Description
Factory-Direct Cold Rolled Square Steel Tube — S235JR and S355 grades produced on our own lines with original mill certificates, shipped to 50+ countries without broker markups.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S235JR/S355 Cold Rolled Square Steel Tube |
| Product Type | Square Steel Tube (Welded) |
| Steel Grade | S235JR, A36, S355, SS400, Q235B |
| Standard | BS, EN, GB, AISI, ASTM, DIN, JIS, ASTM A500, EN10219, EN10210, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Surface Treatment | Cold Rolled |
| Tolerance | ±1% |
| Length | Customized |
| Thickness | Customized |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Alloy Or Not | Non-Alloy |
| Oiled or Non-oiled | Non-oiled |
| Application | Building Structures, Machinery Manufacturing, Home Decor and Furniture, Infrastructure Construction, Vehicle Manufacturing |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building & Construction | Trusses, beams, columns for factories, stadiums, commercial centers |
| Machinery Manufacturing | Machine tool frames, conveyor support structures, automation equipment bases |
| Home Decor & Furniture | Stair handrails, security window frames, furniture structural frames |
| Infrastructure | Bridge auxiliary structures, stage trusses, greenhouse frames |
| Vehicle Manufacturing | Trailer chassis, RV frames, structural support components |
Where ±1% Tolerance Decides Whether a Structural Frame Passes Inspection
Tight tolerance on cold rolled square steel tube is not a luxury — it is the line between clean weld joints and costly rework on site.
I have seen project teams receive square tubes where wall thickness drifted beyond acceptable limits, forcing third-party inspectors to reject entire batches. The root cause is rarely the steel grade itself; it is the forming process and the mill’s tolerance discipline. When you source a Cold Rolled Square Steel Tube Supplier who controls cold rolling in-house, dimensional consistency stays within ±1% across every length. That means flanges meet flush at welded connections, bolt holes align without forcing, and load-bearing calculations hold true under real site conditions. Fragmented sourcing from traders who rebrand generic stock introduces exactly the kind of specification gaps that trigger project delays and compliance failures [NEED_CITE: EN 10219 cold-formed hollow section tolerance requirements].
Matching Structural Geometry to Engineering Load Paths
Cold rolled square sections deliver high torsional resistance and clean angular aesthetics, making them the preferred choice for exposed structural frames in commercial centers and stadium roofs. The ±1% tolerance ensures that when engineers specify S355 sections for primary load-bearing columns, the actual geometry matches the finite element model assumptions. Our cold rolling lines produce square tubes with consistent corner radii and flat faces, which directly improves fit-up quality during on-site welding and reduces grinding time before painting.
Compliance With European and International Structural Codes
Structural hollow sections supplied under EN10219 must meet dimensional and sectional property requirements recognized across EU member states, while ASTM A500 covers North American projects. The Cold Rolled Square Steel Tube Supplier you choose must provide traceable mill test certificates aligned with the correct standard for your destination market. CE certification under EN 10210 and EN 10219 is mandatory for structural use in Europe, and missing documentation causes customs holds that delay crane schedules and penalty clauses [NEED_CITE: CE marking requirements for structural steel hollow sections]. Our production lines carry Lloyd’s CE certification, and every batch ships with original mill test certificates backed by ISO 9001:2015 quality management.
Steel Grade Selection and Cold Rolling Process Explained
S235JR serves general structural applications where moderate yield strength is sufficient, while S355 delivers higher load capacity for heavy-duty frames and long-span trusses. Both grades are non-alloy structural steels, and the cold rolling process improves surface finish and dimensional accuracy compared to hot-formed alternatives. Cold rolled square tubes maintain tighter tolerances on wall thickness and outer dimensions, which matters when sections are used in visible architectural applications or precision machinery frames. Q235B and SS400 provide equivalent performance in Chinese and Japanese standard systems, while A36 covers American projects — our Cold Rolled Square Steel Tube Supplier capability spans all five grades from a single production facility, eliminating the need to coordinate multiple mills. Non-oiled surface treatment ensures the tubes arrive ready for painting or galvanizing without additional degreasing steps.
The Hidden Cost of Accepting Negative Tolerance Beyond Limits
When a supplier delivers square tubes with wall thickness below the specified tolerance, the theoretical weight invoiced no longer matches actual load capacity. Structural engineers design connections based on nominal section properties; if the real wall is thinner, bolt shear capacity drops and weld throat dimensions become inadequate. Engineering验收 fails, third-party inspectors issue non-conformance reports, and the entire batch must be replaced at the supplier’s cost — except when the supplier disappears or refuses liability. Choosing a Cold Rolled Square Steel Tube Supplier who publishes tolerance data in advance and invites SGS or BV third-party inspection prevents this scenario entirely [NEED_CITE: structural hollow section tolerance compliance and project risk].
Why Project Buyers Source Cold Rolled Square Steel Tube From Xin Jiyuan
Our three production lines run simultaneously with monthly capacity exceeding 20,000 tons, covering over 2,800 specifications in ready stock for urgent shipments. Factory-direct pricing means no broker margins on S235JR or S355 square tubes, and volume discount programs reward long-term procurement partners. Every production run passes through our in-house laboratory for three-stage inspection, and original mill test certificates ship with each batch — not photocopies, not retroactive documents. We consolidate multi-product container loading when your project also needs H-beams, plates, or channel steel, reducing shipping cost per ton. Professional export documentation and customs clearance support ensure CE certificates, packing lists, and certificates of origin arrive before the vessel docks.
Documentation & Compliance
- Mill test certificate documenting S235JR and S355 chemical composition and mechanical properties per EN10219, issued per heat number
- CE certificate under EN 10210 and EN 10219 for structural hollow sections destined for European Union markets
- ISO 9001:2015 quality management certificate covering cold rolled square steel tube production processes
- SGS or BV third-party inspection report available upon request for independent verification of dimensions and material properties
- Full material traceability from steel coil heat number through cold forming and final inspection
- Export customs documents including packing list, bill of lading, and certificate of origin aligned with destination country requirements
Packaging, Loading & Delivery
- Cold rolled square tubes bundled with steel strips and edge protectors to preserve the non-oiled surface finish during ocean transit
- Customized length tubes cut to project specifications and marked with heat number, steel grade, and dimension codes on each bundle
- Container loading optimized by our export team to maximize payload for 20ft and 40ft shipments, with weight distribution calculated for port crane operations
- Non-oiled surface treatment allows direct painting or galvanizing upon arrival, eliminating degreasing delays on site
- FOB, CIF, and DDP shipping terms available with real-time tracking and professional documentation handling
- Flexible MOQ from trial orders to full-container bulk shipments, with split shipment options for phased project delivery
Start Your Procurement With Accurate Specifications
Submit your required dimensions, steel grade, quantity, and destination port to receive a competitive bulk quotation within 12 hours, complete with volume discount structure and mill test certificate preview. Our engineering team reviews non-standard size requests and provides processing options including cutting, bending, and punching to reduce your on-site fabrication cost.
Get Your Cold Rolled Square Steel Tube Quote With Mill Test Certificate
Send your specifications via email or WhatsApp to receive factory-direct pricing and compliance documentation for your next structural project.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
Website: www.sdxinjiyuan.com
