Description
Factory-Direct ERW Rectangular Tubes — Every Q235 Q345 ERW welded rectangular steel tube supplier order ships with original mill certificates and in-house lab verification, eliminating middleman markups and documentation gaps.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 ERW Welded Rectangular Steel Tube |
| Product Type | Welded Rectangular Steel Tube / Rectangular Hollow Section (RHS) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1, ASTM |
| Section Shape | Rectangular (also available in Square and Round) |
| Size Range | 20×20 mm, 50×25 mm, 60×40 mm, 80×40 mm, 50×50 mm (custom sizes available) |
| Wall Thickness | Up to 40 mm |
| Length | 5.8–14 m (customer’s request) |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Ends | Plain / Custom processing (Cutting, Welding, Punching, Bending) |
| Application | Structure Pipe, Steel Structures, Construction Frames, Machinery, Scaffolding, Fluid Pipe, Gas Pipe, Boiler Pipe, Oil Pipe, Chemical Fertilizer Pipe, Drill Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors & Construction | Structural frames for warehouses, building skeletons, scaffolding systems, bridge support members |
| Machinery Manufacturers | Equipment frames, conveyor support structures, precision structural components for industrial machines |
| Industrial & Energy Projects | Fluid and gas transport structures, boiler support frameworks, oil and gas platform structural members |
| Infrastructure Developers | Urban rail transit support structures, highway sound barrier frames, power transmission tower bases |
What Missing Certifications Cost on a Q235 Q345 ERW Welded Rectangular Steel Tube Shipment
A single incomplete FPC document can hold an entire container at port for weeks.
I have seen buyers lose thousands of dollars in demurrage fees because their supplier could not produce a complete EN 10219 compliance file at customs. The Q235 Q345 ERW welded rectangular steel tube supplier you choose must provide original mill test certificates with heat-by-heat traceability — not photocopies or templates. Beyond documentation, fragmented sourcing from multiple vendors for tubes, plates, and beams creates coordination failures that delay project timelines. Non-standard rectangular sizes often fall outside standard catalogs, forcing buyers into expensive small-batch orders or unacceptable lead times. [NEED_CITE: EN 10219 cold-formed welded structural hollow sections certification requirements]
How ERW Rectangular Sections Match Structural Engineering Demands
The Q235 Q345 ERW welded rectangular steel tube in wall thicknesses up to 40 mm serves load-bearing frames where flat surfaces simplify bolted and welded connections. For scaffolding and building skeletons, the rectangular profile provides predictable bending resistance along both axes — a structural advantage over round sections in moment-frame applications. Custom processing including cutting, punching, and bending allows these tubes to arrive at the job site ready for assembly, reducing on-site fabrication time and labor costs.
Structural Compliance and Certification Pathways
Engineering specifications for steel structures typically reference EN 1993 or AISC design codes, which require verified material properties and dimensional tolerances. The ±1% tolerance on these Q235 Q345 ERW welded rectangular steel tubes meets the dimensional accuracy demands of structural connections. For European market projects, CE certification under EN 10210 and EN 10219 is mandatory for customs clearance and engineering approval — missing this certificate means the cargo cannot legally enter the EU. Third-party inspection through SGS or BV before loading provides independent verification that the shipment matches purchase order specifications. [NEED_CITE: structural steel hollow section compliance for EU construction projects]
Understanding Q235 and Q345 Grades in ERW Production
The Q-series steel grading system follows Chinese national standards, where the number indicates minimum yield strength in MPa. Q235 serves general structural applications requiring moderate strength, while Q345 provides higher load-bearing capacity for heavy structural frames and machinery bases. In international equivalence, Q235 aligns roughly with S235JR under EN standards and ASTM A36 under US specifications, while Q345 corresponds to S355JR and ASTM A572 Grade 50 — though exact chemical composition and mechanical properties must be verified against project specifications. The ERW welding process creates a longitudinal weld seam through electric resistance heating, producing a continuous bond suitable for structural applications at lower cost than seamless alternatives. Hot rolled surface treatment with slight oiling provides basic corrosion protection during storage and transit, while the ±1% tolerance ensures dimensional consistency across production batches.
