Description
Factory-Direct Galvanized Tube Supply — SPCC through DC04 grades in stock with 30–275 g/m² zinc coating, shipped with original mill certificates and third-party inspection support.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | SPCC Galvanized Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (Galvanized) |
| Steel Grade | SPCC, DC01, DC02, DC03, DC04 |
| Standard | ASTM |
| Section Shape | Square / Rectangular |
| Wall Thickness | 0.5–200 mm |
| Technique | Welded (ERW) |
| Surface Treatment | Galvanized (Zinc Coating 30–275 g/m²) |
| Tolerance | ±1% |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Finish | Silvery (Galvanized), Non-oiled |
| Invoicing | By Theoretical Weight |
| Application | Building construction, architectural decoration, furniture manufacturing, structural frames, machinery fabrication |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building & Construction | Structural frames, column supports, roof trusses, curtain wall skeletons |
| Architectural Decoration | Display racks, handrail systems, interior partition frames, facade cladding supports |
| Furniture Manufacturing | Table legs, shelving frames, bed frames, office furniture structures |
| Machinery Fabrication | Equipment housings, conveyor supports, machine base frames, protective guards |
Why Zinc Coating Weight Determines Whether Your Shipment Clears Customs
Specifying the right zinc class is the single most overlooked detail in galvanized tube procurement — and the most common reason for customs rejection.
Buyers often write “galvanized” on their purchase order without defining the coating weight. The supplier ships 30 g/m² electro-galvanized tubes when the project spec calls for hot-dip minimum 275 g/m². The material arrives, the inspector pulls a coating thickness gauge, and the entire container gets flagged. I have seen this happen on projects in West Africa and the Middle East — not because the tube itself was defective, but because the coating class was never locked down in the contract. [NEED_CITE: galvanized steel coating weight classification per ASTM A653]
When you source a Galvanized Square and Rectangular Steel Pipe Supplier who confirms zinc coating weight in writing before production, you eliminate the most frequent compliance gap in international steel procurement.
Matching Cold-Formed Grades to Structural and Decorative Applications
SPCC and the DC01–DC04 grade family are low-carbon cold-rolled steels selected primarily for formability rather than high load-bearing capacity. In building frames and furniture structures, these grades allow tight-radius bending and punching without cracking — critical when architectural designs call for complex joint geometries. The galvanized zinc layer (30–275 g/m²) provides corrosion resistance proportional to the environment: indoor furniture and decoration typically require the lower coating range, while outdoor structural frames in coastal or humid climates need the upper range. A Galvanized Square and Rectangular Steel Pipe Supplier who stocks the full SPCC-to-DC04 range lets you consolidate structural and decorative tube requirements into a single shipment, reducing split-order logistics costs.
Engineering Compliance and Certification Requirements
Galvanized square and rectangular tubes in SPCC and DC01–DC04 grades manufactured to ASTM standards require clear documentation for project acceptance. For North American projects, ASTM conformance must be traceable through heat-number-linked mill test certificates covering chemical composition and coating weight. European-bound shipments additionally need CE marking under EN 10219 for cold-formed structural hollow sections, even when the base material originates from an ASTM-designated melt. [NEED_CITE: EN 10219 cold-formed structural hollow section certification requirements] Coating thickness verification by SGS or BV third-party inspection is frequently specified by EPC contractors for galvanized products, since visual assessment cannot confirm whether 60 g/m² or 120 g/m² was actually applied. Dimensional tolerance of ±1% across the 0.5–200 mm wall thickness range must be documented per batch, as negative tolerance deviations beyond contractual limits trigger weight-shortage claims at destination.
Understanding SPCC, DC01–DC04 Grade Selection and ERW Welding
SPCC is the Japanese JIS G 3141 designation for general-purpose cold-rolled steel; DC01 through DC04 are the European EN 10130 equivalents, with increasing drawability from DC01 (general forming) to DC04 (deep drawing). The practical difference matters when your fabrication involves severe bending or hydroforming: DC03 and DC04 offer higher elongation and lower yield-to-tensile ratios, reducing springback and crack risk in complex shapes. For standard structural frames with simple welding and cutting, SPCC or DC01 is sufficient and more cost-effective. ERW (Electric Resistance Welding) is the standard production method for these galvanized square and rectangular tubes — the weld seam runs along one face of the section, and post-weld cold-sizing ensures the ±1% dimensional tolerance. The galvanizing process (whether electro or hot-dip depending on coating weight specification) is applied after forming, covering both the outer surface and the weld zone with a continuous zinc layer. [NEED_CITE: SPCC and DC01 DC04 grade equivalence in cold-rolled steel standards]
The Hidden Cost of Buying Galvanized Tubes Without Coating Verification
Ordering galvanized tubes based on price alone, without specifying and verifying zinc coating weight, creates a cascade of downstream costs. A shipment that tests below the specified coating class fails project inspection, requiring either rejection and re-order (adding weeks to the schedule) or on-site recoating (which costs more per square meter than factory galvanizing). Material traceability gaps — missing heat numbers or unlinked mill certificates — prevent customs clearance in markets that enforce import quality audits. [NEED_CITE: steel product import documentation requirements for customs compliance] Negative tolerance abuse on wall thickness compounds the problem: the tube may pass visual inspection but fail structural load calculations, forcing the entire batch off the project. These are not theoretical risks; they are the most common dispute patterns in international galvanized tube trade.
