Description
Factory-direct ERW rectangular tubes — Q235 welded hollow sections shipped with full mill test certificates and CE compliance documentation.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 ERW Welded Rectangular Steel Hollow Section Tube |
| Product Type | Welded Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Rectangular |
| Size Range | 20×20 mm, 50×25 mm, 60×40 mm, 80×40 mm, 50×50 mm |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Custom (per customer request) |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Structural frames for industrial plants and infrastructure projects |
| Construction Companies | Building frames, scaffolding systems, and high-rise structural supports |
| Machinery Manufacturers | Equipment bases, conveyor structures, and precision rectangular tube assemblies |
| System Integrators | Automation frames and industrial system fabrication components |
What Wall-Thickness Tolerance Costs on a Q235 ERW Welded Rectangular Steel Hollow Section Tube Order
±1% tolerance is the difference between passing third-party inspection and facing container rejection at destination port.
I have seen entire shipments held at customs because wall thickness deviated beyond acceptable limits. When your Q235 ERW welded rectangular steel hollow section tube arrives with inconsistent dimensions, the structural engineer cannot sign off, the project timeline collapses, and you pay demurrage charges while waiting for replacement material. Negative tolerance exceeding 0.3mm on a 50×25 rectangular tube triggered a complete rejection on one Dubai project — the third-party inspector measured every piece and found the batch non-compliant with EN 10219 requirements [NEED_CITE: EN 10219 cold-formed welded structural hollow sections tolerance limits].
How Q235 Rectangular Hollow Sections Match Structural Frame Requirements
The Q235 grade delivers adequate yield strength for general structural applications where extreme load-bearing is not the primary concern. Our Q235 ERW welded rectangular steel hollow section tube with hot rolled and slightly oiled surface treatment provides corrosion protection during ocean transit while maintaining weldability for on-site fabrication. EPC contractors ordering 80×40 mm sections for industrial plant frames receive consistent dimensional accuracy that allows direct bolting without secondary machining. The ±1% tolerance ensures that when your structural engineer specifies these tubes for scaffolding or building frames, the actual delivered product matches the design calculations.
Engineering Compliance and Certification Requirements for ERW Rectangular Tubes
Structural applications demand compliance with recognized standards — our Q235 ERW welded rectangular steel hollow section tube conforms to ASTM A213 and DIN EN 10217-1, providing documentation that satisfies both North American and European project specifications [NEED_CITE: steel grade equivalence between Q235 and S235JR standards]. For EU market entry, CE certification under EN 10210/EN 10219 is mandatory, and our factory holds this certification along with Lloyd’s Register verification. The hot rolled surface treatment with light oiling protects against rust during typical 30-45 day sea freight without interfering with subsequent painting or galvanizing processes. Custom cutting and punching services allow delivery of ready-to-install lengths that reduce on-site labor costs and material waste.
Understanding Q235 Steel Grade and ERW Welding Process
Q235 belongs to the Chinese GB/T 700 standard system, offering lower yield strength compared to Q345 but superior formability and weldability for general structural applications. The ERW (Electric Resistance Welded) process creates a longitudinal weld seam by passing electric current through the steel strip edges under pressure — this method produces consistent wall thickness and smooth interior surfaces suitable for fluid transport applications. Hot rolled surface treatment followed by light oiling provides basic corrosion protection during storage and transit, though for harsh marine or chemical environments, galvanized or painted finishes would be more appropriate. The ±1% dimensional tolerance reflects standard ERW production capability, which is tighter than SSAW but slightly wider than seamless tube manufacturing. When invoicing by theoretical weight, the actual weight may vary slightly due to tolerance, but the structural performance remains within specified parameters [NEED_CITE: theoretical weight calculation methods for welded steel hollow sections].
The Hidden Costs of Purchasing Non-Compliant Rectangular Hollow Sections
Material that fails to meet specified steel grade requirements creates cascading problems: structural calculations become invalid, building inspectors reject the installation, and you face costly tear-down and replacement. Missing or incomplete mill test certificates trigger customs delays — I have witnessed shipments held for weeks because the chemical composition documentation did not match the physical material [NEED_CITE: mill test certificate requirements for steel imports]. Negative tolerance beyond specification means you pay for steel that is not there, reducing load-bearing capacity and creating safety liabilities. Certification gaps force expensive third-party testing at destination or complete material rejection, turning a cost-saving purchase into a project disaster.
