Description
Factory-Direct ERW Hollow Sections — 3 production lines running simultaneously with monthly capacity exceeding 20,000 tons, supplying Q235 Q345 ERW square and rectangular steel tube directly from Jinan without middlemen markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 ERW Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Hollow Section |
| Steel Grade | Q195, Q215, Q235, Q345, S235JR, GR.B, STK500 |
| Standard | GB/T 3091-2001, BS 1387-1985, DIN EN 10025, EN 10219, JIS G 3444:2004, ASTM A53, BS EN 10255-2004 |
| Section Shape | Square / Rectangular |
| Size Range | 10mm × 10mm – 500mm × 500mm |
| Wall Thickness | 0.6mm – 20mm |
| Length | 1m / 4m / 5.8m / 6m / 8m / 12m (customizable) |
| Technique | Hot Rolled / Cold Rolled ERW |
| Surface Treatment | Oiled / Black Painted |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded with couplings or sockets; plastic caps and steel rings available |
| Application | Steel structures, construction frames, machinery, scaffolding, furniture, fluid transport |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, portal structures, bridge support columns, urbanization projects under Belt & Road Initiative |
| Machinery Manufacturing | Conveyor frames, equipment bases, hydraulic support structures, OEM factory recurring supply |
| Steel Trading & Distribution | Multi-category container consolidation, regional wholesale inventory, split shipment fulfillment |
| Scaffolding & Temporary Works | Scaffold tubes, formwork supports, access platform frames |
| Furniture & Interior | Table legs, shelving frames, display rack structures |
Where Wall-Thickness Tolerance Decides Structural Integrity on Hollow Section Orders
A ±1% tolerance on 0.6mm wall thickness means 0.006mm deviation — acceptable for furniture frames, but critical when stacking pallets on 500×500 columns.
Procurement teams sourcing Q235 Q345 ERW square and rectangular steel tube often discover tolerance issues only after materials arrive on site. When wall thickness falls below nominal due to uncontrolled negative tolerance, load-bearing calculations become invalid, and structural engineers must redesign connections or reject entire batches. The cost is not just the replacement material — it is delayed project handover, re-engineering fees, and damaged credibility with the end client [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements].
How ERW Hollow Sections Match Structural Frame Requirements
The Q235 Q345 ERW square and rectangular steel tube range from 10×10mm to 500×500mm covers both light-gauge furniture applications and heavy structural columns. For building frames and machinery bases, the hot-rolled ERW process ensures weld seam integrity across the full length, while the ±1% tolerance maintains dimensional consistency during fabrication. When projects require mixed sizes — say 40×80 rectangular tubes for purlins alongside 200×200 square tubes for columns — consolidated container loading reduces freight cost per ton and ensures all materials arrive with matching mill test certificates from the same production batch.
Engineering Compliance and Certification Pathways
Structural hollow sections used in load-bearing frames must comply with regional standards: EN 10219 for European markets, ASTM A53 for North American projects, and GB/T 3091 for domestic Chinese construction. The Q235 grade meets S235JR equivalence under EN 10025, while Q345 corresponds to S355JR in yield strength classification [NEED_CITE: steel grade equivalence between Chinese Q-series and European S-series standards]. For projects requiring third-party verification, SGS or BV inspection reports confirm chemical composition and mechanical properties before shipment. CE certification under EN 10210/10219 is mandatory for structural hollow sections entering European Union customs, and missing documentation causes port holds averaging several weeks.
Steel Grade Selection and ERW Process Fundamentals
The Q195–Q345 range covers increasing yield strength levels: Q195 for non-structural applications, Q235 for general construction frames, and Q345 for heavy-load bearing structures. International equivalents include S235JR (EN), GR.B (API), and STK500 (JIS), allowing procurement teams to specify local standards while sourcing from Chinese mills. The ERW (Electric Resistance Welding) process forms square and rectangular profiles from steel coil, then welds the seam using high-frequency current — this method produces consistent wall thickness and smooth interior surfaces suitable for fluid transport and concealed structural connections. Hot-rolled ERW offers better formability for bending operations, while cold-rolled ERW provides tighter dimensional tolerance for precision machinery frames. Surface treatment options include oiled finish for short-term rust prevention during transit, and black painted coating for indoor applications where appearance matters.
The Hidden Cost of Unverified Material Traceability
Purchasing Q235 Q345 ERW square and rectangular steel tube without original mill test certificates creates downstream risk: if material fails during load testing or structural inspection, the buyer cannot prove compliance with project specifications. Customs authorities in Brazil, Chile, and European ports increasingly require heat number traceability linking each tube to its production batch and chemical analysis [NEED_CITE: import documentation requirements for structural steel in South American markets]. When suppliers cannot provide mill test certificates or third-party inspection reports, projects face rejection at site, forced material replacement, and potential liability claims from end clients. The initial savings from uncertified suppliers disappear within the first failed inspection.