Procurement Confidence Through Verified Supply Chain Control
Our Jinan factory operates three ERW production lines running simultaneously, giving us direct control over forming, welding, and galvanizing quality at every stage — there is no trading company margin between your order and our mill floor. Every batch of SPCC and DC01–DC04 galvanized tubes ships with original mill test certificates linking chemical composition to heat numbers, and we arrange SGS or BV third-party inspection for coating weight and dimensional verification before container sealing. Our inventory covers 2,800+ specifications across square, rectangular, and round sections, so when your project mixes structural frames in DC01 with decorative elements in DC04, we consolidate everything into optimized container loads rather than forcing multiple supplier orders. We handle the full export documentation package — commercial invoice, packing list, bill of lading, certificate of origin — and our loading team designs container plans that maximize weight utilization for heavy-wall galvanized sections while protecting the zinc surface during ocean transit.
Documentation & Compliance
- Mill test certificate documenting SPCC / DC01–DC04 chemical composition (C, Mn, P, S) and mechanical properties per ASTM cold-rolled steel standards, linked to individual heat numbers
- Galvanized coating weight test report confirming 30–275 g/m² zinc layer thickness per batch, verified by triple-spot measurement method
- SGS or BV third-party inspection report covering dimensional tolerance (±1%), coating adhesion, and surface quality before container loading
- ISO 9001:2015 quality management certificate covering the full production process from raw coil intake through galvanizing and final inspection
- CE certificate (EN 10210 / EN 10219) available for shipments destined to European markets requiring structural hollow section compliance marking
- Complete customs document package: commercial invoice, packing list, bill of lading, and certificate of origin formatted per destination country requirements
Packaging, Loading & Delivery
- Galvanized square and rectangular tubes bundled with steel strips and fitted with rubber edge protectors to prevent zinc coating abrasion during handling and ocean transit
- Non-oiled silvery galvanized surface wrapped in waterproof cloth at both open ends to block moisture ingress and prevent white rust formation during container shipping
- Container loading plan optimized per section dimensions — standard 20ft and 40ft configurations calculated to maximize weight utilization for 0.5–200 mm wall thickness ranges while maintaining safe weight distribution
- Custom cut-to-length service available for tubes requiring specific project dimensions, with cut ends deburred and re-galvanized touch-up applied to maintain full coating coverage
- Heat number and steel grade (SPCC / DC01 / DC02 / DC03 / DC04) stenciled on each bundle tag, with matching documentation for full material traceability at destination
- FOB, CIF, and DDP shipping terms available from Chinese ports, with professional export team managing customs clearance and real-time container tracking through to project site
Start Your Procurement With Verified Specifications
Submit your required section dimensions, wall thickness, steel grade (SPCC through DC04), zinc coating weight class, and destination port — we return a detailed quotation with factory-direct pricing, mill test certificate samples, and estimated production lead time within 12 hours. For non-standard dimensions or mixed-grade project requirements, we provide a consolidated loading plan and custom fabrication proposal before you commit to a deposit.
Request Your Galvanized Tube Quotation and Mill Certificate
Send your specifications via email to admin@sdxinjiyuan.com or contact us on WhatsApp at +86 188 5315 7756 to receive pricing, coating verification reports, and container loading plans.
Frequently Asked Questions
Q: What is the difference between SPCC, DC01, and DC04 steel grades for square tubes?
A: SPCC is the Japanese JIS general-purpose cold-rolled grade; DC01 is the European EN equivalent for general forming; DC04 is the deep-drawing grade with higher elongation for complex bending. For standard structural frames, SPCC or DC01 is sufficient. For tubes requiring severe bending or hydroforming, DC03 or DC04 reduces crack risk.
Q: Can you provide third-party inspection reports for zinc coating thickness verification?
A: Yes. We arrange SGS or BV third-party inspection before container loading. The inspection covers zinc coating weight measurement (confirming your specified range within 30–275 g/m²), dimensional tolerance verification, and surface quality assessment. The report is issued with your purchase order number and heat numbers for full traceability.
Q: What are the standard zinc coating weights available and their corrosion resistance levels?
A: We supply galvanized tubes with zinc coating ranging from 30 g/m² to 275 g/m². Lower coating weights (30–60 g/m²) suit indoor applications such as furniture frames and interior decoration. Mid-range (90–120 g/m²) covers general outdoor structural use. The upper range (180–275 g/m²) is specified for coastal, industrial, or high-humidity environments requiring extended corrosion protection.
Q: How do you handle custom sizes and non-standard dimensions with flexible MOQ?
A: Our factory maintains ready stock across 2,800+ standard specifications for immediate dispatch. For non-standard section sizes or custom wall thicknesses outside stock range, we produce to your drawing with a flexible MOQ starting from 5 tons. Custom orders typically require typical production lead times, and we provide dimensional drawings for your approval before rolling begins.
Q: What documentation is provided for customs clearance and project compliance?
A: Every shipment includes the full export document package: commercial invoice, packing list, bill of lading, and certificate of origin. We also supply original mill test certificates linked to heat numbers, and can provide CE certificates (EN 10210/EN 10219) for European market compliance. Third-party inspection reports from SGS or BV are available upon request for coating and dimensional verification.
