Description
Factory-direct bulk supply — Shandong Xin Jiyuan operates 3 production lines with 20,000+ ton monthly capacity, delivering Q235B and Q345B sharp-corner tubes at competitive pricing with no middlemen markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B / Q345B Custom Fabricated Special-Shaped Square & Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (Sharp-Corner / Right-Angle / Special-Shaped) |
| Steel Grade | Q235B, Q345B |
| Standard | GB (Q235B / Q345B); EN 10219 / EN 10210 / ASTM A500 available per customer request |
| Section Shape | Square / Rectangular (Special-Shaped, Right-Angle / Sharp-Corner) |
| Side Length / Width | 150–625 mm |
| Length | 5–15 m (standard 5.8 m / 6 m / 12 m available) |
| Technique | ERW (Electric Resistance Welded) / Hot Rolled |
| Surface Treatment | Hot Rolled / Oiled / Non-Oiled |
| Tolerance | ±1% |
| Ends | Plain Ends |
| Processing Service | Bending, Cutting, Decoiling, Punching, Welding |
| Invoicing | By Theoretical Weight |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, beam connections in commercial and industrial structures |
| Machinery Manufacturing | Equipment bases, conveyor frames, hydraulic support structures for OEM factories |
| Industrial Platforms | Scaffolding systems, working platforms, access walkways in petrochemical and power plants |
| Steel Structure Fabrication | Portal frames, truss members, bracing systems for warehouses and factories |
What Sharp-Corner Tolerance Costs on a Structural Frame Order
Tolerance deviation on right-angle corners forces on-site rework or entire batch rejection during structural inspection.
When监理拿卡尺一量壁厚负公差将近10%, the load-bearing capacity drops below design requirements. I’ve seen entire shipments halted at Riyadh project sites because corner radii exceeded 3mm when drawings specified sharp corners. The custom fabricated sharp-corner square and rectangular steel tube supplier must guarantee ±1% tolerance on wall thickness and precise corner forming. [NEED_CITE: EN 10219 cold-formed hollow section requirements]
Precision Corner Forming for Structural Connections
Sharp-corner and right-angle sections eliminate gaps at beam-column joints, reducing welding filler metal and improving load transfer efficiency. The 150–625 mm side length range covers most structural frame dimensions, while 5–15 m lengths optimize container loading for overseas projects. As a custom fabricated sharp-corner square and rectangular steel tube supplier, we maintain ±1% tolerance through controlled forming processes and in-process dimensional checks.
Engineering Compliance and Certification Requirements
Structural frames in Europe require EN 10219 compliance for cold-formed welded hollow sections, while North American projects specify ASTM A500 Grade B or C. Q235B and Q345B grades meet GB standards and can be cross-referenced to S235JR and S355JR equivalents for international projects. Third-party inspection by SGS or BV verifies chemical composition and mechanical properties before shipment. [NEED_CITE: steel grade equivalence between EN and ASTM standards]
Steel Grade Selection and Welding Process Impact
Q235B offers adequate strength for non-critical structural members and scaffolding, while Q345B provides higher yield strength for load-bearing columns and beams in multi-story buildings. ERW welding creates a longitudinal seam suitable for square and rectangular sections up to 625 mm, with the weld zone heat-treated to match base metal properties. Hot rolled surface treatment removes mill scale and provides better paint adhesion for outdoor exposure. Wall thickness tolerance directly affects theoretical weight calculation and actual load capacity — negative tolerance beyond specification reduces structural safety margins.
Hidden Costs of Incorrect Material Procurement
Material substitution without engineering approval triggers re-inspection costs and project delays. Missing mill test certificates cause customs holds at destination ports, while incomplete CE documentation blocks EU market entry. Negative tolerance exceeding specification limits forces structural recalculation or member replacement. [NEED_CITE: structural steel procurement compliance requirements]
Why Source from Shandong Xin Jiyuan
We operate 3 production lines running simultaneously with 20,000+ ton monthly capacity, eliminating middleman markup on bulk orders. Every batch ships with original mill test certificates documenting chemical composition and mechanical properties per GB standards. Our inventory covers 2,800+ specifications for standard sizes, while custom orders complete within 15–25 days. Lloyd’s CE certification (EN 10210/10219) and ISO 9001:2015 registration ensure international compliance. Professional export teams optimize container loading and handle complete documentation for customs clearance.
Documentation & Compliance
- Mill test certificate documenting Q235B/Q345B chemical composition and yield strength per GB standards
- CE certificate (EN 10210/EN 10219) for European market structural compliance
- ISO 9001:2015 quality management system certificate
- SGS or BV third-party inspection report available upon request
- Material traceability by heat number linking each tube to production batch
- Customs documents including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235B/Q345B tubes bundled with steel strips and edge protectors to prevent corner damage during ocean transit
- Oiled surface treatment applied to non-galvanized tubes to prevent rust during storage and shipping
- Container loading optimized for 5.8 m / 6 m / 12 m standard lengths to maximize payload per shipment
- Custom cutting to project-specific lengths available to reduce on-site waste and welding joints
- Heat number and steel grade marked on each tube for site identification and traceability
- FOB/CIF/DDP terms available with professional logistics coordination to destination port
Streamline Your Bulk Procurement Process
Submit specifications including section dimensions, wall thickness, steel grade, quantity, and destination port via email or WhatsApp. Receive competitive bulk pricing with volume discounts and delivery timeline within 12 hours. Request material samples and mill test certificates for quality verification before placing orders.
Frequently Asked Questions
Q: What is the MOQ for custom fabricated sharp-corner square and rectangular steel tubes?
A: Our minimum order quantity is 1 Ton per size, supporting trial orders for project evaluation before committing to full-container bulk purchases.
Q: How do you ensure sharp-corner tolerance meets structural drawing requirements?
A: We maintain ±1% tolerance through controlled forming processes with in-process dimensional checks. Every batch undergoes three-stage inspection in our in-house lab, and third-party SGS/BV inspection is available for independent verification.
Q: Can you provide cross-reference between Q235B/Q345B and international standards?
A: Yes. Q235B corresponds to S235JR per EN 10219 and ASTM A36 per ASTM standards. Q345B aligns with S355JR per EN 10219 and ASTM A572 Grade 50. We provide mill test certificates documenting compliance with your specified standard.
Q: What is the production lead time for non-standard sizes and custom lengths?
A: Standard sizes ship from ready stock within days. Custom orders for non-standard dimensions or specific lengths typically complete within 15–25 days depending on order volume and specification complexity.
Q: Do you handle export documentation and customs clearance?
A: Yes. Our professional export team prepares complete documentation packages including commercial invoice, packing list, bill of lading, certificate of origin, mill test certificates, and CE/ISO certificates as required by destination country regulations.
Get Factory-Direct Pricing for Your Next Project
Send your specifications — section size, wall thickness, steel grade, quantity, and destination port — to receive competitive bulk pricing and mill test certificates within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
