Description
Factory-Direct ERW Hollow Sections — S355JR square tubes produced in-house with full EN10219 compliance and mill test certificates issued from our own laboratory.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S355JR ERW Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube (ERW Hollow Section) |
| Steel Grade | S235JR, S355JR, S355, Q235B, A36, SS400 |
| Standard | ASTM A500, EN10219, EN10210, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Size Range | 40×40 mm |
| Wall Thickness | 3 mm |
| Length | Customized |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Galvanized / Oiled / Black (per customer requirement) |
| Tolerance | ±1% |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Steel Structures | Portal frames, column bracing, roof trusses for industrial warehouses and commercial buildings |
| Construction Frames | Load-bearing skeleton for mid-rise buildings, modular housing units |
| Machinery Manufacturing | Equipment bases, conveyor support frames, automation rig structures |
| Infrastructure Construction | Sound barrier posts, lighting pole foundations, bridge handrail supports |
| Vehicle Manufacturing | Trailer chassis cross-members, roll-over protection structures |
Where EN10219 Certification Decides Customs Clearance for Your S355JR ERW Welded Square Steel Tube Order
A missing CE mark on EN10219 hollow sections can hold an entire container at EU port for weeks.
Procurement teams ordering S355JR ERW welded square steel tube for European projects frequently discover—after the goods have already shipped—that the mill test certificate references the wrong standard code, or the CE declaration cites EN10210 instead of EN10219 for cold-formed sections. The result is customs rejection, warehouse demurrage charges, and a scramble to arrange third-party re-inspection on-site [NEED_CITE: EN 10219 cold-formed structural hollow section delivery conditions]. Beyond certification mismatches, buyers sourcing from trading companies rather than direct mills often receive material that passes visual inspection but fails chemical composition verification when tested at destination labs—particularly on manganese and sulfur content critical to S355JR weldability.
Matching 40×40×3mm S355JR Square Tubes to Structural Frame Requirements
The 40×40×3mm profile sits at a practical intersection for light-to-medium structural applications: the 3 mm wall provides adequate section modulus for bracing members and secondary frames without excessive weight, while the 40 mm face width accepts standard M8–M12 bolt connections without edge-distance conflicts. For S355JR ERW welded square steel tube used in machinery bases and conveyor structures, the ±1% dimensional tolerance ensures that pre-drilled connection plates align without on-site reaming. Our production lines cover this specification as part of a broader range extending to 40 mm wall thickness, meaning if your engineering team later upsizes to heavier sections for the same project, the material continuity and certification chain remain consistent from a single source.
Engineering Compliance and Surface Protection for S355JR Hollow Sections
Structural designers specifying S355JR to EN10219 expect documented conformity with European execution standards for steel structures (EN 1090-2), which requires CE-marked hollow sections with traceable heat numbers [NEED_CITE: EN 1090-2 execution class requirements for structural steel]. For projects in coastal or industrial-corrosion environments, the hot-dip galvanized surface treatment option extends service life without ongoing maintenance—critical for infrastructure applications like sound barriers and lighting pole foundations where access for repainting is impractical. The ERW welding process produces a longitudinal seam that, when properly normalized, achieves weld-zone mechanical properties matching the parent metal, satisfying the impact testing requirements at 20°C for the JR quality designation. Custom cut-to-length service eliminates on-site cutting waste and reduces secondary processing at the construction yard.
Understanding S355JR Grade Selection and ERW Process Characteristics
S355JR belongs to the European non-alloy structural steel family under EN10025-2, where the “355” indicates minimum yield strength classification and “JR” specifies Charpy impact energy at room temperature. When cross-referencing against ASTM A500 Grade B/C or Chinese Q235B/Q345B, the equivalence is approximate rather than identical—differences exist in phosphorus and sulfur limits, elongation requirements, and the testing temperature for impact verification [NEED_CITE: steel grade equivalence between EN 10025 and ASTM A500 standards]. The ERW process forms the square profile from continuously fed strip steel through progressive roll forming, followed by high-frequency electric resistance welding and external/internal weld bead flash removal. Compared with seamless production, ERW delivers tighter dimensional tolerance on wall thickness and lower cost for the structural grade ranges used in building frames and machinery—while SSAW remains reserved for large-diameter pipeline applications outside the scope of square hollow sections. The galvanized coating applied post-forming provides uniform coverage on all four faces and corner radii, whereas pre-galvanized strip would leave the weld seam with a different coating thickness from the flat surfaces.
