Description
Factory-Direct Galvanized Tube Supply — Every batch of Q235/Q345 Hot-Dip Galvanized Square and Rectangular Steel Tube ASTM A53 DN15-DN200 rolls through our in-house galvanizing line with zinc coating verified before dispatch.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 Galvanized Square and Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube |
| Steel Grade | Q195, Q235, Q345, TDC51D+Z, TDC52D+Z, TS350GD, TS550GD, DX51D+Z |
| Standard | ASTM A53, BS 1387, EN 10255, GB/T 3091, JIS G3444 |
| Section Shape | Square / Rectangular |
| Size Range | DN15–DN200 (approx. 20×20mm–200×200mm) |
| Wall Thickness | 0.1–4.0mm |
| Length | 1–12m |
| Technique | Hot-Dipped Galvanized |
| Surface Treatment | Hot-Dip Galvanized (Zinc Coating 30–600g/m²) |
| Spangle | Zero / Minimum / Regular / Big Spangle |
| Ends | Threaded / Plain |
| Tolerance | ±1% |
| Application | Water supply, Gas pipeline, Fire fighting system, Greenhouse structure, Scaffolding, Construction engineering, Outdoor and humid environments |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Fire fighting risers, scaffolding uprights, structural frames for warehouses |
| Agriculture | Greenhouse support columns, irrigation pipe frameworks |
| Municipal Engineering | Water distribution mains, gas pipeline carriers |
| Industrial Facilities | Conveyor support structures, equipment frames in humid processing areas |
Zinc Coating Consistency Decides Whether Your Galvanized Square and Rectangular Steel Tube ASTM A53 DN15-DN200 Passes Site Inspection
A 20μm shortfall in zinc thickness turns a compliant shipment into rejected cargo.
Importers across Southeast Asia and the Middle East have faced project delays because the galvanized coating measured on arrival fell below the specified minimum. Third-party inspectors pull random samples from mid-bundle, not just the top layer — and if the inner tubes show thinner zinc, the entire lot fails. Hot-dip galvanizing must deliver uniform coverage across all faces, including the inner corners of square sections, which requires controlled bath temperature and withdrawal speed. [NEED_CITE: hot-dip galvanizing coating thickness standards ASTM A123]
How Q235 and Q345 Grades Serve Structural and Fluid-Conveyance Roles
Q235 Hot-Dip Galvanized Square and Rectangular Steel Tube ASTM A53 DN15-DN200 handles standard load-bearing frames and non-pressure fluid lines where formability matters more than ultimate strength. Q345 steps in when the design calls for higher yield capacity — bridge walkways, crane booms, or mezzanine supports in industrial plants. Both grades accept hot-dip galvanizing well, but Q345’s higher carbon equivalent demands stricter bath chemistry control to avoid brittle intermetallic layers. The DN15–DN200 range covers everything from branch-line sprinkler drops to main structural columns, with wall thickness from 0.1mm for light greenhouse purlins to 4.0mm for heavy-duty scaffolding standards.
Meeting EN 10255 and ASTM A53 Simultaneously for Multi-Market Projects
EPC contractors sourcing for projects spanning EU and GCC markets need tubes that satisfy both EN 10255 and ASTM A53 chemical and dimensional requirements. Our production lines adjust manganese and sulfur limits within the overlap zone so a single heat can ship to Rotterdam and Dubai without reordering. Threaded ends per BS 1387 suit fire protection systems, while plain ends serve welded structural connections. [NEED_CITE: dimensional tolerance requirements EN 10255 vs ASTM A53]
The Hidden Cost of Under-Galvanized Square and Rectangular Tubes
Specifying Q345 with 600g/m² zinc but receiving 300g/m² means the tube will corrode through in half the design life — especially at cut edges and weld zones where the coating is thinnest. Replacing buried or enclosed tubes after installation costs ten times the original material price. Certification gaps compound the problem: without a mill test certificate traceable to heat numbers, customs authorities in the EU and Australia hold shipments for independent testing, adding weeks of demurrage. [NEED_CITE: corrosion protection lifecycle cost analysis for galvanized steel]
Procurement Confidence from Mill to Port
Every Hot-Dip Galvanized Square and Rectangular Steel Tube ASTM A53 DN15-DN200 leaves our facility with zinc coating实测值 recorded on the packing slip — not just the contract minimum. Our physical and chemical laboratory tests every heat for coating adhesion, thickness uniformity, and base metal composition before the tubes reach the loading bay. With 2,800+ specifications in stock and custom non-standard sizes available, you consolidate square, rectangular, and round sections in one shipment. CE certification under EN 10210/10219 clears EU customs; SGS and BV reports satisfy Middle Eastern and Australian project specs. Professional container loading plans maximize payload for 6m and 12m lengths, reducing per-ton freight cost.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition, yield strength, and zinc coating mass per ASTM A53 and GB/T 3091
- CE certificate confirming compliance with EN 10210/EN 10219 for structural hollow sections exported to EU markets
- ISO 9001:2015 quality management certificate covering hot-dip galvanizing process control
- SGS or BV third-party inspection report verifying zinc coating thickness and adhesion for project-specific requirements
- Material traceability by heat number linking each bundle to its galvanizing bath record and base metal test
- Customs documents including packing list, bill of lading, and certificate of origin formatted for destination port requirements
Packaging, Loading & Delivery
- Q235/Q345 galvanized square and rectangular tubes bundled with steel strips and edge protectors to prevent zinc coating damage during ocean transit
- Hot-dip galvanized surface left un-oiled for welding applications or lightly passivated for storage in humid ports, per buyer instruction
- DN15–DN60 tubes nested inside larger DN100–DN200 sections to maximize 20ft and 40ft container payload for 6m and 12m lengths
- Custom cut-to-length service available for 1–12m requirements, with cut ends sealed to prevent white rust during transit
- Heat number and steel grade stenciled on each bundle for site traceability, with zinc coating class marked on packing slip
- FOB, CIF, and DDP terms available with door-to-door logistics to 50+ countries including EU, North America, and Middle East destinations
Start Your Hot-Dip Galvanized Square and Rectangular Steel Tube ASTM A53 DN15-DN200 Inquiry
Send your specification sheet — including section dimensions, wall thickness, steel grade, zinc coating class, and destination port — and receive a detailed quotation with mill test certificate sample within 12 hours. Non-standard sizes and custom lengths are quoted separately with typical production lead times confirmed before contract signing.
Request Your Quotation and Mill Test Certificate
Submit your Hot-Dip Galvanized Square and Rectangular Steel Tube ASTM A53 DN15-DN200 requirements via email or WhatsApp to receive factory-direct pricing with full documentation package.
Email: admin@sdxjysteel.com
WhatsApp: +86 188 5315 7756
