Description
Factory-direct ERW rectangular hollow sections — Q195–Q345 grades produced in-house with ±1% dimensional tolerance and full processing services under ASTM/DIN EN standards.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 ERW Welded Rectangular Steel Hollow Section |
| Product Type | Welded Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Rectangular |
| Size Range | 20×20 mm – 80×40 mm (20X20, 50X25, 60X40, 80X40, 50X50) |
| 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 |
| Packing | Standard Seaworthy Packing |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe |
| MOQ | 5 Tons |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Industrial Construction | Steel structure frames for warehouses and light industrial buildings |
| Machinery Manufacturing | Equipment support bases and conveyor frame structures |
| Petrochemical Plants | Fluid and gas transport pipelines within processing facilities |
| Power Generation | Boiler tube supports and auxiliary piping systems |
| Agricultural Infrastructure | Greenhouse framing and irrigation pipeline structures |
What Wall-Thickness Consistency Costs on an ERW Rectangular Hollow Section Order
Inconsistent wall thickness across a batch means rejected weld inspections and re-cut material on site.
When procurement teams order an ERW welded rectangular steel hollow section for structural or fluid conveyance use, the tolerance on wall thickness directly affects weld penetration quality and load-bearing calculations. Suppliers who quote low prices often ship material at the negative edge of tolerance — or worse, below it — forcing fabricators to re-test every piece before welding. For Q195–Q345 grade tubes in the 20×20 to 80×40 mm range, this is especially critical because smaller sections have less material margin to absorb dimensional deviation. [NEED_CITE: EN 10219 cold-formed welded structural hollow section dimensional tolerance requirements]
Matching Small-Section ERW Tubes to Structural and Pipeline Applications
The 20×20 to 80×40 mm size range of this ERW welded rectangular steel hollow section serves applications where moderate load capacity meets tight spatial constraints. In machinery frames, these tubes provide sufficient rigidity for conveyor supports and equipment bases without adding excess weight. For fluid and gas pipelines in chemical fertilizer plants, the ERW weld seam — when produced under controlled conditions — delivers pressure integrity comparable to seamless alternatives at a lower cost point. The hot-rolled surface with slight oiling protects against transit corrosion while remaining compatible with downstream coating or painting processes required by project specifications.
Engineering Compliance Requirements for ERW Rectangular Hollow Sections
Structural applications demand dimensional compliance with recognized standards — DIN EN 10217-1 governs welded steel tubes for pressure purposes, while ASTM A213 covers seamless and welded boiler/superheater tubes. For Q235 and Q345 grades, chemical composition and mechanical properties must align with the designated standard before fabrication begins. [NEED_CITE: ASTM A213 welded steel tube requirements for boiler and pressure service] Corrosion resistance in outdoor or chemical environments requires either additional surface treatment beyond the as-delivered oiled condition or selection of upgraded grades. Custom cut-to-length services eliminate on-site cutting waste and ensure each piece arrives at the exact dimension specified in fabrication drawings. Third-party inspection through SGS or BV before shipment provides independent verification that material matches the mill test certificate.
Understanding Q195–Q345 Steel Grades and ERW Welding for Rectangular Tubes
The Q-series steel grade system used in Chinese standards designates yield strength levels — Q195 offers the lowest yield point suitable for light structural and non-pressure applications, while Q345 provides higher strength for load-bearing frames and moderate-pressure pipelines. This progression allows engineers to select material based on actual stress requirements rather than defaulting to a single grade across an entire project. ERW (Electric Resistance Welded) manufacturing joins the formed strip edges through electrical resistance heating without filler metal, producing a clean, narrow weld seam that maintains dimensional accuracy across the 20×20 to 80×40 mm range. The hot-rolled surface finish results from the forming process at elevated temperatures, providing a mill scale layer that offers baseline corrosion protection during storage and transit. Slight oiling applied after production prevents rust formation during ocean shipping without interfering with subsequent welding or coating operations. The ±1% tolerance specification ensures that theoretical weight calculations remain reliable for cost estimation and that fabricators receive material matching their engineering assumptions.
Hidden Costs of Procuring ERW Rectangular Tubes Without Verified Compliance
Ordering ERW welded rectangular steel hollow sections without confirmed mill test certificates creates downstream risk across the entire project timeline. Material that fails chemical composition verification during independent inspection faces rejection at destination port, triggering return freight costs or local disposal fees that exceed the original material value. Weld seams produced without proper process control may pass visual inspection but fail ultrasonic testing during fabrication — forcing complete rework of assembled structures. [NEED_CITE: weld seam quality verification requirements for ERW steel tubes per EN 10219] Certification gaps become customs barriers in regulated markets where EN or ASTM compliance documentation must accompany every shipment. The true cost of these failures includes project delays, penalty clauses for late delivery, and damaged supplier relationships that complicate future procurement.
