Description
Factory-direct supply with integrated mill traceability — Q235 Q345 ERW square rectangular steel tube produced from our own billet through to finished hollow section, eliminating third-party material gaps.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 ERW Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345, S235JR, GR.B-D, STK500 |
| Standard | GB/T 3091, BS 1387, DIN EN 10025, EN 10219, JIS G3444, ASTM A53, BS EN 10255 |
| Section Shape | Square / Rectangular |
| Size Range | 10mm×10mm – 500mm×500mm |
| Wall Thickness | 0.6mm – 20mm |
| Length | 1m – 12m (customizable per request) |
| Technique | Hot Rolled / Cold Rolled ERW |
| Surface Treatment | Oiled, Black Painted |
| Ends | Plain, Beveled, Threaded with Couplings/Sockets; Plastic caps and steel rings available |
| Tolerance | ±1% |
| Invoicing | By Theoretical Weight |
| Application | Steel structures, Construction frames, Machinery, Scaffolding, Furniture, Fluid transport |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Steel Structure Fabrication | Building frames, column-beam assemblies, truss systems, platform supports |
| Construction & Infrastructure | Scaffolding systems, temporary works, bridge handrails, foundation piling |
| Industrial & Machinery | Conveyor frames, machine bases, equipment supports, crane booms |
| Commercial Buildings | Warehouse purlins, mezzanine floors, curtain wall sub-frames |
| Fluid Transport | Low-pressure water lines, drainage systems, irrigation networks |
Dimensional Tolerance Defines Structural Fit-Up Accuracy on Site
±1% tolerance across the full 10×10mm to 500×500mm range ensures bolt-hole alignment without field rework.
When overseas buyers receive hollow sections with oversized wall thickness deviation or out-of-square corners, connection plates fail to seat properly. Welders spend hours grinding mismatched edges. Engineers issue RFIs for dimensional non-conformance. The root cause often traces back to fabricators sourcing tubes from multiple mills with inconsistent rolling practices. Our Q235 Q345 ERW square rectangular steel tube maintains ±1% tolerance verified by in-process dimensional checks at every shift change [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements].
Matching Section Properties to Load-Bearing Requirements
Structural engineers specify Q345 over Q235 when bending moments exceed certain thresholds — the higher yield strength allows thinner walls while maintaining load capacity. For scaffolding applications, Q195 or Q215 grades suffice since loads remain within elastic limits. Our Q235 Q345 ERW square rectangular steel tube covers this full spectrum from light-duty furniture frames to heavy industrial supports. The 0.6mm to 20mm wall thickness range accommodates both thin-walled architectural profiles and thick-walled structural columns.
Compliance Pathways for International Projects
EU projects require EN 10219 compliance with CE marking — our fabrication division holds EN 10210/EN 10219 certification covering Q235 and Q345 grades. North American specifications calling for ASTM A53 or A500 are met through our GR.B-D production line. The Q-series grades (Q195-Q345) correspond to S235JR/S275JR/S355JR in EN standards, simplifying cross-border material substitution [NEED_CITE: steel grade equivalence between Chinese GB and European EN standards]. Mill test certificates document chemical composition and mechanical properties per the specified standard, enabling customs clearance without re-inspection delays.
ERW Process Selection for Different Service Conditions
Hot rolled ERW tubes suit structural applications where surface finish is secondary — the mill scale provides temporary corrosion resistance during storage. Cold rolled ERW delivers tighter dimensional control and smoother surfaces ideal for visible architectural elements or fluid transport lines. Our Q235 Q345 ERW square rectangular steel tube offers both process options depending on end-use requirements. Black painted or oiled surface treatments protect against transit corrosion without adding cost for galvanizing when indoor service is specified.
Hidden Costs from Material Non-Conformance
Accepting tubes without verified mill certificates risks rejection at project inspection. Dimensional deviations beyond tolerance force fabricators to reject entire batches — the replacement shipment arrives weeks late, missing construction milestones. Material traceability gaps trigger third-party testing charges that exceed the original tube cost. Our Q235 Q345 ERW square rectangular steel tube ships with heat-number traceability from billet to finished section, eliminating these downstream risks [NEED_CITE: material traceability requirements in EN 10204 certification].
