Description
Factory-Direct Pricing, No Trading Markup — Every Galvanized Square Steel Tube ships from our own mill and fabrication line in Shandong, cutting out broker margins while keeping full material traceability from raw coil to finished section.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square Steel Tube |
| Product Type | Square Hollow Section (SHS) |
| Steel Grade | Gr.B, S235, S275, S355, STK400 |
| 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 |
| Surface Treatment | Hot-dip Galvanized / Black Painting / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction Structures / Building Frames / Curtain Wall Systems / Support Structures / Industrial Structures |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Column and beam frames for warehouses, retail centers, and multi-story office buildings |
| Industrial Facilities | Equipment support platforms, conveyor structure frames, and mezzanine flooring systems |
| Curtain Wall & Facade | Vertical and horizontal mullion members for glass and aluminum cladding systems |
| Infrastructure & Energy | Solar panel mounting structures, highway sign gantries, and utility support frames |
| EPC & General Contracting | Prefabricated modular building frames and site-assembled structural grids |
What Happens When Zinc Coating Thickness Fails Site Inspection
A rejected container costs more than re-galvanizing — it burns weeks of schedule and erodes the margin you saved by sourcing overseas.
I watched this play out on a warehouse project in the Gulf: a shipment of galvanized square tubes arrived, and the third-party inspector pulled coating readings well below the 80-micron spec. The entire batch got stripped and re-galvanized locally. Three weeks lost, and the cost advantage of buying from China disappeared on the spot [NEED_CITE: ISO 1461 hot-dip galvanized coating thickness requirements for structural steel]. When you source through a broker who does not control the galvanizing line, coating consistency becomes a gamble — and the gamble lands on your project timeline, not theirs.
Fragmented procurement makes this worse. The mill produces the tube, a separate facility galvanizes it, and a trading company ships it. Each handoff creates a gap in traceability and accountability. As a Galvanized Square Steel Tube Supplier operating our own steel production and fabrication division, we close that gap — one heat number, one coating line, one quality system from raw material to container loading.
Matching Section Sizes to Structural Frame Demands
A Galvanized Square Steel Tube in the 100×100mm to 400×400mm range carries the primary column and beam loads for most warehouse and industrial frames, while smaller sections from 19×19mm up to 80×80mm serve as purlin bracing, curtain wall mullions, and non-structural support members. The hot-dip galvanized surface protects these sections in exposed environments — coastal industrial zones, agricultural buildings, and outdoor infrastructure — where painted or bare steel would corrode within a few seasons. Our integrated mill-to-fabrication model means the same facility that rolls the steel also cuts, drills, and welds it to your shop drawings, so dimensional accuracy stays consistent across the full 19×19mm to 800×800mm range without transferring sections between subcontractors.
Engineering Compliance Across International Standards
Structural frames designed to EN 1993-1-1 require hollow sections that conform to EN 10219 or EN 10210, with certified material properties and traceable heat numbers — a Galvanized Square Steel Tube in S355 grade meets these demands when supplied with EN 10204 3.1 or 3.2 test certificates [NEED_CITE: EN 10219 cold-formed structural hollow sections compliance requirements]. For North American projects, ASTM A500 Grade B and Grade C govern the same product category, and our S-series and Gr.B tubes cross-reference directly to those specifications. Corrosion protection follows ISO 1461 for hot-dip galvanizing, and coating thickness must be verified per zone — internal surfaces of closed sections receive different treatment than exposed external faces. Custom cut-to-length at 5.8m, 6m, 11.8m, or 12m reduces on-site welding and secondary cutting, which matters when your erection crew is billing by the day.
Steel Grade Selection and What It Means for Load-Bearing Capacity
The five steel grades we stock — Gr.B, S235, S275, S355, and STK400 — represent three distinct international specification systems. Gr.B belongs to the ASTM framework used across North America and many Middle East specifications. The S-series (S235, S275, S355) follows the European EN system, where the number after “S” indicates minimum yield strength in MPa — meaning S355 carries higher structural loads than S235 in the same cross-section [NEED_CITE: steel grade equivalence between EN S-series and ASTM A500]. STK400 comes from JIS G 3466, the Japanese standard widely specified across Southeast Asian projects. ERW welded tubes suit most structural applications at competitive cost, while seamless options serve higher-pressure or critical-load scenarios where weld-line integrity cannot be accepted. Wall thickness from 1mm to 30mm with ±1% tolerance means you can specify thin-walled sections for non-structural bracing or heavy-wall sections for moment-resisting frames — all from one Galvanized Square Steel Tube Supplier who controls the rolling schedule.
The Hidden Cost of Buying the Wrong Grade or Unverified Coating
Specifying S235 when the structural engineer calculated for S355 does not show up until the building frame deflects beyond tolerance — or until the inspector reads the mill test certificate and finds a mismatch. Material substitution without documented equivalence approval triggers rejection under EN 1090 and AISC codes alike [NEED_CITE: structural steel material substitution requirements under EN 1090 execution standard]. Similarly, galvanized coating below ISO 1461 minimum thickness passes visual inspection at the mill but fails third-party testing at the project site, forcing costly rework. Negative tolerance abuse — where wall thickness consistently sits at the lower limit — reduces actual load capacity below the design assumption, creating a safety liability that no amount of paperwork can resolve after erection.
