Description
Factory-Direct ERW Rectangular Hollow Sections — Shandong Xin Jiyuan Special Steel Tube Co., Ltd produces Q235 and Q345 ERW rectangular steel hollow section tubes in-house, eliminating third-party sourcing gaps from raw material to finished fabrication.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 Rectangular Welded Steel Hollow Section Tube |
| Product Type | Rectangular Welded Steel Hollow Section (RHS) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Rectangular |
| Size Range | 20×20 mm, 50×25 mm, 60×40 mm, 80×40 mm, 50×50 mm, and other sizes per request |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Customer’s Request |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe, Steel Structures, Construction Frames, Machinery, Scaffolding |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding systems, platform supports, stairway structures |
| Industrial Facilities | Warehouse roof trusses, logistics center columns, machinery frames, conveyor structures |
| Energy & Piping | Fluid transport lines, gas distribution pipes, chemical fertilizer pipeline systems, boiler tubes |
| Oil & Gas | Drill pipe casings, oil well support structures, gas pipeline frameworks |
When Wall-Thickness Tolerance Determines Structural Integrity on Site
A ±1% tolerance on ERW rectangular hollow sections prevents fit-up failures during assembly.
Overseas buyers consistently report dimensional discrepancies when sourcing rectangular hollow sections from suppliers without in-house production control. Wall thickness variations beyond acceptable limits cause welding gaps, misaligned connections, and costly rework at the installation stage. When material sourcing and fabrication are split across different vendors, accountability for tolerance compliance becomes fragmented — the fabricator blames the mill, the mill blames the testing method, and the project timeline collapses. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Rectangular Hollow Sections to Structural Frame Requirements
Q235 and Q345 grades in ERW rectangular hollow sections serve distinct load-bearing roles in structural applications. Q235 provides adequate strength for secondary framing, scaffolding, and non-critical support structures where weight optimization matters less than cost efficiency. Q345 delivers higher yield capacity for primary columns, beam systems, and load-transfer nodes in industrial buildings and warehouse frames. The ERW welding process ensures consistent seam quality across the rectangular profile, while the ±1% tolerance guarantees that connection plates and gussets align precisely during bolted or welded assembly. Our in-house CNC cutting and drilling services eliminate the need for secondary processing at the job site — components arrive ready for installation with pre-punched holes and cut-to-length precision.
Engineering Compliance and Certification for Global Projects
Structural steel fabrication for international projects requires documented compliance with regional standards. Q235 corresponds to S235JR under EN 10025 and approximates A36 under ASTM standards, while Q345 aligns with S355JR and A572 Grade 50 in Western specifications. [NEED_CITE: steel grade equivalence between Chinese GB standards and EN/ASTM systems] For EU-bound shipments, EN 10219 certification validates that the ERW rectangular hollow sections meet European dimensional and mechanical requirements. North American projects typically require ASTM A213 or A500 compliance with full material traceability by heat number. Our mill test certificates document chemical composition and mechanical properties per heat, enabling third-party inspection agencies like SGS or BV to verify compliance before shipment. Surface treatment selection — hot rolled with slight oiling for indoor applications, or custom painting and shot blasting for corrosive environments — must align with project specifications and local climate conditions.
Understanding ERW Process and Steel Grade Selection for Rectangular Hollow Sections
The ERW (Electric Resistance Welded) process forms rectangular hollow sections by rolling steel strip into shape and welding the seam through electrical resistance heating. This method produces consistent wall thickness and smooth internal surfaces suitable for fluid transport and structural applications. Q195 and Q215 grades offer lower strength but excellent formability for light-duty scaffolding and non-structural frames. Q235 serves as the workhorse grade for general construction — balancing strength, weldability, and cost for building frames, machinery bases, and platform structures. Q345 provides enhanced yield strength for heavy-load applications such as industrial crane runways, bridge support columns, and high-rise structural nodes. The hot rolled surface finish with slight oiling protects against transient rust during storage and transit, while maintaining weldability without surface preparation beyond standard degreasing. Negative tolerance control — keeping actual wall thickness within the ±1% range — ensures that theoretical weight calculations match actual delivered weight, preventing cost overruns from over-delivery or structural concerns from under-delivery.
Hidden Costs of Incorrect Grade Selection and Missing Certification
Specifying Q235 when project loads require Q345 creates structural safety risks that surface only during load testing or under service conditions — by then, replacement costs include demolition, re-fabrication, and project delays. Conversely, over-specifying Q345 for light-duty applications inflates material costs without engineering justification. Missing or incomplete mill test certificates trigger customs holds at destination ports, particularly in EU markets where EN 10219 compliance documentation must accompany every shipment. [NEED_CITE: customs clearance requirements for structural steel imports into European Union] Third-party re-inspection costs — when buyers cannot verify material origin and properties from supplier documentation — typically exceed the price difference between certified and uncertified material. Dimensional non-conformance discovered during assembly forces on-site cutting and re-welding, eroding the cost advantage of overseas fabrication.
