Description
Factory-direct Q235B ERW welded square rectangular hollow tube supplier — 2,800+ in-stock specifications with full mill test traceability, shipped to 50+ countries with CE and ISO certification.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B Carbon Steel Welded Square & Rectangular Hollow Tube |
| Product Type | Square / Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q195, Q215, Q235, Q235B |
| Standard | EN 10219 / EN 10210 |
| Section Shape | Square / Rectangular |
| Size Range | 20×20 mm – 100×100 mm (square); 20×50 mm, 40×100 mm, 100×150 mm (rectangular) |
| Wall Thickness | Up to 40 mm |
| Length | 6–12 m |
| Technique | ERW (Electric Resistance Welded) / Hot Rolled |
| Surface Treatment | Hot Rolled (Non-oiled) |
| Tolerance | ±1% |
| Invoicing | By Theoretical Weight |
| Application | Structural pipe / Construction building material / Building frames / Steel structures |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Steel structure frames for industrial plants and warehouses |
| Construction Companies | Building frames, column supports, and load-bearing structures |
| Machinery Manufacturers | Conveyor frames, equipment bases, and structural components |
| Infrastructure Developers | Bridge supports, scaffolding systems, and utility structures |
Where Wall-Thickness Tolerance Decides Project Acceptance
A ±1% tolerance on Q235B ERW welded square rectangular hollow tube means the difference between passing structural inspection and facing costly rework.
When wall thickness drifts beyond specification, load-bearing calculations collapse — engineers designed for a specific cross-section, and any deviation compromises the entire structural integrity. I’ve seen containers held at port because third-party inspectors found wall thickness running under minimum spec, triggering full reinspection and weeks of delay. The Q235B ERW welded square rectangular hollow tube we produce maintains ±1% tolerance through in-house physical and chemical laboratory testing at every production stage, ensuring each piece meets EN 10219 requirements before it leaves the factory floor. [NEED_CITE: EN 10219 cold-formed welded structural hollow sections tolerance requirements]
Matching Structural Load Requirements in Building Frames
The Q235B ERW welded square rectangular hollow tube delivers consistent yield strength across 20×20 mm to 100×150 mm sections, making it suitable for building frames where predictable load distribution matters. Hot rolled non-oiled surface provides adequate corrosion resistance for indoor structural applications, while the ERW welding process ensures uniform seam quality throughout the 6–12 m length. Our proprietary sharp-corner rectangular tube technology fills specification gaps that standard catalogs cannot cover, giving EPC contractors access to non-standard profiles without extended lead times.
Compliance with EN Standards and Customs Clearance
For projects in EU markets, EN 10219 and EN 10210 certification determines whether your Q235B ERW welded square rectangular hollow tube clears customs or gets held for reinspection. The CE marking under these standards confirms that material properties, dimensional tolerances, and welding quality meet European structural requirements. We provide complete documentation including mill test certificates with chemical composition and mechanical properties, third-party verification by SGS or BV, and Singapore FPC certification for Southeast Asian project compliance — eliminating the certification gaps that cause customs delays. [NEED_CITE: CE marking requirements for structural steel hollow sections under EN 10219]
Understanding Q235B Grade and ERW Process Selection
Q235B belongs to the Chinese GB standard system, offering yield strength suitable for general structural applications where high strength is not the primary requirement. The ERW (Electric Resistance Welded) process creates a longitudinal weld seam through heat and pressure without filler material, making it cost-effective for square and rectangular profiles in the 20×20 mm to 100×150 mm size range. Hot rolled non-oiled surface treatment means the tube comes directly from the rolling mill without additional coating, providing a clean base for painting or galvanizing if your project environment demands enhanced corrosion protection. The ±1% tolerance control ensures that theoretical weight calculations match actual delivered weight, preventing cost overruns from negative tolerance variations. [NEED_CITE: Q235B steel grade properties and applications in structural engineering]
Hidden Costs of Incorrect Material Verification
Ordering Q235B ERW welded square rectangular hollow tube without verified mill test certificates creates risk exposure across multiple dimensions. Material that fails to meet declared steel grade specifications triggers structural safety concerns during engineering inspection, while missing CE or EN certification causes customs holds that delay project timelines by weeks. Negative tolerance beyond acceptable limits means you pay for theoretical weight but receive less actual material, inflating project costs while compromising load-bearing capacity. Third-party inspection by SGS or BV before shipment provides independent verification that protects against these hidden costs. [NEED_CITE: importance of mill test certificates in structural steel procurement]
Why Procurement Teams Choose Our Factory
We operate three dedicated production lines with in-house physical and chemical laboratories conducting incoming, in-process, and final inspections — every Q235B ERW welded square rectangular hollow tube ships with full traceability by heat number. Our factory-direct model eliminates middlemen, giving you transparent pricing on 2,800+ specifications including custom non-standard sizes that standard catalogs cannot cover. The 41 patented technologies include proprietary sharp-corner rectangular tube technology that fills global specification gaps, while CE (EN 10210/EN 10219), ISO 9001:2015, Singapore FPC, and third-party SGS/BV verification ensure your material meets international project requirements. Professional loading plans optimize container utilization for 6–12 m lengths, and our export team coordinates door-to-door logistics to 50+ countries including EU, North America, India, Southeast Asia, and Middle East destinations.
