Description
Factory-Direct ERW Square Tubes — 19×19mm to 800×800mm welded square hollow sections produced on dedicated lines with ±1% wall-thickness tolerance and full EN 10219 / ASTM A500 certification.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube |
| Steel Grade | Gr.B, S235, S275, S355, STK400, Q195–Q690, ASTM A500 Gr.A/B/C/D, EN 10219 S235JR–S355J2, JIS G3466 STKR400/490 |
| Standard | ASTM A500, ASTM A53, GB/T 3091, EN 10219, EN 10210, JIS G3466 |
| Section Shape | Square |
| Size Range | 19mm×19mm – 800mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction structures, building frames, curtain walls, support tubes, structural pipe, scaffolding, machinery frames |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, bridge support tubes, scaffolding systems, platform structures |
| Architectural Facades | Glass curtain wall framing, exposed structural columns, decorative steel facades |
| Machinery & Industrial | Conveyor frames, equipment bases, crane booms, industrial support structures |
| Steel Structure Fabrication | Column-to-beam connections, truss members, purlin systems, bracing tubes |
What Negative Tolerance Really Costs on a 120×120 Structural Frame Order
A 120×120 welded square tube at the edge of negative tolerance can shift actual weight by over 10% versus theoretical — and that gap shows up first at the weighbridge, not in the lab.
Back when I was running procurement for a Philippines infrastructure job, we ordered a container of 120×120 welded square tubes. The mill certificates looked clean, but when the trucks hit the site weighbridge, the actual tonnage was far below what the invoice claimed. The wall thickness was sitting right at the allowable negative limit — technically legal, but the监理 rejected the entire lot. We lost two weeks sourcing replacements and the contractor ate the demurrage. That kind of gap between theoretical and actual weight is where most project budgets quietly bleed. With our ASTM A500 Gr.B welded square steel tube supplier line, every heat is measured in-house before it leaves the mill, and ±1% tolerance is enforced on wall thickness, not just averaged across the bundle [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections].
How 120×120 ERW Square Tubes Match Curtain Wall and Structural Frame Loads
For glass curtain wall framing and exposed architectural columns, the 120×120mm section gives a clean, proportional profile that hides bolt connections behind standard bracket depths. The ERW welding process on ASTM A500 Gr.B welded square steel tube delivers consistent corner geometry, which matters when facade mullions need to sit flush against adjacent members. On structural frames carrying vertical loads from multiple floors, the 1–30mm wall range lets engineers step up thickness at base levels without changing the outer dimension — keeping connection details uniform from ground floor to roof.
Engineering Compliance: Load Paths, Corrosion, and Certification
Structural frames designed to EN 1993 or AISC 360 require documented yield strength and verified section properties — which means the mill test certificate must trace back to the heat number on every piece. For coastal or industrial environments, hot-dip galvanized ASTM A500 Gr.B welded square steel tube resists corrosion without adding field-painting cycles that delay handover. Steel grade selection directly governs load capacity: S355JR carries roughly 50% more yield than S235JR in the same section, which can reduce member sizes and free up architectural headroom. EU-bound shipments need CE marking under EN 10219 or EN 10210 to clear customs — missing the correct standard reference on the certificate is the most common reason containers get held at Rotterdam or Hamburg [NEED_CITE: CE marking requirements for structural hollow sections under EN 10219].
Steel Grade Selection and ERW Welding: What the Spec Sheet Does Not Say
The ASTM A500 Gr.B welded square steel tube sits in the mid-range yield family — Gr.B requires minimum 290 MPa yield, while Gr.C pushes to 345 MPa, enough to downsize members in heavily loaded frames. EN 10219 S235JR through S355J2 follows the same logic: the J2 suffix adds Charpy impact testing at -20°C, which matters for unheated warehouses in northern climates. ERW welding produces a longitudinal seam that is induction-heated and forged under pressure — the weld zone grain structure is refined, making it suitable for static and moderate dynamic loads. For purely aesthetic applications where the weld line is visible, black painting or varnish covers the seam; for buried or splash-zone use, galvanized coating adds 60–80 microns of zinc protection. Wall thickness tolerance of ±1% means a specified 6mm wall will measure between 5.94mm and 6.06mm — tight enough that theoretical weight calculations hold in the field [NEED_CITE: steel grade equivalence between ASTM A500 and EN 10219 standards].
Hidden Costs When Material Certificates Do Not Match Site Reality
Ordering ASTM A500 Gr.B welded square steel tube without verified mill test certificates creates three failure modes: customs rejection at destination, structural engineer sign-off delays, and — worst case — in-service cracking at weld zones under cyclic loading. A container held at port for missing CE documentation costs more in demurrage than the steel itself. Material substitution — shipping S235 when S355 was specified — passes visual inspection but fails mechanical testing, forcing full bundle replacement and schedule collapse. The fix is simple: require EN 10204 3.1 certificates with heat-by-heat chemistry and mechanical data, and confirm third-party inspection rights before signing the PI [NEED_CITE: EN 10204 inspection document types for steel products].