Why Procurement Teams Choose Xin Jiyuan for Hollow Section Supply
Factory-direct pricing eliminates trader markup on every ton of Q235 Q345 ERW square and rectangular steel tube, with volume discounts structured for long-term partners ordering multiple containers annually. The Jinan facility operates 3 production lines simultaneously, maintaining ready stock across 2,800+ specifications including standard sizes from 10×10mm to 500×500mm, enabling urgent orders to ship within days rather than weeks. Every batch ships with original mill test certificates documenting chemical composition and mechanical properties, and third-party SGS/BV inspection is available for projects requiring independent verification. Professional export teams optimize container loading plans — critical for rectangular hollow sections where improper stacking causes deformation during ocean freight — and handle complete documentation including certificates of origin for customs clearance in destination countries.
Documentation & Compliance
- Mill test certificate documenting Q235 and Q345 chemical composition, yield strength, and tensile properties per GB/T 3091 and EN 10219 standards
- CE certificate under EN 10210 (seamless) and EN 10219 (welded) for structural hollow sections entering European Union markets
- ISO 9001:2015 quality management certificate covering production processes and inspection procedures
- SGS or BV third-party inspection report verifying dimensional tolerance, surface quality, and material traceability by heat number
- Material traceability documentation linking each tube bundle to production heat number, chemical analysis, and mechanical test results
- Complete customs documents including packing list, bill of lading, certificate of origin, and commercial invoice formatted for destination port requirements
Packaging, Loading & Delivery
- Q235 and Q345 ERW square and rectangular steel tubes bundled with steel strips and edge protectors to prevent surface damage during handling and transit
- Oiled surface treatment applied before bundling to prevent rust formation during ocean freight, with plastic caps protecting tube ends from moisture ingress
- Container loading plans optimized for rectangular hollow sections (40×80, 25×50, 40×60) with wooden separators between layers to distribute weight and prevent deformation
- Custom length cutting available for 5.8m and 6m tubes to maximize container utilization and reduce on-site waste for construction projects
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability verification during installation
- FOB, CIF, and DDP shipping terms available with professional logistics coordination from Jinan inland depot to destination port or project site
How to Initiate Your Hollow Section Procurement
Submit your specifications including section dimensions, wall thickness, steel grade, quantity, and destination port via email or WhatsApp to receive competitive bulk pricing within 12 hours. For non-standard sizes or custom lengths outside the 10×10mm to 500×500mm range, request a tailored production quotation with typical lead times for your order volume. Confirm certification requirements (CE, mill test certificates, third-party inspection) and loading specifications to ensure documentation matches your customs clearance needs.
Request Factory-Direct Pricing with Mill Test Certificates
Send your Q235 Q345 ERW square and rectangular steel tube inquiry to admin@sdxinjiyuan.com or contact via WhatsApp at +86 188 5315 7756 for bulk pricing, technical specifications, and certification documentation.
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 steel grades for structural applications?
A: Q235 offers lower yield strength suitable for general construction frames, scaffolding, and non-critical structural elements, while Q345 provides higher yield strength for heavy-load bearing columns, bridge supports, and machinery bases subject to dynamic forces. Both grades are available in square and rectangular hollow sections from 10×10mm to 500×500mm with wall thickness 0.6mm–20mm.
Q: Can you provide mill test certificates for customs clearance in Brazil and Chile?
A: Yes, every batch of Q235 Q345 ERW square and rectangular steel tube ships with original mill test certificates documenting chemical composition and mechanical properties. For South American markets requiring additional verification, SGS or BV third-party inspection reports are available upon request, and heat number traceability links each tube to its production batch.
Q: What is the minimum order quantity for custom non-standard sizes?
A: Flexible MOQ ranges from 1-ton trial orders for testing and sampling to full-container bulk shipments. Standard sizes from 10×10mm to 500×500mm maintain ready stock for urgent delivery, while custom non-standard dimensions or lengths outside 1m–12m require typical production lead times depending on order volume.
Q: How do you prevent rectangular hollow sections from deforming during ocean freight?
A: Professional container loading plans use wooden separators between layers, edge protectors, and weight distribution calculations specific to rectangular profiles like 40×80, 25×50, and 40×60. Each container ships with a detailed loading diagram, and our export team coordinates with logistics providers to secure cargo against shifting during transit.
Q: Do your hollow sections comply with European CE certification requirements?
A: Yes, Q235 Q345 ERW square and rectangular steel tubes carry CE certification under EN 10210 (seamless hollow sections) and EN 10219 (cold-formed welded hollow sections), meeting dimensional tolerance, material properties, and traceability requirements for structural applications in European Union markets.
