Description
Direct Mill Supply for Q235 Q345 ERW Welded Rectangular Steel Hollow Section Tube — In-house steel production and fabrication under one roof ensures full material traceability from billet to finished RHS.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 ERW Welded Rectangular Steel Hollow Section Tube |
| Product Type | Welded Rectangular Steel Hollow Section (RHS) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213-2001, DIN EN 10217-1-2005 |
| 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 | Customers’ 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 & Industrial Construction | Structural frames for warehouses, factory buildings, and equipment platforms |
| Oil & Gas / Chemical | Fluid transport pipelines, gas distribution lines, chemical fertilizer process piping |
| Infrastructure & Civil Works | Scaffolding systems, machinery support structures, bridge handrails |
| Energy & Power | Boiler tubes, drill pipe casings, heat exchanger supports |
What Negative Tolerance Really Costs on a Rectangular Hollow Section Order
A ±1% tolerance claim means nothing without verified wall thickness at every bundle.
When overseas buyers source an ERW welded rectangular steel hollow section tube from fragmented suppliers, the mill test certificate often looks clean on paper — but the actual wall thickness at the weld seam tells a different story. I have seen entire container loads held at port because the buyer’s third-party inspector found negative tolerance exceeding acceptable limits at the corner radii. The cost is not just the rejected steel; it is the crane idle time, the re-fabrication schedule, and the credibility loss with the project owner. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed welded hollow sections]
How Q235 and Q345 RHS Match Structural Frame Requirements
For warehouse frames and industrial building columns, the ERW welded rectangular steel hollow section tube in Q235 offers adequate yield strength for light-to-medium load-bearing members, while Q345 steps up for heavier spans and crane-runway beams. The ±1% dimensional tolerance ensures that connection plates and bolt-hole patterns align during assembly — a detail that saves hours of on-site reaming. Our in-house mill produces the raw coil, and our fabrication division cuts, punches, and welds the RHS to shop drawing dimensions, so the material traceability chain stays unbroken from steelmaking to final bundle.
Meeting Engineering Codes and Customs Clearance for ERW Rectangular Tubes
Structural frames exported to Europe must demonstrate compliance with EN 10219 for cold-formed welded hollow sections, while North American projects typically reference ASTM A500 or A53. The Q235 grade roughly corresponds to S235JR under EN standards, and Q345 aligns with S355JR in terms of minimum yield strength — but equivalence is not automatic acceptance. Customs authorities in the EU increasingly demand CE marking backed by EN 10219 factory production control certificates, and a missing declaration can delay clearance by weeks. [NEED_CITE: steel grade equivalence mapping between Chinese GB standards and European EN standards] The hot-rolled surface with slight oiling provides basic corrosion protection during ocean transit, but for aggressive environments or exposed architectural applications, downstream galvanizing or painting must be specified at the inquiry stage.
Understanding ERW Welding, Steel Grade Selection, and Surface Protection
The ERW (Electric Resistance Welded) process forms the rectangular profile from hot-rolled coil and welds the seam through resistance heating — no filler metal is added, which keeps the weld zone metallurgically consistent with the base material. This makes ERW welded rectangular steel hollow section tube suitable for structural applications where seam integrity matters but extreme internal pressure is not the primary concern. Q195 and Q215 serve light structural and fencing applications; Q235 covers general construction frames; Q345 is selected when higher load capacity or longer spans are required. The slight oiling applied after hot rolling prevents flash rust during storage and shipping but is not a substitute for galvanized or painted finishes in corrosive atmospheres. Wall thickness tolerance of ±1% is tight enough for precision fit-up in bolted connections, yet buyers should always verify actual thickness at the weld seam — not just the flat faces — because ERW seam areas can thin during the forming pass. [NEED_CITE: ERW weld seam quality inspection methods for structural hollow sections]
The Hidden Price of Unverified Material in Rectangular Hollow Sections
Ordering the correct steel grade on paper does not guarantee the correct steel grade in the container. When Q345 material is substituted with Q235 without disclosure, the structural engineer’s load calculations become invalid — and the consequence is not a paperwork issue but a safety liability. Similarly, missing or forged mill test certificates trigger customs holds and project suspension. [NEED_CITE: material traceability requirements under EN 1090 structural steel fabrication standard] The true cost of cheap, unverified ERW welded rectangular steel hollow section tube is measured in re-welding, re-inspection, and reputation damage — not in the purchase price difference.