Procurement Advantages for ERW Welded Rectangular Steel Hollow Sections
Our production facility manufactures Q195–Q345 ERW rectangular tubes across the 20×20 to 80×40 mm range with in-house physical and chemical laboratories that test every heat for composition and mechanical properties before release. The ±1% tolerance standard applies consistently across all sizes, eliminating the batch-to-batch variation that plagues traders sourcing from multiple mills. We hold ISO 9001:2015 certification alongside Lloyd’s CE marking for EN 10219 compliance, ensuring documentation satisfies EU customs requirements without additional third-party certification costs. Custom cutting, punching, and bending services process tubes to exact project specifications before shipment, reducing on-site labor and material waste at the fabrication facility. Professional container loading protocols prevent the surface damage and dimensional distortion that occur when tubes shift during ocean transit. As a designated supplier for major state-owned enterprises, we maintain the production discipline and quality documentation that regulated markets require.
Documentation & Compliance
- Mill test certificate documenting Q195/Q235/Q345 chemical composition and mechanical properties per DIN EN 10217-1 or ASTM A213 standards
- CE certificate confirming EN 10217-1 compliance for pressure applications in EU markets
- ISO 9001:2015 quality management system certificate covering ERW welded rectangular hollow section production
- SGS or BV third-party inspection report verifying dimensional accuracy and weld seam quality before shipment
- Material traceability documentation linking each tube to specific heat numbers and production batch records
- Complete customs documentation including packing list, bill of lading, and certificate of origin for destination clearance
Packaging, Loading & Delivery
- Q195–Q345 ERW rectangular tubes bundled with steel strips and edge protectors to prevent surface damage to the hot-rolled oiled finish during handling
- Slight oil coating applied uniformly across all 20×20 to 80×40 mm sections to prevent rust formation during ocean transit in open-top or standard containers
- Custom cut-to-length service eliminates on-site cutting waste, with each piece marked to project drawing dimensions before bundling
- Container loading optimized for 20×20 to 80×40 mm rectangular sections using wooden cradles and anti-shift bracing to maintain dimensional integrity
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability verification during fabrication
- FOB, CIF, and DDP shipping terms available with professional export documentation for 50+ country destinations
Initiating Your ERW Rectangular Hollow Section Procurement
Submit your required dimensions, steel grade preference, quantity, and destination port to receive a detailed quotation including unit pricing, production lead time, and applicable certifications. We provide mill test certificates and arrange third-party inspection before shipment to confirm compliance with your project specifications. Custom cutting and processing services are quoted alongside material pricing to consolidate your procurement into a single order.
Request Your ERW Welded Rectangular Steel Hollow Section Quotation
Send your specifications including size, grade, quantity, and destination to receive pricing and mill test certificate samples within 12 hours.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 steel grades for rectangular tubes?
A: Q235 offers lower yield strength suitable for light structural applications and non-pressure pipelines, while Q345 provides higher strength for load-bearing frames and moderate-pressure systems. The selection depends on your engineering load calculations and applicable design codes.
Q: Can you provide custom lengths and cut-to-size services for ERW rectangular hollow sections?
A: Yes, we offer cutting, punching, bending, and decoiling services to process Q195–Q345 ERW rectangular tubes to your exact project specifications. Custom lengths eliminate on-site cutting waste and ensure each piece arrives ready for fabrication.
Q: How do you ensure weld seam quality in ERW welded steel tubes?
A: Our in-house physical and chemical laboratory tests every heat for composition and mechanical properties. We perform dimensional inspection and weld seam verification before shipment, with third-party inspection through SGS or BV available upon request.
Q: What certifications are available for exporting rectangular steel tubes to EU markets?
A: We hold Lloyd’s CE certification for EN 10219 compliance, ISO 9001:2015 quality management certification, and provide complete mill test certificates documenting chemical composition and mechanical properties per DIN EN 10217-1 standards.
Q: What is the theoretical weight calculation method for rectangular hollow sections?
A: Theoretical weight is calculated based on outer dimensions, wall thickness, and steel density per standard formulas. We invoice by theoretical weight as specified in our quotation, with actual dimensions verified against the ±1% tolerance standard.
