Description
Factory-direct galvanized SHS from integrated mill — Own steel production lines and fabrication workshop eliminate third-party galvanizing gaps for S235 to S355JR grades.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square Steel Tube |
| Product Type | Square Steel Tube (SHS) |
| Steel Grade | S235, S275, Q235B, Q345B, SS400, STK400, A500 Grade A/B/C, A53 Grade B, S355JR |
| Standard | ASTM A53, A500, A36, A795; BS1387; EN10255; ISO65; ANSI C80; DIN2440; JIS G3444; GB/T3091, GB/T13793 |
| Section Shape | Square |
| Size Range | 21.3mm–660mm (1/2″–26″) |
| Wall Thickness | Customized per order |
| Length | 5.8m / 6m / 11m or as customer needs |
| Technique | Hot-dip Galvanizing / ERW |
| Surface Treatment | Hot-dip Galvanized (High Zinc Coating) |
| Tolerance | ±1% |
| Ends | Plain ends, Beveled ends, Threaded ends, Grooved ends |
| Application | Steel structures, Construction frames, Machinery parts, Hydraulic systems, Fluid transport, Power, Boiler, Petrochemical, Building industry |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC & General Contractors | Structural steel frames for industrial warehouses and logistics centers |
| Construction & Infrastructure | Scaffolding systems, building column assemblies, bridge support structures |
| Power & Petrochemical | Hydraulic piping racks, fluid transport conduits, boiler support frames |
| Machinery Manufacturing | Conveyor structures, equipment base frames, machinery support columns |
| Commercial Building | Curtain wall sub-frames, mezzanine platforms, stairway handrail systems |
When Third-Party Galvanizing Breaks Your Zinc Coating Guarantee
Outsourced galvanizing creates invisible quality gaps that surface only at site inspection.
Overseas buyers regularly discover inconsistent zinc thickness, poor adhesion, and missing material certificates when fabrication and galvanizing are handled by separate vendors. A fabricator sends black tubes to a nearby galvanizing shop, pays per ton by weight, and has no incentive to verify coating thickness on every bundle. The buyer receives mill test certificates for the base steel but zero documentation on zinc layer uniformity. [NEED_CITE: hot-dip galvanizing coating thickness standards per ISO 1461] When third-party inspectors arrive at the destination port with coating thickness gauges, entire shipments fail acceptance — and返工 costs fall on the buyer, not the supplier who never controlled the galvanizing line.
Matching Galvanized SHS to Structural and Corrosive Environments
Hot-dip galvanized square steel tubes in S235 through S355JR grades serve projects where structural load capacity meets aggressive corrosion exposure. The zinc coating formed during immersion in molten zinc creates a metallurgical bond with the steel substrate — not merely a surface layer that chips or peels under mechanical stress. For warehouse frames in coastal Southeast Asia or industrial structures in Middle East humidity, this metallurgical bond sustains corrosion protection for decades without maintenance. Our vertically integrated production line controls every stage from ERW forming through hot-dip galvanizing, ensuring zinc coating thickness remains consistent across the full 21.3mm–660mm size range.
Engineering Compliance Across EN, ASTM, and JIS Frameworks
Structural steel procurement for international projects demands compliance with multiple certification frameworks simultaneously. EU-bound shipments require CE marking under EN 10210 or EN 10219, while North American projects specify ASTM A500 Grade B or C. Japanese infrastructure projects reference JIS G3444, and Middle East EPC contracts often accept GB/T3091 with supplementary third-party inspection. [NEED_CITE: EN 10219 cold-formed structural hollow section technical delivery conditions] The galvanized square steel tube we produce carries full chemical composition and mechanical property documentation per the requested standard, with heat number traceability from raw coil to finished bundle. Wall thickness tolerance held at ±1% ensures dimensional compliance for bolted connections and welded joints specified in engineering drawings.
Steel Grade Selection and Hot-Dip Galvanizing Process Fundamentals
Steel grade selection directly determines structural load capacity — S235 serves light-frame construction and scaffolding, S275 handles medium-load industrial structures, and S355JR carries heavy structural frames for multi-story buildings and crane support systems. The Q-series grades (Q235B, Q345B) follow Chinese GB standards with equivalent mechanical properties to S235 and S355JR respectively, while SS400 and STK400 meet Japanese JIS requirements for structural and pipe applications.
Hot-dip galvanizing immerses formed ERW square tubes in molten zinc at approximately 450°C, creating a series of zinc-iron alloy layers bonded metallurgically to the steel surface. This process differs fundamentally from pre-galvanizing (electro-galvanizing), which deposits a thinner zinc layer suitable only for indoor or mild environments. High zinc coating from hot-dip galvanizing provides sacrificial corrosion protection — the zinc corrodes preferentially to protect the underlying steel, even at cut edges or minor coating damage. [NEED_CITE: hot-dip galvanizing vs pre-galvanized coating thickness comparison]
Wall thickness tolerance at ±1% matters for both theoretical weight calculation and actual load-bearing capacity. Negative tolerance beyond specification reduces structural safety margins, while excessive positive tolerance increases material cost without engineering benefit. Our integrated mill controls rolling parameters directly, holding tolerance within specification across the full production run.
