Description
Factory-Direct Galvanized Tubes, No Trading Markup — Every Q235B and Q345B square tube leaves our own mill and galvanizing line, backed by heat-number traceability from slab to finished product.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B/Q345B Galvanized Square Steel Tube |
| Product Type | Galvanized Square / Rectangular Steel Tube |
| Steel Grade | Q235, Q235B, Q345, Q345B, SS400, A53 Grade B, A500 Grade A/B/C, S355JR |
| Standard | ASTM A53, ASTM A500, ASTM A36, BS1387, EN10255, EN10219, ISO65, DIN2440, JIS G3444, GB/T3091, GB/T13793, API 5L |
| Section Shape | Square / Rectangular |
| Size Range (Side Length) | 21.3 mm – 660 mm (1/2″ – 26″) |
| Length | 5.8 m / 6 m / 11 m or customized |
| Technique | Hot Rolled / Cold Rolled (ERW / Welded) |
| Surface Treatment | Hot-Dip Galvanized / Pre-Galvanized |
| Tolerance | ±1% |
| Pipe Ends | Plain ends / Beveled ends / Threaded ends / Grooved ends |
| Application | Construction frames / Steel structures / Scaffolding / Machinery frames / Fluid transportation |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial & Industrial Construction | Warehouse portal frames, mezzanine columns, equipment support platforms |
| Infrastructure & Civil Works | Bridge handrail posts, sound-barrier frames, utility pole bases |
| Scaffolding & Access Systems | Ledger tubes, standard vertical posts, base jack sleeves |
| Machinery & Hydraulic Equipment | Conveyor frames, crane boom sections, hydraulic cylinder housings |
| Petrochemical & Power Plants | Pipe rack structures, cable tray supports, boiler frame bracing |
Why Galvanized Coating Weight Determines Inspection Pass or Rejection on Site
A 20-micron shortfall in zinc thickness can void an entire batch during third-party inspection.
Procurement teams sourcing a Galvanized Square Steel Tube from disconnected traders often receive material where the galvanizing was subcontracted to a separate facility — meaning coating thickness, adhesion, and surface finish vary between heats. On projects requiring EN 10219 or ASTM A500 compliance, inspectors measure zinc mass per square meter against the standard’s minimum, and inconsistent coating triggers full-batch rejection. [NEED_CITE: hot-dip galvanized coating thickness requirements per ASTM A123]
When the steel mill, rolling line, and galvanizing bath operate under one roof, every tube carries the same production lot identity. That eliminates the documentation gap between raw material certificate and coating report — the single most common reason for customs holds on galvanized hollow sections entering the EU and Middle East.
Matching Structural Load Paths to Square Tube Geometry
Square and rectangular hollow sections concentrate material away from the neutral axis, giving them higher torsional rigidity than round tubes of equivalent weight — which is why Q345B galvanized square tubes are specified for moment-resisting frames in warehouse and plant construction. The flat faces simplify bolted and welded connections to gusset plates and base brackets, reducing on-site fitting time. For scaffolding and access structures, the uniform geometry allows standardized clamp fittings to engage consistently across every joint.
Engineering Compliance Across ASTM, EN, and GB Frameworks
Projects specifying ASTM A500 Grade B or C require documented yield strength and chemical composition per heat, while EU-bound shipments must carry CE marking under EN 10219 for cold-formed welded structural hollow sections. [NEED_CITE: EN 10219 cold-formed structural hollow section compliance requirements] Our Galvanized Square Steel Tube production covers Q235B through S355JR, with mill certificates mapping each heat to its corresponding grade under multiple standard systems — simplifying compliance for contractors working across jurisdictions. Hot-dip galvanizing to 65–80 microns meets C3–C4 atmospheric corrosion categories, suitable for coastal and industrial environments without field touch-up.
