Description
Factory-Direct ERW SHS — Own mill and fabrication workshop control every heat from raw plate to finished 800×800mm square tube.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube (Square Hollow Structural Section) |
| Steel Grade | Gr.B, S235, S275, S355, STK400, Q235B, Q345B |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| 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 | Steel structures / Construction frames / Building structures / Curtain wall supports / Machinery / Scaffolding |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial & Industrial Construction | Building frames, warehouse portals, mezzanine beams, curtain wall support grids |
| Infrastructure & Energy | Conveyor structures, solar mounting frames, bridge handrails, equipment platforms |
| Machinery & Equipment | Scaffolding systems, crane booms, machine guards, material handling frames |
| EPC & General Contracting | Column-to-beam assemblies, truss chords, bracing members for mid-rise structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a 30mm-wall ASTM A500 welded square steel tube is the difference between passing dimensional inspection and scrapping an entire container at the port.
Overseas buyers who source SHS from trading companies rather than integrated mills often discover wall-thickness drift only after SGS measures the lot at destination. A 7–8% negative tolerance on a 130×130 section — which I have seen firsthand — means theoretical weight and actual weight diverge by nearly a ton per batch, triggering warehouse rejection and contractual penalties. When the fabricator does not own the steel mill, material traceability breaks at the heat-number level, and no amount of paperwork can close that gap. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Wall Thickness to Load Path in Building Frames
An ASTM A500 welded square steel tube in S355 grade with 10–20mm wall thickness carries primary frame loads in warehouse and industrial building projects, while 1–5mm sections serve secondary bracing and curtain wall supports. The ERW weld seam, when produced under certified WPS with in-process NDT, delivers a joint efficiency that matches the parent metal — critical for moment-resisting connections in seismic zones. Our own mill produces the strip coil, rolls it into square sections, and welds under the same quality system, so every heat number on the MTC traces back to our ladle analysis.
Engineering Compliance Across ASTM, EN, and JIS Frameworks
Projects spanning multiple regions require steel grades that cross-reference cleanly: ASTM A500 Gr.B aligns broadly with EN S275JR in yield tier, while Q345B serves as the domestic equivalent for S355-class load requirements. [NEED_CITE: steel grade equivalence tables between ASTM A500 and EN 10219] EU-bound shipments need CE marking per EN 10210 or EN 10219, and North American EPCs typically insist on ASTM A500 with Charpy impact data at specified test temperatures. Our shop drawing review process catches specification conflicts before material is cut, avoiding the RFI delays that push fabrication schedules by weeks.
Why ERW Process and Grade Selection Matter for SHS
ERW welding forms the square profile from continuously rolled strip, then passes the seam through an induction forge that consolidates the weld under heat and pressure — producing a joint zone with grain structure comparable to the parent metal. This makes ERW ASTM A500 welded square steel tube cost-effective for structural applications where seamless is not mandated by code. Steel grade selection follows the load path: S235 suits light bracing and non-load-bearing frames, S275 covers typical warehouse portal frames, and S355 is specified for heavy-load columns and crane-supporting beams. Surface treatment choice — hot-dip galvanized for outdoor or corrosive environments, black painted for interior dry conditions, or bare for field-coated projects — directly affects both procurement cost and long-term maintenance cycles.
The Hidden Cost of Sourcing SHS Without Mill Traceability
When a buyer accepts a lower unit price from a trader who sources tubes from multiple small mills, the hidden costs emerge at three checkpoints: customs clearance fails because the MTC does not match the heat number stamped on the tube; structural inspection reveals wall thickness below the ±1% tolerance band, forcing on-site reinforcement or full replacement; and welding procedure qualification fails because the actual chemistry differs from what the certificate claims. [NEED_CITE: consequences of material certification non-compliance in structural steel procurement] These are not theoretical risks — they are the exact failure sequence I witnessed on a Southeast Asian warehouse project where 130mm square tubes arrived with undocumented negative tolerance, and the entire lot was rejected at the port warehouse.
