Description
Factory-direct galvanized tube supply — Every batch of Q195–Q345 galvanized square and rectangular steel tube ships with original mill test certificates and optional SGS/BV third-party inspection, eliminating compliance risk at destination port.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square and Rectangular Steel Tube |
| Product Type | Square / Rectangular Steel Tube (Galvanized) |
| Steel Grade | Q195, Q235, Q235B, Q345, Q345B, SS400, SGCC, CGCC, DX51D+Z, TDC51DZM, TDC52DTS350GD, TS550GD |
| Standard | ASTM, ISO 9001, JIS, API, TISI |
| Section Shape | Square / Rectangular |
| Size Range | 20×20 mm – 200×200 mm |
| Wall Thickness | 1.5 – 30 mm |
| Length | 1 – 12 m |
| Technique | ERW (Welded) |
| Surface Treatment | Galvanized Coating (Hot Rolled / Cold Rolled + Galvanized) |
| Tolerance | ±1% |
| Ends | Plain / Beveled |
| Application | Construction structure, Building frames, Machinery, Scaffolding, Furniture, Industrial fabrication |
| MOQ | 25 Tons (1×20ft container) |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Structural frames, scaffolding systems, building support columns |
| Industrial Fabrication | Machinery bases, equipment frames, modular platform structures |
| Commercial Projects | Furniture frames, perimeter fencing, architectural façade elements |
| Energy & Utilities | Solar panel mounting structures, cable tray supports |
Where Galvanized Coating Thickness Decides Port Acceptance
A 45μm reading against an 80μm contract specification means the entire container gets rejected at destination.
I learned this the hard way when a 200×200 square tube shipment to the Middle East failed third-party re-inspection at port. The zinc coating fell short, the cargo was returned for re-galvanizing, and the freight loss alone ran into five figures. Since then, every galvanized square and rectangular steel tube leaving our facility carries a coating thickness report verified against the purchase order before loading. [NEED_CITE: hot-dip galvanized coating thickness standards for structural steel] Quality uncertainty remains the top concern for global steel buyers — inconsistent material properties and unclear grade traceability can trigger customs holds and project compliance failures that no amount of price negotiation can fix.
Matching Corrosion Resistance to Structural Environment
Galvanized square and rectangular steel tube in Q235B and Q345B grades serves projects where atmospheric corrosion resistance directly determines service life. The zinc coating on ERW welded base tubes provides uniform protection across all four faces, including weld seams, making it suitable for outdoor scaffolding, solar mounting structures, and industrial frames exposed to moisture. For coastal or high-humidity environments, specifying SGCC or DX51D+Z grades with thicker zinc layers ensures the coating survives handling, cutting, and welding at the job site without premature breakdown. Our inventory covers over 2,800 specifications across square and rectangular profiles, so project buyers consolidating multiple sizes into one container avoid the coordination overhead of fragmented sourcing.
Engineering Compliance and Certification Requirements
Structural galvanized tubes for load-bearing frames must conform to recognized engineering standards — ASTM A500 for North American projects, EN 10219 for European markets, and JIS G3466 for Southeast Asian specifications. [NEED_CITE: EN 10219 cold-formed hollow section requirements] Steel grade selection directly affects load calculations: Q345B offers higher yield capacity than Q235B for the same cross-section, reducing material weight while meeting structural design codes. Galvanized coating adds corrosion protection but must be accounted for in welding procedures — post-weld touch-up with zinc-rich paint is standard practice at connection points. Every batch ships with mill test certificates documenting chemical composition and mechanical properties per the specified standard, and Lloyd’s CE certification under EN 10210/10219 is available for European customs clearance. [NEED_CITE: steel grade equivalence between EN and ASTM standards]
Steel Grade Selection and ERW Welding Process
The Q-series grades (Q195 through Q345) follow the Chinese GB standard system where the number indicates minimum yield strength in MPa — Q235B yields at approximately 235 MPa, suitable for general structural frames, while Q345B steps up for heavier load requirements. SS400 from the JIS system and SGCC/CGCC from the galvanized sheet standard serve different procurement traditions but overlap significantly in mechanical performance for non-critical structural use. ERW welding produces a longitudinal seam that, when properly controlled and heat-treated, delivers consistent strength across the tube cross-section at lower cost than seamless alternatives. The galvanized coating applied over the ERW base — whether hot-dip or pre-galvanized — seals the weld zone against moisture ingress, which is critical for scaffolding and outdoor structural applications where corrosion starts at the seam first. Wall thickness tolerance of ±1% ensures that theoretical weight calculations match actual delivered weight, preventing disputes over quantity at destination.
