Description
Direct Factory Supply for S255JR Seamless Square Tubes — Every S255JR seamless square steel tube rolls through our in-house laboratory for dimensional and mechanical verification before shipment, backed by EN 10219 and ASTM A500 mill test certificates.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S255JR Seamless Square Steel Tube |
| Product Type | Seamless Square and Rectangular Hollow Sections |
| Steel Grade | S255JR, Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091, EN 10219, EN 10210 |
| Section Shape | Square |
| Size Range | 19mm × 19mm – 800mm × 800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures, Construction frames, Curtain wall framing, Support tubes, Machinery, Scaffolding |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Steel Structure & Construction | Column and beam framing for high-rise buildings, industrial warehouse frames, bridge support structures |
| Architectural Facade | Curtain wall mullion and transom framing, exposed structural facades, canopy support systems |
| Machinery & Equipment | Conveyor frame structures, crane boom sections, industrial platform supports |
| Infrastructure | Scaffolding uprights and ledgers, sound barrier posts, solar panel mounting structures |
What Negative Tolerance Exceedance Costs on a Structural Frame Order
A mill test certificate that passes visual inspection but fails dimensional re-check at the destination port turns a routine delivery into a full-container rejection.
Procurement teams ordering S255JR seamless square steel tube for structural frames often assume that a quoted wall thickness matches the delivered product. In practice, some mills push negative tolerance beyond acceptable limits, meaning the actual wall thickness falls below the minimum specified in EN 10219 or ASTM A500. When SGS or BV re-inspects at the discharge port, the entire shipment can be flagged. The contractor faces project delays, replacement production costs, and potential structural recalculations — all because a dimension on paper did not match the steel in the container [NEED_CITE: EN 10219 cold-formed and seamless hollow section dimensional tolerance requirements].
How S255JR Seamless Square Tubes Match Structural Frame Requirements
S255JR seamless square steel tube in the 19×19mm to 800×800mm range covers the full spectrum from light curtain wall framing to heavy column sections in industrial structures. The seamless manufacturing process eliminates the weld seam found in ERW alternatives, providing uniform strength distribution across all four sides — critical when the tube serves as a load-bearing column subject to multi-directional stress. Our ±1% wall thickness tolerance ensures that structural engineers can rely on the published section properties without applying additional safety deductions for dimensional uncertainty.
Engineering Compliance and Certification Requirements
Structural frames designed under EN 1993 (Eurocode 3) require hollow sections that conform to EN 10219 or EN 10210, with documented chemical composition and mechanical properties traceable to each heat number. For projects entering the EU market, the CE mark under EN 10210/10219 is not optional — customs authorities routinely block shipments lacking Factory Production Control certification from accredited bodies such as Lloyd’s Register [NEED_CITE: CE marking requirements for structural steel hollow sections under EN 10210]. The S255JR grade specified here meets the S235–S355 range under EN 10219, with equivalent cross-references available for ASTM A500 Gr.B and GB/T 700 Q235B, eliminating grade substitution errors during international procurement.
Steel Grade Selection and Seamless Process Advantages
The S255JR grade sits in the lower-to-mid strength range of structural carbon steels, offering adequate yield performance for general construction framing while maintaining excellent weldability and formability. When projects demand higher load capacity, upgrading to S355 within the same product family provides increased yield strength without changing the procurement workflow or connection details. The seamless production method used for these square tubes differs fundamentally from ERW: the solid billet is pierced and drawn through a die sequence, producing a homogeneous grain structure with no longitudinal weld line. This makes seamless square tubes preferable for applications involving dynamic loading, external corrosion exposure, or visible architectural surfaces where weld line appearance matters. Surface treatment selection — bare for indoor use, black painted for moderate protection, or hot-dip galvanized for outdoor or coastal environments — should align with the project’s corrosion category per EN ISO 12944.
Hidden Costs of Procuring Without Verified Certification
Ordering S255JR seamless square steel tube based on price alone, without confirmed mill test certificates and third-party inspection rights, exposes the project to three categories of hidden cost. First, material that fails to meet the declared standard at destination triggers customs holds or rejection, with demurrage and reshipment expenses accumulating daily. Second, wall thickness below the specified tolerance reduces the actual load-bearing capacity, forcing the structural engineer to order additional material or redesign connections — changes that cascade through the construction schedule. Third, missing or falsified CE documentation blocks EU market entry entirely, regardless of the physical quality of the steel [NEED_CITE: consequences of non-compliant structural steel imports in EU markets].