Hidden Costs of Procurement Errors in Rectangular Hollow Sections
Ordering the wrong steel grade for a load-bearing application triggers engineering rejection during inspection — the entire batch must be replaced, not just the deficient pieces. Missing or incomplete mill test certificates cause customs holds that generate demurrage charges exceeding the original product value. Negative tolerance beyond specification limits reduces actual wall thickness, compromising structural integrity and failing engineering load calculations. Dimensional inaccuracy in rectangular sections creates gaps at welded connections, forcing on-site rework that delays project completion. [NEED_CITE: consequences of steel grade mismatch in structural engineering projects]
Why Source Your Q235 Q345 ERW Welded Rectangular Steel Tube From Our Factory
Our dedicated production lines manufacture over 2,800 specifications of rectangular, square, and round steel tubes — including non-standard sizes that typical suppliers cannot produce without extended lead times. The proprietary sharp-corner rectangular tube technology fills gaps in the global market where standard ERW processes cannot achieve tight corner radii required for precision structural connections. Every shipment includes original mill test certificates verified by our in-house physical and chemical laboratory, providing heat-by-heat traceability from raw material to finished product. With CE certification under EN 10210 and EN 10219, ISO 9001:2015 quality management, and verification through SGS and BV, our documentation package satisfies customs and engineering compliance requirements across 50+ countries. Custom processing services — cutting, welding, punching, and bending — deliver tubes ready for installation according to your project drawings, eliminating secondary fabrication costs. Professional loading plans optimize container space for rectangular sections, reducing freight costs per ton compared to less experienced suppliers.
Documentation & Compliance
- Mill test certificate documenting Q235 and Q345 chemical composition and mechanical properties per ASTM A213 and DIN EN 10217-1, with heat number traceability
- CE certificate under EN 10210 and EN 10219 for European market customs clearance and structural engineering compliance
- ISO 9001:2015 quality management system certificate covering the full production process from raw material inspection to final dimensional verification
- SGS or BV third-party inspection report available upon request, verifying dimensional accuracy, weld seam integrity, and surface treatment quality
- Material traceability documentation linking each tube to its original heat number, enabling project-specific quality audits
- Complete customs document package including packing list, bill of lading, and certificate of origin for smooth port clearance
Packaging, Loading & Delivery
- Q235 Q345 ERW welded rectangular steel tubes bundled with steel strips and edge protectors to prevent surface damage during ocean transit
- Hot rolled surface with slight oil coating preserved through waterproof wrapping, preventing rust formation during long-distance shipping
- Custom cutting to 5.8–14 m lengths accommodates container dimensions, with loading plans optimized for rectangular section geometry to maximize payload per shipment
- Heat number and steel grade marked on each tube end for on-site identification and traceability verification
- FOB, CIF, and DDP shipping terms available, with door-to-door logistics coordination to 50+ countries including EU, North America, and Southeast Asia
- Professional container loading service ensures weight distribution compliance and prevents cargo shift during transit
How to Request a Quotation for Your Rectangular Tube Project
Submit your specifications including section dimensions, wall thickness, steel grade, quantity, and destination port to receive a detailed quotation within 12 hours. Our engineering team will confirm dimensional feasibility, recommend optimal steel grade for your application, and provide mill test certificate samples for your review. For non-standard sizes or custom processing requirements, share your project drawings and we will provide a tailored production plan with lead time and pricing.
Frequently Asked Questions
Q: How do Q235 and Q345 grades compare to international standards like S235JR or ASTM A500?
A: Q235 roughly corresponds to S235JR under EN standards and ASTM A36 under US specifications, while Q345 aligns with S355JR and ASTM A572 Grade 50. However, exact chemical composition and mechanical properties vary between standards, so we provide original mill test certificates for your engineering team to verify compliance with your project specifications.
Q: Can you produce non-standard rectangular sizes beyond your listed dimensions?
A: Yes, our production lines cover over 2,800 specifications including custom non-standard rectangular sizes. Share your required dimensions and we will confirm feasibility, tooling requirements, and minimum order quantity for your specific profile.
Q: What certifications do you provide for EU customs and engineering compliance?
A: Every shipment includes CE certification under EN 10210 and EN 10219, which is mandatory for structural hollow sections entering the European market. We also provide ISO 9001:2015 certificates, original mill test certificates with heat number traceability, and optional SGS or BV third-party inspection reports.
Q: How do you handle cutting, welding, and custom processing services?
A: Our facility offers cutting to your specified lengths, punching for bolt holes, bending to your angle requirements, and welding for custom assemblies. Share your project drawings and we will provide pricing for the finished components, reducing your on-site fabrication labor and time.
Q: What is the difference between theoretical weight and actual weight invoicing?
A: We invoice by theoretical weight based on standard steel density and nominal dimensions, which provides pricing predictability. The ±1% tolerance means actual weight may vary slightly, but theoretical weight invoicing eliminates measurement disputes and simplifies budget calculations for your project.
Get Your Q235 Q345 ERW Welded Rectangular Steel Tube Quotation Today
Send your specifications, steel grade requirements, and destination port to receive pricing, lead time, and mill test certificate samples within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjysteel.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjysteel.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
