Description
Factory-Direct Galvanized Tubes — Every Q195 Q235 Q345 Galvanized Square Rectangular Steel Tube ships from our Jinan mill with in-house lab verification, cutting broker markups entirely.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q195/Q235/Q345 Galvanized Square and Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube |
| Steel Grade | Q195, Q235, Q345, STK400, STK500, S235, S355 |
| Standard | ASTM, EN10219, EN10210, JIS G3466, ISO9001 |
| Section Shape | Square / Rectangular |
| Size Range | 15×15mm – 1000×1000mm |
| Wall Thickness | 1.2 – 15.7 mm |
| Length | 6m / 6.4m / 12m (customizable) |
| Technique | Hot Rolled Based / ERW |
| Surface Treatment | Galvanized (Z41–Z120 coating) |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures, Construction frames, Machinery, Fencing, Greenhouse, Fluid transport, Scaffolding |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Building frames, industrial shed structures, pipe rack supports |
| Construction Companies | Scaffolding systems, curtain wall frames, foundation piles |
| Machinery Manufacturers | Conveyor frames, equipment bases, hydraulic support columns |
| Agricultural Infrastructure | Greenhouse skeletons, irrigation pipe supports, livestock fencing |
| System Integrators | Automation line frames, sorting system structures, cable tray supports |
What Zinc Coating Thickness Costs You on a Greenhouse Project
A 40-micron coating instead of 60 means half your batch fails third-party inspection on arrival.
I once loaded a container of 3-inch galvanized pipes for a Nigerian greenhouse project. The zinc coating measured only 40 microns against the specified 60. The client’s inspector caught it at the port. Half the shipment was rejected, and we air-frept replacements at our own expense. Since then, every Q195 Q235 Q345 Galvanized Square Rectangular Steel Tube leaving our facility goes through real-time coating thickness verification in our physical and chemical laboratories. [NEED_CITE: hot-dip galvanized coating thickness standards for structural steel]
Specification gaps create another hidden trap. Standard catalogs rarely cover non-standard sizes, and custom orders often face extended lead times with high minimum quantities. When your structural frame design calls for a 200×100mm rectangular tube at 8mm wall thickness, you need a supplier who can deliver exactly that — not a substitute grade or a near-size compromise.
Matching Structural Frames to Corrosive Environments
Galvanized square and rectangular tubes serve as the backbone for greenhouse structures, industrial sheds, and scaffolding systems where corrosion resistance directly determines service life. The Z41–Z120 coating range allows project engineers to select protection levels matching environmental exposure — lighter coatings for indoor machinery frames, heavier coatings for coastal construction or agricultural humidity. Our ERW and hot-rolled based production processes maintain ±1% dimensional tolerance across the full 15×15mm to 1000×1000mm size range, ensuring precise fit-up during on-site assembly.
Engineering Compliance and Certification Requirements
Structural applications demand strict adherence to load-bearing standards and material traceability. Q235 and Q345 grades meet Chinese GB/T standards, while S235 and S355 conform to European EN10219 cold-formed hollow section requirements [NEED_CITE: EN 10219 cold-formed structural hollow sections]. For EU market entry, CE certification under EN10210 (hot-finished) or EN10219 (cold-formed) is mandatory for customs clearance. Our mill test certificates document chemical composition and mechanical properties per heat number, satisfying third-party inspection requirements from SGS or BV. Custom cut-to-length services at 6m, 6.4m, or 12m reduce on-site waste and welding joints.
Steel Grade Selection and Manufacturing Process
The Q-series (Q195, Q235, Q345) represents Chinese standard grades where the number indicates minimum yield strength in MPa. Q235 serves general structural applications, while Q345 provides higher strength for load-bearing frames. The S-series (S235, S355) follows European EN standards with equivalent yield strength classifications. STK400 and STK500 are Japanese JIS G3466 structural carbon steel grades for architectural applications.
ERW (Electric Resistance Welded) production offers cost efficiency for standard sizes with consistent weld seam quality, while hot-rolled based processes suit heavier wall thicknesses up to 15.7mm. The galvanized coating process applies zinc at Z41–Z120 thickness (measured in microns), providing sacrificial corrosion protection. Our proprietary sharp-corner rectangular tube technology — one of 41 patented innovations — achieves tight radius corners that improve connection fit-up and structural aesthetics compared to standard rounded-corner profiles.
