Description
Factory-Direct ERW Hollow Sections — 3 production lines running simultaneously with 2,800+ specifications in ready stock, eliminating middlemen markups on Q235 Q345 welded square and rectangular steel tube orders.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 Welded Square and Rectangular Steel Tube |
| Product Type | Welded Square and Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345B, S235JR, S355JR, SS400 |
| Standard | ASTM A213, DIN EN 10217-1, JIS |
| Section Shape | Square / Rectangular / Round |
| Size Range | Up to 300×300mm |
| Wall Thickness | 1mm–3mm |
| Length | 6m / 6.4m / 12m (or customer request) |
| Technique | ERW (Cold Rolled / Hot Rolled) |
| Surface Treatment | Hot Rolled / Oiled / Non-oiled |
| Tolerance | ±1% |
| Invoicing | By Theoretical Weight |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Construction / Building Material / Steel Structures / Machinery / Furniture / Architectural Decoration |
| MOQ | 1 Ton (trial) / 5 Tons (bulk) |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Building | Building frames, scaffolding systems, support columns, structural beams |
| Machinery Manufacturing | Equipment frames, conveyor structures, machine bases, hydraulic supports |
| Architectural Decoration | Curtain wall frames, furniture structures, interior decorative columns |
| Infrastructure Projects | Bridge supports, solar panel mounting structures, wind farm foundations |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on 2mm wall Q345B square tubes means the difference between passing site inspection and scrapping an entire container.
Global steel buyers consistently report quality uncertainty as their primary procurement barrier. When wall thickness negative tolerance exceeds acceptable limits, structural load calculations become unreliable — site supervisors with calipers reject shipments, containers sit at ports, and project timelines collapse. The Q235 Q345 welded square and rectangular steel tube market is fragmented across suppliers who cannot guarantee dimensional consistency, forcing buyers to coordinate multiple vendors for pipes, plates, and fabrication. Missing or incomplete mill test certificates compound the problem: customs delays and compliance failures become routine rather than exceptional. [NEED_CITE: EN 10219 cold-formed hollow section requirements]
How ERW Welded Hollow Sections Match Structural Engineering Demands
The Q235 Q345 welded square and rectangular steel tube produced via ERW process delivers dimensional precision that cold-formed structural applications require. Wall thickness ranging from 1mm to 3mm with ±1% tolerance ensures predictable load-bearing behavior across building frames and machinery structures. The ERW welding technique, available in both cold rolled and hot rolled variants, provides consistent seam integrity that meets EN 10219 requirements for non-alloy and fine grain steel hollow sections. Surface treatment options — hot rolled, oiled, or non-oiled — allow specification matching to end-use environments, from indoor furniture frames to outdoor scaffolding systems exposed to weather.
Engineering Compliance and Certification Requirements
Structural hollow sections must conform to project-specific engineering codes: EN 1993 (Eurocode 3) governs steel structure design in European markets, while AISC standards apply in North American construction. The Q235 Q345 welded square and rectangular steel tube in grades Q195 through Q345B meets GB/T 6728 requirements, while S235JR and S355JR conform to EN 10219 for cold-formed welded structural hollow sections. SS400 grade satisfies JIS G3466 specifications for Japanese market projects. CE certification under EN 10210/EN 10219 is mandatory for European Union construction products regulation compliance, and original mill test certificates documenting chemical composition and mechanical properties are non-negotiable for customs clearance. [NEED_CITE: steel grade equivalence between EN and ASTM standards] Third-party inspection by SGS or BV provides independent verification that material properties match declared specifications.
Steel Grade Selection and ERW Process Fundamentals
The Q-series steel grades (Q195, Q215, Q235, Q345B) follow the Chinese GB standard system where the “Q” prefix denotes yield strength in MPa — Q235 indicates minimum 235 MPa yield strength, while Q345B provides higher load-bearing capacity for demanding structural applications. The S-series (S235JR, S355JR) follows EN 10219 European standards, with JR designation indicating room temperature impact testing requirements. SS400 represents the Japanese JIS G3466 equivalent for general structural applications. ERW (Electric Resistance Welding) process forms steel coil into tubular shape and welds the seam through electrical resistance heating — this method produces consistent wall thickness and smooth surface finish suitable for architectural applications where appearance matters. Cold rolled ERW provides tighter dimensional tolerance and superior surface quality, while hot rolled ERW offers cost advantages for applications where surface finish is secondary to structural performance. [NEED_CITE: ERW welded steel tube manufacturing process advantages]
Hidden Costs of Incorrect Material Specification
Specifying incorrect steel grade or accepting excessive negative tolerance creates downstream costs that dwarf initial purchase price savings. Material that fails to meet declared yield strength compromises structural integrity — engineering calculations based on Q345B properties become invalid if actual material performs as Q235. Missing CE certification blocks customs clearance in European markets, triggering demurrage charges and project delays. Incomplete mill test certificates prevent material traceability, making it impossible to verify heat numbers against original production records. [NEED_CITE: consequences of missing mill test certificates in steel procurement] Site rejection due to dimensional non-conformance forces return shipping or local scrapping — both options erase any per-ton cost advantage from the original purchase.
Why Procure Q235 Q345 Welded Square and Rectangular Steel Tube from Xin Jiyuan
Factory-direct pricing eliminates trading company markups — volume discounts apply to long-term partners with recurring procurement needs. Three production lines running simultaneously deliver monthly capacity exceeding 20,000 tons, with 2,800+ specifications maintained in ready stock for urgent fulfillment. Every batch ships with original mill test certificates documenting chemical composition and mechanical properties per declared steel grade. ISO 9001:2015 quality management system, Lloyd’s CE certification under EN 10210/EN 10219, and FPC certification ensure compliance with international construction product regulations. Third-party inspection by SGS or BV available upon request provides independent verification for quality-critical projects. Professional export team handles documentation, customs clearance, and container loading optimization — consolidated multi-product shipments reduce per-unit logistics costs. Flexible MOQ from 1-ton trial orders to full-container bulk quantities accommodates both project-specific procurement and ongoing inventory replenishment.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345B chemical composition and yield strength per GB/T 6728 standard
- CE certificate confirming EN 10210/EN 10219 compliance for European Union construction products regulation
- ISO 9001:2015 quality management system certificate covering production process and quality control
- SGS or BV third-party inspection report verifying dimensional tolerance and surface quality
- Material traceability by heat number linking each tube to original steel coil and production batch
- Complete customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235 Q345 welded square and rectangular steel tube bundled with steel strips in seaworthy packaging suitable for 6m and 12m lengths
- Oiled surface treatment applied to non-galvanized tubes prevents rust formation during ocean transit and storage
- Container loading optimization maximizes payload per 20ft and 40ft containers based on tube dimensions and wall thickness
- Custom cutting to non-standard lengths available per customer drawing requirements with ±5mm tolerance
- Heat number and steel grade标识 marked on each bundle for site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional logistics coordination from Jinan port to destination
How to Request Quotation and Technical Documentation
Submit your specification requirements including section dimensions, wall thickness, steel grade, quantity, and destination port via email or WhatsApp. Receive competitive bulk quotation with volume discount pricing, FOB/CIF terms, typical production lead times, and payment conditions within 12 hours. Request material samples and original mill test certificates for quality verification before contract commitment. Confirm CE certification and third-party inspection availability for your specific project compliance requirements.
Request Factory-Direct Pricing with Mill Test Certificates
Submit your Q235 Q345 welded square and rectangular steel tube specifications to receive bulk quotation and material documentation within 12 hours.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Email: admin@sdxinjiyuan.com
WhatsApp: +86 188 5315 7756
