Description
Direct Mill Supply, No Trading Markup — Every A500 Grade B galvanized square steel tube rolls from our own 3-line steel mill with full heat-number traceability to the raw coil.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square Steel Tube |
| Product Type | Square / Rectangular Steel Tube (Hollow Section) |
| Steel Grade | A53 Grade B / A500 Grade A / Grade B / Grade C / STK400 / SS400 / ST42.2 / S355JR |
| Standard | ASTM A53 / A500 / A36 / A795 / BS1387 / EN10255 / ISO65 / ANSI C80 / DIN2440 / JIS G3444 / GB/T3091 / GB/T13793 |
| Section Shape | Square / Rectangular |
| Size Range | 21.3mm–660mm (1/2″–26″) |
| Wall Thickness | 6mm |
| Length | 5.8m / 6m / 11m / 12m or customized |
| Technique | Hot-dip Galvanized / ERW |
| Surface Treatment | Hot-dip Galvanized |
| Tolerance | ±1% / ±5% |
| Pipe Ends | Plain ends / Beveled ends / Threaded ends / Grooved ends |
| Processing Service | Punching / Cutting / Bending |
| Application | Steel structures / Construction frames / Machinery parts / Fluid transportation / Power / Boiler / Petrochemical / Building industry / Hydraulic precision machinery |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Gate posts, structural columns, building frames, support columns for commercial and industrial buildings |
| EPC Projects | Galvanized tube packages for power plants, petrochemical facilities, and water treatment plants |
| Machinery & Equipment | Hydraulic precision machinery parts, equipment frames requiring corrosion protection |
| Industrial Facilities | Conveyor structures, platform supports, warehouse framing, scaffolding systems |
What Inconsistent Zinc Coating Costs on a Galvanized Square Steel Tube Order
A 25μm shortfall in galvanizing thickness turns a container shipment into an expensive return shipment.
I have watched entire batches of 80×80 gate posts get rejected at site because the hot-dip galvanized coating measured under 40μm against a 65μm specification. The freight to ship them back for re-dipping exceeded the product value. When overseas buyers source galvanized square steel tube from fragmented suppliers who outsource galvanizing to third-party coaters, there is no single point of accountability for coating consistency. Material traceability breaks down, mill test certificates become unreliable, and dimensional tolerances drift without anyone noticing until the steel arrives at the job site. [NEED_CITE: hot-dip galvanizing coating thickness standards for structural steel]
Matching Galvanized SHS/RHS to Structural Frame Requirements
Hot-dip galvanized square steel tube in A500 Grade B delivers the corrosion resistance that outdoor structural frames demand — gate posts exposed to tropical humidity, industrial building columns in coastal zones, and petrochemical support structures where salt spray accelerates rust. The ERW welding process produces consistent seam integrity across the 21.3mm to 660mm size range, while the 6mm wall thickness handles typical structural loading for medium-duty frames. Our vertically integrated mill-to-fabrication model means every tube ships with coating thickness reports tied to the original heat number, so site engineers can verify material identity without chasing paperwork from three different vendors.
Structural Compliance and Certification for Galvanized Hollow Sections
Galvanized square steel tube used in load-bearing frames must satisfy both material standards and fabrication codes. A500 Grade B conforms to ASTM requirements for structural hollow sections, while S355JR meets EN 10210 specifications for European projects. The hot-dip galvanizing process must deliver minimum coating thickness per ASTM A123 or EN ISO 1461 depending on destination market. For EPC projects in the Middle East or Southeast Asia, third-party inspection by SGS or BV validates both base metal chemistry and zinc coating weight before container loading. Dimensional tolerance of ±1% on side length ensures that pre-drilled connection plates align on site without costly reaming. [NEED_CITE: ASTM A500 structural tube dimensional tolerance requirements]
Steel Grade Selection and Galvanizing Process Fundamentals
A500 Grade B provides higher yield strength than Grade A, making it the preferred choice for structural columns and load-bearing frames where deflection limits matter. The ERW (Electric Resistance Welding) process forms the tube from flat strip, then applies hot-dip galvanizing by immersing the finished tube in molten zinc at approximately 450°C. This metallurgical bond creates a zinc-iron alloy layer that resists chipping during handling and provides cathodic protection even if the coating gets scratched. Hot-dip galvanizing outperforms pre-galvanized (electro-galvanized) coating for outdoor applications because the thicker zinc layer — typically 65-85μm on structural sections — delivers longer service life before red rust appears. The 6mm wall thickness on these galvanized square steel tubes balances structural rigidity with weight efficiency for shipping.