Hidden Costs of Incorrect Material Procurement
Selecting the wrong steel grade or accepting out-of-tolerance dimensions creates cascading project failures. Undersized wall thickness reduces load capacity, triggering structural safety concerns during engineering inspections. Missing or incomplete mill test certificates cause customs delays at destination ports, particularly for EU markets requiring CE documentation. Coating thickness below specification accelerates corrosion in humid environments, leading to premature replacement costs that far exceed initial material savings. [NEED_CITE: steel grade equivalence between EN ASTM and GB standards]
Why Source Your Galvanized Tubes From Our Jinan Mill
Our facility operates three dedicated production lines covering 2,800+ specifications with wall thicknesses reaching 40mm, eliminating the need to source from multiple suppliers. The in-house physical and chemical laboratories verify every batch before shipment — no reliance on external testing delays. Factory-direct pricing removes broker markups, while our professional export team handles documentation for 50+ countries including EU, North America, and Southeast Asia. Custom non-standard sizes and proprietary sharp-corner technology fill specification gaps that standard catalogs cannot cover. Complete certification packages (CE EN10210/10219, ISO 9001:2015, SGS/BV verification) ensure smooth customs clearance. Professional loading plans optimize container space for 6m/12m lengths, reducing freight costs per ton.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition and yield strength per EN10219 or ASTM A500 standards
- CE certificate confirming compliance with EN10210 (hot-finished) or EN10219 (cold-formed) for EU market access
- ISO 9001:2015 quality management system certification covering production and inspection processes
- SGS or BV third-party inspection report verifying dimensional tolerance and galvanized coating thickness
- Material traceability documentation linking each bundle to heat number and production batch
- Complete customs package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized tubes bundled with steel strips and edge protectors to preserve zinc coating during ocean transit
- Seaworthy packaging with waterproof wrapping for Q195/Q235 grades destined for humid tropical climates
- Container loading optimization for 6m and 12m lengths, maximizing payload per 20ft or 40ft container
- Custom cut-to-length services at 6m, 6.4m, or 12m to match project specifications and reduce on-site waste
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability
- Flexible shipping terms (FOB/CIF/DDP) with door-to-door logistics to 50+ countries
Initiating Your Procurement Inquiry
Submit your specifications including dimensions, wall thickness, steel grade, quantity, and destination port to receive a detailed quotation within 12 hours. Our engineering team will confirm material availability, provide mill test certificate samples, and advise on optimal container loading for your Q195 Q235 Q345 Galvanized Square Rectangular Steel Tube order.
Request Your Galvanized Tube Quotation Today
Send your specifications via email or WhatsApp to receive pricing, mill test certificates, and delivery schedules within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjysteel.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjysteel.com
Frequently Asked Questions
Q: What is the difference between Q235 and S235 steel grades for galvanized tubes?
A: Q235 follows Chinese GB/T standards while S235 conforms to European EN standards. Both offer similar yield strength levels for general structural applications. We supply both grades with equivalent mill test certificates and can provide grade equivalency documentation for international projects.
Q: Can you provide third-party inspection for galvanized coating thickness?
A: Yes. Our in-house laboratory verifies zinc coating thickness (Z41–Z120) before shipment. We also accommodate SGS or BV third-party inspections upon request, with inspection reports included in the documentation package.
Q: What is the minimum order quantity for custom non-standard sizes?
A: We cover 2,800+ standard specifications from 15×15mm to 1000×1000mm. For non-standard sizes outside our regular range, MOQ depends on dimensions and quantity. Contact us with your specifications for a tailored production quote.
Q: Do you provide CE certification for EU market customs clearance?
A: Yes. Our galvanized square and rectangular tubes carry CE certification under EN10210 (hot-finished) or EN10219 (cold-formed) standards. The CE certificate, along with mill test certificates and declaration of performance, is included in the customs documentation package.
Q: How do you ensure galvanized coating quality during shipping?
A: Galvanized tubes are bundled with steel strips and edge protectors to prevent coating damage. We use seaworthy packaging with waterproof wrapping for ocean transit. Professional loading plans optimize container space while protecting the zinc coating from abrasion.
