Description
Direct Mill Supply for ERW Square Tubes — XJY Structure produces S355JR ERW square steel tubes from our own steel mill, eliminating third-party material sourcing and ensuring full heat-level traceability from slab to finished 80×40×2 mm section.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S355JR ERW Square Steel Tube |
| Product Type | ERW Square Steel Tube |
| Steel Grades | S235JR, S355JR, A36, SS400, Q235B |
| Standard | BS, EN, GB, AISI, ASTM, DIN, JIS, ASTM A500, EN10219, EN10210, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Outer Diameter or Side Length | 80×40 mm |
| Wall Thickness | 2 mm |
| Length | Customized |
| Technique | ERW |
| Surface Treatment | Cold Rolled |
| Tolerance | ±1% |
| Ends | Non-oiled |
| Application | Building structures, machinery manufacturing, home decor, infrastructure, vehicle manufacturing |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial & Industrial Construction | Steel frame structures, trusses, columns, and beam assemblies for factories, warehouses, and commercial centers |
| Machinery Manufacturing | Machine tool frames, conveyor support frames, automation equipment bases |
| Infrastructure | Auxiliary bridge structures, stage trusses, greenhouse frame systems |
| Vehicle Manufacturing | Trailer chassis frames, recreational vehicle structural frames |
| Architectural & Decorative | Stair handrails, security window frames, furniture structural frames |
What Material Traceability Gaps Cost on an 80×40 ERW Square Tube Order
A missing heat number on a mill certificate can halt customs clearance or trigger full-batch rejection at site inspection.
When procurement teams order S355JR ERW square steel tube from overseas fabricators who source raw material from third-party traders, the certification chain breaks. Mill test certificates reference heat numbers that cannot be cross-checked against actual chemistry. Buyers discover copper and chromium content below specification only after SGS testing at destination — by then, an entire container of 80×40×2 mm tubes has already been cut and welded into facade panels. [NEED_CITE: material traceability requirements in EN 10219 cold-formed hollow sections]
The S355JR ERW square steel tube supplier you choose must control steel production in-house. Vertically integrated mills issue MTCs tied to real heat-level chemistry, not forwarded documents from unknown sub-suppliers.
How 80×40×2 mm ERW Sections Match Structural Frame Requirements
The 80×40 mm rectangular profile with 2 mm wall thickness delivers an optimal strength-to-weight ratio for non-primary structural members. Cold rolled surface finish provides dimensional consistency across long production runs, while the ±1% tolerance ensures connection plates and gussets fit without on-site reaming. The S355JR ERW square steel tube in this profile serves as purlin supports, secondary bracing, and equipment mounting frames where full S355 structural grade is specified but heavy-wall sections would add unnecessary weight.
Engineering Compliance and Certification Pathways
Structural frames for EU-market projects require EN10219 compliance for cold-formed welded structural hollow sections. The S355JR grade meets the minimum yield strength threshold for EN 1993 design calculations, while A36 and SS400 equivalents serve projects following ASTM or JIS frameworks respectively. Non-oiled ends arrive ready for site welding without grinding off protective coatings. For projects demanding third-party verification, SGS or BV inspection can be arranged before shipment to validate dimensional accuracy and surface condition. [NEED_CITE: EN 10219 dimensional tolerance classes for cold-formed structural hollow sections]
Understanding ERW Process and S355JR Grade Selection
ERW (Electric Resistance Welding) forms the square section by cold-rolling steel strip into shape and welding the seam through electrical resistance heat. This process produces a clean internal weld bead with minimal heat-affected zone, making it suitable for structural applications where the weld line does not face direct bending stress. The cold rolled surface treatment follows forming, delivering a smooth finish that accepts paint or powder coating without additional grinding.
S355JR sits in the mid-range of European structural grades — higher yield than S235JR for reduced section sizes, but without the impact testing requirements of S355J2 for sub-zero environments. For projects in tropical or temperate climates, S355JR provides adequate toughness at standard service temperatures. The Q235B and SS400 alternatives serve equivalent roles in GB and JIS specification systems respectively. [NEED_CITE: steel grade equivalence mapping between EN 10025 and ASTM A572 standards]
Hidden Costs of Sourcing ERW Square Tubes Without Verified Certification
Ordering 80×40×2 mm ERW tubes at the lowest quoted price often means accepting material from traders who cannot guarantee chemistry. When actual composition deviates from S355JR specification, the tubes may fail weld procedure qualification tests, forcing complete re-fabrication. Customs authorities in EU member states increasingly request EN10219 compliance documentation — shipments without CE marking face rejection at port. Negative tolerance beyond the declared ±1% reduces actual load-bearing capacity, creating structural safety concerns that only surface during engineer inspection. [NEED_CITE: structural steel compliance requirements for CE marking under EN 1090]
Why XJY Structure Delivers Verified S355JR ERW Square Tubes
XJY Structure operates as the fabrication division of Shandong Xin Jiyuan Special Steel Tube Co., Ltd, which runs its own steel production facility with three production lines. This vertical integration means the S355JR ERW square steel tube you order comes from steel we melted, not steel we bought from traders. Our in-house理化实验室 tests every heat for chemical composition before release. The fabrication workshop holds AWS and EN certified welding procedures, with qualified welders producing shop drawings reviewed against your project specifications. We maintain over 2,800 raw material specifications in stock, allowing custom length cutting for 80×40×2 mm sections without waiting for mill rolling schedules. Professional loading teams plan container stowage for oversized structural sections, reducing transport damage risk.
Documentation & Compliance
- Mill Test Certificate documenting S355JR chemical composition including carbon, manganese, silicon, sulfur, phosphorus content per EN10219 requirements
- CE certificate confirming EN10219 compliance for cold-formed welded structural hollow sections exported to EU markets
- ISO 9001 quality management certificate covering the full production process from steelmaking through ERW forming and cold rolling
- SGS or BV third-party inspection report verifying dimensional tolerance, surface finish, and weld quality for 80×40×2 mm sections
- Full material traceability linking each tube bundle to specific heat number with chemistry and mechanical test results
- Export documentation package including packing list, bill of lading, and certificate of origin for customs clearance
Packaging, Loading & Delivery
- Cold rolled S355JR ERW square tubes bundled with steel strips and edge protectors to preserve surface finish during ocean transit
- Custom length 80×40×2 mm sections cut to order and packed in seaworthy bundles optimized for 20ft or 40ft container loading
- Non-oiled ends protected with plastic caps to prevent moisture ingress and edge damage during handling
- Heat number and S355JR grade stenciled on each bundle for site identification and traceability verification
- Professional loading plans for oversized structural sections with proper lashing to prevent shifting during transit
- FOB, CIF, and DDP shipping terms available with complete export documentation for door-to-door delivery
Getting Your S355JR ERW Square Tube Quote
Submit your project drawings in PDF or DWG format along with required steel grades, quantities, and destination port. Our engineering team reviews specifications within 24 hours and provides a detailed quotation including material cost, fabrication, surface treatment, packing, and shipping. Shop drawings are prepared for your approval before production begins, ensuring dimensional accuracy for your structural connections.
Request Your S355JR ERW Square Steel Tube Quotation
Send your specifications to admin@xjystructure.com or contact us via WhatsApp at +86 188 5315 7756 for pricing, mill test certificates, and delivery schedules.
