Description
Full-Range Galvanized Tube Supply — 2,800+ specifications in stock, from 20×20 mm to 200×200 mm with wall thickness up to 40 mm, ready for single-source structural procurement.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Hollow Sections |
| Steel Grade | Q195, Q235, Q235B, Q345, Q345B, SS400, SGCC, CGCC, TDC51DZM, TDC52D, TS350GD, TS550GD, DX51D+Z |
| Standard | ASTM; EN 10219 / EN 10210 / JIS G3466 / GB/T 6728 available per request |
| Section Shape | Square / Rectangular |
| Size Range | 20×20 – 200×200 mm |
| Wall Thickness | 0.5 – 40 mm |
| Length | 1 – 12 m |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot-dip Galvanized / Pre-galvanized |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction structures, steel frames, building facades, curtain walls, machinery frames, scaffolding, infrastructure |
| MOQ | 25 Tons (1×20ft container) |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Facade | Glass curtain wall framing, architectural steel facades, exposed structural columns, canopy supports |
| Steel Structure Fabrication | Portal frames, industrial warehouse trusses, bridge handrails, mezzanine flooring systems |
| Infrastructure & Civil Engineering | Highway sound barriers, solar panel mounting structures, utility pole bases, fencing systems |
| Machinery & Equipment | Conveyor frames, crane boom sections, equipment support bases, pallet racking uprights |
| Scaffolding & Temporary Works | Shoring tower legs, scaffold ledger tubes, formwork support frames |
Why Galvanized Coating Thickness Determines Whether Your Shipment Clears Customs
A zinc coating below the specified minimum triggers rejection at third-party inspection and can block EU customs clearance entirely.
Procurement teams ordering Galvanized Square and Rectangular Steel Tube for regulated markets frequently discover that the coating weight stated on the commercial invoice does not match the physical sample tested at destination. Hot-dip galvanized tubes specified at Z275 coating class sometimes arrive with only Z120 or less, particularly when the original mill cuts corners on immersion time or uses undersized base material. For projects in the Middle East and Southeast Asia where coastal corrosion is a daily reality, this gap between specification and delivery means premature rust bloom, failed engineer sign-off, and costly on-site re-galvanizing — or full container rejection. [NEED_CITE: hot-dip galvanizing coating thickness requirements per ASTM A123 and EN ISO 1461]
Matching Galvanized RHS and SHS to Structural and Corrosion Demands
Galvanized Square and Rectangular Steel Tube in Q235B and Q345B grades serves as the primary structural skeleton for curtain wall systems and exposed architectural frames where both load-bearing capacity and long-term corrosion resistance matter. The hot-dip zinc coating provides sacrificial protection that extends service life in C3 and C4 corrosion environments without additional painting, making it the default choice for infrastructure projects in humid and coastal regions. Wall thickness from 0.5 mm to 40 mm covers everything from light-gauge purlin sections to heavy-load column members, while the ±1% dimensional tolerance ensures that connection plates and bolt holes align on-site without forced fitting. Our patented sharp-corner rectangular tube technology eliminates the rounded radii found on standard ERW sections, giving facade contractors clean 90-degree edges that sit flush against glass panels and stone cladding.
Engineering Compliance and Certification Requirements for Galvanized Hollow Sections
Structural engineers specifying Galvanized Square and Rectangular Steel Tube for load-bearing frames typically require compliance with EN 1993-1-1 for steel structures or AISC 360 for American projects, and the tube must carry a valid CE mark under EN 10219 (cold-formed) or EN 10210 (hot-finished) for European market acceptance. [NEED_CITE: CE marking requirements for structural hollow sections under EN 10219 and Construction Products Regulation] The mill test certificate must document chemical composition and mechanical properties traceable to each heat number, and third-party inspection by SGS or BV is often mandated before container sealing. For projects in Singapore and the broader Southeast Asian market, the Singapore FPC (Factory Production Control) certification becomes a separate but equally critical requirement that not all Chinese mills hold. Galvanized coating thickness must be verified against ISO 1461 or ASTM A123 standards depending on the destination market, and coating uniformity tests on internal surfaces are increasingly requested for tubes used in enclosed structural applications.
