Description
Factory-Direct Mill Stock — Over 2,800 specifications of hot dip galvanized square and rectangular steel tubes held in our own yard, shipped without broker markups.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square and Rectangular Steel Tube |
| Product Type | Square / Rectangular / Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q195, Q235, Q345, SGCC, CGCC, TDC51DZM, TDC52D, TS350GD, TS550GD, DX51D+Z, A53 Grade B, A500 Grade A/B/C, STK400, SS400, ST42.2, S355JR |
| Standard | ASTM A53, ASTM A500, ASTM A36, ASTM A795, BS1387, EN10255, EN10219, EN10210, ISO65, ANSI C80, DIN2440, JIS G3444, JIS G3466, AS1163, GB/T3091, GB/T13793 |
| Section Shape | Square / Rectangular / Round |
| Size Range | Outer Diameter 21.3 mm – 660 mm (1/2″ – 26″) |
| Wall Thickness | 1.5 – 33 mm |
| Length | 5.8 m / 6 m / 11 m / 12 m (or as required) |
| Technique | Hot Rolled / Cold Rolled / ERW |
| Surface Treatment | Hot Dip Galvanized / Pre-Galvanized |
| Ends | Plain / Beveled / Threaded / Grooved |
| Tolerance | ±1% |
| Application | Steel structures, construction frames, fluid transport, hydraulic machinery, power and boiler, petrochemical, scaffolding |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial & Industrial Construction | Building frames, column grids, mezzanine supports, warehouse portal frames |
| Infrastructure & Civil Engineering | Bridge handrails, highway sign gantries, sound barrier posts, lighting mast bases |
| Power & Petrochemical | Pipe rack stanchions, boiler support frames, conveyor stringers, equipment skids |
| Scaffolding & Access | Cup-lock scaffolding uprights, shoring towers, temporary works platforms |
| Machinery & Hydraulic Systems | Cylinder barrels, telescopic boom sections, agricultural equipment frames |
What Wall-Thickness Tolerance Costs on a Hot Dip Galvanized Square and Rectangular Steel Tube Order
A ±1% tolerance on wall thickness is the difference between passing dimensional inspection on site and paying for air freight replacements.
When overseas buyers source galvanized steel tubes from China, the most frequent dispute is not about chemistry — it is about geometry. A 1.5 mm wall specified at minus tolerance arrives at 1.38 mm, the galvanizing layer adds another 45–85 microns unevenly, and the third-party inspector flags the lot before it ever reaches the erection crew. [NEED_CITE: EN 10219 cold-formed hollow section tolerance requirements for structural applications]. Fragmented procurement — buying black tube from one mill and sending it to a separate galvanizer — widens that tolerance gap further, because the hot dip cycle adds its own dimensional drift. XJY Structure controls the entire chain from raw coil to finished galvanized section, so the tolerance stated on the mill test certificate matches what arrives on the quayside.
Matching Hot Dip Galvanized Square and Rectangular Steel Tube to Structural Frame Requirements
Cold-formed SHS and RHS sections produced to EN10219 and ASTM A500 carry load through their closed geometry, which means corner integrity and wall uniformity matter more than on open profiles. Our Q345 and S355JR hot dip galvanized square and rectangular steel tubes are formed on dedicated roll lines that hold corner radius within structural code limits, then galvanized in our own bath so the zinc metallurgical bond covers every edge uniformly. For EPC contractors building portal frames in coastal or industrial atmospheres, that continuity of coating is what buys twenty-plus years without maintenance touch-up.
Engineering Compliance Across EN, ASTM, and JIS Jurisdictions
A single project specification may call for S355JR under EN10219, A500 Grade B under ASTM, or STK400 under JIS G3466 — and the mill test certificate must reference the exact standard the engineer signed off on. [NEED_CITE: steel grade equivalence between EN 10219 and ASTM A500 standards]. Our documentation package maps each heat number to the declared standard, includes CE marking for EN10210/EN10219 structural hollow sections, and is packaged for EU customs clearance without re-inspection delays. Wall thickness from 1.5 mm to 33 mm covers everything from light-gauge purlin bracing to heavy column stubs, and定尺 cutting to 5.8 m, 6 m, 11 m, or 12 m reduces on-site welding joints.
Steel Grade Selection and Galvanizing Process Fundamentals
The Q-series grades (Q195, Q235, Q345) dominate Asian and African infrastructure work because they balance weldability with moderate strength, while S355JR is the default for European structural frames under EN10219. Hot dip galvanizing deposits a zinc-iron alloy layer that is metallurgically bonded to the steel substrate — unlike electro-galvanized or pre-galvanized coatings, it survives the cutting, drilling, and welding that happen during fabrication without peeling at the edges. For sections thicker than 6 mm, the immersion time is extended to ensure full alloy diffusion, which is why our hot dip galvanized square and rectangular steel tube inventory separates heavy-wall RHS from light-gauge SHS in the galvanizing queue. ERW welding produces a longitudinal seam that is induction-heated and upset-forged, then cold-formed into square or rectangular profile — the weld zone is fully covered by the subsequent galvanizing bath, eliminating the corrosion weak point that concerns specifiers.
Hidden Costs of Procuring the Wrong Grade or Coating Thickness
Ordering pre-galvanized tube when the specification calls for hot dip is a mistake that only surfaces during salt-spray testing or on-site corrosion inspection — and by then the container has already cleared customs. [NEED_CITE: hot dip galvanizing coating thickness requirements per ISO 1461 for structural steel]. Material traceability gaps — where the fabricator cannot link the delivered tube back to the original heat number — trigger rejection under EN 10204 3.2 inspection regimes, forcing the buyer to either pay for destructive re-testing or scrap the lot. Negative tolerance abuse on wall thickness compounds the problem: the theoretical weight on the invoice no longer matches the structural capacity the engineer calculated, and the liability falls on the purchaser who accepted the delivery note.
