Description
Factory-Direct Galvanized SHS Supply — Vertically integrated steel mill and fabrication workshop producing Hot Dipped Galvanized Square Steel Tube in 19×19mm to 800×800mm with 1–30mm wall thickness, backed by 2,800+ raw material specifications and complete MTC traceability.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Hot Dipped Galvanized ERW Square Steel Tube |
| Product Type | Square Steel Tube |
| Steel Grade | Gr.B, S235, S275, S355, STK400, Q235B |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Square |
| Size Range | 19mm×19mm – 800mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) / Seamless available |
| Surface Treatment | Hot Dipped Galvanized / Black Painting / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction structures / Building frames / Curtain wall / Support tubes / Structural pipe |
| MOQ | 1 Ton |
| Origin | China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building frames, column systems, mezzanine structures |
| Industrial Facilities | Warehouse support columns, machinery platforms, equipment bases |
| Infrastructure | Bridge railing posts, sound barrier supports, utility structures |
| Architectural Facades | Curtain wall mullions, decorative structural elements |
| Logistics Centers | Racking systems, conveyor support frames, loading dock structures |
Zinc Coating Thickness Determines Site Acceptance or Rejection
Hot dipped galvanizing must achieve uniform coating thickness across all surfaces — corners and edges included — to pass third-party inspection at destination.
When overseas buyers receive Hot Dipped Galvanized Square Steel Tube with inconsistent zinc coverage, the consequences extend beyond surface appearance. Thin spots at weld seams or sharp corners become corrosion initiation points within months of installation. Third-party inspectors measuring below specified micron thresholds reject entire batches, leaving contractors with demurrage charges and schedule delays. Material traceability gaps between the galvanizing line and original mill certificate compound the problem — customs officials in EU markets demand EN 10204 3.1 documentation linking heat numbers to coating test results [NEED_CITE: hot dip galvanizing coating thickness standards for structural hollow sections].
Structural Frame Integration for EPC Projects
Hot Dipped Galvanized Square Steel Tube in S355 and Gr.B grades integrates directly into prefabricated frame systems where dimensional accuracy at ±1% tolerance ensures bolt-hole alignment and weld preparation without field modification. The ERW welding process produces consistent seam quality across the 19×19mm to 800×800mm range, while hot dipped galvanizing provides corrosion protection suitable for both indoor industrial environments and exterior exposure conditions. Plain ends arrive ready for site welding or mechanical connection, eliminating secondary processing delays that fragment procurement chains.
Engineering Compliance Across International Standards
Structural hollow sections must satisfy multiple compliance frameworks depending on destination market — EN 10219 for European projects requiring CE marking, ASTM A500 for North American construction, and GB/T 3091 for domestic applications. Steel grade selection directly influences load-bearing capacity: S355 offers higher yield strength than S235 for demanding structural applications, while STK400 serves Japanese-specification projects. Hot dipped galvanizing thickness must align with environmental exposure categories defined in ISO 12944, with coating reports documenting zinc layer uniformity for consultant approval [NEED_CITE: structural steel coating requirements for corrosion protection].
Steel Grade Selection and Manufacturing Process
The S-series grades (S235, S275, S355) follow European EN standards with increasing yield strength suitable for progressive load requirements — S235 for light structural frames, S275 for medium-duty applications, S355 for heavy-load bearing members. ASTM Gr.B corresponds roughly to S235 in mechanical properties, while Q235B represents the Chinese national standard equivalent. ERW (Electric Resistance Welding) technology produces square tubes with consistent wall thickness and smooth internal surfaces, making it cost-effective for structural applications where seamless pipe’s pressure ratings are unnecessary. Hot dipped galvanizing immerses fabricated tubes in molten zinc baths, creating metallurgical bonding that provides decades of corrosion protection — superior to pre-galvanized or painted alternatives for outdoor or humid environments.
Hidden Costs of Incorrect Material Procurement
Specifying the wrong steel grade or accepting substandard coating thickness creates downstream costs that dwarf initial purchase savings. ASTM A500 Gr.B tubes substituted with lower-grade material fail structural calculations during engineer review, requiring complete replacement. Missing MTC documentation delays customs clearance in EU ports, triggering storage fees and project schedule penalties. Coating thickness below 65μm on hot dipped galvanized products accelerates corrosion in marine or industrial atmospheres, leading to premature maintenance costs and potential structural safety concerns [NEED_CITE: consequences of non-compliant steel materials in construction projects].
