Description
Direct Mill Supply, No Middleman Markup — every Q235B and Q345B galvanized ERW welded square and rectangular steel tube leaves our Jinan facility with in-house lab testing and full export documentation.
Technical Specifications + Markdown 表格(Parameter | Value)
| Parameter | Value |
|---|---|
| Designation | Q235B/Q345B Welded Square and Rectangular Steel Tube |
| Product Type | Welded Square and Rectangular Steel Tube |
| Steel Grade | Q195, Q235, Q235B, Q345, Q345B, St37, St37-2, St35, St35.4, St42, St52.4 |
| Standard | GB |
| Section Shape | Square / Rectangular / Round |
| Length | 6 m, 12 m |
| Technique | ERW (Hot Rolled / Cold Rolled) |
| Surface Treatment | Galvanized Coating |
| Tolerance | ±1% |
| Ends | Plain Ends |
| Application | Fluid transport, gas pipeline, oil pipeline, chemical fertilizer, boiler, drill pipe, hydraulic pipe, structure pipe |
| MOQ | 25 tons |
| Origin | China |
Application Suitability + 表格(Industry | Typical Applications)
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Structural framing, scaffolding systems, support columns |
| Industrial Machinery | Hydraulic cylinders, equipment frames, material handling structures |
| Fluid & Gas Transport | Pipeline networks for oil, gas, water, chemical fertilizer distribution |
| Energy & Utilities | Boiler tubes, drill pipe casings, power plant support structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance deviation means the difference between passing inspection and air-freighting replacements at your expense.
I once shipped a container of welded rectangular tubes to a Dubai facade contractor — the wall thickness measured 5.2mm on arrival, well below the 6mm spec. Their third-party inspector flagged the whole lot, and we had to replace the entire shipment. That lesson stuck: tolerance isn’t a number on paper, it’s what the client’s caliper reads on site. When sourcing Galvanized ERW Welded Square and Rectangular Steel Tube from multiple suppliers, inconsistent coating thickness and dimensional drift create rejection risks at destination ports. [NEED_CITE: EN 10219 cold-formed hollow section requirements]
How Galvanized Coating Extends Service Life in Corrosive Environments
The zinc coating on Q235B and Q345B galvanized ERW welded square and rectangular steel tube provides sacrificial protection against atmospheric corrosion, extending service life in outdoor construction and industrial applications. For scaffolding and structural framing exposed to humidity, the galvanized layer prevents rust formation at weld seams and cut edges where bare steel would deteriorate within months. Our in-house laboratory verifies coating thickness per batch before shipment, ensuring consistent corrosion resistance across the entire order.
Meeting Structural Engineering Requirements with GB Standards
Galvanized ERW welded square and rectangular steel tube manufactured to GB standards meets dimensional and mechanical requirements for load-bearing applications in construction and infrastructure projects. The Q235B grade provides adequate yield strength for general structural framing, while Q345B offers higher strength for heavy-duty support systems. Third-party inspection through SGS or BV confirms compliance with project specifications and facilitates customs clearance in regulated markets. [NEED_CITE: steel grade equivalence between GB and EN standards]
Understanding Q-Series vs St-Series Steel Grade Selection
The Q-series grades (Q195, Q235, Q235B, Q345, Q345B) follow Chinese GB standards, where the number indicates minimum yield strength in MPa. Q235B and Q345B are the most widely specified for structural applications, offering reliable weldability and formability. The St-series (St37, St37-2, St35, St35.4, St42, St52.4) represents German DIN standards, with St37 equivalent to S235 in EN standards and St52.4 corresponding to higher-strength applications. ERW welding technique produces consistent seam quality suitable for pressure ratings up to medium levels, while hot-rolled or cold-rolled processes affect surface finish and dimensional precision. Galvanized coating adds corrosion protection without compromising the base steel’s mechanical properties, though coating thickness must be verified for long-term durability in aggressive environments.