Steel Grade Selection and What It Means for Load-Bearing Design
Q235B remains the default for general structural framing in domestic and Southeast Asian projects, offering adequate strength for gravity-load members at competitive cost. Q345B steps up yield capacity for longer-span beams and heavily loaded columns, reducing section size and self-weight in the same design envelope. When projects demand international grade equivalence — A500 Grade B for North America, S355JR for Europe — the underlying chemistry and rolling practice differ, and substituting one for another without engineering approval risks non-conformance during structural review. [NEED_CITE: steel grade equivalence mapping between GB Q-series and ASTM A500]
Hot-dip galvanizing immerses the formed tube in molten zinc at approximately 450°C, creating a metallurgical bond with the steel substrate through a series of zinc-iron alloy layers. Pre-galvanized tube, by contrast, is coated at the coil stage before forming — the zinc layer is thinner and the cut edges at weld seams remain unprotected. For structural applications exposed to weather or chemical atmospheres, hot-dip provides superior edge coverage and sacrificial protection at weld points.
The Hidden Cost of Unverified Galvanized Tube Procurement
Purchasing a Galvanized Square Steel Tube based on price alone, without verified mill test certificates and independent coating-thickness measurement, exposes projects to cascading failures: sub-spec zinc coating accelerates corrosion at connections, triggering maintenance claims years after handover; undocumented steel chemistry fails weld procedure qualification, halting fabrication; and missing CE or ASTM paperwork blocks customs clearance, stranding containers at port for weeks. [NEED_CITE: consequences of non-compliant structural steel in international construction projects]
Vertically Integrated Production Eliminates the Supplier-Fabricator Gap
Our Galvanized Square Steel Tube leaves a single facility where raw slab is rolled, formed, welded, galvanized, and inspected under one quality management system. With over 2,800 specifications in stock across square and rectangular profiles, we consolidate multi-size orders into shared container loads — reducing freight cost per ton for mixed-dimension projects. Every heat carries a unique traceability number linking the mill certificate, galvanizing bath record, and dimensional inspection report. Third-party inspection by SGS, BV, or TÜV is arranged before shipment at the buyer’s request, and professional lashing with timber dunnage and edge protectors preserves the zinc finish through ocean transit.
Documentation & Compliance
- Mill Test Certificate documenting Q235B/Q345B chemical composition and mechanical properties per GB/T3091 and ASTM A500, indexed by heat number
- CE Certificate confirming EN 10219 compliance for cold-formed welded structural hollow sections, required for EU customs clearance
- ISO 9001 Quality Management System certificate covering the full production chain from rolling through galvanizing and final inspection
- SGS / BV / TÜV third-party inspection report verifying coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability sheet linking each bundle’s heat number to its corresponding galvanizing batch and coating mass record
- Full customs documentation package: commercial invoice, packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235B and Q345B galvanized square tubes bundled with high-tensile steel strips and timber dunnage, sized to match 5.8 m and 6 m standard lengths for 20ft and 40ft container optimization
- Hot-dip galvanized surface protected by rubber edge guards at bundle contact points, preventing zinc coating abrasion during loading and ocean transit
- Pre-galvanized tubes wrapped in waterproof kraft paper and plastic sheeting to prevent white rust formation during humidity exposure in tropical destinations
- Custom-cut lengths to project specification, with cut ends sealed to prevent moisture ingress and edge corrosion before delivery
- Each bundle tagged with heat number, steel grade (Q235B/Q345B/S355JR), and galvanizing coating mass, enabling on-site verification against mill certificates
- FOB Jinan/Qingdao, CIF, and DDP delivery terms available, with professional lashing plans for oversized rectangular sections exceeding standard container width
Getting Your Galvanized Tube Order Quoted and Certified
Share your project drawings, required steel grade, section dimensions, total tonnage, and destination port — our engineering team responds within 24 hours with a detailed quotation including material cost, galvanizing specification, production schedule, and container loading plan. For non-standard sizes or custom end finishes, we provide shop drawing confirmation before production begins. Certification and mill test documentation are confirmed at quotation stage to ensure smooth customs clearance at your port.
Request Your Galvanized Square Steel Tube Quotation with Full Mill Certification
Submit your specifications, steel grade, and quantity to receive a detailed quotation and mill test certificate preview.
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
