Description
Factory-Direct Cold Rolled Square Steel Tube Supply — S235JR, S355, and Q235B grades produced on dedicated lines with in-house physical and chemical laboratory testing before every shipment leaves Jinan.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S235JR / S355 / Q235B Square Steel Tube |
| Product Type | Cold Rolled Square Steel Tube (Welded) |
| Steel Grade | S235JR, S355, Q235B, SS400, A36 |
| Standard | EN 10219, EN 10210, ASTM A500, JIS G3466, GB/T 6728 |
| Section Shape | Square |
| Technique | Cold Rolled |
| Surface Treatment | Cold Rolled Finish |
| Tolerance | ±1% |
| Length | Customized |
| Thickness | Customized |
| Ends | Plain / Beveled per requirement |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Alloy | Non-Alloy |
| Oiled or Non-oiled | Non-oiled |
| Application | Building Structures, Machinery Manufacturing, Infrastructure, Vehicle Manufacturing |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors & Construction | Steel frames for factories, stadiums, commercial centers, bridge trusses |
| Machinery Manufacturing | Machine tool frames, conveyor support structures, automation equipment frameworks |
| Infrastructure Construction | Greenhouse frames, stage trusses, bridge support members |
| Vehicle Manufacturing | Trailer chassis, RV structural frames |
| Home Decor & Furniture | Stair handrails, security window frames, furniture structural frames |
What Negative Tolerance Does to a Structural Frame Budget
A ±1% cold rolled tolerance keeps theoretical weight invoicing aligned with actual load-bearing capacity.
When procurement teams order Cold Rolled Square Steel Tube S235JR S355 Supplier products for structural frames, the gap between theoretical weight and actual weight becomes a real cost driver. Negative tolerance beyond acceptable limits means the steel arrives lighter than specified — the structural engineer’s load calculations no longer match the material on site, and the监理 rejects the batch at inspection. I have seen entire container loads held at destination ports because wall thickness measurements failed caliper checks, turning a straightforward delivery into weeks of demurrage and renegotiation. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections]
Matching Structural Load Requirements Across Building and Machinery Applications
Cold Rolled Square Steel Tube S235JR S355 Supplier products in square section deliver closed-profile torsional resistance that open sections such as channels or angles cannot match. For factory buildings and stadium frames, the square profile distributes bending moments evenly across all four faces, reducing the number of bracing members needed. Machinery manufacturers value the same geometry for conveyor supports and automation equipment frames where flat mounting surfaces on all sides simplify bolt-on connections. Our production lines cover wall thicknesses up to 40mm across 2,800+ specifications, meaning a single order can combine structural columns, beam members, and lighter gauge bracing tubes without splitting the purchase across multiple vendors.
Engineering Compliance and Certification for International Project Delivery
Structural steelwork in the European Union requires CE marking under EN 10210 or EN 10219, and customs authorities at ports from Rotterdam to Dubai routinely check for valid factory production control certificates before releasing hollow section shipments. North American projects reference ASTM A500 Grade B or C, while Southeast Asian and Middle Eastern specifiers often accept JIS G3466 or GB/T 6728 equivalents. Cold Rolled Square Steel Tube S235JR S355 Supplier shipments from our facility carry Lloyd’s Register EU CE certification, Singapore FPC approval, and ISO 9001:2015 quality management documentation as standard. [NEED_CITE: CE marking requirements for structural steel hollow sections under EN 10210] Custom-cut lengths arrive with heat number traceability stamped on each piece, so site welders and inspectors can match every member back to its original mill test certificate without guesswork.
Steel Grade Selection and Cold Rolled Process Fundamentals
The S-series grades (S235JR, S355) follow the European EN standard system where the number indicates minimum yield strength in MPa — S355 delivers roughly 50% higher yield than S235, making it the preferred choice for heavily loaded columns and long-span beams. Q235B follows the Chinese GB system and maps closely to S235JR in both chemistry and mechanical behavior, while A36 and SS400 serve as ASTM and JIS equivalents for projects requiring cross-standard substitution. Cold rolling produces a smoother surface finish and tighter dimensional tolerance compared to hot rolled alternatives, which matters when tubes must slide into prefabricated connection nodes or accept painted finishes without additional surface preparation. The welded seam in ERW square tubes runs along one face; for applications where torsional loading concentrates stress at the weld line, specifying seamless or requesting weld-line repositioning during fabrication avoids premature failure. Wall thickness tolerance directly affects theoretical weight invoicing — a tube specified at 6mm wall that delivers 5.4mm due to excessive negative tolerance carries 10% less steel than paid for, and more critically, carries 10% less load capacity than the structural engineer calculated. [NEED_CITE: steel grade equivalence between EN 10219, ASTM A500, and GB/T 6728 standards]
Hidden Costs When Material Certificates Do Not Match the Steel on Site
Ordering Cold Rolled Square Steel Tube S235JR S355 Supplier products without verified mill test certificates creates a chain of downstream failures. Customs authorities in EU member states hold shipments lacking valid CE EN 10219 documentation, adding storage fees and delaying project start dates. On site, if the chemical composition in the certificate does not match the actual material — for example, carbon content exceeding the weldable range for S235JR — structural welds crack during fabrication and the entire batch requires replacement. Negative tolerance abuse compounds the problem: the steel passes visual inspection, fails load testing, and the contractor faces the choice of absorbing replacement costs or risking structural failure. [NEED_CITE: consequences of non-compliant steel certificates in EU construction projects]
Why Project Procurement Teams Source from Our Jinan Facility
Our three dedicated production lines in Jinan manufacture Cold Rolled Square Steel Tube S235JR S355 Supplier products across 2,800+ specifications with wall thicknesses reaching 40mm, covering standard and non-standard sizes from a single factory without broker markups. The in-house physical and chemical laboratory tests every heat of incoming steel and every production batch before release — no shipment leaves without a mill test certificate documenting actual chemistry and mechanical performance. Our proprietary sharp-corner rectangular tube technology, covered by 41 invention patents, fills a gap that standard production methods cannot address, giving architects and engineers access to tight-radius corners for aesthetic and structural connection advantages. Lloyd’s Register EU CE certification under EN 10210 and EN 10219, Singapore FPC approval, and third-party verification through SGS and BV ensure that documentation matches the steel in every container. Professional loading plans optimize container utilization for mixed-size orders, and our logistics team coordinates FOB, CIF, and DDP shipments to ports across the EU, North America, Southeast Asia, and the Middle East with real-time tracking.
