Description
Factory-Direct Galvanized Rectangular Steel Tube — Hot-dip galvanized Z81–Z120 coating applied on cold-formed sections from our own steel mill, eliminating third-party material gaps before fabrication begins.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube |
| Steel Grade | SGCC, CGCC, TDC51D+ZM, TDC52D, TS350GD, TS550GD, DX51D+Z, Q195, Q235, Q345 |
| Standard | ASTM A53, A500, A36, A795; BS1387; EN10255; ISO65; ANSI C80; DIN2440; JIS G3444; GB/T3091, GB/T13793 |
| Section Shape | Square / Rectangular |
| Size Range | 40mm×40mm – 80mm×80mm (2.5×2.5 inch – 4×4 inch) |
| Wall Thickness | 0.12–5 mm |
| Length | 5.8m / 6m / 11m or as customer needs |
| Technique | Hot Rolled / Cold Rolled based, Galvanized |
| Surface Treatment | Galvanized Coated (Z81–Z120), Zero Spangle, Skin Pass, Non-oiled |
| Ends | Plain ends / Beveled ends / Threaded ends / Grooved ends |
| Hardness | Full Hard |
| Application | Steel structures, construction frames, machinery, scaffolding, furniture, fluid transportation, building industry |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building frame columns, roof truss bracing, curtain wall support purlins |
| Industrial Facilities | Machinery base frames, conveyor support structures, platform handrails |
| Scaffolding & Temporary Works | Scaffold ledger tubes, brace members, access tower uprights |
| Infrastructure | Sound barrier posts, signage gantry frames, cable tray supports |
| Furniture & Interior | Display rack uprights, mezzanine decking beams, warehouse shelving frames |
Where Coating Thickness Variance Triggers Site Rejection
A galvanized rectangular steel tube with uneven zinc coverage fails inspection before the first bolt is tightened.
I once watched a full container of galvanized tubes get rejected at a Saudi warehouse site because the site engineer’s Elcometer readings showed local coating below 60 microns on a Z80-specified batch. The entire lot went back for re-galvanizing — three weeks of delay, double freight cost, and a damaged relationship with the main contractor. That kind of failure does not come from bad intentions; it comes from fragmented sourcing where the tube mill, the galvanizing line, and the exporter are three different entities passing blame. When you source a galvanized rectangular steel tube from a vertically integrated producer, the coating is measured against the same heat number recorded at the rolling stage, and the mill test certificate reflects what actually left the line. [NEED_CITE: hot-dip galvanized coating thickness testing per ISO 1461]
Matching Hollow Section Geometry to Structural Connection Details
The 40mm–80mm size range of this galvanized rectangular steel tube covers the most frequently specified dimensions for light-to-medium structural framing — the exact sections that connect to gusset plates, base plates, and bolted moment connections in warehouse and commercial building projects. Full hard quality with skin pass treatment ensures flat edges and dimensional stability, so when your site team drills or welds on-site, the tube holds its geometry without local buckling at the connection zone. Multiple end treatments — plain, beveled, threaded, or grooved — allow direct integration into your erection sequence without secondary machining at the laydown yard.
Engineering Compliance Across EN, ASTM, and GB Frameworks
Structural hollow sections exported to EU markets must conform to EN 10219 for cold-formed welded profiles, while North American projects typically reference ASTM A500 for structural tubing. The steel grades offered — from Q195 and Q235 through to TS350GD and TS550GD — span the yield strength classes required by both systems, and equivalence mapping between EN, ASTM, and GB designations is provided with every quotation to avoid specification mismatches at the approval stage. [NEED_CITE: steel grade equivalence between EN 10219 and ASTM A500 standards] For projects requiring CE marking under EN 10219, the documentation package includes Factory Production Control certificates and third-party inspection reports that satisfy notified body audits. Wall thickness from 0.12 mm to 5 mm covers both light gauge cladding supports and heavier load-bearing members, with tolerance control aligned to EN 10219 dimensional requirements.