Why Procurement Teams Choose an Integrated Mill-Fabricator
An ASTM A500 welded square steel tube from XJY Structure comes from a vertically integrated supply chain: our own steel mill produces the raw coil across 2,800+ specifications, and our fabrication workshop welds, cuts, and finishes the tube under one quality management system. This eliminates the material-traceability gap that occurs when fabricators buy from third-party mills. Every order ships with a complete documentation package — WPS, PQR, weld maps, dimensional inspection reports, and coating thickness measurements — not just a generic MTC. We hold CE certification per EN 10210 and EN 10219 for EU market access, ISO 9001 for quality management, and welcome SGS or BV third-party inspection at our facility before shipment. For project-specific requirements, our engineering team reviews shop drawings, optimizes material usage, and sequences fabrication to match site installation schedules.
Documentation & Compliance
- Mill Test Certificate documenting Gr.B / S355 chemical composition and mechanical properties per ASTM A500, with heat-number traceability to our own steel mill ladle analysis
- CE certificate per EN 10210 / EN 10219 for hot-finished and cold-formed welded hollow structural sections, required for EU customs clearance and structural approval
- ISO 9001 quality management certificate covering the full production chain from raw steel coil to finished galvanized or painted square tube
- SGS or BV third-party inspection report available upon request, covering dimensional checks, coating thickness, and weld seam quality before container loading
- Material traceability report linking each bundle to its heat number, WPS, and PQR records for welding procedure compliance
- Full export documentation set: packing list, bill of lading, certificate of origin, and fumigation certificate for destination-country customs
Packaging, Loading & Delivery
- ERW welded square tubes bundled with high-tensile steel strips and edge protectors, sized to match 5.8m / 6m / 11.8m / 12m lengths for optimal 20ft and 40ft container loading
- Galvanized ASTM A500 welded square steel tube surfaces wrapped with waterproof paper and plastic film to prevent white rust formation during ocean transit
- Black painted or bare tubes coated with anti-rust oil on inner and outer surfaces, with heat number and steel grade stenciled on each bundle for site identification
- Custom cutting to project-specific lengths available, with kerf allowance calculated to minimize waste on 6m and 12m standard sizes
- Professional loading plans for oversized sections up to 800×800mm, with lashing and bracing designed to prevent shifting during container or breakbulk shipment
- Delivery terms FOB / CIF / DDP with full container tracking and door-to-door logistics coordination for EPC project sites
How to Initiate a Procurement Inquiry for Your Project
Share your project drawings (PDF or DWG), required steel grades, wall thickness, surface treatment preference, and destination port — our team responds within 24 hours with a detailed quotation including material cost, fabrication charges, coating, packing, and shipping. For non-standard sizes outside the 19×19 to 800×800mm range or custom lengths, we provide engineering assessment and MOQ flexibility based on project volume. All certification and third-party inspection requirements are confirmed before contract signing, so there are no surprises at customs or on-site inspection.
Frequently Asked Questions
Q: Can you supply ASTM A500 welded square steel tube in both Gr.B and S355 grade for the same project?
A: Yes. Our own mill produces strip coil covering ASTM A500 Gr.B, EN S235/S275/S355, JIS STK400, and GB Q235B/Q345B. We can ship mixed-grade orders in one container, with each bundle clearly marked by steel grade and heat number for site sorting.
Q: What documentation do you provide for EU customs clearance and structural approval?
A: Every shipment includes CE marking per EN 10210 or EN 10219, Mill Test Certificate with full chemical and mechanical data, and traceability from our own steel mill heat number. We also provide packing list, bill of lading, and certificate of origin for customs.
Q: Do you accept third-party inspection before shipment?
A: Yes. SGS and BV inspections are welcome at our facility. We coordinate the inspection schedule with your surveyor and provide all required samples, test pieces, and documentation for their review.
Q: What is the minimum order quantity for custom non-standard sizes?
A: Standard sizes within 19×19 to 800×800mm and 1–30mm wall thickness have a 5-ton MOQ. For non-standard dimensions or special lengths, we evaluate based on project volume and can adjust MOQ accordingly.
Q: How do you handle surface treatment for galvanized versus black painted tubes?
A: Hot-dip galvanizing is applied for outdoor or corrosive environments, with coating thickness measured per project specification. Black painted or varnished finish is used for interior applications. Bare tubes are supplied with anti-rust oil for field coating. Each finish is documented in the coating inspection report.
Get Your ASTM A500 Welded Square Steel Tube Quotation with Full Mill Test Certificate
Send your project specifications — steel grade, size, wall thickness, quantity, and destination port — to receive a detailed quotation and Mill Test Certificate sample within 24 hours.
Tel: +86 531 8573 6315
Mobile / WhatsApp / WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Website: www.xjystructure.com