Steel Grade Selection and ERW Welding Process Explained
The Q-series grades (Q195 through Q345B) follow the Chinese GB standard system where the number indicates minimum yield strength in MPa — Q235B delivers approximately 235 MPa yield for general structural framing, while Q345B steps up to roughly 345 MPa for heavier load conditions. SS400 from the JIS system and SGCC/CGCC from the galvanized sheet grade family serve different purposes: SS400 is a general structural carbon steel, while SGCC and DX51D+Z are substrate grades designed specifically for galvanizing where formability matters more than raw strength. The ERW welding process forms the tube by rolling steel strip into shape and fusing the seam through high-frequency electric current, producing a clean weld line suitable for galvanizing without the porosity risks associated with submerged arc welding. [NEED_CITE: steel grade equivalence mapping between GB, EN, ASTM, and JIS systems for structural hollow sections] Hot-dip galvanizing immerses the finished ERW tube in molten zinc at approximately 450°C, creating a metallurgical bond with the steel substrate that produces coating layers ranging from the gamma phase (hardest, closest to steel) to the eta phase (pure zinc, outermost), providing both barrier and cathodic protection. Wall thickness tolerance of ±1% means that a specified 3.0 mm wall could measure between 2.97 mm and 3.03 mm — tight enough for structural calculation accuracy while remaining within commercial rolling practice.
Hidden Costs of Procuring Galvanized Tubes Without Verified Compliance
Ordering Galvanized Square and Rectangular Steel Tube based on price alone, without verified mill test certificates and independent coating thickness reports, exposes projects to compounding downstream costs. Tubes with actual wall thickness below the ordered specification reduce load-bearing capacity and may fail structural engineer approval, forcing complete replacement rather than simple rework. Missing or incorrect CE documentation under EN 10219 blocks customs clearance in European ports, leaving containers stranded at the quay with daily demurrage charges accumulating. [NEED_CITE: consequences of non-compliant steel imports under EU Construction Products Regulation] Inconsistent zinc coating — where external surfaces meet Z275 but internal coating falls below Z120 — accelerates corrosion from inside the tube, a failure mode that remains invisible until structural integrity is compromised.
Procurement Advantages When Sourcing from Our Production Line
Every Galvanized Square and Rectangular Steel Tube leaving our facility passes through an in-house physical and chemical laboratory that tests dimensional accuracy, weld seam integrity, coating thickness by magnetic gauge, and mechanical properties before release. Our production lines cover 2,800+ specifications spanning the full 20×20 to 200×200 mm range with wall thickness up to 40 mm, meaning projects requiring mixed sizes can consolidate into a single container rather than splitting orders across multiple suppliers. The 41 invention patents include China’s original sharp-corner rectangular tube technology, which produces true 90-degree external corners that standard ERW forming cannot achieve — critical for architects specifying flush-fit curtain wall frames. Full certification coverage includes ISO 9001:2015 quality management, Lloyd’s CE marking under EN 10219 and EN 10210, Singapore FPC, and pre-shipment verification by SGS or BV at buyer’s request. Custom non-standard sizes, cut-to-length service, and professional container loading with anti-damage measures are standard practice rather than premium add-ons.
