Description
Factory-Direct Galvanized Tube Supply — Hot dip galvanized square and rectangular steel tubes produced on 3 dedicated ERW lines at our Jinan mill, shipped to 50+ countries without intermediary markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 Galvanized Square and Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube (Welded / ERW) |
| Steel Grade | Q195, Q235 (Q235A/B/C/D), Q345 (Q345B/C/D/E), Q355, Q390, Q420, Q460, Q500, Q550, Q620, Q690, S235JR, S275JR, S355JR, S420NL, S460NL, S500Q, S550Q, S620Q, S690Q, ASTM Grade B/C/D, A36, Grade 40/42/50/55/60/65/80, SS330, SS400, SPHC/SPHD/SPHE/SPFC |
| Standard | AISI, ASTM, DIN, JIS, GB, EN |
| Section Shape | Square / Rectangular |
| Size Range | 20 mm – 500 mm |
| Wall Thickness | 0.3 mm – 100 mm |
| Length | 5.8 m – 12 m (customizable) |
| Technique | ERW / Hot Rolled / Cold Rolled |
| Surface Treatment | Hot Dip Galvanized (30 g – 275 g zinc coating), PVC coated, Black, Color painting, Transparent oil, Anti-rust oil |
| Ends | With or without end caps |
| Application | Steel structures, Construction frames, Machinery, Scaffolding, Furniture, Architectural facades, Glass curtain walls, Industrial equipment |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, bridge support structures, scaffolding systems, foundation piling |
| Architectural Facades | Glass curtain wall framing, sharp-corner decorative columns, exposed structural members |
| Machinery Manufacturing | Industrial equipment frames, conveyor structures, hydraulic support columns |
| Steel Structure Fabrication | Portal frames, warehouse roofing trusses, mezzanine floor beams |
| Furniture & Interior | Display shelving supports, industrial-style furniture frames, retail fixture structures |
What Rounded Corners and Missing CE Marks Cost on a Facade Order
Sharp-corner geometry and valid EN 10219 certification determine whether galvanized square and rectangular steel tubes pass site inspection or get rejected at customs.
Architectural facade contractors specifying galvanized square and rectangular steel tubes for glass curtain walls routinely face two failures: standard ERW rectangular tubes arrive with R≥2t rounded corners that look unfinished against flat glass panels, and shipments to EU destinations get held at port because the CE mark references the wrong harmonized standard. A mill cert stamp alone does not clear customs — the certificate must cite EN 10219 or EN 10210 explicitly, with mechanical test data matching the declared steel grade. [NEED_CITE: EN 10219 cold-formed structural hollow sections delivery technical conditions]
How Wall Thickness and Zinc Coating Match Structural and Corrosion Demands
Galvanized square and rectangular steel tubes in Q235 and Q345 grades serve load-bearing frames where both structural capacity and atmospheric corrosion resistance matter. The hot dip galvanizing process applies 30 g to 275 g of zinc per square meter, selected based on the exposure environment — light indoor framing may use the lower range, while coastal or industrial atmosphere projects require the heavier coating. Wall thickness from 0.3 mm to 100 mm covers everything from light-gauge furniture frames to heavy structural columns, all produced on our 3 ERW lines with dimensional checks at every stage.
