Description
Factory-Direct S255JR Square Steel Tube — Own steel mill produces raw billets through to finished ERW and seamless square hollow sections, eliminating third-party material sourcing gaps.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S255JR Square Steel Tube |
| Product Type | Square Steel Tube (Seamless & ERW) |
| Steel Grade | S255JR, Gr.B, S235, S275, S355, STK400 |
| 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 | Welded (ERW) / Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures / Construction frames / Building structures / Curtain walls / Support tubes / Machinery |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Warehouse frames, logistics center columns, factory building portals |
| Infrastructure | Platform support structures, pipe racks, stairway stringers |
| EPC Projects | Structural bracing members, equipment support frames, modular skid bases |
| Machinery | Conveyor support structures, machine base frames, equipment guarding posts |
What Negative Tolerance Really Costs on a Structural Frame Order
Every percent of wall thickness below specification shifts load-bearing capacity and triggers rejection at site inspection.
When a fabricator sources S255JR square steel tube from a third-party trader rather than rolling it in-house, the material certification chain develops gaps. Buyers receive mill test certificates that reference heat numbers they cannot trace back to actual production batches. On a recent Southeast Asian warehouse project, a container of square tubes arrived at the port with wall thickness deviation far beyond acceptable limits — the actual weight fell nearly twelve percent below theoretical calculations. The entire shipment was held pending re-inspection.
This is not an isolated incident. Quality control distance between the buyer and an unknown subcontractor creates exactly this type of exposure. Material traceability breaks down when the fabricator does not control the steelmaking process, and dimensional accuracy becomes a matter of trust rather than verified fact. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching S255JR Square Steel Tube to Structural Frame Requirements
Square hollow sections serve as primary load-bearing members in portal frames, column systems, and bracing configurations where bidirectional bending resistance matters. The S255JR grade provides adequate yield strength for medium-rise commercial structures and industrial facilities across moderate climate zones. Our vertically integrated production means the S255JR square steel tube you receive carries full traceability from billet to finished section — no material sourcing gaps between mill and fabrication shop.
Engineering Compliance and Certification Pathways
Structural steel members for EU-bound projects must comply with EN 10210 for hot-finished or EN 10219 for cold-formed hollow sections, with CE marking mandatory under the Construction Products Regulation. North American projects typically require ASTM A500 Grade B or Grade C compliance, verified through mill test certificates showing chemical composition and mechanical properties. The S255JR grade under EN 10025 corresponds broadly to ASTM A500 Grade B in yield strength terms, though equivalence requires project engineer approval. [NEED_CITE: steel grade equivalence between EN 10025 S255JR and ASTM A500 standards] Surface treatment selection — hot-dip galvanized for coastal or high-humidity environments, black painted for interior applications, or bare for sites requiring field welding — directly affects long-term corrosion performance and maintenance intervals.
Understanding S255JR Grade and ERW Manufacturing Process
The S-series designation under EN 10025 indicates structural steel with specified minimum yield strength — S255JR delivers 255 MPa yield at nominal thickness up to 16mm, with the JR suffix denoting room-temperature Charpy impact toughness at 27 Joules. This grade sits between S235 and S355 in the strength hierarchy, making it the default choice for general construction frames where higher grades offer no structural advantage but increase material cost. ERW (Electric Resistance Welded) manufacturing forms the square section from coil through progressive rolling stations and welds the seam through electrical resistance heating — this process produces tight dimensional tolerance and consistent mechanical properties across the section. [NEED_CITE: ERW versus seamless hollow section manufacturing process comparison] Wall thickness tolerance of ±1% ensures that theoretical weight calculations match actual delivered weight, preventing the hidden cost of under-specification material that fails structural verification at site.
The Hidden Cost of Procuring Without Verified Certification
Material substitution without proper documentation creates cascading failures: customs authorities reject shipments lacking valid EN 10204 3.1 or 3.2 certificates, structural engineers refuse to approve as-built documentation, and project owners face liability exposure if certified grades cannot be demonstrated. A square tube that looks dimensionally correct but carries insufficient wall thickness will fail ultrasonic thickness testing during quality audits. The cost of replacing rejected material after arrival at site — including demurrage, re-shipping, and project delay penalties — typically exceeds the original material cost by a significant multiple. [NEED_CITE: structural steel certification requirements for international construction projects]
Why Source S255JR Square Steel Tube from Our Mill
Our facility operates three dedicated production lines for square and rectangular hollow sections, backed by an integrated steel mill that produces the raw material. This vertical integration means we control chemistry from the billet stage through final dimensioning — every S255JR square steel tube carries a heat number traceable to our ladle analysis records. We maintain over 2,800 specifications in stock across multiple grades and dimensions, reducing lead time for urgent project requirements. Our in-house laboratory performs chemical composition analysis and mechanical testing per EN ISO 17025 standards, issuing mill test certificates that meet EN 10204 3.1 requirements. Third-party inspection through SGS, BV, or TUV is available for projects requiring independent verification. We hold CE certification under EN 1090 for structural steel components, ISO 9001 for quality management, and certified welding procedures under AWS and EN standards for fabrication services.
Documentation & Compliance
- Mill test certificate documenting S255JR chemical composition (C, Mn, Si, P, S content) and mechanical properties (yield strength, tensile strength, elongation) per EN 10025-2
- CE certificate confirming EN 10219 compliance for cold-formed structural hollow sections, required for EU market access under Construction Products Regulation
- ISO 9001 quality management system certificate covering the full production process from raw material incoming inspection through final dimensional verification
- SGS or BV third-party inspection report available upon request, covering visual examination, dimensional checks, and witness testing for specific heat numbers
- Material traceability documentation linking each bundle to its heat number, production date, and corresponding mill test certificate
- Export documentation package including commercial invoice, packing list, bill of lading, and certificate of origin for customs clearance at destination port
Packaging, Loading & Delivery
- S255JR square steel tubes bundled with high-tensile steel strips at intervals preventing bundle separation during ocean transit, with edge protectors preserving surface treatment integrity
- Galvanized square tubes packed with separation layers preventing zinc coating damage from contact friction during transport and handling
- Black painted or varnished surfaces wrapped in waterproof paper or plastic sheeting to prevent moisture contact and surface degradation during container shipping
- Container loading optimized for 5.8m and 6m lengths in 20-foot containers, 11.8m and 12m lengths in 40-foot open-top or flat-rack containers for oversized sections above 400mm
- Each bundle marked with heat number, steel grade (S255JR), size specification, and length for site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional stowage planning for heavy structural sections, ensuring weight distribution complies with container safety standards
Initiating Your S255JR Square Steel Tube Inquiry
Submit project specifications including steel grade requirement, section dimensions, wall thickness, total tonnage, and destination port to receive a detailed quotation with production timeline and mill test certificate sample. Our engineering team reviews your drawings to confirm section suitability and suggests material optimization where alternative grades or dimensions reduce cost without compromising structural performance. We confirm certification requirements specific to your destination market — CE marking for EU projects, ASTM compliance for North American specifications, or SGS pre-shipment inspection for markets requiring independent verification.
Request Quotation with Mill Test Certificate
Send your S255JR square steel tube specifications to receive pricing, certification documentation, and production schedule within 24 hours.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Email: admin@xjystructure.com
Tel: +86 531 8573 6315
WhatsApp: +86 188 5315 7756