Documentation & Compliance
- Mill test certificate documenting Q235B or Q345B chemical composition (C, Mn, Si, P, S) and mechanical properties (yield strength, tensile strength, elongation) per GB/T 6728 or EN 10219, traceable to heat number
- CE certificate under EN 10219 for cold-formed welded structural hollow sections or EN 10210 for hot-finished sections, required for European Union market access and Construction Products Regulation compliance
- ISO 9001:2015 quality management system certificate covering the full production process from raw material incoming inspection through galvanizing and final dimensional check
- SGS or BV third-party inspection report verifying galvanized coating thickness (Z60–Z275 per ISO 1461), dimensional tolerance, and visual surface quality before container sealing
- Material traceability documentation linking each tube bundle to its heat number, production date, and galvanizing bath record for project quality audits
- Export customs documents including commercial invoice, packing list, bill of lading, and certificate of origin formatted for destination port requirements
Packaging, Loading & Delivery
- Galvanized Square and Rectangular Steel Tube bundled with high-tensile steel strips at intervals matching the 1–12 m length range, with edge protectors preventing zinc coating damage at contact points during ocean transit
- Hot-dip galvanized surface protected by passivation treatment and optional oiled coating to prevent white rust formation during humidity exposure in container shipping
- Container loading optimized by mixing size profiles — larger 200×200 mm sections positioned as base layers with smaller 20×20 mm tubes nested above, maximizing payload within the 25-ton MOQ per 20ft container
- Cut-to-length service available for 1–12 m specified lengths, with saw-cut ends deburred and marked with heat number, steel grade (Q235B/Q345B), and dimensional identification
- Shipping terms available as FOB, CIF, or DDP to 50+ countries, with professional tube loading plans preventing shifting and bending during sea freight
Request a Quotation with Mill Test Preview
Submit your required dimensions (width × height × wall thickness), steel grade preference, total tonnage, and destination port to receive a detailed quotation including unit price, production lead time, and a sample mill test certificate format for your engineer’s review. Non-standard sizes outside the 2,800+ specification range can be evaluated for custom production feasibility, and certification requirements (CE EN 10219, SGS inspection, Singapore FPC) should be confirmed at inquiry stage to avoid documentation delays.
Get Your Galvanized Tube Quote with Full Certification Package
Send your specification list and destination details to receive pricing, available stock sizes, and mill test certificate samples within 12 hours.
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Frequently Asked Questions
Q: What is the difference between hot-dip galvanized and pre-galvanized square tubes?
A: Hot-dip galvanizing immerses the finished ERW tube in molten zinc, producing a coating of 60–275 g/m² (Z60–Z275) with metallurgical bonding to the steel substrate, suitable for outdoor and corrosive environments. Pre-galvanized tubes are made from already-coated steel strip, resulting in thinner zinc layers (typically Z60–Z120) that are adequate for indoor or mild environments but less durable for exposed structural applications.
Q: Can you supply Galvanized Square and Rectangular Steel Tube with CE certification for European projects?
A: Yes. Our production carries Lloyd’s CE certification under both EN 10219 (cold-formed welded structural hollow sections) and EN 10210 (hot-finished welded structural hollow sections). The CE documentation includes Declaration of Performance, Factory Production Control certificate, and mill test certificates formatted to EN 10204 3.1 requirements, enabling customs clearance and engineer approval across EU member states.
Q: What steel grade equivalents should I specify when ordering from China?
A: Q235B (GB standard) is broadly equivalent to S235JR (EN 10025) and ASTM A500 Grade B. Q345B corresponds to S355JR and ASTM A500 Grade C. For galvanized substrate grades, SGCC aligns with DX51D+Z. We provide cross-reference documentation with each quotation to prevent ordering errors caused by different national standard systems.
Q: What is the minimum order quantity and can you mix sizes in one container?
A: The MOQ is 25 tons per 20ft container. Mixed sizes are standard practice — you can combine different widths, heights, wall thicknesses, and lengths from our 2,800+ specification range within a single order. Custom non-standard sizes outside stock range are also available with typical production lead times of 15–25 days depending on complexity.
Q: How do you ensure the galvanized coating thickness meets my project specification?
A: Every production batch undergoes coating thickness verification using magnetic gauges at our in-house laboratory, testing both external and internal surfaces. Results are documented in the mill test certificate with readings taken at multiple points per tube. Third-party inspection by SGS or BV can be arranged for independent verification before shipment, and coating class (Z60, Z100, Z180, Z275) is confirmed against ISO 1461 or ASTM A123 standards per your project requirements.