Why Procurement Teams Specify Our Hollow Sections
Our vertically integrated operation controls quality from steelmaking through fabrication — the same facility producing raw tube also processes it into finished structural components. This eliminates the blame-shifting between material supplier and fabricator when dimensional issues arise. We maintain 2,800+ specifications in stock, enabling same-week dispatch for standard sizes while custom lengths ship within typical production lead times. Every Q235 Q345 ERW square rectangular steel tube undergoes dimensional verification before packing, with reports available in the mill test certificate package. Our loading teams use segregated pallets and cross-stacking patterns developed from years of overseas shipment experience — no more bent tubes from improper container loading.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition and yield strength per GB/T 3091 or EN 10219 as specified
- CE certificate confirming EN 10210/EN 10219 compliance for EU market entry
- ISO 9001 quality management certificate covering production and inspection processes
- SGS or BV third-party inspection report available for projects requiring independent verification
- Material traceability by heat number linking each tube to its original billet test results
- Customs documents including packing list, bill of lading, and certificate of origin formatted per destination country requirements
Packaging, Loading & Delivery
- Q235 and Q345 tubes bundled with steel strips at maximum 3-ton capacity, with edge protectors preventing black paint damage during handling
- Oiled surface treatment applied uniformly before bundling to prevent rust formation during ocean transit to tropical ports
- Container loading optimized by separating 10×10mm to 100×100mm small sections from 200×200mm to 500×500mm large sections on dedicated pallets to prevent deformation
- Custom cutting to 1m–12m lengths performed before packing, with plastic end caps protecting beveled or threaded ends
- Heat number and steel grade stenciled on each bundle for site identification and inspection traceability
- FOB, CIF, or DDP terms available with door-to-door tracking for project sites requiring just-in-sequence delivery
Initiating Your Procurement Process
Submit your project drawings specifying Q235 or Q345 grade requirements, section dimensions, wall thickness, and total tonnage to receive a detailed quotation within 24 hours. Our engineering team reviews shop drawings for fabrication feasibility and confirms EN 10219 or ASTM A53 compliance before production begins. Specify your destination port and certification requirements so we can prepare mill test certificates and customs documentation aligned with local import regulations.
Frequently Asked Questions
Q: Can Q235 be substituted for S235JR in European projects?
A: Yes, Q235 meets the chemical composition and mechanical property requirements of S235JR per EN 10025-2, making it acceptable for most structural applications in EU markets when supported by proper mill test certification.
Q: What documentation accompanies the Q235 Q345 ERW square rectangular steel tube shipment?
A: Each shipment includes mill test certificates with chemical analysis and mechanical test results, heat number traceability records, dimensional inspection reports, and packing lists. CE certificates and third-party inspection reports are provided when specified in the purchase order.
Q: How do you ensure dimensional accuracy across the 10×10mm to 500×500mm size range?
A: In-process dimensional checks occur at every production shift using calibrated measurement equipment. Final inspection verifies ±1% tolerance compliance before tubes are approved for packing and shipment.
Q: What surface treatment options are available for corrosion protection?
A: Standard options include oiled treatment for temporary protection during storage and transit, or black painted finish for indoor applications. Galvanizing can be arranged as a secondary process when specified for outdoor or corrosive environment service.
Q: Can non-standard lengths or custom end finishes be produced?
A: Yes, lengths from 1m to 12m are available with custom cutting to project specifications. End finishes include plain ends, beveled ends for welding preparation, or threaded ends with couplings for mechanical connections.
Request Your Quotation with Mill Test Certification
Send your specification sheet detailing Q235 or Q345 grade, section size, wall thickness, quantity, and destination port to receive pricing and delivery confirmation. Our team responds within 24 hours with a complete offer including material certification and loading plan.
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
