Description
Factory-Direct Rectangular ERW Steel Tube Supply — Q235 and Q345 hollow sections produced to ASTM and EN standards with original mill test certificates, shipped from Jinan with full traceability.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Rectangular ERW Steel Tube ASTM Standard |
| Product Type | Rectangular Steel Tube / Hollow Section (ERW Welded) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213-2001, DIN EN 10217-1-2005 |
| Section Shape | Rectangular |
| Size Range | 300×300 mm (per title reference) |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Custom (Customers’ Request) |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Application | Structure Pipe, Fluid Pipe, Boiler Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Drill Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, bridge handrails, scaffolding systems |
| Oil & Gas | Pipeline support structures, drilling platform frameworks, gas distribution headers |
| Industrial Manufacturing | Machinery frames, conveyor structures, equipment bases, crane booms |
| Pressure & Process Engineering | Boiler support frames, chemical fertilizer plant pipe racks, fluid transfer structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
Dimensional accuracy on ASTM Rectangular ERW Steel Tube 300×300 Supplier shipments determines whether your steel passes site inspection or gets rejected at the port.
Buyers sourcing rectangular hollow sections for structural frames routinely encounter two problems: grade equivalence confusion between GB, ASTM, and EN systems, and wall-thickness deviations that exceed acceptable fabrication limits [NEED_CITE: steel grade equivalence between EN and ASTM standards]. When a 300×300 mm tube arrives with actual wall thickness below the specified tolerance, the structural engineer must recalculate load capacity — or the entire batch fails third-party inspection. We have seen orders delayed for weeks because the mill certificate did not match the physical measurement, and the buyer had no leverage to claim replacement.
How Q235 and Q345 Rectangular Tubes Match Structural Engineering Requirements
The Q235 and Q345 grades in this ASTM Rectangular ERW Steel Tube 300×300 Supplier range cover the most common structural and medium-load applications in construction and industrial framing. Q235 provides adequate yield strength for general building frames and scaffolding, while Q345 steps up to higher load-bearing scenarios such as crane beams and heavy equipment bases. The ERW welding process produces a continuous weld seam with ±1% dimensional tolerance, which keeps fabrication accuracy tight enough for bolted and welded connections without on-site rework. Hot-rolled surface with slight oiling protects the tube during ocean transit without adding coating cost.
Engineering Compliance and Certification for Rectangular Hollow Sections
Structural projects in Europe require EN 10219 compliance for cold-formed welded structural hollow sections, while North American projects reference ASTM A500 for cold-formed welded and seamless carbon steel tubing [NEED_CITE: EN 10219 cold-formed hollow section requirements]. The Q235 and Q345 grades in our ASTM Rectangular ERW Steel Tube 300×300 Supplier range map to S235JR and S355JR under EN standards, and to ASTM A500 Grade B and C respectively. CE marking and ISO 9001:2015 certification ensure that shipment documentation clears customs in EU and GCC markets. Custom cutting to project-specific lengths eliminates on-site sawing waste, and third-party inspection through SGS or BV before loading gives the buyer independent verification of chemical composition and mechanical properties.
Understanding ERW Welding, Grade Selection, and Tolerance Control
ERW (Electric Resistance Welded) rectangular tubes are formed by rolling steel strip into shape and welding the seam through electrical resistance heat — a process that delivers consistent wall thickness and tight dimensional tolerance at lower cost than seamless alternatives. The Q195, Q215, Q235, and Q345 grade range covers mild carbon steel through medium-strength structural steel, with Q345 offering roughly 50% higher yield strength than Q235 for applications requiring greater load capacity [NEED_CITE: structural steel grade comparison Q235 Q345 S235 S355]. Hot-rolled surface treatment with slight oiling provides short-term corrosion protection during storage and shipping, suitable for indoor structural applications or as a base for further coating. The ±1% tolerance on the 300×300 mm section ensures that connection plates and gussets fit without force-fitting, which matters when dozens of joints must align on a single frame.
Hidden Costs of Buying Rectangular Tubes Without Verified Tolerance
Purchasing ASTM Rectangular ERW Steel Tube 300×300 Supplier products without original mill test certificates or third-party inspection creates risk that compounds at every project stage. Tubes with excessive negative tolerance pass visual inspection but fail load calculations, forcing the structural engineer to reject the batch after erection has begun. Missing heat number traceability means the buyer cannot prove material compliance during final handover, and customs authorities in strict markets may hold the shipment for documentation review [NEED_CITE: mill test certificate requirements for steel imports]. The real cost is not the per-ton price difference — it is the crane standby time, the re-fabrication of connection plates, and the delayed project completion penalty.
