Description
Factory-direct pricing with no middlemen — every DX51D and SGCC galvanized square steel tube rolls from our own production lines, eliminating trader markups on bulk orders.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square Steel Tube |
| Product Type | Galvanized Square Steel Tube |
| Steel Grade | DX51D, SGCC, Q195, Q235, Q345, SS400, S355JR |
| Standard | ASTM A53, ASTM A500, ASTM A36, 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 | 0.6mm–8mm |
| Length | 5.8m / 6m / 11.8m or custom |
| Technique | Hot Rolled / Cold Rolled, Welded |
| Surface Treatment | Hot Dipped Galvanized / Pre-Galvanized |
| Spangle | Big / Medium / Small / Zero |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded / Grooved |
| Application | Steel structures, construction frames, scaffolding, machinery, fluid transport, building industry, power, petrochemical |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Structural frames for warehouses, scaffolding systems, building support columns |
| Industrial & Energy | Machinery base frames, power plant support structures, petrochemical pipe racks |
| Fluid Transport | Low-pressure oil, gas, and water pipeline systems |
| Commercial Building | Curtain wall supports, mezzanine structures, roofing purlins |
What Zinc Coating Thickness Costs You at Customs
A 40-micron coating where 65 microns were specified will hold your container at port.
I watched a full 40-foot load of galvanized square steel tubes sit in Jebel Ali for two weeks because the zinc layer came in below spec. The SGS inspector caught it during routine verification, and replacement stock had to be air-freighted at the supplier’s expense. Galvanized thickness is not a line item you shave — it is the only barrier between structural steel and corrosion. Buyers who accept undocumented coating weights or skip third-party inspection before shipment often discover the gap only after the container doors open at destination. [NEED_CITE: hot-dip galvanized coating thickness standards per ASTM A123]
Matching Galvanized SHS to Structural and Corrosion Demands
Galvanized square steel tubes in DX51D and SGCC grades serve environments where bare carbon steel would corrode within months. The hot-dipped process bonds zinc metallurgically to the base metal, providing cathodic protection even at cut edges and weld points. For indoor structural frames with controlled humidity, pre-galvanized tubes offer adequate protection at lower cost. For outdoor scaffolding, coastal construction, or petrochemical pipe racks exposed to salt spray and chemical vapors, hot-dipped coating with minimum 65-micron thickness becomes mandatory. Our production lines cover both processes across the full 21.3mm–660mm range, allowing project buyers to specify coating type by zone rather than accepting a single standard across the entire order.
Engineering Compliance and Certification Requirements
Structural applications demand more than dimensional accuracy — they require traceable material certification and recognized quality standards. Galvanized square steel tubes conforming to EN10219 must carry CE marking for European construction projects, while ASTM A500 compliance governs North American structural use. The Q195–Q345 grade range covers Chinese GB standards and maps to international equivalents for projects requiring dual certification. Wall thickness tolerance of ±1% ensures theoretical weight invoicing matches actual delivery, preventing disputes over short-weight claims. Third-party inspection by SGS or BV verifies coating thickness, dimensional accuracy, and mechanical properties before shipment — a step that separates compliant suppliers from those hoping the buyer will not check. [NEED_CITE: EN 10219 cold-formed structural hollow section certification requirements]
Steel Grade Selection and Galvanizing Process Fundamentals
DX51D and SGCC are commercial-quality cold-rolled grades optimized for galvanizing adhesion and formability, making them the default choice for general structural and fabrication work. Q195 through Q345 represent the Chinese grade system where the number indicates minimum yield strength in MPa — Q235 delivers moderate strength for standard frames, while Q345 provides higher load capacity for heavy structural members. SS400 and S355JR serve Japanese and European specifications respectively, with S355JR offering superior toughness for dynamic load applications. The hot-dipped galvanizing process immerses formed tubes in molten zinc at approximately 450°C, creating a zinc-iron alloy layer bonded to the steel substrate. Pre-galvanized tubes receive coating before forming, resulting in thinner but more uniform coverage suitable for less demanding environments. Spangle selection — big, medium, small, or zero — affects surface appearance but not corrosion resistance, allowing aesthetic matching for exposed architectural applications.
