Description
Direct Mill Supply, Zero Middlemen — Raw galvanized coils processed into rectangular tubes on our own 3 production lines, backed by 2,800+ steel specifications in stock.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Rectangular Steel Tube |
| Product Type | Rectangular Steel Tube / Galvanized Square and Rectangular Steel Tube |
| Steel Grade | Q195, Q235, Q345, A36, A53, A106, 10#, 20#, 45# |
| Standard | ASTM, CE, RoHS, BIS, SASO, SABS, JIS, ISO9001, API |
| Section Shape | Rectangular / Square |
| Size Range | Rectangular tube (e.g., 2×1 inch and similar sizes) |
| Wall Thickness | 1.2 mm – 15.7 mm |
| Length | 6 m / 6.4 m / 12 m |
| Technique | Cold Rolled Based (sheet); ERW / Welded (tube) |
| Surface Treatment | Galvanized (Z81 – Z120 coating), Zero Spangle, Non-oiled, Skin Pass |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures, Construction frames, Carports, Fences, Containers, Scaffolding, Machinery |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & EPC | Building frames, warehouse portals, scaffolding uprights |
| Agricultural & Rural | Carport canopies, livestock shelter frames, equipment sheds |
| Industrial Infrastructure | Container corner castings, conveyor support structures, machine guards |
| Fencing & Security | Perimeter fence posts, gate frames, barrier systems |
What Galvanized Coating Weight Actually Means for Your Project Timeline
Z81 versus Z120 is not a pricing decision — it is a corrosion-life decision that determines whether your structure passes inspection in year three or year ten.
When overseas buyers source a galvanized rectangular steel tube from China, the coating weight specification often gets reduced to a line item on a purchase order without real engineering review. A Z81 coating may suffice for an indoor scaffolding frame in a dry climate, but the same tube used as a carport rafter in a coastal Middle East environment will show white rust within months [NEED_CITE: galvanized coating thickness selection based on ISO 1461 environmental categories]. The result is not just premature corrosion — it is a rejected shipment, a return-to-fabricator cost, and a delayed project handover. Material traceability gaps compound the problem: when the fabricator sources raw coil from a third-party mill, the coating weight certificate becomes a paper exercise rather than a verifiable fact.
Matching Wall Thickness to Structural Load Paths
A galvanized rectangular steel tube in 2×1 inch profile with 1.2 mm wall thickness serves light-duty fencing and non-load-bearing cladding supports. Move to 3.0 mm or above on the same section, and the tube becomes a viable beam element for carport rafters and warehouse purlins. The ±1% tolerance we hold across the full 1.2 mm to 15.7 mm range means the as-delivered section modulus matches the engineer’s calculation — no hidden negative tolerance eroding load capacity at mid-span. Our own cold-rolled sheet line feeds directly into the ERW tube mill, so coating adhesion and dimensional accuracy are controlled in a single production sequence rather than across two unrelated suppliers.
Engineering Compliance Across Destination Markets
Structural frames destined for the European Union must demonstrate conformity with EN 10219 for cold-formed welded structural hollow sections, including CE marking and factory production control documentation [NEED_CITE: EN 10219 cold-formed hollow section compliance requirements]. North American projects typically call for ASTM A500 or A53, where mill test certificates must trace each heat number to chemical composition and mechanical test results. Middle East specifications frequently add SASO or SASO-IEC requirements for customs clearance. The steel grades we stock — Q235, Q345, A36, A53 — cover these standard systems, and our engineering team prepares cross-reference equivalence tables during the shop drawing review stage so that a Q235 supply can be validated against S235JR or A36 requirements without re-testing at destination.
Steel Grade Selection and ERW Weld Integrity
Q195 and Q235 are low-carbon structural grades with good formability, suited to light frames, fencing, and non-critical bracing. Q345 and A36 deliver higher yield strength for primary structural members in warehouse portals and equipment supports. The ERW welding process we use produces a longitudinal weld seam that, when properly normalized and inspected, achieves weld zone properties matching the parent metal. For galvanized rectangular steel tube, the zinc coating is applied after welding, which means the weld seam receives the same corrosion protection as the base metal — a critical detail that hot-dip galvanized seamless tube cannot always guarantee at the same coating weight.
The Hidden Cost of Unverified Tolerance and Coating Claims
Ordering a galvanized rectangular steel tube at a price point that seems competitive often means accepting negative tolerance beyond the stated ±1%, or a zinc coating that measures Z60 when the purchase order specified Z120. The consequences are not abstract: dimensional shortfall triggers rejection at the engineer’s site inspection; coating shortfall accelerates corrosion and voids the project’s durability specification [NEED_CITE: ASTM A123 zinc coating thickness minimum requirements for structural steel]. When the fabricator cannot produce the original mill’s coating weight certificate because the coil was sourced from a trader rather than a mill, the buyer has no documentary path to resolve the dispute. Single-source procurement from a vertically integrated producer eliminates this gap — the heat number on the tube stamp traces back to our own coil production records.
