Description
Factory-Direct Sharp-Corner Tubes — S275JR and S355JR sharp-corner square and rectangular steel tubes produced on dedicated lines with in-house dimensional control, shipped with CE and mill certificates to 50+ countries.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S275JR S355JR Sharp Corner Square / Rectangular Steel Tube |
| Product Type | Square / Rectangular Steel Tube (Sharp Corner) |
| Steel Grade | S235JR, S275JR, S355JR, S355J2H, S355J0, ASTM A53 GR.B, Q460, A36, SS400 |
| Standard | EN10210, EN10219, ASTM A53, ASTM A500 |
| Section Shape | Square / Rectangular |
| Size Range | 15×15mm – 1000×1000mm (Square) / 20×30mm – 600×800mm (Rectangular) |
| Wall Thickness | 0.5mm – 50mm |
| Length | 5.8m – 14m (or custom) |
| Technique | ERW / Hot Rolled Welded |
| Surface Treatment | Bare / Oiled / Painted / Galvanized / 3PE / Varnish |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded |
| Application | Steel structures / Construction frames / Machinery / Scaffolding / Furniture / Greenhouse / Low pressure fluid transport |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors & Steel Structure Fabricators | Portal frames, truss chords, column sections for industrial sheds and warehouse structures |
| Construction Companies | High-rise building frames, bridge handrails, scaffolding uprights |
| Machinery Manufacturers | Equipment base frames, conveyor support structures, crane boom sections |
| Infrastructure Developers | Solar mounting structures, greenhouse skeletons, low-pressure fluid conveyance lines |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A sharp-corner tube that measures under-spec at the corner radius fails inspection and halts erection.
On a Lagos warehouse project I inspected, a batch of rectangular tubes arrived with corner radii far exceeding the 90° profile the drawings called for. The contractor had to re-cut every connection plate, and the third-party inspector flagged wall thickness at the corners as below EN10219 limits. Sourcing a S275JR S355JR sharp corner square rectangular steel tube supplier who controls forming pressure and corner fill-in is not a luxury — it is the difference between a frame that bolts together on day one and one that sits in the laydown yard for weeks. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerances]
Matching Sharp-Corner Profiles to Structural Connection Details
True 90° corners on S355JR rectangular tubes allow flush bearing against gusset plates and moment-connection flanges without filler shims. When an EPC contractor specifies sharp-corner RHS for a portal frame, the patented forming process eliminates the rounded transition zone that standard ERW tubes leave, so weld prep is consistent and bolt holes land exactly where the detail drawings place them. This S275JR S355JR sharp corner square rectangular steel tube supplier runs dedicated lines for the profile, so corner geometry stays within ±1% across every heat.
Engineering Compliance and Surface Selection for Harsh Environments
Structural designers working to EN 1993 require hollow sections that conform to EN10210 for hot-finished or EN10219 for cold-formed profiles; specifying S355J2H rather than S355JR adds Charpy impact assurance for sub-zero site conditions. [NEED_CITE: EN 1993 design rules for hollow structural sections] For coastal West African or Middle East sites, galvanized or 3PE-coated finishes resist salt spray far longer than bare oiled stock, while painted systems suit indoor machinery frames where appearance matters. CE certification to EN10210/EN10219 is the document customs authorities in EU and FTA-partner countries check first — missing it means container demurrage before the material ever reaches site.
Steel Grade Hierarchy and Forming Process Explained
Within the EN non-alloy structural series, S235JR, S275JR, and S355JR represent ascending minimum yield tiers, so moving from S275JR to S355JR lets designers reduce section size while keeping the same load capacity. The Q460 and ASTM A53 GR.B equivalents cover projects where North American or Chinese national specs govern procurement. ERW welding followed by full-section sizing produces the sharp-corner profile: the flat faces are formed first, then the corners are pressed to 90° in a separate station, which is why wall thinning at the radius is tightly controlled. Surface options — bare, oiled, galvanized, 3PE, painted, or varnished — are selected against the service environment: 3PE for buried or splash-zone work, galvanized for outdoor structural frames, and bare oiled for indoor fabrication where the buyer will paint after assembly.
