SSAB Domex Tube 355J2H

Product identity

SSAB's Domex Tube 355J2H minimum A5 elongation of 20% drops by two percentage points when (B + H)/(2T) < 12.5 for square or rectangular sections, or D/T < 15 for round sections. A hypothetical 100 × 100 × 10 mm square gives (100 + 100)/(2 × 10) = 10, so the adjusted minimum is 18%. Confirm availability separately. SSAB applies impact testing at ≥6 mm wall. Check the actual test record. SSAB mechanical table and test footnotes

SSAB Domex Tube 355J2H is a cold-formed, high-frequency-welded structural hollow-section product meeting or exceeding EN 10219 requirements. It is not a generic designation for every S355 tube or a pressure-pipe approval. Identify the producer product, section and inspection documentation together when purchasing. SSAB product description

SSAB's 2016 structural-hollow-section handbook distinguishes 355J2H from Tube Double Grade, which has separate S355J2H and S420MH certification. Its worked structural examples use Double Grade. Do not transfer that product's higher-strength certification or an example's resistance to a shipment identified only as 355J2H. SSAB handbook, chapter 1, sections 1.1 and 1.6

Available sections and mechanical properties

The product page lists circular diameters 42.4–323.9 mm, square sections 40 × 40–300 × 300 mm, rectangular sections 50 × 30–400 × 200 mm, and walls 2.0–12.5 mm. These are range envelopes; confirm the actual size–wall combination. SSAB dimension tables

*The minimum elongation is reduced by two percentage points for D/T < 15 in round sections or (B + H)/(2T) < 12.5 in square/rectangular sections. Rectangular-section mechanical testing is on the longer side. SSAB lists 27 J at −40°C, referenced to a 10 × 10 mm Charpy-V specimen; impact testing under EN ISO 148-1 applies at wall thicknesses ≥6 mm. SSAB mechanical table and both footnotes

Assess structural toughness for the actual detail, stress, service temperature and fabrication.

Geometry, tolerances and calculation inputs

A structural hollow section has rounded corners and manufacturing tolerances. Use the applicable section tables for area, mass, second moments and section moduli; a sharp-corner rectangular idealization is only an explicitly stated approximation. The SSAB handbook supplies section-property tables and structural design guidance, but is an older edition tied to the standards identified in its text. SSAB handbook, chapter 1 and annex 11.1

For a fitted assembly, establish the tolerances that affect function before ordering: outside dimensions, wall, corner profile, straightness, twist, cut length and squareness. A nominal wall thickness is not a guaranteed minimum everywhere. A catalog mass is not a weighing certificate. Where an internal sleeve must fit, verify internal clearance and weld-seam interference using the actual supplied section rather than subtracting twice the nominal wall from the outside size.

Illustrative material-strength comparison: assume a separately verified gross section area of 1,000 mm² and use the listed minimum yield value of 355 N/mm². Their product is 355,000 N = 355 kN. This is a deliberately limited area-times-stress calculation, not an allowable load or a code design resistance. It omits member buckling, local slenderness, eccentricity, holes, connections and design factors. The area is an example assumption, not a published section size. Material-value basis: SSAB

Welding and surface protection

SSAB's handbook explains that its Domex Tube chemistry permits welding in the cold-formed corner region within the cited EN 1993-1-8 provisions. That product-specific statement should not be generalized to unidentified cold-formed hollow sections. It also does not replace selection and qualification of a welding procedure for the actual joint. SSAB handbook, sections 1.1 and 1.12

For fabrication, establish joint preparation, access, consumables, heat control, distortion allowance and inspection requirements through the applicable procedure. Do not derive preheat or heat input from the yield-strength number alone. Preserve material identification through cutting so the completed fabrication remains connected to the delivered inspection record.

For hot-dip galvanizing, hollow assemblies need a design that admits and drains process fluids and zinc while releasing air. The American Galvanizers Association recommends venting at high points and drainage at low points in the immersion orientation, with each enclosed section vented. Agree the actual hole sizes and locations with the galvanizer before fabrication; this page supplies no universal hole pattern. AGA, Hollow Structures

Ordering and acceptance

Record the exact product and grade, section dimensions, quantity and lengths, relevant standard editions, inspection-document requirements and any special fabrication or surface requirements. Confirm which producer guarantees apply to the order and which results are reported for the delivered lot. A reseller's generic S355 description does not establish SSAB provenance or Double Grade certification.

At receipt, reconcile markings and documents with the order, check the dimensions and condition relevant to the assembly, and resolve substitutions before fabrication. Keep structural acceptance separate from material receipt: the final component still needs its specified design, execution and inspection evidence.

Source dates and related reference

The cited SSAB product page and AGA guidance display no revision date used here. The SSAB handbook explicitly identifies its 2016 edition in the foreword; its historical standard references are not asserted to be current editions. Sources reviewed 2026-11-01, America/Los_Angeles. Confirm current supply documentation when ordering.

See Stock forms and dimensions.