Documentation & Compliance
- Mill test certificate documenting S235JR, S355, or Q235B chemical composition and mechanical properties per EN 10219 or ASTM A500, traceable to heat number
- Lloyd’s Register EU CE certificate confirming compliance with EN 10210 and EN 10219 for structural hollow sections
- ISO 9001:2015 quality management system certificate covering production and inspection processes
- SGS or BV third-party inspection report available upon request for projects requiring independent verification
- Material traceability documentation linking each tube to its original heat number and production batch
- Customs document package including packing list, bill of lading, and certificate of origin formatted for destination port requirements
Packaging, Loading & Delivery
- Cold rolled square tubes bundled with steel strips and edge protectors to preserve the smooth surface finish during ocean transit
- Non-oiled surface treatment requires moisture barrier wrapping for extended sea freight to prevent surface oxidation before site delivery
- Mixed-size container loading plans optimize space utilization for orders combining structural columns, beams, and lighter bracing members in customized lengths
- Custom cutting to project-specific lengths reduces on-site waste and secondary processing for EPC contractors assembling factory frames and stadium structures
- Heat number and steel grade markings stamped on each tube end for positive identification during site inspection and welding
- FOB, CIF, and DDP shipping options with door-to-door logistics coordination to ports across 50+ countries
Getting Your Cold Rolled Square Steel Tube Quote Started
Submit your specification sheet — including steel grade (S235JR, S355, Q235B, or cross-standard equivalent), section dimensions, wall thickness, length, quantity, and destination port — and our engineering team returns a detailed quotation with unit pricing, production lead time, certification package, and loading plan within 12 hours. For non-standard sizes or custom processing including cutting, bending, and punching, share your fabrication drawings and we confirm feasibility and pricing against our 2,800+ specification range.
Request Your Cold Rolled Square Steel Tube Quotation with Mill Test Certificate
Send your specifications, steel grade requirements, and destination port to receive a detailed quotation and material certification package.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjysteel.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjysteel.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: Can you supply Cold Rolled Square Steel Tube in S235JR, S355, and Q235B to the same project with cross-standard equivalence documentation?
A: Yes. We produce S235JR, S355, Q235B, SS400, and A36 grades on the same production lines and provide mill test certificates documenting chemical composition and mechanical properties per EN 10219, ASTM A500, or GB/T 6728 as required. For projects mixing standards, we supply equivalence mapping documentation confirming that Q235B meets S235JR requirements and that A36 aligns with specified grades.
Q: What is the minimum order quantity for custom non-standard sizes outside your 2,800+ specification range?
A: MOQ depends on section dimensions and wall thickness. Standard sizes from our existing specification range have no minimum beyond one bundle. For custom non-standard sizes requiring new roll tooling, we evaluate the drawing and confirm MOQ based on production efficiency — typically one container load for specialized profiles.
Q: How does cold rolled surface treatment compare to hot rolled or galvanized for outdoor structural applications?
A: Cold rolled finish delivers a smooth surface and tight dimensional tolerance ideal for indoor structural frames, machinery, and applications requiring painted finishes. For outdoor or corrosive environments, galvanized treatment provides zinc coating protection. We supply cold rolled, hot rolled, and galvanized options from the same facility and advise on the best choice based on your project environment and finishing requirements.
Q: What certification documents do you provide for EU customs clearance of structural square tubes?
A: Every shipment to EU destinations includes Lloyd’s Register CE certificate confirming EN 10210 or EN 10219 compliance, mill test certificates with heat number traceability, ISO 9001:2015 quality certificate, and a complete customs package (packing list, bill of lading, certificate of origin). SGS or BV third-party inspection reports are available for projects requiring independent verification.
Q: Do you invoice by theoretical weight or actual weight, and how does tolerance affect billing?
A: We invoice by theoretical weight based on specified dimensions and standard steel density. Our cold rolled production maintains ±1% dimensional tolerance, ensuring that theoretical weight invoicing aligns with actual material delivered. Mill test certificates include actual measured dimensions so you can verify compliance before accepting the shipment.