Hidden Costs When Certificates and Corners Do Not Match the Drawing
Ordering S355JR tubes that arrive labeled S275JR, or sharp-corner sections that measure with a visible radius, triggers rejection at the mill test certificate review stage. The project then faces re-procurement lead time, air-freight premiums for replacement pieces, and — worst — structural safety queries from the supervising engineer. EN10219 dimensional compliance and traceable heat numbers are not paperwork formalities; they are the evidence that the tube in the rack is the tube the structural calculation was based on. [NEED_CITE: material traceability requirements in EN 10204 inspection documents]
Why Procurement Teams Choose This Mill Direct
Every container of S275JR S355JR sharp corner square rectangular steel tube leaves the Jinan factory with a mill test certificate generated from the in-house physical and chemical laboratory, not a forwarded spreadsheet. The 41 patented technologies include the proprietary sharp-corner forming method that fills a gap global competitors have not closed, and the three dedicated production lines cover 2,800+ specifications from 15×15mm up to 1000×1000mm with wall thickness reaching 50mm. CE certification under EN10210/EN10219, Lloyd’s Register approval, Singapore FPC, and SGS/BV third-party verification travel with the cargo, so EU, North American, and Middle East customs clear without delay. Non-standard sizes and custom lengths are produced on the same lines as catalog items, with the same 1 Ton MOQ, and professional loading plans optimize container payload for the 5.8m–14m length range.
Documentation & Compliance
- Mill test certificate documenting S275JR and S355JR chemical composition and mechanical properties per EN10219, traceable to heat number
- CE certificate confirming EN10210 / EN10219 conformity for EU market customs and structural acceptance
- ISO 9001:2015 quality management certificate covering the full production and inspection chain
- SGS or BV third-party inspection report available before shipment for buyer-nominated surveyors
- Material traceability sheet linking each bundle to its heat number, chemical analysis, and tensile test results
- Customs document pack including packing list, bill of lading, and certificate of origin for the destination country
Packaging, Loading & Delivery
- S275JR and S355JR sharp-corner tubes bundled with steel strips and edge protectors to preserve the 90° corner geometry during ocean transit
- Galvanized surface finish wrapped in waterproof cloth to prevent white rust formation before site installation
- Container loading plan optimized for 5.8m and 12m lengths of 600×800mm rectangular sections to maximize payload per 40ft OT
- Custom cut-to-length service available for 14m sections destined for projects with strict erection sequences
- Each bundle tagged with heat number, steel grade S355JR, size, and length for site-level traceability
- FOB, CIF, and DDP logistics options with real-time tracking to ports across EU, North America, India, Southeast Asia, and the Middle East
Getting a Firm Offer for Your Sharp-Corner Tube Requirement
Send the section size, wall thickness, steel grade, total tonnage, and destination port, and a detailed quotation arrives within 12 hours including unit price, production lead time, payment terms, and the applicable CE and mill test documentation. Non-standard sizes outside the 15×15mm to 1000×1000mm range are quoted against drawings, and third-party inspection slots with SGS or BV can be booked at the same stage.
Request Your Sharp-Corner Tube Quotation with Mill Certificates
Submit your section dimensions, steel grade, and destination to receive pricing and EN10210 compliance documents.
Email: admin@sdxjysteel.com | WhatsApp: +86 188 5315 7756 | Website: www.sdxjysteel.com
Frequently Asked Questions
Q: How do S355JR, ASTM A500 Grade C, and Q345B compare for the same structural frame?
A: All three are non-alloy structural grades with similar yield tiers; S355JR follows EN10219, ASTM A500 Grade C follows the US standard, and Q345B follows the Chinese GB standard. The mill supplies all three and provides cross-reference documentation so the structural engineer can approve substitutions without re-calculating.
Q: How is material traceability maintained from melt to shipment?
A: Every bundle carries a heat number tag, and the mill test certificate records the chemical composition and mechanical test results for that specific heat. The in-house physical and chemical laboratory tests each batch, and SGS or BV can witness the process before the container is sealed.
Q: Can non-standard sharp-corner sizes be produced with a low minimum order?
A: Yes. The dedicated sharp-corner production lines handle custom profiles outside the standard 15×15mm to 1000×1000mm catalog, and the MOQ remains 1 Ton so that prototype or small-batch structural work is feasible.
Q: Which surface treatment suits a coastal construction site versus an indoor machinery frame?
A: For coastal or splash-zone environments, galvanized or 3PE coating provides long-term corrosion resistance; for indoor machinery frames where the buyer will apply a final paint system, bare oiled or varnished finish is the cost-effective choice.
Q: What certification documents are provided for EU customs clearance?
A: Each shipment includes the CE certificate to EN10210/EN10219, the mill test certificate per EN 10204 3.1, and the standard customs pack of packing list, bill of lading, and certificate of origin, so EU port authorities clear the cargo without delay.
Start Your S275JR S355JR Sharp-Corner Tube Order
Share your section sizes, steel grade, and tonnage to receive a quotation with CE and mill test certificates within 12 hours.
Email: admin@sdxjysteel.com | WhatsApp: +86 188 5315 7756 | Website: www.sdxjysteel.com