Understanding Steel Grade Selection and Galvanizing Process
The grade range from SGCC and DX51D+Z through Q195, Q235, and Q345 covers the spectrum from commercial quality forming steels to structural grades with defined yield strength. For projects requiring higher strength-to-weight ratios, TS350GD and TS550GD offer structural-grade performance within the galvanized hollow section format, reducing section size while maintaining load capacity. The hot-dip galvanizing process applies a Z81–Z120 zinc coating that metallurgically bonds to the steel substrate, providing sacrificial corrosion protection that outperforms paint systems in harsh environments — particularly important for scaffolding, industrial platforms, and exterior building frames where maintenance access is limited. Zero spangle finish delivers a uniform, paintable surface that meets architectural exposure requirements without the visual inconsistency of regular spangle patterns. [NEED_CITE: hot-dip galvanizing coating adhesion and corrosion protection mechanisms]
The Hidden Cost of Unverified Coating and Material Traceability
When a galvanized rectangular steel tube arrives at site without a verifiable mill test certificate linking coating thickness to a specific heat number, the buyer absorbs the risk of non-conformance. Coating below specification accelerates corrosion at weld zones and cut ends, compromising structural integrity long before the design service life is reached. Material traceability gaps mean that if a structural member fails inspection, the entire batch becomes suspect — triggering costly re-testing, project delays, and potential liability exposure. [NEED_CITE: structural steel material traceability requirements per EN 10204]
Why Project Teams Source Galvanized Rectangular Steel Tube from XJY Structure
Our production begins with hot-rolled and cold-rolled coil from our own steel mill, giving us direct control over substrate chemistry and mechanical properties before galvanizing. The fabrication workshop downstream handles cutting, drilling, welding, and assembly to engineering drawings, so the galvanized rectangular steel tube you receive is dimensionally verified against your shop drawings — not generic catalog sizes. Over 2,800 specifications of raw material and finished sections are maintained in inventory, enabling consolidated shipments that combine structural tubes, scaffolding components, and custom-fabricated connections in a single container. Third-party inspection by SGS, BV, or TÜV is arranged before dispatch, with coating thickness and adhesion tested against ISO 1461 requirements. Professional loading plans optimize container utilization for 5.8m, 6m, and 11m lengths, reducing freight cost per ton.
Documentation & Compliance
- Mill Test Certificate documenting Q235/Q345 chemical composition and mechanical properties per GB/T3091 and GB/T13793
- CE certificate confirming EN 10219 compliance for cold-formed welded structural hollow sections exported to EU markets
- ISO 9001 quality management certificate covering the integrated steel production and fabrication process
- SGS or BV third-party inspection report verifying Z81–Z120 galvanized coating thickness per ISO 1461
- Material traceability by heat number linking each galvanized rectangular steel tube to its original coil test data
- Customs documents including packing list, bill of lading, and certificate of origin for destination-country clearance
Packaging, Loading & Delivery
- Galvanized rectangular steel tubes bundled with steel strips and edge protectors to preserve the zero spangle zinc coating during ocean transit
- Non-oiled surface finish ensures immediate weldability upon arrival, with plastic end caps protecting beveled or threaded ends from damage
- 5.8m and 6m lengths optimized for 20-foot container loading; 11m lengths shipped in 40-foot open-top or flat-rack containers with lashing plans
- Custom cut-to-length service available for 40mm–80mm sections, with kerf loss calculated and quoted transparently
- Heat number and steel grade stenciled on each bundle for site identification and inspection traceability
- FOB, CIF, and DDP terms available with door-to-door logistics coordination for project sites in the Middle East, Southeast Asia, and Africa
Submit Drawings for Quotation and Mill Test Review
Share your project drawings in PDF or DWG format along with required steel grades, coating specifications, and quantity to receive a detailed quotation including fabrication, coating, and shipping costs. Our engineering team will review shop drawings and confirm dimensional compliance before production begins, with typical lead times communicated upon order confirmation.
Request Your Galvanized Rectangular Steel Tube Quotation
Send your specifications to receive pricing, mill test certificates, and third-party inspection reports 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
Frequently Asked Questions
Q: How do SGCC and DX51D+Z grades compare to ASTM A500 or EN 10219 structural grades?
A: SGCC and DX51D+Z are commercial quality cold-rolled steel grades primarily specified for forming and light structural applications, while ASTM A500 and EN 10219 define structural hollow sections with mandatory yield strength and tensile properties. For projects requiring structural-grade performance, Q235, Q345, TS350GD, and TS550GD meet the mechanical requirements of EN 10219 and ASTM A500, and we provide grade equivalence tables with every quotation.
Q: What testing methods confirm Z81–Z120 galvanized coating compliance?
A: Coating thickness is measured using magnetic induction gauges per ISO 1461, with readings taken at multiple points along the tube length and around the perimeter. Adhesion testing verifies that the zinc-iron alloy layers remain bonded during bending and forming operations. Third-party inspection reports from SGS, BV, or TÜV document compliance before shipment.
Q: Can you produce non-standard dimensions below 1-ton quantity?
A: Standard sizes from 40mm×40mm to 80mm×80mm are available from stock with a 1-ton minimum order. Non-standard dimensions or custom lengths require minimum production runs based on mill setup requirements, and we will advise the feasible MOQ after reviewing your specification.
Q: What is the difference between zero spangle and regular spangle finishes?
A: Zero spangle galvanized coating provides a uniform, smooth surface ideal for architectural exposure and painting, while regular spangle shows visible crystalline patterns that may be acceptable for industrial applications where appearance is not critical. Our galvanized rectangular steel tube is produced with zero spangle finish as standard.
Q: How does negative wall thickness tolerance affect pricing and delivery?
A: Steel tubes are typically produced to nominal dimensions with allowable negative tolerance per the applicable standard. We quote based on theoretical weight calculated from nominal dimensions, and actual weight is verified by third-party inspection before shipment. If your project requires minimum wall thickness rather than nominal, we will specify the guaranteed minimum in the quotation and mill test certificate.