Why Buyers Choose Xin Jiyuan for Rectangular ERW Steel Tubes
Xin Jiyuan operates as a dedicated plate and coil supplier with full control over sourcing, processing, and export documentation — no trading middlemen adding margin or obscuring material origin. Every ASTM Rectangular ERW Steel Tube 300×300 Supplier shipment ships with original mill test certificates showing heat number, chemical composition, and mechanical properties, backed by our in-house quality team. We maintain ready stock across common specifications in Q195 through Q345 grades, and our processing line handles custom cutting, punching, and bending to project drawings. Professional heavy-cargo logistics experience means flatbed and open-top container loading is planned to prevent transit damage and overweight penalties. ISO 9001:2015 and CE certification are standard, and SGS or BV third-party inspection is arranged at buyer’s request before container sealing.
Documentation & Compliance
- Mill test certificate documenting Q235 and Q345 chemical composition and mechanical properties per ASTM A213 and EN 10217-1, with traceable heat number
- CE certificate confirming compliance with EN 10219 for structural hollow sections, required for EU market customs clearance
- ISO 9001:2015 quality management certificate covering the full production and inspection process
- SGS or BV third-party inspection report verifying dimensional tolerance, surface condition, and weld seam quality before shipment
- Material traceability sheet linking each bundle to its heat number, chemical test result, and mechanical test result
- Full customs document set including packing list, bill of lading, and certificate of origin for destination-country clearance
Packaging, Loading & Delivery
- Q235 and Q345 rectangular tubes bundled with steel strips and edge protectors to prevent surface damage to the hot-rolled oiled finish during ocean transit
- Slight oil coating applied before packing to preserve surface condition of 300×300 mm sections through typical 30-45 day shipping windows
- Open-top container or flatbed loading planned by our logistics team to maximize payload within port weight limits for heavy-wall rectangular sections
- Custom cutting to project-specified lengths available before packing, reducing on-site waste and handling for construction crews
- Each bundle labeled with heat number, steel grade (Q235 or Q345), section size, and piece count for site identification
- FOB, CIF, and DDP shipping terms available from Jinan port to major construction markets in Southeast Asia, Middle East, Africa, and South America
Start Your Rectangular Tube Procurement With Verified Documentation
Submit your required steel grade, section size, wall thickness, length, and destination port to receive a detailed quotation with material cost, processing fees, and shipping terms within 12 hours. We will provide the mill test certificate for your quality team to review before you confirm the order, and third-party inspection can be arranged at any stage.
Get Your ASTM Rectangular ERW Steel Tube 300×300 Supplier Quote With Mill Test Certificate
Send your specifications and quantity to receive a quotation and original mill test certificate within 12 hours.
- Website: www.xjyplate.com
- Tel: +86 531 8573 6315
- Mobile/WhatsApp/WeChat: +86 188 5315 7756
- Email: admin@xjyplate.com
- Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do Q235 and Q345 grades compare to ASTM A500 and EN S235/S355?
A: Q235 maps to S235JR under EN 10219 and ASTM A500 Grade B, while Q345 corresponds to S355JR and ASTM A500 Grade C. We provide grade equivalence documentation with every shipment so your structural engineer can verify compliance with the project specification.
Q: Can you provide third-party inspection before shipment?
A: Yes. SGS and BV inspection reports are available at buyer’s request. The inspection covers dimensional tolerance, surface condition, weld seam quality, and chemical composition verification against the mill test certificate.
Q: What is the MOQ for custom-cut rectangular tubes?
A: The minimum order quantity is 5 tons. Custom cutting, punching, and bending to your project drawings are available within this MOQ, and we will confirm the processing lead time once we receive your detailed specifications.
Q: How do you handle negative tolerance and theoretical weight invoicing?
A: Our ASTM Rectangular ERW Steel Tube 300×300 Supplier products are manufactured within ±1% dimensional tolerance. Invoicing is by theoretical weight per the standard section dimensions, and the mill test certificate confirms the actual measured values for your records.
Q: What shipping options are available for heavy rectangular tubes?
A: We offer FOB, CIF, and DDP terms. For 300×300 mm rectangular tubes, open-top containers or flatbed loading is used to handle the weight and length. Our logistics team plans the loading to maximize container payload while staying within port weight limits.