Procurement Advantages of Vertically Integrated Supply
Shandong Xin Jiyuan Special Steel Tube Co., Ltd operates both steel production facilities and structural steel fabrication workshops under one roof. This vertical integration means the Q235 and Q345 ERW rectangular hollow sections you order come from our own mill — not sourced from third parties with inconsistent quality control. Our in-house理化实验室 (physical and chemical testing laboratory) generates mill test certificates for every heat number, documenting chemical composition and mechanical properties before material enters fabrication. With over 2,800 specifications in our raw material inventory, we fulfill custom size requests without forcing minimum order quantities that exceed project needs. Certified welding procedures (WPS/PQR) and qualified welders per AWS and EN standards ensure that any cutting, punching, or welding services we perform maintain the same quality baseline as the base material. Professional loading and lashing planning for oversized fabricated components prevents transit damage and simplifies site receiving.
Documentation & Compliance
- Mill test certificate documenting Q235 and Q345 chemical composition (carbon, manganese, silicon, sulfur, phosphorus content) and mechanical properties (yield strength, tensile strength, elongation) per heat number, compliant with DIN EN 10217-1 and ASTM A213 requirements
- CE certificate confirming EN 10219 compliance for rectangular hollow sections destined for European Union construction projects, with Declaration of Performance available for structural engineering approval
- ISO 9001 quality management system certificate covering the entire production chain from steel strip procurement through ERW forming, welding, cutting, and final inspection of rectangular hollow sections
- SGS or BV third-party inspection report available upon request, verifying dimensional accuracy, weld seam quality, surface treatment thickness, and material traceability for Q235/Q345 ERW rectangular steel hollow section tube orders
- Material traceability documentation linking each delivered piece to its original heat number, enabling project-specific quality tracking and compliance verification during structural engineering audits
- Complete customs documentation package including commercial invoice, packing list with piece count and weight breakdown by size, bill of lading, and certificate of origin for smooth clearance at destination ports
Packaging, Loading & Delivery
- Q235 and Q345 ERW rectangular hollow sections bundled with steel strips at intervals preventing bundle distortion during crane handling, with edge protectors preserving the hot rolled surface finish and slight oiling layer against transit abrasion
- Cut-to-length rectangular tubes packed in wooden crates or steel-frame containers for sizes exceeding 6 meters, preventing bending damage to longer sections during ocean freight
- Surface protection maintained through slight oiling applied immediately after ERW production, providing rust prevention during typical 30-60 day storage and transit periods without requiring solvent removal before welding
- Container loading optimized for rectangular hollow section geometry — smaller sizes (20×20 mm, 50×25 mm) nested within larger sections (80×40 mm) to maximize container utilization and reduce per-ton shipping costs
- Heat number and steel grade stenciled on each bundle tag, with corresponding mill test certificate reference numbers enabling immediate material identification at the construction site
- FOB, CIF, and DDP shipping terms available from Qingdao or Tianjin ports, with professional lashing plans for fabricated rectangular hollow section components exceeding standard container dimensions
Initiating Your Q235/Q345 Rectangular Hollow Section Inquiry
Submit project drawings (PDF/DWG format) specifying steel grade, section dimensions, wall thickness, length requirements, and applicable standards to receive a detailed quotation within 24 hours. Our engineering team reviews shop drawings for fabrication feasibility, suggests material optimization alternatives, and confirms delivery timelines based on your project schedule. Request mill test certificates, third-party inspection arrangements, and customs documentation requirements during the initial inquiry to ensure compliance with your destination country’s import regulations.
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 steel grades for rectangular hollow sections?
A: Q235 offers lower yield strength suitable for secondary structures, scaffolding, and light-duty frames where cost efficiency takes priority. Q345 provides higher yield strength for primary structural members, load-bearing columns, and heavy-duty industrial frames. Both grades maintain excellent weldability and formability in ERW rectangular hollow section production.
Q: Can you provide mill test certificates for third-party inspection verification?
A: Yes, every batch of Q235 and Q345 ERW rectangular hollow sections includes mill test certificates documenting chemical composition and mechanical properties by heat number. Third-party inspection agencies such as SGS, BV, or TÜV can verify these certificates against physical samples before shipment.
Q: What surface treatment options are available for rectangular hollow sections?
A: Standard delivery includes hot rolled finish with slight oiling for rust prevention during transit. Custom surface treatments including shot blasting, primer painting, galvanizing, or specialized coating systems are available based on project specifications and environmental exposure requirements.
Q: Do you offer custom cutting and fabrication services for rectangular hollow sections?
A: Yes, our in-house fabrication workshop provides CNC cutting, punching, bending, and welding services to engineering drawings. Components arrive at your site ready for installation with pre-fabricated connections, eliminating secondary processing costs and project delays.
Q: What is the minimum order quantity for Q235/Q345 rectangular hollow sections?
A: The minimum order quantity is 5 tons per size specification. For mixed-size orders totaling 5 tons or more, we can accommodate multiple section dimensions within a single shipment to optimize container loading and freight costs.
Get Your Q235/Q345 ERW Rectangular Hollow Section Quote
Send your project specifications including steel grade, section size, wall thickness, quantity, and destination port to receive pricing with mill test certificates and delivery timeline.
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
