Description
Factory-Direct ERW Square Tubes — ASTM A500 and EN 10219 certified S355JR sections ship straight from our Jinan mill, cutting distributor markups on every metric ton.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S355JR ERW Square Steel Tube |
| Product Type | Welded Square Steel Tube (ERW) |
| Steel Grade | S235JR, A36, S355, SS400, Q235B |
| Standard | ASTM A500, EN 10219, EN 10210, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Technique | ERW (Electric Resistance Welding) |
| Surface Treatment | Cold Rolled / Oiled or Non-oiled / Galvanized (optional) |
| Tolerance | ±1% |
| Length | Customized |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Steel trusses and column frameworks for industrial plants, stadiums, and commercial centers |
| Machinery Manufacturers | Machine tool frames, conveyor support structures, automation equipment bases |
| Construction Companies | High-rise building frameworks, bridge auxiliary structures, stage trusses |
| Infrastructure | Greenhouse frames, trailer chassis, RV structural frames |
| Architectural & Decor | Stair handrails, security window frames, furniture structural frames |
Where ASTM A500 Certification Decides Your Customs Clearance and Project Approval
Missing or mismatched mill certificates turn a routine shipment into a port-side rejection.
I have watched entire containers of square tubes sit at Jebel Ali because the mill test report listed S235 while the purchase order specified ASTM A500 Grade B. The steel was fine; the paperwork was not. When you source an ASTM A500 ERW square steel tube supplier, the certification chain must match your project specification exactly — EN 10219 for European structural work, ASTM A500 for North American jobs, JIS G3466 for Japanese-spec infrastructure. Fragmented sourcing from multiple vendors means juggling different certificate formats, inconsistent heat numbers, and grade equivalences that nobody bothered to document. [NEED_CITE: EN 10219 cold-formed structural hollow section certification requirements]
Matching S355JR Sections to Structural Frame Demands
S355JR ERW square steel tubes carry higher yield strength than S235JR alternatives, making them the default choice for load-bearing columns and truss members in industrial buildings and stadium roofs. The ERW welding process produces a clean, consistent longitudinal seam that holds up under the punching and bending operations common in steel fabrication shops. For machinery manufacturers building conveyor frames and automation equipment bases, the ±1% dimensional tolerance means connection plates bolt up without forcing or reaming. Our in-house physical and chemical laboratory tests every heat before release, so the mill test certificate you receive matches the steel that arrives on your job site.
Engineering Compliance Across EN, ASTM, and JIS Frameworks
Structural hollow sections used in European construction must conform to EN 10219 for cold-formed welded sections or EN 10210 for hot-finished profiles, with CE marking under the Construction Products Regulation. North American projects typically call for ASTM A500 Grade B or C, which requires different chemical composition limits than the S-series European grades. When your project spans multiple regions — say, a Middle East EPC contract specifying British Standards alongside local authority requirements — you need a supplier who can produce to EN, ASTM, and JIS standards on the same production line and issue the correct certificate for each destination. [NEED_CITE: steel grade equivalence between EN 10219 and ASTM A500 standards] Our Lloyd’s Register EU CE certification and Singapore FPC cover these compliance pathways, and third-party inspection through SGS or BV is available for projects that demand independent verification.
Understanding ERW Welding, Grade Selection, and Surface Treatment Trade-offs
ERW (Electric Resistance Welding) square tubes form from cold-rolled coil through a continuous forming process where the edges are heated by electrical resistance and forged together under pressure. This produces a tight, uniform weld seam suitable for structural applications at a lower cost than seamless alternatives. The S355JR grade offers higher yield strength than S235JR or Q235B, meaning you can reduce wall thickness — and therefore weight and cost — while maintaining the same load-bearing capacity. For corrosive environments such as greenhouse frames or coastal infrastructure, galvanized surface treatment extends service life significantly compared to oiled or bare cold-rolled finishes. The choice between oiled and non-oiled depends on whether the tubes will undergo further fabrication like welding or painting; oiled surfaces protect during transit but must be cleaned before coating application. Wall thickness tolerance of ±1% keeps theoretical weight calculations reliable for invoicing and structural engineering load calculations. [NEED_CITE: ERW welded steel tube manufacturing process and quality control]
The Hidden Cost of Wrong Grade Substitution and Tolerance Shortfalls
Ordering S235JR when the structural engineer specified S355JR does not show up until the building inspector requests the mill test certificate — at which point the steel is already welded into the frame. Replacing it means demolition, re-fabrication, and schedule delays that dwarf the original price difference between grades. Similarly, tubes that arrive with wall thickness below the specified tolerance trigger rejection under EN 10219 dimensional requirements, even if the steel chemistry is correct. Certification gaps cause customs holds that incur port storage fees running into thousands of dollars per container per week. [NEED_CITE: consequences of non-compliant steel certificates in international construction projects]
Why Engineering Procurement Teams Source From Our Jinan Mill
We run three dedicated production lines covering over 2,800 specifications with wall thickness up to 40mm, so your non-standard square section does not require sourcing from a second or third supplier. Every ASTM A500 ERW square steel tube that leaves our facility passes through our in-house physical and chemical laboratory, which tests chemical composition, tensile properties, and dimensional accuracy before release. Our 41 invention patents include proprietary sharp-corner rectangular tube technology that delivers tight corner radii for cleaner architectural connections. We hold CE certification under EN 10210 and EN 10219, ISO 9001:2015, Singapore FPC, and third-party verification from SGS and BV — covering compliance requirements across the EU, North America, and Southeast Asia. Professional loading plans optimize container utilization for long-length square tubes, and we coordinate door-to-door logistics to over 50 countries including the EU, North America, India, the Middle East, and Southeast Asia.
