainless Steel Square Hollow Section EN 10219 Modular Structure

Heavy wall stainless steel square hollow sections in the 200 x 200 x 12 mm class solve a specific problem: structural engineers want the corrosion immunity of austenitic stainless steel in a member that can carry real bending and compression load without a protective coating that will eventually fail. This section is formed from hot rolled coil on a heavy gauge forming line, welded with a full penetration corner seam, then laser or plasma cut to length and, when required, shot blasted to remove the heat tint that would otherwise become a corrosion initiation site.

The wall thickness range from 6 mm to 12 mm keeps the section in Class 1 and Class 2 slenderness for most national codes, so it can be designed as a plastic or compact section instead of a thin walled tube governed by local buckling. Straightness is held to 0.15 percent of length and twist to 1 mm per metre, which matters when sections are bolted into modular frames where tolerance stack up decides whether a module fits on site on the first lift.

• Thick Wall Load Capacity: Wall thickness from 6 mm to 12 mm delivers section modulus and compression resistance suited to primary structural members rather than trim and cladding support.
• Full Penetration Weld: Corner seams are welded with full penetration and inspected by ultrasonic or dye penetrant testing on request, so the weld is not the weak link under fatigue or seismic loading.
• EN 10219 Dimensional Control: Outside dimension, corner radius, squareness and straightness follow the tolerances of EN 10219 part 2, giving European fabricators a known fit up condition.
• Heat Tint Removal: Pickled and passivated or shot blasted finishes remove chromium depleted weld oxide, restoring full corrosion resistance at the seam and preventing preferential attack.
• Grade Flexibility: Available in 304L for general structure, 316L for coastal and chemical exposure, and duplex 2205 where higher yield strength or chloride resistance is required.
• Fabrication Ready: Sections can be supplied cut to length, with drilled bolt holes, welded end plates or mitred corners to reduce site labour and scrap in the fabrication shop.

These hollow sections are used for primary columns and beams in modular steel buildings, support frames for conveyor galleries in ports and mines, curtain wall mullions carrying large wind load, canopy and station structures, and machine base frames where washdown chemicals would destroy a painted carbon steel member. Architects also specify the section in exposed applications where the mill finish and tight corner radius become part of the visual language of the building.

Sections are bundled with steel strapping, interleaved with timber dunnage to protect the surface, and shipped in open top containers or on flat racks with lifting points marked. Documentation includes the mill test certificate to EN 10204 3.1, dimensional inspection record and weld inspection report where applicable. Wall thickness and grade are verified by ultrasonic thickness gauge and PMI chemical analysis before every dispatch.