Why Global Contractors Source Hot Dip Galvanized Square and Rectangular Steel Tube from XJY Structure
We operate our own steel mill with three production lines and a dedicated galvanizing facility, so the hot dip galvanized square and rectangular steel tube you order is produced, coated, inspected, and documented under one quality system. Our yard holds over 2,800 specifications in Q195 through S355JR, meaning standard sizes ship within typical production lead times without waiting for a rolling campaign. Every heat is tested in our in-house laboratory, and the mill test certificate records chemical composition, yield strength, tensile strength, and elongation against the declared standard — EN10219, ASTM A500, or JIS G3466. Third-party inspection by SGS, BV, or TÜV is welcomed before shipment, and our CE certification for EN10210/EN10219 structural hollow sections clears EU customs without re-inspection. For non-standard dimensions or project-specific lengths, our engineering team reviews shop drawings and confirms fabrication sequencing before the first cut.
Documentation & Compliance
- Mill test certificate documenting S355JR or Q345B chemical composition and mechanical properties per EN10219 or GB/T3091, with full heat number traceability
- CE certificate for EN10210 and EN10219 structural hollow sections, required for construction product regulation compliance in EU member states
- ISO 9001 quality management system certificate covering the entire production chain from raw material procurement to final galvanizing
- SGS or BV third-party inspection report verifying coating thickness, dimensional tolerance, and surface quality before container loading
- Material traceability report linking each bundle to its original heat number, rolling record, and galvanizing bath log
- Complete customs documentation package including packing list, bill of lading, certificate of origin, and commercial invoice formatted for destination port requirements
Packaging, Loading & Delivery
- Hot dip galvanized square and rectangular steel tubes bundled with high-tensile steel strips and edge protectors to preserve the zinc coating during ocean transit
- Seaworthy packaging with waterproof paper wrapping and steel frame palletization for RHS sections in 6 m and 12 m lengths, optimized for 20-foot and 40-foot container loading
- Custom cutting to 5.8 m, 6 m, 11 m, or 12 m lengths reduces on-site waste and maximizes container payload for S355JR structural frames
- Each bundle marked with heat number, steel grade, section dimensions, and wall thickness for on-site identification and traceability
- FOB, CIF, and DDP shipping terms available with professional oversized cargo loading plans for heavy-wall Q345B sections exceeding standard container dimensions
- Complete export documentation provided for smooth customs clearance at destination ports across the EU, Middle East, Southeast Asia, and Africa
Getting a Firm Quote for Your Hot Dip Galvanized Square and Rectangular Steel Tube Requirement
Submit your project drawings, section dimensions, steel grade, surface treatment preference, and destination port — we respond within 24 hours with a detailed quotation including material cost, galvanizing cost, packaging, and freight, plus the mill test certificate template and production schedule. For non-standard sizes or project-specific lengths outside our 2,800+ specification inventory, our engineering team confirms feasibility and lead time before you commit.
Request Your Quotation and Mill Test Certificate Today
Send your specification package to admin@xjystructure.com or contact us via WhatsApp at +86 188 5315 7756 to receive pricing, material certification, and delivery terms for your hot dip galvanized square and rectangular steel tube order.
Frequently Asked Questions
Q: What is the difference between hot dip galvanized and pre-galvanized square and rectangular steel tubes?
A: Hot dip galvanizing immerses the finished tube in molten zinc, creating a metallurgical zinc-iron alloy layer that covers all surfaces including weld seams and edges, providing superior corrosion resistance for structural and outdoor applications. Pre-galvanized tube is made from already-coated coil, so the cut edges and weld zones are exposed and require touch-up painting. For structural frames, scaffolding, and infrastructure projects, hot dip galvanized square and rectangular steel tube is the industry standard.
Q: Can you provide mill test certificates for EN10219 and ASTM A500 on the same order?
A: Yes. Our mill test certificates are issued per heat number and reference the specific standard declared on the purchase order — EN10219 for European projects, ASTM A500 for North American work, or JIS G3466 for Japanese-specification contracts. If your project requires dual certification or third-party re-inspection by SGS, BV, or TÜV, we coordinate the inspection before shipment.
Q: What is the minimum order quantity for custom dimensions outside your standard inventory?
A: Our standard inventory holds over 2,800 specifications in Q195 through S355JR, and the minimum order quantity is 1 ton. For non-standard dimensions or project-specific lengths, we review your shop drawings and confirm feasibility, tooling requirements, and production lead time before you commit.
Q: How do you ensure coating thickness meets ISO 1461 requirements for hot dip galvanized tubes?
A: Every batch of hot dip galvanized square and rectangular steel tube is tested for coating thickness using magnetic induction gauges per ISO 1461, and the results are recorded in the quality documentation package. For structural sections in aggressive environments, we can apply additional passivation or chromate treatment to extend service life.
Q: What shipping terms and logistics support do you provide for international orders?
A: We offer FOB, CIF, and DDP shipping terms with professional packing and loading plans optimized for container and breakbulk cargo. Our logistics team coordinates with freight forwarders to ensure smooth customs clearance, and we provide complete export documentation including packing list, bill of lading, certificate of origin, and mill test certificates.
