Description
Factory-Direct Galvanized RHS — Vertically integrated from raw steel coil to finished ASTM A500 GR.B rectangular hollow sections under one quality system.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 GR.B Hot Dipped Galvanized Rectangular Steel Tube |
| Product Type | Hot Dipped Galvanized Rectangular Steel Tube (RHS) |
| Steel Grade | GR.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Rectangular / Square |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Dipped Galvanized (Zinc Coated 200-700g/sqm) / Black Painting / Bare |
| Ends | Plain |
| Tolerance | ±1% |
| Application | Steel structures / Building construction / Curtain wall / Support structures |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Warehouse frames, logistics center columns, factory building structures |
| Infrastructure | Belt & Road support structures, bridge handrails, signage gantries |
| Industrial Facilities | Plant mezzanine platforms, conveyor support frames, equipment bases |
| Architectural Engineering | Curtain wall mullions, facade structural frames, canopy supports |
Where Zinc Coating Thickness Decides Project Acceptance on Galvanized Rectangular Steel Tube Orders
A 45-micron reading against an 80-micron contract spec halts the entire shipment at third-party inspection.
Outsourcing galvanized steel fabrication overseas introduces a traceability gap that no amount of email correspondence can close. When the zinc coating falls short of the specified 200-700g/sqm range, the material fails corrosion resistance testing on arrival — and by then, the container is already at the port. I have seen Middle East project teams face weeks of delay because the galvanizing bath temperature was not monitored, producing a brittle coating that cracked during transport handling. Without a vertically integrated supply chain controlling both the base steel chemistry and the galvanizing line parameters, buyers inherit the risk of inconsistent coating adhesion and premature white rust formation. [NEED_CITE: hot dip galvanizing coating thickness standards for structural steel]
How 200-700g/sqm Zinc Coating Matches Harsh Environment Structural Demands
The hot dipped galvanizing process on this Hot Dipped Galvanized Rectangular Steel Tube produces a metallurgical bond between the zinc and the GR.B steel substrate, forming zinc-iron alloy layers that resist mechanical damage during site handling. For coastal infrastructure in Southeast Asia or industrial plants in the Middle East where chloride exposure accelerates corrosion, specifying 400g/sqm or 700g/sqm coating weight extends maintenance-free service life significantly compared to pre-galvanized alternatives. Our in-house galvanizing line controls bath temperature, immersion time, and withdrawal speed to ensure uniform coating distribution across the full 15×20mm to 700×800mm dimension range — a capability that matters when structural frames must withstand twenty years of tropical humidity without recoating.
Structural Load Requirements and International Standard Compliance
Engineering specifications for steel structures increasingly reference EN 1090 execution classes or AISC 360 design provisions, which demand verifiable material certification rather than supplier declarations. The GR.B grade under ASTM A500 provides defined minimum yield strength for structural calculations, while the ±1% dimensional tolerance on this Hot Dipped Galvanized Rectangular Steel Tube ensures that connection details — bolted end plates, welded gussets, moment-resisting joints — fit as designed without field rework. For projects entering the European market, EN 10210 compliance documentation becomes a customs clearance prerequisite, not an optional add-on. [NEED_CITE: EN 10210 hot finished structural hollow sections certification requirements] Specifying S355 over S235 for heavily loaded columns reduces section size and self-weight, but only if the mill test certificate confirms actual chemistry and mechanical properties match the declared grade.
Understanding ERW Welding and Hot Dipped Galvanizing Process Interaction
Electric Resistance Welding produces a longitudinal seam with a heat-affected zone that requires proper normalization to restore ductility before galvanizing. If the weld zone is not adequately treated, the differential microstructure between weld metal and base metal causes uneven zinc pickup — visible as streaks or bare patches along the seam. Our WPS procedures for ERW welding of GR.B and S-series grades include post-weld heat treatment parameters calibrated to the specific steel chemistry, ensuring the weld region accepts zinc coating at the same thickness as the parent metal. The hot dipped process itself operates at approximately 450°C, which can affect the mechanical properties of cold-formed sections if the base material was not properly normalized after forming — a detail that separates structural-grade RHS from decorative tubing. Wall thickness from 1mm to 30mm spans both light-gauge purlin applications and heavy-duty column sections, but the galvanizing bath drainage behavior differs significantly between thin and thick walls, requiring adjusted withdrawal speeds to prevent internal coating buildup that reduces effective bore diameter.