Documentation & Compliance
- Mill test certificate documenting Q235B chemical composition and mechanical properties per GB standard, with heat number traceability for each batch
- CE certificate confirming compliance with EN 10219 and EN 10210 for structural hollow sections in European market projects
- ISO 9001:2015 quality management certificate covering production processes and inspection procedures
- SGS or BV third-party inspection report verifying dimensional tolerance, surface quality, and welding seam integrity
- Material traceability documentation linking each Q235B ERW welded square rectangular hollow tube to specific heat number and production batch
- Complete customs documentation including packing list, bill of lading, and certificate of origin for smooth clearance at destination port
Packaging, Loading & Delivery
- Q235B ERW welded square rectangular hollow tube bundled with steel strips in seaworthy packaging, with edge protectors preventing surface damage during ocean transit
- Hot rolled non-oiled surface requires no additional coating protection, reducing packaging weight and maximizing container payload capacity
- 6–12 m lengths loaded with professional stacking plans that optimize 20ft and 40ft container utilization for square and rectangular sections from 20×20 mm to 100×150 mm
- Custom cutting to specific lengths available upon request, with cut ends deburred and marked with heat number and steel grade Q235B for site identification
- Each bundle marked with heat number, steel grade, dimensional specifications, and production date for full traceability at project site
- FOB, CIF, and DDP shipping terms available with real-time tracking and door-to-door delivery coordination to 50+ countries
Getting Your Q235B ERW Welded Square Rectangular Hollow Tube Quote
Submit your specifications including section size, wall thickness, total quantity, steel grade requirement, and destination port — we respond within 12 hours with detailed pricing, delivery timeline, and applicable certification documentation. For non-standard sizes outside the 20×20 mm to 100×150 mm range, our engineering team provides custom fabrication options with typical production lead times. We confirm all certification requirements including CE, mill test certificates, and third-party inspection before production begins, ensuring your Q235B ERW welded square rectangular hollow tube meets project compliance from day one.
Frequently Asked Questions
Q: What is the difference between Q235B and S235JR steel grades?
A: Q235B follows the Chinese GB standard system while S235JR follows European EN standards. Both offer similar yield strength for general structural applications, but certification requirements differ by project location — EU projects typically require EN standard grades with CE marking, while projects in Asia and Middle East often accept Q series grades with mill test certificates.
Q: Can you provide mill test certificates for Q235B ERW welded square rectangular hollow tube?
A: Yes, every batch ships with original mill test certificates documenting chemical composition and mechanical properties, with heat number traceability. We also offer third-party inspection by SGS or BV for independent verification before shipment.
Q: What is the minimum order quantity for custom non-standard sizes?
A: Standard sizes from 20×20 mm to 100×150 mm have 1 Ton MOQ. Custom non-standard sizes outside this range require discussion with our engineering team, as MOQ depends on specification complexity and production line setup requirements.
Q: How do you ensure wall thickness tolerance of ±1%?
A: Our in-house physical and chemical laboratory conducts incoming material inspection, in-process monitoring during ERW welding and forming, and final dimensional verification before shipment. Full inspection reports are provided with each delivery.
Q: Do you offer surface treatment options beyond hot rolled non-oiled?
A: Yes, we provide galvanized coating, painting, and other surface treatment options based on your project environment and corrosion protection requirements. Contact us with your specifications for surface treatment recommendations.
Get Your Q235B ERW Welded Square Rectangular Hollow Tube Quote Today
Send your specifications to admin@sdxjysteel.com or WhatsApp +86 188 5315 7756 — receive detailed pricing, mill test certificate samples, and delivery confirmation within 12 hours.
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
