Square tube
The workhorse band: purlins, racking uprights, trailer bearers and general fabrication. Stocked in Q355B for same-week dispatch.
Cross-section
Outside dimension 70×70 mm, wall 2.5–5.0 mm, corner radius 2–3 × wall.
Specification
| Section | 70×70 mm |
|---|---|
| Wall range | 2.5 – 5.0 mm |
| Weight / m | 5.3 – 10.2 kg |
| Length | 6 / 9 / 12 m, or cut to length |
| Production line | 80 |
| Standards | GB/T 6728 · GB/T 3094 · EN 10219 · ASTM A500 |
| Tolerance | Wall ±10 % · squareness 90° ±1° · straightness ≤0.15 % L |
| Certificate | EN 10204 3.1 mill certificate with every heat |
Weights assume 7.85 g/cm³. Made to order — 10–25 days.
Grades
Other grades and equivalent EN / ASTM designations are quoted on request. Tell us the standard, not just the grade — we will match it.
Applications
Cut to length and drilled to your DXF, delivered as a bolt-on part.
Mill certificate traceable to the heat, so your inspector signs off without a second trip.
Consistent wall and squareness batch to batch — welding fixtures stay in tolerance.
FAQ
70×70 is made to order on the 80 line, typically 10–25 days depending on grade and coating.
Between 5.3 and 10.2 kg/m across the 2.5–5.0 mm wall range (theoretical, 7.85 g/cm³).
Q235B, Q355B–E, Q420B, 510L/610L/700L, 500TM/700TM and SPA-H; other grades on request.
Nearby sizes
Send the drawing or the standard — quote within 48 hours.