Hidden Costs of Incorrect Grade and Missing Certification
Ordering Q195 when the structural engineer specified Q345B means the tubes cannot carry the designed load — re-procurement delays the project and the original cargo becomes dead stock. Missing or incomplete mill test certificates trigger customs holds at ports with strict import documentation requirements, adding demurrage charges and inspection fees. [NEED_CITE: steel import documentation requirements for customs clearance] Coating thickness below contract specification leads to rejection at third-party re-inspection, forcing return shipments or on-site re-galvanizing at multiples of the original coating cost. These failures are not theoretical — they recur across markets where buyers prioritize unit price over material traceability and certification completeness.
Procurement Confidence Through Verified Supply Chain
Factory-direct pricing means no trading margin layered onto the galvanized square and rectangular steel tube — volume buyers securing recurring orders access tiered discount programs reviewed every six months. Our in-house laboratory conducts three-stage inspection covering dimensional accuracy, coating thickness, and weld integrity before any batch leaves the facility. With 2,800+ specifications in ready stock across square and rectangular profiles, urgent orders and split shipments move without waiting for production slots. ISO 9001:2015 certified production, Lloyd’s CE under EN 10210/10219, and FPC certification provide the documentation backbone for project compliance across 50+ export markets. Custom non-standard dimensions and定尺 lengths are available with typical production lead times, and every container is loaded under professional plans that optimize weight distribution and protect the galvanized surface during ocean transit.
Documentation & Compliance
- Mill test certificate documenting Q235B/Q345B chemical composition and mechanical properties per ASTM or EN standard specified in the purchase order
- Lloyd’s CE certificate under EN 10210/10219 for galvanized hollow sections destined for European Union markets
- ISO 9001:2015 quality management system certificate covering the full production and inspection process
- SGS or BV third-party inspection report verifying coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability by heat number linking each tube bundle to its original steel coil and production batch
- Complete customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized square and rectangular tubes bundled with steel straps and edge protectors to preserve the zinc coating during handling and ocean transit
- Surface protection maintained through careful stacking with separation layers, preventing zinc scratch damage on SGCC and DX51D+Z coated tubes
- Container loading optimized for 20ft and 40ft units based on tube dimensions — 20×20 mm to 200×200 mm profiles nested to maximize weight utilization within the 25-ton MOQ
- Cut-to-length service available across the 1–12 m range, reducing on-site waste and secondary cutting costs for scaffolding and frame applications
- Each bundle marked with heat number, steel grade, size specification, and coating class for traceability at destination
- FOB, CIF, and door-to-door delivery options with professional export documentation handling
Securing Your Quotation with Complete Specifications
Submit your galvanized square and rectangular steel tube requirements — including section dimensions, wall thickness, steel grade, coating specification, quantity, and destination port — to receive a factory-direct quotation with volume pricing and delivery schedule. Non-standard dimensions and custom length requests are reviewed with technical drawings before production confirmation. Mill test certificates and third-party inspection arrangements are confirmed at the contract stage to ensure full compliance with your project specifications.
Request Factory-Direct Pricing and Mill Test Certificates
Send your specification sheet via email or WhatsApp to receive a detailed quotation with coating thickness confirmation and delivery timeline within 12 hours.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
