Description
Factory-Direct Galvanized Tubes — Q195–Q345 grades produced on our own lines, shipped without trading markups.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q195-Q345 Galvanized Square Steel Tube |
| Product Type | Galvanized Square Steel Tube |
| Steel Grade | Q195, Q235, Q345, SGCC, CGCC, TDC51DZM, TDC52DTS350GD, TS550GD, DX51D+Z, SS400, STK400, A53 Grade B, A500 Grade A/B/C, S355JR |
| Standard | ASTM A500, ASTM A53, ASTM A36, EN10219, EN10210, JIS G3444, JIS G3466, AS1163, GB/T3091, GB/T13793, BS1387, ISO65 |
| Section Shape | Square |
| Size Range | 21.3 mm – 660 mm |
| Wall Thickness | 1.5 – 33 mm |
| Length | 5.8 m / 6 m / 11 m / 12 m (or as required) |
| Technique | Hot Rolled / Cold Rolled |
| Surface Treatment | Galvanized (Hot Dipped / Pre-Galvanized) |
| Tolerance | ±1% |
| Ends | Plain ends / Beveled ends / Threaded ends / Grooved ends |
| Application | Steel structures / Construction frames / Fluid transport / Machinery / Scaffolding / Power and boiler / Petrochemical / Building industry |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Structural frames for industrial plants, pipeline support racks, equipment platforms |
| Construction Companies | Scaffolding uprights, building column frames, high-rise structural bracing |
| Machinery Manufacturers | Conveyor system bases, automation equipment frames, machine guarding structures |
| Infrastructure Developers | Bridge handrail posts, sound barrier supports, solar mounting structures |
What Zinc Coating Thickness Decides on a Tropical Job Site
A galvanized square steel tube that passes visual inspection can still fail third-party coating-weight tests — and that failure shows up months after installation.
On a warehouse project in West Africa, 1.5-inch galvanized tubes arrived with a uniform bright finish. Three months into the rainy season, blistering appeared along weld seams and cut edges. Independent testing revealed zinc coating at 35μm against a 65μm minimum specification. The entire batch was rejected. Claims exceeded the original order value. [NEED_CITE: hot-dip galvanized coating thickness requirements for corrosive environments] This is not an isolated case — coating inconsistency remains one of the most expensive hidden variables in galvanized steel procurement for tropical and coastal projects.
How Q195–Q345 Grades Match Structural Load Requirements
Every Galvanized Square Steel Tube in this range carries grade designation traceable to mill test certificates. Q195 and Q235 serve light structural applications — fencing, handrails, non-load-bearing frames — where formability matters more than yield strength. Q345 and S355JR step into primary structural roles: column members, beam connections, and load-bearing scaffolding uprights. The Galvanized Square Steel Tube selection between hot-dipped and pre-galvanized finish depends on the corrosion exposure: hot-dipped coating suits outdoor and marine environments, while pre-galvanized suffices for indoor machinery frames and dry storage structures.
Engineering Compliance Across ASTM, EN, and JIS Frameworks
Structural engineers specifying Galvanized Square Steel Tube to EN10219 or EN10210 require CE-marked documentation for EU-bound shipments. ASTM A500 Grade B and C govern North American structural hollow sections, while JIS G3466 applies to general-purpose square tubes in Southeast Asian and Japanese-spec projects. The ±1% dimensional tolerance ensures fit-up accuracy for welded connections and bolted splice plates. [NEED_CITE: EN 10219 cold-formed structural hollow sections dimensional tolerances] Pre-beveled, threaded, or grooved ends reduce on-site cutting and welding time — critical for EPC schedules where labor costs dominate field expenses.
Understanding Steel Grade Systems and Galvanizing Processes
The Q-series (Q195, Q235, Q345) follows Chinese GB standards where the number indicates minimum yield strength in MPa. ASTM A500 Grade A/B/C and S355JR represent equivalent strength tiers in Western specification systems. [NEED_CITE: steel grade equivalence between Chinese GB, ASTM, and EN standards] Hot-dipped galvanizing immerses formed tubes in molten zinc, producing a metallurgically bonded coating of 65–100μm — the standard for structural and outdoor applications. Pre-galvanized tubes receive coating on the strip before forming, resulting in thinner zinc layers suited for indoor use. Cold-rolled Galvanized Square Steel Tube offers tighter dimensional control for precision machinery applications, while hot-rolled variants serve heavier structural sections up to 33 mm wall thickness.