Hidden Costs of Unverified Galvanized Procurement
Accepting galvanized square steel tubes without mill test certificates or independent coating verification creates risks that surface only during project inspection or customs clearance. Undersized zinc coating fails corrosion tests within months of installation, forcing costly replacement of structural members already welded into place. Missing CE or ASTM documentation triggers customs holds, demurrage charges, and project delays that dwarf the original price savings from choosing an unverified supplier. Negative tolerance abuse — where actual wall thickness falls below the specified minimum — reduces load capacity and violates structural engineering calculations, creating safety liability for the buyer. [NEED_CITE: consequences of non-compliant galvanized coating in structural applications]
Why Project Buyers Source Galvanized SHS From Xin Jiyuan
Our factory operates three dedicated production lines for galvanized square steel tubes, maintaining ready stock across 2,800+ specifications in DX51D, SGCC, and Q195–Q345 grades. Every shipment includes original mill test certificates documenting chemical composition and mechanical properties per the specified standard. We hold ISO 9001:2015 certification and Lloyd’s CE marking for EN10210/EN10219 compliance, with SGS and BV third-party inspection available on request. Custom sizes outside standard catalogs and non-standard lengths ship within typical production lead times, with flexible MOQ starting from 1 ton for trial orders. Our export team handles container loading optimization, combining multiple specifications into single shipments to reduce freight costs per ton. Volume discount programs reward long-term partnerships with pricing that improves as annual procurement grows.
Documentation & Compliance
- Mill test certificate documenting DX51D or SGCC chemical composition and coating weight per ASTM A653 or EN10346
- CE certificate confirming EN10219 compliance for structural hollow sections destined for European markets
- ISO 9001:2015 quality management certificate covering galvanizing process control and dimensional inspection
- SGS or BV third-party inspection report verifying zinc coating thickness, dimensional tolerance, and surface quality
- Material traceability by heat number linking each bundle to its original steel coil and galvanizing batch
- Complete customs documentation including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized square steel tubes bundled with steel strips and edge protectors to preserve zinc coating during ocean transit
- Surface protection through passivation treatment or light oiling to prevent white rust formation during storage and shipping
- Container loading optimization combining 5.8m, 6m, and 11.8m lengths to maximize payload per 20-foot or 40-foot container
- Custom cutting to project-specific lengths available, reducing on-site waste and labor costs
- Heat number and grade identification marked on each bundle for traceability and inspection verification
- FOB, CIF, and DDP shipping terms available with professional export documentation handling
Getting Your Galvanized SHS Quote Started
Submit your specification sheet including size range, wall thickness, steel grade, coating type, and destination port to receive competitive bulk pricing within 12 hours. Our team will confirm mill test certificate availability, third-party inspection options, and container loading plans before you commit to a deposit. Custom sizes and non-standard lengths receive engineering review for feasibility and typical production lead times.
Request Factory-Direct Galvanized SHS Pricing
Send your specifications to admin@sdxinjiyuan.com or contact us via WhatsApp at +86 188 5315 7756 for immediate quotation with mill test certificates.
Frequently Asked Questions
Q: What is the difference between hot-dipped and pre-galvanized square steel tubes?
A: Hot-dipped galvanizing immerses formed tubes in molten zinc, creating a thicker coating with superior corrosion resistance suitable for outdoor and harsh environments. Pre-galvanized tubes receive coating before forming, offering thinner but more uniform coverage at lower cost for indoor applications.
Q: Can you provide mill test certificates for DX51D and SGCC grades?
A: Every shipment includes original mill test certificates documenting chemical composition, mechanical properties, and coating weight per the specified standard. Third-party inspection by SGS or BV is available on request for additional verification.
Q: What is the minimum order quantity for galvanized square steel tubes?
A: Our flexible MOQ starts from 1 ton, supporting trial orders and small project requirements. Volume discounts apply for larger orders and long-term partnerships.
Q: Do you stock non-standard sizes and custom lengths?
A: We maintain ready stock across 2,800+ specifications covering 21.3mm–660mm sizes and 0.6mm–8mm wall thickness. Custom sizes and non-standard lengths ship within typical production lead times.
Q: How do you ensure coating thickness meets project specifications?
A: Our in-house laboratory conducts three-stage inspection including coating thickness measurement. Third-party SGS or BV verification is available before shipment to confirm compliance with ASTM A123, ASTM A653, or EN10346 standards.