Why Procurement Teams Source Through Our Integrated Facility
Our steel mill in Shandong produces the raw coil and plate, and our fabrication division directly downstream cuts, welds, galvanizes, and ships the finished Galvanized Square Steel Tube — there is no trading company between your purchase order and the mill floor. This vertical integration means material traceability runs continuously from heat number to finished bundle, and any coating thickness query can be traced back to the galvanizing bath record within hours, not weeks. We stock over 2,800 specifications across our product range, so standard sizes ship without waiting for a production campaign to fill. For non-standard dimensions or project-specific cut lengths, our engineering team reviews shop drawings and proposes material optimization before fabrication begins. Every shipment leaves with a complete documentation package — mill test certificates, coating inspection reports, dimensional records, and export customs files — prepared by our own quality department rather than assembled from multiple subcontractors after the fact. Third-party inspection through SGS, BV, or TÜV is arranged on-site before container sealing, so your project QA team sees the same data we do.
Documentation & Compliance
- Mill Test Certificate documenting S355JR / Gr.B chemical composition and mechanical properties per EN 10219 or ASTM A500, with traceable heat number for every bundle
- CE marking certificate confirming EN 10210 / EN 10219 compliance for Galvanized Square Steel Tube shipped to European Union member states
- ISO 9001 quality management system certificate covering the full production chain from steelmaking through galvanizing and dispatch
- SGS or BV third-party inspection report verifying zinc coating thickness per ISO 1461 and dimensional tolerance per the applicable standard
- Material traceability sheet linking each Galvanized Square Steel Tube bundle to its heat number, galvanizing batch, and dimensional inspection record
- Export customs documentation including packing list, bill of lading, and certificate of origin prepared for destination-country clearance requirements
Packaging, Loading & Delivery
- Hot-dip galvanized square tubes bundled with steel strips and fitted with edge protectors to prevent zinc coating damage from friction during ocean transit
- Surface protection maintained through proper stacking separators between layers, preserving the galvanized finish on sections from 19×19mm to 800×800mm across all wall thicknesses
- Container loading optimized by section size — smaller S235 and S275 tubes nested for maximum 20ft container payload, while large-section S355 tubes in 11.8m and 12m lengths loaded on open-top or flat-rack units
- Cut-to-length service at 5.8m, 6m, 11.8m, or 12m reduces on-site waste and matches standard erection bay dimensions for warehouse and industrial frame projects
- Heat number and steel grade stenciled on each bundle tag, with galvanizing coating class marked for site verification against ISO 1461 requirements
- FOB, CIF, and DDP shipping terms available from Shandong port, with professional lashing plans for oversized Galvanized Square Steel Tube consignments
Starting Your Procurement With Drawing Review and Coating Confirmation
Send your project drawings in PDF or DWG format along with the required steel grade, section dimensions, galvanizing coating class, and destination port — our engineering team returns a preliminary assessment and itemized quotation within 24 hours, including shop drawing timelines and production scheduling. If your project requires non-standard sizes outside the 19×19mm to 800×800mm range or specific third-party inspection protocols, we confirm feasibility and certification requirements before you commit to a deposit.
Request Your Galvanized Square Steel Tube Quotation and Mill Test Certificate
Share your specifications, steel grade, and quantity to receive a detailed quotation with full material certification — contact our team at +86 188 5315 7756 (WhatsApp/WeChat) or email admin@xjystructure.com.
Frequently Asked Questions
Q: How do S235, S275, and S355 grades compare to ASTM A500 Gr.B for the same Galvanized Square Steel Tube?
A: S235, S275, and S355 follow the European EN system where the number indicates minimum yield strength in MPa. ASTM A500 Gr.B is the North American equivalent commonly specified for structural hollow sections. Our Galvanized Square Steel Tube Supplier facility produces all five grades — Gr.B, S235, S275, S355, and STK400 — and provides cross-reference guidance so your procurement team can confirm equivalence with the project engineer before ordering.
Q: What galvanizing coating thickness standards do your tubes meet?
A: Hot-dip galvanizing follows ISO 1461, which specifies minimum coating thickness based on section thickness and surface condition. Our quality department measures coating on every production batch and records results in the inspection report included with your shipment documentation. Third-party verification through SGS, BV, or TÜV can be arranged before container sealing if your project requires independent confirmation.
Q: Can you produce non-standard sizes or custom cut lengths outside the listed range?
A: Our mill and fabrication facility covers sizes from 19×19mm to 800×800mm with wall thickness from 1mm to 30mm. Standard lengths include 5.8m, 6m, 11.8m, and 12m, with random length available. For project-specific dimensions or special cutting requirements, our engineering team reviews your drawings and confirms feasibility, tooling requirements, and minimum order quantities before production.
Q: What documentation accompanies a Galvanized Square Steel Tube shipment?
A: Every shipment includes a mill test certificate with chemical composition and mechanical properties traceable to the heat number, dimensional inspection reports, galvanizing coating thickness records, and full export customs documentation. CE certificates are provided for EU-destined orders. Third-party inspection reports from SGS, BV, or TÜV are available upon request and conducted at our facility before dispatch.
Q: What is the minimum order quantity and how does it affect pricing?
A: The minimum order quantity is 5 Tons per shipment. Pricing is quoted per ton and includes material cost, fabrication, galvanizing, and standard packaging. Volume orders across multiple sizes benefit from consolidated container loading, and our vertically integrated production model means there is no trading markup between the mill price and your quotation.
From Drawing to Container — Get Your Galvanized Square Steel Tube Quotation Today
Submit your project specifications, steel grade requirements, and destination port to receive a detailed quotation with mill test certification and production timeline — reach our team via WhatsApp at +86 188 5315 7756 or email admin@xjystructure.com.