Why Project Procurement Teams Source ASTM A500 Gr.B Welded Square Steel Tube Here
Every ASTM A500 Gr.B welded square steel tube leaving this mill runs through an in-house physical and chemical laboratory — dimensional checks, tensile tests, and chemical composition analysis happen before the bundle gets tagged. The factory covers over 2,800 specifications across square, rectangular, and round sections, so a project needing 120×120 structural tubes plus matching H-beams and channels sources from one PO instead of three suppliers. Full CE certification under EN 10219 and EN 10210 means EU customs clearance is documented, not negotiated at the port. Custom non-standard sizes and cut-to-length service eliminate site waste, and professional container loading with anti-damage measures prevents the bending and surface scratches that trigger rejection at destination. Third-party inspection through SGS or BV is arranged on request, and every shipment carries traceable heat numbers from mill to site.
Documentation & Compliance
- Mill Test Certificate documenting ASTM A500 Gr.B chemical composition and mechanical properties per heat number, conforming to EN 10204 3.1
- CE certificate under EN 10219 and EN 10210 for structural hollow sections, required for EU market access and customs clearance
- ISO 9001:2015 quality management certificate covering ERW welding process control and dimensional inspection
- SGS or BV third-party inspection report available for pre-shipment verification of wall thickness, coating weight, and mechanical properties
- Material traceability by heat number stamped on each tube, matching mill test certificate and packing list
- Full customs documentation set: commercial invoice, packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- ASTM A500 Gr.B welded square steel tubes bundled with high-tensile steel strips, separated by timber dunnage to prevent surface scoring during ocean transit
- Galvanized square tubes packed with edge protectors and waterproof wrapping to preserve zinc coating integrity through humid port storage
- 6m and 12m lengths loaded in dedicated 20ft or 40ft containers with optimized nesting for 120×120mm and larger sections, maximizing payload per shipment
- Cut-to-length service available for 5.8m, 11.8m, or random lengths to match project framing modules and reduce site cutting waste
- Heat number, steel grade, and size stenciled on each bundle tag, matching mill test certificate for site verification
- FOB, CIF, and DDP shipping terms available with full export documentation and container tracking until port arrival
Getting Your ASTM A500 Gr.B Quote and Mill Test Certificate
Submit your size range, wall thickness, steel grade, surface treatment, and destination port — the engineering team responds within 12 hours with unit pricing, lead time, and sample mill test certificates for your review. Custom non-standard sizes and cut-to-length options are quoted alongside standard stock ranges, and third-party inspection can be confirmed before the deposit is paid.
Request Your ASTM A500 Gr.B Welded Square Steel Tube Quotation
Send your specification sheet to receive pricing, EN 10204 3.1 mill test certificates, and CE documentation for your destination market.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do ASTM A500 Gr.B and EN 10219 S235JR compare for the same structural application?
A: ASTM A500 Gr.B requires minimum 290 MPa yield strength, while EN 10219 S235JR requires 235 MPa — so Gr.B carries higher load in the same section. Both are ERW welded square tubes, but the certification path differs: ASTM for North American projects, EN 10219 with CE marking for EU customs. We supply both grades from the same production line with full mill test certificates for either standard.
Q: Can you produce non-standard sizes outside the 19×19mm to 800×800mm range?
A: Custom non-standard sizes are available with low MOQ for project-specific requirements. The factory covers over 2,800 specifications, and dedicated tooling handles non-standard side lengths or wall thicknesses outside the standard range. Submit your drawing or dimension sheet for a custom quote with lead time confirmation.
Q: What surface treatment is best for coastal or high-humidity environments?
A: Hot-dip galvanized coating provides 60–80 microns of zinc protection, suitable for coastal facades, bridge supports, and outdoor scaffolding. Black painting or varnish works for indoor structural frames where corrosion risk is low. Bare tubes are shipped for projects that apply field coating after fabrication.
Q: What documentation is required for EU customs clearance?
A: EU imports of structural hollow sections require CE marking under EN 10219 or EN 10210, with a Declaration of Performance and mill test certificate conforming to EN 10204 3.1. We provide full CE certification and customs documentation for every EU-bound shipment, and third-party inspection through SGS or BV can be arranged before loading.
Q: How is theoretical weight calculated, and does negative tolerance affect invoicing?
A: Theoretical weight is calculated from nominal dimensions and standard steel density. Our ±1% wall thickness tolerance means actual weight stays close to theoretical, and invoicing can be based on theoretical or actual weight per your preference. Full dimensional inspection reports are provided before shipment to confirm compliance.
Deliver Your ASTM A500 Gr.B Welded Square Steel Tube Inquiry Today
Submit your size, grade, and quantity to receive a detailed quotation with mill test certificates and CE documentation within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
