Description
Factory-direct pricing, no middlemen — Q195, Q235, and Q345 hot dipped galvanized square rectangular steel tube produced on our own ERW lines with zinc coating up to 275g/m², shipped with original mill test certificates from Jinan.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q195 Q235 Q345 Hot Dipped Galvanized Square Rectangular Steel Tube |
| Product Type | Square and Rectangular Galvanized Steel Tube |
| Steel Grade | Q195, Q235, Q345 |
| Standard | BS EN, GB, AISI, ASTM, DIN, JIS |
| Section Shape | Square / Rectangular |
| Size Range | 10mm – 1000mm side length |
| Wall Thickness | 0.6 – 28mm |
| Length | 1 – 12m (standard 6m / 10m / 12m) |
| Technique | ERW (Hot Rolled / Cold Rolled) |
| Surface Treatment | Hot Dipped Galvanized (Zinc Coating 30 – 275g/m²) |
| Ends | Plain / Beveled / Threaded with Couplings or Sockets |
| Application | Steel structures, construction frames, machinery, trailers, sign posts |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Architecture | Building frames, bridge railings, decorative structural elements |
| Industrial Fabrication | Machinery frames, trailer beds, equipment support bases |
| Infrastructure | Sign post columns, agricultural equipment structures, scaffolding systems |
| Manufacturing | Conveyor structures, storage rack uprights, machine guard frames |
What Zinc Coating Thickness Costs You on a Galvanized Frame Project
Coating consistency determines whether your galvanized tubes pass third-party inspection or get rejected at the port.
I started on the rolling floor in Foshan before moving into export sales. Years back, a batch of 100×100×4mm hot dipped galvanized square tubes shipped to a Lagos contractor — zinc coating tested at 45μm instead of the promised 80μm minimum. The third-party inspector rejected the entire 20ft container on the dock. That loss taught me something I never forgot: galvanized pipes live or die by coating consistency, not just the price on the invoice. When sourcing a Q235 Q345 hot dipped galvanized square rectangular steel tube supplier, buyers routinely face coating thickness variance between batches, missing mill test certificates, and specification gaps on non-standard dimensions — all of which translate into customs delays, on-site rework, and structural compliance failures. [NEED_CITE: hot dip galvanizing coating thickness standards per ASTM A123]
Matching Galvanized Square and Rectangular Tubes to Structural Load Requirements
The 10mm to 1000mm side length range and 0.6–28mm wall thickness coverage of this Q235 Q345 hot dipped galvanized square rectangular steel tube allow engineers to select sections that balance load-bearing capacity with weight constraints across construction frames, machinery bases, and infrastructure supports. Hot dipped galvanizing with zinc coating up to 275g/m² provides corrosion resistance suitable for outdoor exposure, industrial atmospheres, and coastal environments where painted or bare steel would deteriorate within months. Our ERW production lines hold 2,800+ specifications in ready stock, meaning a contractor ordering 150×150×6mm tubes for a warehouse frame does not wait for a custom rolling campaign — the material ships from Jinan within days, complete with heat-number traceability.
Engineering Compliance and Certification for Global Project Delivery
Structural galvanized hollow sections used in load-bearing frames must conform to recognized standards — EN 10210 for hot-finished or EN 10219 for cold-formed sections in European projects, ASTM A500 Grades B and C for North American specifications, and GB/T 6728 for domestic Chinese engineering. The Q195, Q235, and Q345 grades supplied here meet the chemical composition and dimensional tolerance requirements of these frameworks, with every batch accompanied by original mill test certificates documenting yield behavior and coating weight. For EU-bound shipments, CE certification under EN 10210/10219 with Factory Production Control is mandatory for customs clearance — a gap that frequently causes container hold-ups when buyers source from uncertified workshops. [NEED_CITE: CE marking requirements for structural steel hollow sections under EN 10219] Wall thickness tolerance directly affects theoretical weight calculations used in structural design; negative tolerance beyond standard limits reduces actual load capacity without changing the invoice weight, creating a hidden safety margin erosion that only third-party inspection can catch.
Steel Grade Selection and Hot Dipped Galvanizing Process
Q195, Q235, and Q345 represent a carbon steel strength progression widely used in structural and fabrication applications — Q195 suits light-duty frames and non-load-bearing structures, Q235 serves as the general-purpose structural grade for building frames and machinery supports, and Q345 provides higher yield strength for heavier load conditions in bridges and industrial equipment. The ERW welding process used to form these square and rectangular tubes offers cost efficiency and dimensional consistency for sizes up to 1000mm, with the weld seam fully covered by the hot dipped galvanizing layer to prevent corrosion initiation at the joint. Hot dipped galvanizing immerses the formed tube in molten zinc, creating a metallurgical bond that produces coating weights from 30g/m² for indoor or temporary applications up to 275g/m² for long-term outdoor and industrial exposure — significantly exceeding the protection offered by electro-galvanized or pre-galvanized strip alternatives. Wall thickness options from 0.6mm to 28mm allow the same Q235 Q345 hot dipped galvanized square rectangular steel tube supplier to serve both light gauge framing and heavy structural column applications from a single production source.