Hidden Costs of Galvanizing Quality Failures on Project Sites
Incorrect steel grade documentation or insufficient zinc coating thickness creates cascading costs that far exceed the original material price difference. Engineering inspectors reject structural frames when mill test certificates show grade substitution — S235 material delivered where S355JR was specified triggers complete structural recalculation and potential redesign. Coating thickness below ISO 1461 minimum requirements forces on-site recoating or full shipment rejection, with返工 costs running multiples of the original galvanizing expense. [NEED_CITE: consequences of non-compliant galvanizing coating in structural steel projects] Customs authorities in EU markets detain shipments lacking CE marking or proper EN 10219 declaration of performance, incurring demurrage charges while documentation is corrected.
Integrated Mill Control from Raw Steel to Galvanized Finish
Our production facility operates three steel rolling lines with over 2,800 specification combinations in stock, eliminating the material sourcing gaps that plague brokers who purchase black tubes from unknown mills and subcontract galvanizing separately. Every galvanized square steel tube leaving our facility carries full traceability from raw material heat number through ERW welding parameters to hot-dip galvanizing bath chemistry and coating thickness measurements. Our in-house laboratory performs chemical composition analysis, mechanical testing, and zinc coating thickness verification before shipment — not as an afterthought, but as integrated process control. Third-party inspection from SGS, BV, or TÜV is available for every shipment, with reports issued before container sealing. Professional loading supervision ensures oversized SHS bundles are secured properly for ocean transit, preventing zinc coating damage from friction or impact during transport.
Documentation & Compliance
- Mill test certificate documenting S235/S275/S355JR chemical composition and mechanical properties per EN 10219, or A500 Grade B/C per ASTM A500, with heat number traceability
- CE certificate confirming compliance with EN 10210 for hot-finished or EN 10219 for cold-formed structural hollow sections, required for EU market access
- ISO 9001 quality management system certificate covering integrated production from steel forming through hot-dip galvanizing and final inspection
- SGS or BV third-party inspection report verifying zinc coating thickness per ISO 1461, dimensional tolerance, and visual quality before shipment
- Material traceability documentation linking each bundle to specific heat numbers, welding parameters, and galvanizing batch records
- Complete customs documentation package including packing list, bill of lading, certificate of origin, and commercial invoice formatted for destination country requirements
Packaging, Loading & Delivery
- Hot-dip galvanized square steel tubes bundled with high-tensile steel strips and edge protectors to preserve zinc coating integrity during handling and ocean transit
- Plastic caps installed on both ends of each tube to prevent zinc damage at tube edges and block moisture ingress during container shipping
- Standard seaworthy packaging with woven bag wrapping for 5.8m and 6m lengths, optimized for 20ft and 40ft container loading with maximum weight utilization
- Custom length cutting available for 11m or project-specific dimensions, with cut ends deburred and recoated to maintain corrosion protection
- Heat number and steel grade markings stenciled on each bundle for site identification and inspection traceability
- FOB, CIF, and DDP shipping terms available with professional loading supervision ensuring proper weight distribution and lashing for galvanized SHS bundles
Initiating Your Galvanized SHS Procurement
Submit your project specifications including steel grade requirements, dimensional specifications, quantity, and destination port to receive a detailed quotation with production timeline and mill test certificate samples. Our engineering team reviews your drawings for shop drawing compatibility and provides material optimization recommendations for standard size availability. Confirm certification requirements for your destination market and we prepare the complete documentation package before production begins.
Request Quotation with Mill Test Certificate
Send your galvanized square steel tube specifications to receive pricing, production schedule, and compliance documentation.
Company: 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
Frequently Asked Questions
Q: What zinc coating thickness does your hot-dip galvanizing process achieve?
A: Our hot-dip galvanizing process follows ISO 1461 standards, achieving zinc coating thickness appropriate for the steel grade and tube wall thickness. For S235 and S275 grades in standard wall thickness ranges, coating thickness meets or exceeds minimum requirements for long-term corrosion protection in industrial and outdoor environments. Each shipment includes coating thickness measurement reports from our in-house laboratory, with third-party verification available upon request.
Q: Can you provide steel grade equivalence documentation between EN, ASTM, and JIS standards?
A: Yes. We supply cross-reference documentation showing chemical composition and mechanical property equivalence between S235/S275/S355JR (EN standards), A500 Grade A/B/C and A53 Grade B (ASTM standards), Q235B/Q345B (GB standards), and SS400/STK400 (JIS standards). Mill test certificates document actual test results per your specified standard, with supplementary test data available when projects require dual-standard compliance verification.
Q: What is the minimum order quantity for custom size galvanized square tubes?
A: The minimum order quantity is 1 Ton for standard sizes from our stock range covering 21.3mm to 660mm outer dimensions. Custom wall thickness or non-standard lengths may require higher minimum quantities depending on production scheduling. We maintain over 2,800 specification combinations in inventory, enabling small-quantity orders for project samples or phased procurement without extended lead times.
Q: How do you ensure zinc coating adhesion and uniformity on every batch?
A: Our vertically integrated production controls the entire process from ERW tube forming through hot-dip galvanizing in our own facility. We monitor zinc bath temperature, immersion time, and withdrawal speed to ensure consistent metallurgical bonding. Coating thickness and adhesion testing occurs on every production batch before shipment. This integrated control eliminates the quality gaps that occur when fabricators outsource galvanizing to third-party coating shops.
Q: What export documentation do you provide for customs clearance?
A: We supply a complete documentation package including mill test certificates with chemical composition and mechanical properties, packing lists with bundle identification, bill of lading, certificate of origin, and commercial invoice. For EU markets, CE certificates and EN 10219 declaration of performance are included. Third-party inspection reports from SGS, BV, or TÜV are available when required by the buyer or destination country regulations. All documents are prepared in English and formatted for smooth customs clearance at your destination port.