The Hidden Cost of Unverified Coating and Missing Certificates
Ordering Galvanized Square Steel Tube without requiring mill test certificates or third-party inspection creates downstream risk. Coating below specification triggers project rejection at handover — re-procurement, demurrage, and schedule delays compound the original savings. Missing CE documentation holds containers at EU ports. [NEED_CITE: customs clearance requirements for CE-marked structural steel in European Union] Negative tolerance stacking on wall thickness reduces actual load capacity below design calculations, creating structural safety exposure that only surfaces during loading tests or, worse, under service conditions.
Procurement Confidence from Mill to Port
Every Galvanized Square Steel Tube leaves our facility with chemistry and mechanical test results from our in-house laboratory — not broker-supplied paperwork. Our three dedicated production lines cover over 2,800 specifications in square and rectangular profiles, meaning mixed-grade project orders ship in consolidated containers rather than fragmented LCL shipments. We hold CE EN10210/EN10219 certification for European compliance, ISO 9001:2015 for process control, and arrange SGS or BV third-party inspection before loading. Custom non-standard dimensions and cut-to-length processing eliminate on-site waste. Professional container loading plans maximize payload per shipment, and our logistics team coordinates FOB, CIF, or DDP delivery to ports across 50+ countries.
Documentation & Compliance
- Mill Test Certificate documenting Q195–Q345 chemical composition and mechanical properties per ASTM A500 or EN10219
- CE Certificate confirming EN10210/EN10219 compliance for EU customs clearance
- ISO 9001:2015 Quality Management System certificate covering production and inspection processes
- SGS or BV Third-Party Inspection Report verifying coating thickness, dimensions, and surface quality before loading
- Heat Number Traceability linking each Galvanized Square Steel Tube bundle to raw material test records
- Customs Documentation including packing list, Bill of Lading, and Certificate of Origin for destination clearance
Packaging, Loading & Delivery
- Galvanized Square Steel Tube bundles secured with steel strips and edge protectors to preserve zinc coating during ocean transit
- Hot-dipped galvanized surfaces wrapped with waterproof paper and plastic film to prevent white rust formation in humid conditions
- 6-meter and 12-meter lengths container-optimized with nested loading plans maximizing payload for 21.3–200 mm size ranges
- Cut-to-length processing available per project drawing, with bundled labeling showing heat number, steel grade, and piece count
- FOB Qingdao/Tianjin ports with CIF and DDP options to major destinations across Southeast Asia, Middle East, Africa, and Europe
Start Your Procurement With Verified Specifications
Submit your Galvanized Square Steel Tube requirements — size range, wall thickness, steel grade, quantity, and destination port — to receive a detailed quotation including unit pricing, production timeline, and applicable certification documentation. Our team responds within 12 hours with mill test certificate samples and loading plans tailored to your project schedule.
Request Factory-Direct Pricing and Mill Test Certificates
Send your specifications via email or WhatsApp to receive a complete quotation with material documentation within one business day.
Email: admin@sdxjysteel.com
Mobile/WhatsApp: +86 188 5315 7756
Frequently Asked Questions
Q: What is the difference between hot-dipped and pre-galvanized square steel tubes?
A: Hot-dipped galvanizing immerses finished tubes in molten zinc, producing a thicker metallurgically bonded coating of 65–100μm suitable for outdoor and corrosive environments. Pre-galvanized tubes receive zinc coating on the steel strip before forming, resulting in a thinner coating layer appropriate for indoor applications and dry conditions.
Q: Can you provide Galvanized Square Steel Tube in custom non-standard dimensions?
A: Yes. Our production lines cover over 2,800 specifications including custom non-standard sizes beyond standard catalogs. Minimum order quantity is 1 Ton, and we provide cut-to-length processing per your project drawings.
Q: What documentation accompanies each shipment?
A: Every shipment includes original Mill Test Certificates traceable to heat numbers, packing lists, and Bills of Lading. CE certificates (EN10210/EN10219) are provided for EU-bound orders. SGS or BV third-party inspection reports are available upon request before container loading.
Q: Which steel grades are available for structural applications?
A: We supply Q195, Q235, Q345 for Chinese GB standard projects, S355JR for EN10219/EN10210 European specifications, and ASTM A500 Grade A/B/C for North American structural requirements. All grades are produced on our dedicated lines with in-house laboratory testing.
Q: How do you ensure coating thickness meets project specifications?
A: Our in-house physical and chemical laboratory conducts incoming, in-process, and final inspections including coating thickness measurement. Full inspection reports are provided before shipment, and third-party verification by SGS or BV is available for critical projects.