Documentation & Compliance
- Mill test certificate documenting S355JR chemical composition and mechanical properties per EN 10219 or ASTM A500 as specified
- Lloyd’s Register EU CE certificate covering EN 10210 and EN 10219 cold-formed and hot-finished structural hollow sections
- ISO 9001:2015 quality management system certificate covering the full production and inspection process
- SGS or BV third-party inspection report available upon request for project-specific material verification
- Full material traceability by heat number linking each bundle to its original mill test certificate
- Customs documentation package including packing list, bill of lading, and certificate of origin formatted for destination port requirements
Packaging, Loading & Delivery
- S355JR ERW square tubes bundled with high-tensile steel strips and edge protectors to prevent surface damage during ocean transit
- Galvanized square tubes wrapped with waterproof paper and secured on wooden cradles to preserve the zinc coating through humidity exposure
- Custom-length tubes cut to project specifications and grouped by size for efficient container loading and on-site identification
- Heat number and steel grade stenciled on each bundle for immediate traceability verification at the job site
- Professional loading plans optimized for square tube geometry, maximizing container payload while preventing shifting during transit
- FOB, CIF, and DDP shipping options with real-time tracking from Jinan mill to destination port or project site
Getting Your ASTM A500 ERW Square Steel Tube Quote Started
Send your specification sheet — including section dimensions, wall thickness, steel grade, quantity, surface treatment preference, and destination port — and we return a detailed quotation within 12 hours covering unit price, certification scope, production timeline, and shipping options. For non-standard sections or custom lengths outside our standard catalog, we provide a technical feasibility review and lead time estimate before you commit.
Request Your Mill Test Certificate and Project Pricing Today
Submit your ASTM A500 ERW square steel tube requirements by email or WhatsApp to receive a detailed quotation with material certification options and delivery timeline.
Email: admin@sdxjysteel.com
WhatsApp: +86 188 5315 7756
Website: www.sdxjysteel.com
Frequently Asked Questions
Q: How do S355JR, A36, and Q235B compare across EN, ASTM, and GB standards?
A: These grades belong to different standard systems — S355JR follows EN 10219, A36 follows ASTM, and Q235B follows GB/T 6728 — with varying chemical composition and mechanical property requirements. We produce to all three standards on the same production line and issue the corresponding mill test certificate for your project specification.
Q: Can you provide third-party inspection reports and material traceability documentation?
A: Yes. Every shipment includes mill test certificates with heat number traceability linking each bundle to its production batch. SGS and BV third-party inspection is available for projects requiring independent verification of chemical composition and dimensional accuracy.
Q: What is the MOQ for non-standard sizes and custom wall thickness?
A: We produce over 2,800 specifications with wall thickness up to 40mm. For custom non-standard sections outside our regular catalog, we evaluate feasibility based on your quantity and technical requirements and provide a tailored quotation.
Q: When should I choose galvanized versus oiled versus cold-rolled finish?
A: Galvanized finish suits corrosive environments such as coastal structures, greenhouses, and outdoor infrastructure. Oiled finish protects bare steel during transit and storage before painting or welding. Cold-rolled finish provides a clean surface for architectural applications where the tubes will be painted or powder-coated on site.
Q: Do your CE and ISO certificates meet EU and North American import requirements?
A: Our Lloyd’s Register EU CE certification covers EN 10210 and EN 10219 for European structural hollow sections. For North American projects requiring ASTM A500 compliance, we issue mill test certificates conforming to ASTM requirements. Both certification pathways are supported by our ISO 9001:2015 quality management system.