Why Source Q235 ERW Welded Rectangular Steel Hollow Section Tube From Our Factory
We operate three dedicated production lines with in-house physical and chemical laboratories that test every heat before release — you receive original mill test certificates documenting chemical composition and mechanical properties per heat number. Our factory holds 41 invention patents including proprietary sharp-corner rectangular tube technology that fills gaps in global market specifications, and we maintain 2,800+ specifications in stock for immediate dispatch. CE certification under EN 10210/EN 10219, ISO 9001:2015 quality management, and third-party verification by SGS and BV ensure your Q235 ERW welded rectangular steel hollow section tube meets international compliance requirements. We provide custom cutting, punching, and bending services to your exact drawings, eliminating secondary fabrication costs at your site. Professional loading plans optimize container utilization for rectangular sections, and our logistics team coordinates FOB/CIF/DDP shipments to 50+ countries with real-time tracking.
Documentation & Compliance
- Mill test certificate documenting Q235 chemical composition and mechanical properties per heat number, conforming to ASTM A213 requirements
- CE certificate under EN 10210/EN 10219 for European market compliance on structural hollow sections
- ISO 9001:2015 quality management system certification covering entire production process
- SGS or BV third-party inspection report available upon request before shipment
- Material traceability documentation linking each tube to specific heat number and production batch
- Complete customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235 ERW rectangular tubes bundled with steel strips and edge protectors to prevent surface damage during ocean transit
- Hot rolled and slightly oiled surface treatment provides rust protection for typical sea freight duration without interfering with subsequent coating processes
- Custom length cutting service allows delivery of site-ready sections that optimize container loading and reduce on-site waste
- Heat number and steel grade markings stenciled on each bundle for easy identification and traceability at destination
- Professional loading plans maximize container utilization for 50×25 mm, 60×40 mm, and 80×40 mm rectangular sections
- FOB/CIF/DDP logistics options with door-to-door delivery coordination to 50+ countries
How to Request Quotation for Q235 ERW Welded Rectangular Steel Hollow Section Tube
Submit your specifications including section dimensions, wall thickness, total quantity, steel grade requirement, and destination port via email or WhatsApp. We respond within 12 hours with detailed quotation covering unit price, delivery timeline, payment terms, and applicable certifications. For non-standard dimensions or custom processing requirements, our technical team provides engineered solutions based on your project drawings.
Frequently Asked Questions
Q: What is the steel grade equivalence between Q235 and international standards?
A: Q235 roughly corresponds to S235JR in EN 10025 and ASTM A36 in the US system, though exact chemical composition and mechanical properties vary slightly. We provide mill test certificates documenting the actual composition so your structural engineer can verify compliance with project specifications.
Q: Can you provide third-party inspection before shipment?
A: Yes, we arrange SGS or BV inspection at our factory before loading. The inspection covers dimensional verification, surface quality, and witness of mechanical testing. You receive the original inspection report with your shipping documents.
Q: What is the minimum order quantity for custom sizes?
A: Standard MOQ is 5 tons. For non-standard dimensions outside our regular size range, MOQ may vary based on production scheduling. Contact us with your specific requirements for custom quotation.
Q: How do you handle negative tolerance and weight invoicing?
A: We invoice by theoretical weight based on specified dimensions and standard density. The ±1% tolerance applies to dimensional accuracy. Actual weight may vary slightly, but structural performance remains within specified parameters per EN 10219 requirements.
Q: Can you provide custom cutting and processing services?
A: Yes, we offer cutting, punching, bending, and welding services to your exact drawings. This allows delivery of ready-to-install sections that reduce your on-site fabrication costs and material waste.
Get Your Q235 ERW Welded Rectangular Steel Hollow Section Tube Quotation
Send your specifications to admin@sdxjysteel.com or contact us via WhatsApp at +86 188 5315 7756. We respond within 12 hours with pricing, mill test certificate samples, and delivery timeline for your project.