Integrated Supply Chain Advantages
Vertically integrated production from raw steel to finished Hot Dipped Galvanized Square Steel Tube eliminates the traceability gaps that plague fragmented procurement. Our own steel mill with 3 production lines and 2,800+ specifications ensures material consistency from billet to final galvanized product — one quality system, one point of accountability. Certified welding procedures (AWS/EN) and qualified welders produce ERW seams meeting international standards, while in-process dimensional checks maintain ±1% tolerance across the full 19×19mm to 800×800mm range. Complete quality documentation packages including WPS, PQR, weld maps, and coating reports satisfy the most demanding EPC specifications. Professional packing and oversized cargo loading experience across EU, Middle East, Southeast Asia, and African projects ensures intact delivery regardless of destination.
Documentation & Compliance
- Mill Test Certificate documenting S355JR chemical composition and yield strength per EN 10219, with heat number traceability from steelmaking to galvanizing
- CE Certificate confirming EN 10210/EN 10219 compliance for structural hollow sections entering European Union markets
- ISO 9001 Quality Management System certificate covering the complete production chain from raw material procurement to finished galvanized tube dispatch
- SGS or BV Third-Party Inspection Report verifying zinc coating thickness, dimensional accuracy, and surface quality before shipment
- Material Traceability Records linking each Hot Dipped Galvanized Square Steel Tube bundle to specific heat numbers, galvanizing batch, and coating test results
- Export Documentation Package including commercial invoice, packing list, bill of lading, and certificate of origin for destination customs clearance
Packaging, Loading & Delivery
- Hot Dipped Galvanized Square Steel Tube bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit and handling
- Surface protection maintained through proper stacking separators and moisture barriers preventing white rust formation on galvanized surfaces
- Container loading optimization for 5.8m and 6m lengths in 20ft containers, 11.8m and 12m lengths in 40ft open-top or flat-rack configurations
- Plain end protection with plastic caps preventing damage during transport while maintaining readiness for site welding operations
- Bundle identification tags displaying steel grade (S355/Gr.B), size specifications, heat number, and coating thickness for site verification
- Flexible shipping terms including FOB, CIF, and DDP with professional oversized cargo handling for large-section tubes exceeding standard container dimensions
Project Inquiry and Quotation Process
Submit project drawings (PDF/DWG), steel grade requirements, size specifications, and destination port to receive detailed quotation including material, fabrication, coating, packing, and shipping costs within 24 hours. Our engineering team reviews shop drawings for material optimization and fabrication sequencing before production begins, ensuring Hot Dipped Galvanized Square Steel Tube specifications align with structural design requirements and international standards compliance.
Frequently Asked Questions
Q: What is the difference between hot dipped galvanized and pre-galvanized square tubes?
A: Hot dipped galvanizing immerses finished tubes in molten zinc at approximately 450°C, creating metallurgical bonding with coating thickness typically 65-100μm providing 20-50 years corrosion protection. Pre-galvanized tubes use electro-galvanized coil with thinner coating (20-30μm) suitable for indoor applications only. For structural applications in corrosive environments, hot dipped galvanizing is the specified standard.
Q: Can you provide steel grade equivalence between ASTM A500 Gr.B and EN 10219 S355?
A: ASTM A500 Gr.B has minimum yield strength of 290 MPa, while EN 10219 S355JR requires 355 MPa minimum yield. These grades are not directly equivalent — S355 offers approximately 20% higher strength. We supply both grades with full MTC documentation for projects specifying either standard system.
Q: What quality documentation do you provide for EU customs clearance?
A: We provide EN 10204 3.1 Mill Test Certificates with chemical composition and mechanical properties, CE marking certificates for EN 10210/EN 10219 compliance, third-party inspection reports (SGS/BV), and complete export documentation including certificate of origin. All Hot Dipped Galvanized Square Steel Tube shipments include coating thickness test reports and dimensional inspection records.
Q: What is the minimum order quantity and can you produce custom sizes?
A: MOQ is 1 Ton for standard sizes in our 2,800+ specification range covering 19×19mm to 800×800mm with 1-30mm wall thickness. Custom sizes outside standard range are available based on production feasibility — submit drawings for engineering review and quotation.
Q: How do you ensure zinc coating quality on galvanized square tubes?
A: Our hot dipped galvanizing process includes surface preparation (degreasing, pickling, fluxing), controlled immersion timing, and post-galvanizing inspection. Every batch receives coating thickness measurement using magnetic gauges at multiple points including corners and edges. Coating adhesion and salt spray test reports are available upon request for project specifications requiring additional verification.
Get Your Hot Dipped Galvanized Square Steel Tube Quotation
Send your project specifications including drawings, steel grades, quantities, and destination port to receive detailed pricing with complete Mill Test Certificate documentation within 24 hours.
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