Hidden Costs of Sourcing Galvanized Tubes from Unverified Suppliers
Material substitution costs more than the price difference between grades. When a supplier delivers A53 Grade B tubes stamped as A500 Grade B, the lower yield strength creates deflection problems that only show up after the structure is erected. Missing mill test certificates delay customs clearance in markets that require EN 1090 or AISC compliance documentation. Negative tolerance abuse — where wall thickness sits at the lower limit across every tube — reduces load capacity below design calculations. Coating thickness below specification means premature corrosion in aggressive environments, forcing expensive maintenance or full replacement within years instead of decades. [NEED_CITE: material certification requirements for structural steel imports]
Why Project Procurement Teams Choose Our Galvanized Square Steel Tube
Our own steel mill operates 3 production lines with over 2,800 specifications in raw material inventory, so we control quality from the coil to the finished galvanized tube. Every shipment includes complete documentation: mill test certificates with chemical composition and mechanical properties, dimensional inspection reports, and coating thickness measurements. We hold EN 1090, AWS, and AISC certifications for fabrication work, and our in-house laboratory tests material properties before any tube leaves the facility. Third-party inspection by SGS or BV is available for projects requiring independent verification. Custom lengths, end treatments, and processing services including CNC cutting, punching, and bending eliminate secondary fabrication delays at the job site.
Documentation & Compliance
- Mill test certificate documenting A500 Grade B chemical composition and mechanical properties per ASTM A500
- CE certificate confirming compliance with EN 10210 for hot-finished structural hollow sections
- ISO 9001 quality management system certificate covering the full production process
- SGS or BV third-party inspection report validating coating thickness and dimensional accuracy
- Material traceability by heat number linking each galvanized square steel tube to its original coil
- Complete customs documentation including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized square steel tube bundled with steel strips and edge protectors to preserve the zinc coating during ocean transit
- Plastic caps on tube ends prevent moisture ingress and protect threaded or grooved finishes
- Standard seaworthy packing with woven bag wrapping for 5.8m, 6m, 11m, and 12m lengths
- Container loading optimization for 21.3mm-660mm size range maximizes payload per 20ft or 40ft container
- Heat number and steel grade marked on each bundle for site identification and traceability
- FOB, CIF, and DDP shipping terms available with door-to-door logistics coordination
Request Quotation with Mill Test Certificate
Submit your project specifications including steel grade, dimensions, wall thickness, quantity, and destination port to receive a detailed quotation with production schedule. We provide shop drawing review, material optimization recommendations, and complete certification packages for customs clearance. Confirm coating thickness requirements and third-party inspection needs before production begins.
Get Your Galvanized Square Steel Tube Quote Today
Share your project drawings and specifications to receive pricing with full mill test certificates within 24 hours.
Contact: 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: How do ASTM A500 Grade B and S355JR compare for structural applications?
A: Both grades serve structural hollow section applications, but they follow different standard systems. A500 Grade B follows ASTM specifications common in North American and Middle Eastern projects, while S355JR conforms to EN 10210 for European markets. The yield strength levels differ slightly, so structural engineers must specify the correct grade based on design calculations and local building codes.
Q: What documentation supports material traceability for galvanized square steel tube?
A: Every shipment includes mill test certificates showing chemical composition and mechanical properties tied to the original heat number. We provide dimensional inspection reports, coating thickness measurements, and third-party inspection certificates from SGS or BV when required. This documentation package satisfies customs clearance requirements in markets enforcing EN 1090 or AISC compliance.
Q: Can you produce non-standard dimensions and what is the minimum order quantity?
A: We manufacture galvanized square steel tube in sizes from 21.3mm to 660mm with 6mm wall thickness as standard. Custom lengths of 5.8m, 6m, 11m, or 12m are available, and we offer CNC cutting, punching, and bending services for project-specific requirements. The minimum order quantity is 1 ton, making it practical for both large EPC projects and smaller construction packages.
Q: What is the difference between hot-dip galvanized and pre-galvanized coating?
A: Hot-dip galvanizing immerses the finished tube in molten zinc, creating a metallurgical bond with 65-85μm coating thickness that provides decades of corrosion protection for outdoor structural applications. Pre-galvanized (electro-galvanized) coating is thinner at 10-25μm and suits indoor applications where corrosion exposure is minimal. For gate posts, building frames, and industrial structures exposed to weather, hot-dip galvanizing is the specified method.
Q: How are galvanized tubes packed for export and what loading options exist?
A: Galvanized square steel tube is bundled with steel strips and edge protectors to prevent coating damage during transit. Plastic caps protect end finishes, and woven bag wrapping provides additional surface protection. We optimize container loading based on tube dimensions to maximize payload, and offer FOB, CIF, or DDP shipping terms with complete export documentation including packing lists and certificates of origin.