Hidden Costs of Sourcing the Wrong Galvanized Tube Specification
Ordering galvanized square and rectangular tubes without verified coating weight, confirmed steel grade, and certified dimensional tolerance creates costs that surface only after the container arrives at site. Material that fails to meet the specified zinc coating thickness will corrode prematurely, requiring replacement that exceeds the original purchase price many times over. Steel grade substitution — receiving Q195 when Q345 was specified — reduces structural load capacity and can trigger engineering safety review failures during project inspection. Missing or incomplete mill test certificates cause customs holds in markets requiring CE or ASTM documentation, generating demurrage charges and delivery delays that cascade through the project schedule. [NEED_CITE: consequences of non-conforming steel materials in structural engineering projects]
Procurement Confidence from Direct Factory Supply
Our three ERW production lines in Jinan run simultaneously, producing over 20,000 tons monthly across square, rectangular, and round tube categories — eliminating the markup and communication delays introduced by trading intermediaries. Every Q195 Q235 Q345 hot dipped galvanized square rectangular steel tube leaving our facility carries an original mill test certificate tied to its heat number, with in-house laboratory conducting three-stage inspection covering dimensional tolerance, coating weight measurement, and weld seam integrity. Buyers ordering for EU or North American projects receive CE certification under EN 10210/10219 with active Factory Production Control, while SGS or BV third-party inspection is arranged on request for additional verification. Our inventory covers 2,800+ standard specifications, supporting urgent orders and split shipments without requiring minimum production runs, and our export team handles container loading optimization to maximize payload while protecting the galvanized surface during ocean transit.
Documentation & Compliance
- Mill test certificate documenting Q195, Q235, or Q345 chemical composition and mechanical properties per GB/T 6728 or EN 10219, linked to heat number for full traceability
- CE certificate under EN 10210/EN 10219 with Factory Production Control for structural hollow sections destined for European Union markets
- ISO 9001:2015 quality management certificate covering the complete production process from raw material receiving through hot dipped galvanizing
- SGS or BV third-party inspection report verifying zinc coating thickness, dimensional tolerance, and surface quality before container sealing
- Material traceability documentation linking each bundle to its production heat number and galvanizing batch for project audit compliance
- Complete customs document package including packing list, bill of lading, and certificate of origin formatted for destination port requirements
Packaging, Loading & Delivery
- Q195 Q235 Q345 hot dipped galvanized square rectangular steel tube bundled with steel strips and edge protectors to preserve the zinc coating from abrasion during ocean transit
- Galvanized surface protected by waterproof wrapping on outer layers to prevent white rust formation during container shipping in humid conditions
- Container loading optimized by our export team based on tube side length and wall thickness, maximizing payload for 20ft and 40ft shipments while maintaining weight distribution
- Cut-to-length service available for orders requiring specific lengths within the 1–12m range, reducing on-site cutting waste for construction frame applications
- Heat number and steel grade stenciled on each bundle for immediate identification at project site, supporting material traceability during engineering inspection
- FOB, CIF, and DDP shipping terms available with professional documentation handling for customs clearance at destination ports across 50+ countries
Starting Your Galvanized Tube Procurement
Submit your required specifications — side length, wall thickness, steel grade, quantity, and destination port — and receive a competitive bulk quotation within 12 hours, including volume pricing, mill test certificate confirmation, and production lead time. For non-standard dimensions or custom zinc coating requirements, our technical team provides feasibility assessment and pricing for tailored production runs.
Request Your Quotation and Mill Test Certificate
Send your specification list to admin@sdxinjiyuan.com or contact us via WhatsApp at +86 188 5315 7756 to receive pricing, coating weight confirmation, and certification documentation for your Q195 Q235 Q345 hot dipped galvanized square rectangular steel tube order.
Frequently Asked Questions
Q: What is the difference between Q195, Q235, and Q345 steel grades for galvanized square and rectangular tubes?
A: These grades represent increasing yield strength levels in the Chinese standard system — Q195 suits light structural and non-load-bearing applications, Q235 serves as the standard structural grade for building frames and general fabrication, and Q345 provides higher strength for heavy-load conditions in bridges and industrial equipment. All three grades are compatible with hot dipped galvanizing and can be welded using standard procedures.
Q: Can you provide mill test certificates and third-party inspection for customs clearance?
A: Every batch of Q195 Q235 Q345 hot dipped galvanized square rectangular steel tube ships with original mill test certificates documenting chemical composition and mechanical properties. For markets requiring additional verification, we arrange SGS or BV third-party inspection before shipment, and our CE certification under EN 10210/10219 supports EU customs clearance for structural applications.
Q: What is the minimum order quantity for custom sizes and non-standard dimensions?
A: Our flexible MOQ starts from 1 ton, supporting both trial orders and full-container bulk shipments. For non-standard side lengths or wall thicknesses outside our 2,800+ ready-stock specifications, custom production runs are available with typical lead times of 15–25 days depending on order volume.
Q: How does hot dipped galvanizing compare to other surface treatments for corrosion resistance?
A: Hot dipped galvanizing creates a metallurgical zinc-iron bond with coating weights from 30g/m² to 275g/m², providing significantly longer corrosion protection than electro-galvanized or painted alternatives. For outdoor construction frames, infrastructure supports, and industrial environments, hot dipped galvanizing delivers decades of maintenance-free service life.
Q: What standard lengths are available and can you provide cut-to-size delivery?
A: Standard lengths range from 1m to 12m, with 6m, 10m, and 12m most commonly stocked. Cut-to-length service is available for orders requiring specific dimensions within this range, reducing on-site cutting waste and accelerating construction frame assembly at your project location.