Why Project Procurement Teams Source ERW Rectangular Tubes from XJY Structure
Our vertically integrated operation means the same facility that rolls the steel coil also fabricates the finished RHS — there is no gap between material supplier and processor where traceability can break. Every bundle of Q235 Q345 ERW welded rectangular steel hollow section tube carries a heat number that links back to our mill’s chemical composition and mechanical test records. Our fabrication workshop handles CNC cutting, drilling, bending, and welding per approved WPS, so project-specific components arrive ready for assembly. We maintain certified welding procedures and qualified welders under AWS and EN standards, and our quality documentation package includes WPS, PQR, weld maps, dimensional inspection reports, and coating certificates — the complete set that general contractors and EPC firms need for project handover. With over 2,800 specifications in raw material inventory and production lines dedicated to structural steel, we handle both standard and custom non-standard dimensions without the typical multi-supplier coordination delays.
Documentation & Compliance
- Mill Test Certificate documenting Q235/Q345 chemical composition and mechanical properties per DIN EN 10217-1, linked to individual heat numbers for full material traceability
- CE Certificate confirming compliance with EN 10219 for cold-formed welded structural hollow sections, required for EU market customs clearance
- ISO 9001 Quality Management System certificate covering the entire production process from raw steel to finished ERW welded rectangular steel hollow section tube
- SGS or BV third-party inspection report verifying dimensional accuracy, wall thickness, and weld seam quality before shipment
- Complete export documentation package including packing list, bill of lading, and certificate of origin for destination-country customs clearance
- Welding procedure specifications (WPS) and procedure qualification records (PQR) per AWS D1.1 or EN ISO 15614 for any fabricated connections
Packaging, Loading & Delivery
- Q235/Q345 ERW rectangular tubes bundled with steel strips and edge protectors to preserve the slightly oiled hot-rolled surface during ocean freight
- Custom-length cutting available per project specifications, with each bundle labeled by heat number, steel grade, and dimensional profile for on-site identification
- Container loading optimized for 20×20 mm to 80×40 mm rectangular profiles, maximizing weight utilization while protecting corner radii from deformation
- Slight oiling applied post-rolling provides transit corrosion protection; additional VCI wrapping available for extended sea voyages or humid destination climates
- FOB, CIF, and DDP shipping terms supported with professional oversized cargo lashing plans for mixed-size shipments
- Every bundle tagged with mill test certificate reference number and ERW welded rectangular steel hollow section tube specification for immediate verification upon arrival
Ready to Move Forward with Your ERW Rectangular Tube Inquiry
Share your project drawings, steel grade requirements, and target quantity — our engineering team responds within 24 hours with a preliminary assessment, detailed quotation including fabrication and coating costs, and a shop drawing timeline. We will confirm material traceability documentation, third-party inspection availability, and container loading plans before contract signing.
Get Your ERW Welded Rectangular Steel Hollow Section Tube Quote with Full Mill Documentation
Submit your specifications, steel grade, and destination port to receive a detailed quotation and mill test certificate sample.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do Q235 and Q345 steel grades compare to European S235JR and S355JR?
A: Q235 generally corresponds to S235JR in minimum yield strength, and Q345 aligns with S355JR. However, formal equivalence depends on chemical composition and mechanical test results documented in the mill test certificate. We provide grade mapping documentation for customs and engineering approval.
Q: Can you provide third-party inspection before shipment?
A: Yes. SGS and BV third-party inspections are available for dimensional verification, wall thickness measurement, and weld seam quality assessment of the ERW welded rectangular steel hollow section tube. Inspection reports are included in the export documentation package.
Q: What is the minimum order quantity for custom-length rectangular tubes?
A: The standard MOQ is 5 tons. Custom lengths and non-standard dimensions can be accommodated within this quantity, subject to fabrication schedule confirmation.
Q: Is the hot-rolled oiled surface sufficient for outdoor structural applications?
A: The slight oiling provides corrosion protection during transit and short-term storage. For long-term outdoor exposure or corrosive environments, we recommend specifying galvanized or painted surface treatment at the inquiry stage.
Q: How is invoicing calculated — by actual weight or theoretical weight?
A: All ERW welded rectangular steel hollow section tubes are invoiced by theoretical weight based on standard density calculations. Actual weight verification is available through third-party inspection if required by the purchase contract.
