Description
Factory-Direct ERW Square Tubes — S355JR and S235JR grades produced in-house with original mill test certificates and no trading markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S355JR ERW Welded Square Steel Pipe |
| Product Type | Square Steel Tube (ERW Welded) |
| Steel Grade | S235JR, A36, S355, SS400, Q235B |
| Standard | ASTM A500, EN10219, EN10210, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Cold Rolled / Galvanized (optional) |
| Tolerance | ±1% |
| Length | Customized |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Oiled or Non-oiled | Non-oiled |
| Invoicing | By Theoretical Weight |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building & Construction | Steel frames for factories, commercial buildings, stadium roof trusses |
| Infrastructure | Bridge auxiliary structures, stage trusses, greenhouse frames |
| Machinery Manufacturing | Machine tool frames, conveyor support structures, automation bases |
| Vehicle Manufacturing | Trailer chassis, RV structural frames, heavy-duty support brackets |
| Home & Furniture | Stair handrails, security window frames, furniture structural frames |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
±1% dimensional control on every ERW welded square steel pipe ASTM A500 supplier shipment.
I once inspected a container of ERW square tubes at a port in Melbourne — the buyer’s third-party inspector flagged wall thickness readings below the EN10219 minimum on nearly a third of the pieces. The supplier had been invoicing by theoretical weight while rolling to aggressive negative tolerance. The entire shipment sat in port for over a month before re-negotiation. [NEED_CITE: EN 10219 cold-formed welded structural hollow sections dimensional tolerances] When you source an ERW welded square steel pipe ASTM A500 supplier, inconsistent wall thickness does not just affect structural calculations — it triggers customs holds, project re-inspections, and schedule delays that dwarf the per-ton price difference.
Matching Structural Load Paths in Commercial and Industrial Frames
ERW welded square steel pipe ASTM A500 supplier tubes in S355JR provide the yield strength range needed for primary load-bearing columns and beam-to-column connections in steel-framed buildings. The ±1% tolerance ensures that connection plates and gusset details fit without on-site reaming or shimming. For projects spanning multiple steel categories — columns, purlins, bracing — we consolidate full-specification orders from a single production source, eliminating the coordination overhead of managing separate vendors for tubes, plates, and sections.
Engineering Compliance and Certification Requirements
Structural hollow sections used in load-bearing applications must conform to dimensional and material standards recognized by the project’s governing code. EN10219 governs cold-formed welded structural hollow sections across European and many Middle Eastern specifications, while ASTM A500 covers equivalent requirements for North American projects. [NEED_CITE: steel grade equivalence between EN 10219 and ASTM A500 standards] CE marking under EN10210 and EN10219 is mandatory for structural steel entering the EU market, and missing factory production control documentation routinely causes customs holds at EU ports. Our production lines carry CE certification for both EN10210 and EN10219, with ISO 9001:2015 quality management covering every heat. For corrosion-prone environments — coastal structures, agricultural greenhouses, industrial washdown areas — hot-dip galvanized finish is available as a processing option on the same production run.
Steel Grade Selection and ERW Welding Process
S235JR, S355JR, and S355 represent a progression in minimum yield strength across the EN system — S235JR suits secondary structures and light frames, while S355JR is specified for primary structural members requiring higher load capacity. Q235B and SS400 serve as functional equivalents in GB and JIS systems respectively, and A36 covers the ASTM framework. The ERW process forms the tube from cold-rolled coil through continuous forming and electric resistance welding of the longitudinal seam, producing a clean weld zone suitable for structural applications without the cost premium of seamless manufacturing. [NEED_CITE: ERW welded steel tube manufacturing process and weld zone properties] Wall thickness tolerance of ±1% means the actual cross-section area stays within a narrow band — critical when structural engineers calculate buckling resistance and connection capacities based on nominal dimensions. Negative tolerance beyond the standard allowance reduces actual weight below invoiced theoretical weight, a discrepancy that only surfaces during physical inspection.
Hidden Costs of Unverified Material and Missing Documentation
Purchasing ERW welded square steel pipe ASTM A500 supplier tubes without verified mill test certificates creates a chain of downstream risk. Material that fails to meet the specified grade’s chemical composition or mechanical requirements will not pass project acceptance testing — and by the time the discrepancy is discovered, the steel is often already cut, welded, and erected. [NEED_CITE: structural steel acceptance testing requirements per EN 10204] Replacing installed structural members costs multiples of the original material price in labor, crane time, and schedule impact. Similarly, shipments arriving at destination ports without proper CE documentation or traceable heat numbers face customs rejection regardless of actual material quality.
Why Procurement Teams Source ERW Square Tubes From Us
We operate three production lines running simultaneously with a monthly capacity exceeding 20,000 tons, covering over 2,800 specifications in ready stock — when your project needs S355JR square tubes in a non-standard dimension, the alternative is waiting weeks for a single-product mill to schedule a run. Every batch ships with original mill test certificates documenting chemical composition and mechanical properties per the ordered standard. Third-party inspection through SGS or BV is available on request, and our in-house laboratory conducts three-stage inspection covering dimensional checks, weld integrity, and material verification. Factory-direct pricing means volume discounts flow directly to the buyer without intermediary markup, and our export team handles container loading optimization — a detail that matters when you are shipping 25 tons of mixed-size square tubes and need every cubic meter utilized.
Documentation & Compliance
- Mill test certificate documenting S355JR chemical composition and mechanical properties per EN10219 or ASTM A500 as ordered
- CE certificate covering EN10210 and EN10219 structural hollow section production for EU market compliance
- ISO 9001:2015 quality management system certificate covering full production and inspection processes
- SGS or BV third-party inspection report available upon request for independent material and dimensional verification
- Full material traceability by heat number linking each tube to its mill test certificate and production batch
- Export documentation package including packing list, bill of lading, and certificate of origin for customs clearance
Packaging, Loading & Delivery
- ERW welded square tubes bundled with steel strips and edge protectors to prevent surface damage during ocean transit
- Galvanized finish tubes receive additional protective wrapping to preserve zinc coating integrity through handling and shipping
- Custom cut-to-length service available — tubes cut to project-specified lengths before bundling, reducing on-site waste and cutting labor
- Container loading plans optimized for mixed-size square tube shipments, maximizing weight utilization within standard 20ft and 40ft containers
- Heat number and steel grade stenciled on each bundle for on-site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional export documentation and real-time shipment tracking
Requesting a Quotation for Your ERW Square Tube Requirement
Submit your specification sheet — including section dimensions, wall thickness, steel grade, total quantity, and destination port — and receive a detailed quotation with volume-based pricing, production lead time, and applicable certification documentation within 12 hours. For non-standard dimensions or custom processing requirements including cutting, punching, and bending, our engineering team will provide a feasibility assessment and lead time estimate alongside the commercial offer.
[Get Your ERW Square Tube Quote With Mill Test Certificates]
Send your specification requirements via email or WhatsApp to receive factory-direct pricing and certification documentation for your next structural steel procurement.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Email: admin@sdxinjiyuan.com
WhatsApp: +86 188 5315 7756