The Hidden Cost of Unverified Material Certification
Ordering Galvanized ERW Welded Square and Rectangular Steel Tube without proper mill test certificates risks customs delays, project rejection, and structural safety concerns. Missing CE documentation blocks EU market entry, while incomplete chemical composition records fail third-party inspection requirements. Negative tolerance abuse — where actual wall thickness falls below specified minimums — creates load-bearing deficiencies that only surface during structural testing or failure analysis. [NEED_CITE: consequences of non-compliant steel imports in construction projects]
Why Procure Galvanized ERW Welded Square and Rectangular Steel Tube from Xin Jiyuan
Our Jinan facility operates three production lines covering 2,800+ specifications with wall thickness up to 40mm, eliminating the need to source from multiple suppliers. Every batch undergoes dimensional, mechanical, and chemical testing in our in-house physical and chemical laboratories before shipment. We hold full international certifications including ISO 9001:2015, Lloyd’s CE (EN 10219), Singapore FPC, and SGS/BV verification, ensuring smooth customs clearance across 50+ export destinations. Custom non-standard sizes and cutting services reduce on-site waste and labor costs for your project. Professional container loading with anti-damage measures prevents bending and surface damage during ocean transit, protecting the galvanized coating integrity.
Documentation & Compliance
- Mill test certificate documenting Q235B/Q345B chemical composition and mechanical properties per GB standards
- CE certificate compliant with EN 10219 for EU market access and customs clearance
- ISO 9001:2015 quality management system certification covering production and testing processes
- SGS or BV third-party inspection report available upon request for project-specific verification
- Material traceability by heat number linking each tube to production batch and test results
- Complete export documentation including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized tubes bundled with steel strips and edge protectors to preserve zinc coating during ocean transit
- 6m and 12m standard lengths optimized for 20ft and 40ft container loading to maximize freight efficiency
- Custom cutting services available to reduce on-site waste and accommodate specific project dimensions
- Heat number and steel grade markings stenciled on each tube for site identification and traceability
- Professional container loading with anti-damage measures preventing bending and surface scratches
- FOB, CIF, and DDP shipping terms available with complete tracking until destination port arrival
Ready to Source Galvanized ERW Welded Square and Rectangular Steel Tube?
Submit your specifications including section shape, dimensions, steel grade, quantity, and destination port to receive a detailed quotation within 12 hours. We provide mill test certificates, third-party inspection coordination, and custom cutting services to match your project requirements. Confirm CE certification and export documentation needs to ensure smooth customs clearance at your destination.
Get Your Quotation and Mill Test Certificate Today
Send your inquiry with product specifications and quantity to receive pricing, lead time, and material certification details.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Frequently Asked Questions
Q: What steel grades are available for galvanized welded square and rectangular tubes?
A: We supply Q195, Q235, Q235B, Q345, Q345B, St37, St37-2, St35, St35.4, St42, and St52.4 grades. Q235B and Q345B are the most commonly specified for structural applications, offering reliable weldability and formability.
Q: How does galvanized coating thickness affect corrosion resistance and service life?
A: Thicker galvanized coating provides longer-lasting protection against atmospheric corrosion, especially in outdoor and industrial environments. Our in-house laboratory verifies coating thickness per batch to ensure consistent corrosion resistance across your order.
Q: Can you provide custom cutting and non-standard lengths to reduce project waste?
A: Yes, we offer custom cutting services for galvanized ERW welded square and rectangular steel tube to match your specific project dimensions. This reduces on-site waste and labor costs compared to standard 6m or 12m lengths.
Q: What documentation is included for EU customs clearance and CE compliance?
A: Each shipment includes mill test certificates, CE certification compliant with EN 10219, ISO 9001:2015 quality certificates, and complete export documentation. Third-party inspection reports from SGS or BV are available upon request.
Q: How do you ensure dimensional accuracy and corner quality for structural applications?
A: Every batch undergoes dimensional testing in our in-house laboratory before shipment, with ±1% tolerance maintained across all specifications. Professional container loading with anti-damage measures prevents bending and deformation during transit.