The Hidden Cost of Unverified Material on Galvanized Rectangular Steel Tube Projects
Accepting a lower price from a trader who cannot provide heat-number traceability creates downstream liability that dwarfs the initial savings. When coating thickness falls below the 200g/sqm minimum specified for marine environments, the structure begins corroding within months — and replacement costs include not just new steel, but demolition, disposal, and project downtime. Material substitution without notification — S235 delivered where S355 was specified — compromises structural safety margins that the engineer calculated assuming higher yield strength. [NEED_CITE: consequences of material substitution in structural steel construction] Customs authorities in the EU and Middle East increasingly reject shipments lacking proper CE marking or certificate of origin, stranding containers at port with demurrage charges accumulating daily.
Why Project Teams Source This Hot Dipped Galvanized Rectangular Steel Tube From Us
Our own steel mill produces the raw material, our fabrication workshop welds and galvanizes it, and our quality department documents every step — eliminating the gap between material supplier and fabricator that creates traceability failures. The in-house metallurgical laboratory tests every heat for chemical composition before the steel enters the ERW line, and every finished Hot Dipped Galvanized Rectangular Steel Tube undergoes coating thickness measurement at multiple points per piece. With over 2,800 specification combinations in inventory, we consolidate orders spanning multiple sizes and grades into single shipments, reducing your procurement complexity and freight costs. Our welding procedures and welder qualifications are certified to AWS and EN standards, and we provide complete documentation packages including WPS, PQR, weld maps, and dimensional inspection reports — not as optional extras, but as standard deliverables with every order. Professional loading planning for oversized rectangular sections maximizes container utilization while protecting the galvanized surface from transport damage.
Documentation & Compliance
- Mill Test Certificate documenting GR.B chemical composition and mechanical properties per ASTM A500, traceable to heat number
- CE Certificate confirming EN 10210 / EN 10219 compliance for Hot Dipped Galvanized Rectangular Steel Tube entering European markets
- ISO 9001 Quality Management System certificate covering the integrated steel production and fabrication process
- SGS or BV Third-Party Inspection Report verifying zinc coating thickness 200-700g/sqm and dimensional tolerance ±1%
- Material Traceability Report linking each piece to its original heat number, chemical analysis, and mechanical test results
- Export Documentation Package including packing list, bill of lading, and certificate of origin for customs clearance
Packaging, Loading & Delivery
- Hot Dipped Galvanized Rectangular Steel Tube bundled with high-tensile steel strips and edge protectors to preserve the zinc coating during ocean transit
- Galvanized surface protected by waterproof wrapping at bundle ends to prevent white rust formation from condensation during container shipping
- Custom length cutting available from 5.8m to 12m random lengths, optimized for 40ft high-cube container loading to minimize freight cost per ton
- Heat number and steel grade stenciled on each piece for site identification and traceability verification during installation
- Professional lashing and bracing plans for oversized sections up to 700×800mm, ensuring load stability without damaging the galvanized coating
- FOB, CIF, and DDP delivery terms available with door-to-door logistics coordination for project sites worldwide
Initiating Your Procurement Process for Galvanized Rectangular Steel Tube
Submit your project drawings or specification schedule indicating required sizes, steel grades, coating weight, and destination port to receive a detailed quotation including material, fabrication, coating, and shipping costs. Our engineering team reviews shop drawings within 24 hours and provides preliminary technical assessment confirming compliance with your project standards. Confirm certification requirements and third-party inspection needs before contract signing to ensure complete documentation delivery with your shipment.
Request Quotation and Mill Test Certificate for Your ASTM A500 GR.B Hot Dipped Galvanized Rectangular Steel Tube Order
Share your project specifications, required quantities, and destination port to receive a detailed quotation with complete material certification package.
Contact:
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Email: admin@xjystructure.com
Website: www.xjystructure.com