Hidden Costs of Procuring Non-Conforming S355JR ERW Welded Square Steel Tube
Ordering S355JR ERW welded square steel tube from suppliers who cannot provide verifiable mill test certificates creates compounding downstream risks. Material that fails chemical composition verification at destination—particularly carbon equivalent values affecting weldability—forces either rejection and replacement or costly engineering reassessment of welded connections. Negative tolerance stacking beyond the ±1% declaration means actual wall thickness falls below design assumptions, reducing load-bearing capacity and potentially triggering structural engineer re-approval requirements [NEED_CITE: dimensional tolerance requirements for cold-formed structural hollow sections per EN 10219]. Certification gaps—missing CE marks, incorrect EN standard references, or incomplete third-party inspection reports—translate directly into customs holds, project acceptance delays, and contractual penalties on time-sensitive construction programs.
Procurement Confidence Through Direct Mill Capability
As the original inventor of sharp-corner rectangular steel tubes in China holding 41 patents, our factory operates three dedicated production lines covering over 2,800 specifications—including the 40×40×3mm S355JR ERW welded square steel tube profile—with wall thickness capability extending to 40 mm for heavy structural requirements. Our in-house physical and chemical laboratory issues mill test certificates for every heat, eliminating the documentation delays common when trading companies must request certificates from upstream mills. Full international certification coverage includes Lloyd’s CE marking per EN10210 and EN10219, Singapore FPC approval, and verification reports from SGS and BV—ensuring customs clearance across EU, Middle Eastern, and Southeast Asian ports. We participated in drafting China’s cold-formed steel industry standards in 2018, reflecting technical depth that translates into consistent production quality for export orders. Professional container loading with anti-damage measures—corner protectors, timber separators, and weight-distributed stowage—prevents the surface dents and edge deformation that cause rejection at destination.
Documentation & Compliance
- Mill test certificate documenting S355JR chemical composition (C, Mn, Si, P, S) and mechanical properties (yield strength, tensile strength, elongation) per EN10219
- CE certificate of conformity covering EN10210 and EN10219 standards for structural hollow sections exported to EU markets
- ISO 9001:2015 quality management system certificate covering the full production process from raw material inspection to finished product dispatch
- SGS or BV third-party inspection report available upon request, covering dimensional verification, visual examination, and coating thickness measurement for galvanized S355JR square tubes
- Heat number traceability stamped on each tube, linking back to the original steel coil test certificate
- Export documentation package including commercial invoice, packing list, bill of lading, and certificate of origin for customs clearance
Packaging, Loading & Delivery
- S355JR ERW welded square steel tubes bundled with steel strips and edge protectors to maintain bundle integrity during ocean freight
- Galvanized surface protected with moisture-resistant wrapping and timber separators to prevent white rust formation during transit
- Container loading optimized for 40×40×3mm profile dimensions, maximizing payload per 20ft or 40ft container while maintaining weight distribution
- Custom cut-to-length service available, with tubes bundled and labeled by specified length to reduce on-site sorting
- Heat number and steel grade (S355JR) stenciled on each bundle tag for traceability verification at destination
- FOB, CIF, and DDP shipping terms supported with professional export documentation and tracking through to project site
Initiating Your S355JR ERW Welded Square Steel Tube Inquiry
Submit your required dimensions, steel grade preference, surface treatment specification, and destination port to receive a detailed quotation including unit pricing, production lead time, and applicable certification documents. For non-standard sizes or custom processing requirements—cutting, punching, or bending—our engineering team provides technical feasibility confirmation before order placement.
Request Quotation and Mill Test Certificate
Send your specification details to receive pricing, certification confirmation, and container loading plan for your S355JR ERW welded square steel tube order.
Company: 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