Procurement Confidence Through In-House Verification
Every S255JR seamless square steel tube produced at our facility passes through our own physical and chemical laboratory before release. We do not outsource material testing to third parties for routine production — our in-house lab performs dimensional checks, tensile testing, and chemical composition analysis on every heat, generating mill test certificates that document actual results rather than specification ranges. This direct control over testing eliminates the gap between what the certificate states and what arrives on site. Our 2,800+ specification range means that non-standard sizes outside typical catalog offerings can be produced without splitting orders across multiple suppliers. For projects requiring mixed sizes in a single container, our loading team plans the stowage sequence to prevent surface damage and bending during ocean transit — a detail that matters when galvanized tubes or precision-cut lengths arrive at the project site.
Documentation & Compliance
- Mill test certificate documenting S255JR chemical composition (C, Mn, Si, P, S) and mechanical properties per EN 10219, traceable to heat number
- CE certificate under EN 10210/EN 10219 issued by Lloyd’s Register, required for structural hollow sections entering EU customs
- ISO 9001:2015 quality management system certificate covering the full production and inspection process
- SGS or BV third-party inspection report available upon request, covering dimensional verification, visual inspection, and witness testing before shipment
- Singapore FPC certification for projects in Southeast Asian markets requiring additional factory production control validation
- Full customs documentation package including packing list, bill of lading, and certificate of origin for each shipment
Packaging, Loading & Delivery
- Seamless square tubes bundled with steel strips at intervals appropriate to the 5.8m–12m length range, with end caps on galvanized finishes to protect the zinc coating at cut edges
- Black painted or varnished surfaces wrapped in waterproof paper within each bundle to prevent moisture damage during ocean transit
- Container loading planned by our team to maximize weight utilization within the 5-ton MOQ while preventing tube deformation — heavier wall thickness sections (20–30mm) positioned as base layers
- Custom cutting to project-specific lengths available before shipment, with each piece marked by heat number and steel grade for site traceability
- FOB, CIF, and DDP shipping terms available with full export documentation; professional container loading with anti-damage measures for all surface treatments
- Shipment tracking provided from factory gate to destination port, with inspection photos shared before container sealing
Requesting a Quotation for S255JR Seamless Square Steel Tube
Submit your required dimensions (outer size × wall thickness × length), steel grade, surface treatment preference, total quantity, and destination port to receive a detailed quotation including unit pricing, production lead time, and shipping terms. Non-standard sizes outside the 19×19mm to 800×800mm catalog range can be evaluated for custom production. Mill test certificates and third-party inspection arrangements are confirmed at the quotation stage, before any deposit is placed.
Frequently Asked Questions
Q: How does S255JR compare to ASTM A500 Gr.B and Chinese Q235B?
A: S255JR (EN 10219), ASTM A500 Gr.B, and Q235B (GB/T 700) are broadly equivalent structural carbon steel grades with similar yield strength ranges. The exact chemical composition limits differ slightly between standards, so the mill test certificate should confirm compliance with the specific standard called out in your project specification.
Q: Can you provide third-party inspection before shipment?
A: Yes. SGS and BV inspection services can be arranged for any order. The inspection covers dimensional verification, visual quality check, and witness testing, with the report issued before container loading.
Q: What is the minimum order quantity for custom non-standard sizes?
A: The standard MOQ is 5 tons. For non-standard sizes outside the regular production range, the minimum depends on the specific dimension and quantity — we evaluate each inquiry individually and confirm feasibility during the quotation stage.
Q: Do your S255JR tubes carry CE marking for EU import?
A: Yes. Our structural hollow sections carry CE certification under EN 10210 and EN 10219, issued by Lloyd’s Register. The CE certificate, along with the Declaration of Performance and Factory Production Control documentation, is included in the shipment file for EU customs clearance.
Q: What surface treatment options are available for outdoor applications?
A: For outdoor or corrosive environments, hot-dip galvanizing provides the longest service life. Black painting offers moderate protection for sheltered outdoor use. Bare tubes are suitable for indoor applications or projects where the contractor applies their own coating system on site.
Get Your S255JR Seamless Square Steel Tube Quote with Mill Test Certificate
Send your specification details — size, wall thickness, grade, quantity, and destination — to receive pricing and certification confirmation within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