Why Procurement Teams Choose Our Mill for Rectangular Tube
We operate three dedicated production lines for cold-rolled sheet and ERW welded tube, holding over 2,800 raw material specifications in our own yard. This means your galvanized rectangular steel tube order is fulfilled from coil to finished bundle within one facility, under one quality management system certified to ISO 9001. Our in-house laboratory issues mill test certificates for every heat, and we welcome SGS or BV third-party inspection at any production stage. For projects requiring CE marking under EN 10219, our factory production control system is audited and certified. We also handle the full export documentation chain — packing lists, bills of lading, certificates of origin — and coordinate professional container loading with internal bracing to protect tube edges and zinc coating during ocean transit.
Documentation & Compliance
- Mill test certificate documenting Q235 / A36 chemical composition and mechanical properties per ASTM and GB standards, traceable by heat number
- CE certificate confirming EN 10219 compliance for cold-formed welded structural hollow sections exported to European Union markets
- ISO 9001 quality management system certificate covering the full production chain from cold-rolled coil to galvanized finished tube
- SGS or BV third-party inspection report verifying dimensional tolerance, coating thickness (Z81–Z120), and weld seam quality
- Material traceability documentation linking each bundle’s heat number to the originating coil and galvanizing batch
- Customs clearance documents including packing list, bill of lading, and certificate of origin formatted to destination country requirements
Packaging, Loading & Delivery
- Galvanized rectangular tubes bundled with steel strips and edge protectors to preserve the zero spangle zinc coating during handling and ocean transit
- Internal container bracing using timber dunnage and steel wire lashing to prevent tube corner damage — a lesson learned from early export shipments where inadequate bracing led to coating scrape-off at destination
- 6 m and 12 m standard lengths loaded in 20ft and 40ft containers with weight distribution optimized for road transport limits at destination port
- Plain ends capped with plastic protectors to prevent moisture ingress and edge damage during storage at the project site
- Heat number and steel grade stenciled on each bundle tag for on-site identification and traceability verification by the receiving engineer
- FOB, CIF, and DDP shipping terms available with full export documentation and container tracking until site delivery
Starting Your Procurement Process
Send your project drawings, steel grade requirements, coating specification (Z81 or Z120), and destination port — we respond within 24 hours with a preliminary assessment, detailed quotation including fabrication and coating costs, and a shop drawing timeline. For non-standard dimensions or custom cutting and welding, our engineering team reviews your specifications and confirms feasibility before contract signing.
Request Your Quotation and Mill Test Certificate
Submit your galvanized rectangular steel tube specifications, steel grade, quantity, and destination port to receive a detailed quotation with full material certification.
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
Frequently Asked Questions
Q: What is the difference between Q235 and A36 for a galvanized rectangular steel tube?
A: Q235 is the Chinese national standard equivalent grade, while A36 is the ASTM specification commonly required for North American projects. Both are low-carbon structural steels with similar yield strength ranges and weldability. Our engineering team provides cross-reference equivalence tables during the quotation stage so you can confirm which grade meets your project standard without ordering separate test batches.
Q: Can I request third-party inspection before shipment?
A: Yes. We welcome SGS, BV, or other internationally recognized inspection agencies to verify dimensional tolerance, zinc coating thickness, and weld seam quality at any stage of production. The mill test certificate from our in-house laboratory is issued for every heat, and third-party inspection reports are provided as part of the standard export documentation package.
Q: How do I choose between Z81 and Z120 galvanized coating for my project?
A: The choice depends on the service environment and required design life. Z81 coating is suitable for indoor or dry environments such as interior scaffolding and machine guards. Z120 coating provides thicker zinc coverage for outdoor exposure, coastal environments, and structures requiring longer corrosion resistance. If your project specification references ISO 1461 or a minimum coating mass, we match the galvanizing process to that requirement during production planning.
Q: Do you offer custom cutting and welding for project-specific dimensions?
A: Yes. In addition to standard 6 m and 12 m lengths, we provide cutting, welding, punching, and bending services to your project drawings. Custom fabrication is coordinated through our shop drawing review process, where our engineering team confirms dimensions, connection details, and material optimization before production begins.
Q: What shipping terms and documentation do you provide for international orders?
A: We offer FOB, CIF, and DDP shipping terms with professional container loading, internal bracing, and full export documentation including packing list, bill of lading, certificate of origin, and mill test certificates. Container tracking is provided from loading at our facility until delivery at your destination port or project site.