Engineering Compliance and Steel Grade Selection for Load-Bearing Frames
Structural engineers designing with galvanized square and rectangular steel tubes must verify that the declared steel grade satisfies the project’s governing code — Q235 and Q345 for GB-spec projects, S235JR through S355JR for EN 1993 Eurocode structures, and ASTM A500 Grades B/C/D for North American AISC designs. Each standard system defines different yield strength floors and impact testing requirements, and mixing them without proper equivalence mapping leads to material substitution errors. Third-party inspection by SGS or BV before shipment confirms that chemical composition and mechanical properties match the purchase order, while Lloyd’s CE certification under EN 10210 and EN 10210 ensures EU customs clearance proceeds without delay. [NEED_CITE: steel grade equivalence mapping between GB Q-series and EN S-series structural steels]
Steel Grade Systems and ERW Welding Process Explained
The Q-series (Q235, Q345, Q460) follows the Chinese GB standard where the number indicates minimum yield strength in MPa. The S-series (S235JR, S355JR, S420NL) follows EN 10025, with the letter suffix indicating impact test temperature — JR for room temperature, J0 for 0°C, J2 for -20°C. ASTM A500 Grades B, C, D serve the North American market with different tensile and elongation floors. Our ERW welding process forms the tube from hot-rolled or cold-rolled coil, welding the longitudinal seam under controlled pressure — suitable for structural applications up to moderate pressure, with the advantage of tight dimensional tolerance and consistent wall thickness. Hot dip galvanizing follows the welding and forming stage, immersing the finished tube in molten zinc to create a metallurgical bond that protects both external and internal surfaces. For architectural applications requiring right-angle aesthetics, our patented sharp-corner forming process produces rectangular tubes with minimal corner radius, eliminating the rounded profile that standard ERW dies leave on flat faces. [NEED_CITE: hot dip galvanizing coating thickness measurement per ISO 1461]
Hidden Costs of Unverified Material and Tolerance Deviation
Purchasing galvanized square and rectangular steel tubes without requiring mill test certificates tied to specific heat numbers creates downstream risk: if the actual yield strength falls below the declared grade, structural connections designed to that grade may fail under load, triggering re-engineering and project delays. Negative tolerance abuse — where wall thickness consistently sits at the lower limit — reduces the theoretical weight per meter, meaning the buyer pays for steel that is not there, while the structural capacity drops proportionally. Missing or incorrect CE documentation blocks EU import clearance, leaving containers stranded at port with demurrage charges accumulating daily. [NEED_CITE: consequences of negative tolerance abuse in structural steel hollow sections]
Why Procurement Teams Source Galvanized Square and Rectangular Steel Tube From SD XJY Pipe
Every galvanized tube leaving our Jinan mill passes through our in-house physical and chemical laboratory before release — zinc coating thickness, yield strength, and wall thickness get tested against the purchase order spec, not just stamped on a paper certificate. Our 2,800+ specification range covers side lengths from 20 mm to 500 mm and wall thickness up to 100 mm, meaning projects requiring mixed sizes for columns, beams, and bracing members source from a single production facility rather than splitting orders across multiple mills. The 41 invention patents include China’s original sharp-corner rectangular tube technology, giving facade contractors access to right-angle sections that standard mills cannot produce. Full international certification — ISO 9001:2015, Lloyd’s CE under EN 10219 and EN 10210, Singapore FPC — clears customs in regulated markets, while SGS and BV third-party inspections are arranged on request for projects requiring independent verification. Custom non-standard sizes and lengths are available with low minimum order quantities, and our export loading team uses dedicated anti-damage measures to prevent bending and zinc coating abrasion during container transit.
Documentation & Compliance
- Mill Test Certificate documenting Q235/Q345 chemical composition and mechanical properties per heat number, conforming to EN 10204 3.1 format
- Lloyd’s CE certificate referencing EN 10219 for cold-formed welded structural hollow sections and EN 10210 for hot-finished profiles
- ISO 9001:2015 quality management system certificate covering the full production and testing process
- SGS or BV third-party inspection report confirming zinc coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability sheet linking each bundle to its heat number, steel grade, and production date
- Export customs documentation including packing list, bill of lading, and certificate of origin for destination clearance
Packaging, Loading & Delivery
- Hot dip galvanized Q235 and Q345 tubes bundled with steel strips and edge protectors to preserve the zinc coating from abrasion during ocean transit
- Bundles sized to fit 20ft and 40ft containers based on tube outer diameter and wall thickness, maximizing payload while staying under port weight limits
- Lengths cut to 5.8 m, 6 m, or 12 m per order requirement, with custom lengths available for specific project dimensions
- Each bundle tagged with heat number, steel grade, size specification, and gross/net weight for site identification
- FOB, CIF, and DDP shipping terms available, with professional container loading using timber dunnage and steel wire lashing to prevent shifting
- End caps fitted on request to protect internal surfaces and prevent debris entry during transport and site storage
Getting Your Galvanized Tube Quote and Mill Test Certificate
Submit your specification sheet — including steel grade (Q235, Q345, S355JR, or ASTM equivalent), outer dimensions, wall thickness, length, surface treatment, and destination port — and receive a detailed quotation with unit pricing, production lead time, and available mill test certificate formats within 12 hours. For non-standard sizes or sharp-corner rectangular sections, our engineering team provides a custom feasibility assessment and tooling timeline.
Request Your Galvanized Square and Rectangular Steel Tube Quotation
Send your specifications and quantity to receive pricing, production schedule, and mill test certificate samples.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
