Description
Factory-Direct Galvanized Tubes — Every batch ships with in-house lab MTC and third-party SGS/BV zinc coating verification before container sealing.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Galvanized Square and Rectangular Steel Tube |
| Product Type | Square / Rectangular / Round Hollow Sections |
| Steel Grade | Q195, Q235, Q345, SGCC, CGCC, TDC51D+ZM, 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, ASTM A106, BS1387, EN10255, EN10219, EN10210, ISO 65, ANSI C80, DIN 2440, JIS G3444, JIS G3466, GB/T 3091, GB/T 13793, AS1163, API 5L, API 5CT |
| Section Shape | Square / Rectangular / Round |
| Size Range | 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 customer needs) |
| Technique | Hot Rolled / Cold Rolled / ERW |
| Surface Treatment | Hot Dip Galvanized / Pre-Galvanized |
| Tolerance | ±1% |
| Pipe Ends | Plain ends / Beveled ends / Threaded ends / Grooved ends |
| Application | Construction structures, steel structure frames, scaffolding, fluid transportation, hydraulic and precision machinery parts, power and boiler systems, petrochemical industry |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors & Construction | Structural frames for industrial buildings, scaffolding systems, curtain wall supports |
| Machinery Manufacturers | Hydraulic cylinder housings, precision equipment frames, conveyor support structures |
| Industrial Distributors | Oil, gas, and water fluid transmission lines, petrochemical piping networks |
| Infrastructure & Power | Power tower bracing, boiler support structures, solar farm mounting systems |
Where Zinc Coating Thickness Decides Whether Your Shipment Clears Site Inspection
A galvanized tube that fails third-party zinc thickness testing on arrival costs more than the tube itself — it costs the project schedule.
I watched an entire container of hot dip galvanized tubes get rejected at a Riyadh construction site because the zinc coating measured 35μm against a contractual 60μm minimum. The re-inspection, renegotiation, and replacement shipment delayed the structural frame erection by nearly three weeks. That kind of failure does not show up in a visual check — it requires an MTC with coating weight data and, ideally, a pre-shipment SGS or BV test report. When sourcing a Hot Dip Galvanized Square and Rectangular Steel Tube, the zinc layer is not a marketing point; it is the baseline acceptance criterion. [NEED_CITE: hot dip galvanized coating thickness requirements per ASTM A123 and EN ISO 1461]
Matching Structural Load Paths and Corrosion Environments
A Hot Dip Galvanized Square and Rectangular Steel Tube produced to ASTM A500 Grade B or EN 10219 S355JR carries the yield strength needed for primary structural frames while the galvanized zinc layer provides corrosion protection rated for outdoor and industrial atmospheres. Our sharp-corner rectangular tube technology — covered under patented processes — delivers tighter corner radii that improve welding fit-up and load transfer at moment connections, which standard ERW tubes cannot achieve without secondary machining. For EPC contractors building in coastal or petrochemical environments, specifying hot dip galvanized over pre-galvanized shifts the corrosion protection from a surface coating to a metallurgical bond that resists mechanical damage during transport and installation.
Engineering Compliance Across ASTM, EN, and JIS Frameworks
Structural hollow sections used in load-bearing frames must conform to the design code governing the project — EN 1993-1-1 for European spec, AISC 360 for North American, or JIS for Japanese-engineered infrastructure. The Hot Dip Galvanized Square and Rectangular Steel Tube we supply meets EN 10210 for hot-finished and EN 10219 for cold-formed hollow sections, carrying CE marking required for EU customs and project handover documentation. For Southeast Asian projects, Singapore FPC certification ensures the product passes BCA regulatory inspection. Steel grade equivalence between Q345, S355JR, and ASTM A500 Grade C must be confirmed per the project engineer’s approval before ordering, as chemistry and elongation limits differ across standards. [NEED_CITE: steel grade equivalence mapping between EN 10219 and ASTM A500]
Steel Grade Selection and Galvanizing Process Fundamentals
The steel grades we offer span three major classification systems: Chinese Q-series (Q195, Q235, Q345), European S-series (S355JR), and American ASTM (A53 Grade B, A500 Grade A/B/C). Q235 and S355JR are not interchangeable — S355JR delivers higher minimum yield strength and tighter Charpy impact requirements at sub-zero temperatures, making it the specified grade for structural frames in cold-climate projects. For the galvanizing process, hot dip galvanizing immerses the formed tube in molten zinc at approximately 450°C, creating a zinc-iron alloy layer bonded to the steel substrate; this differs fundamentally from pre-galvanized (electro-galvanized) coating, which is thinner and suited only for indoor or low-corrosion applications. Wall thickness tolerance of ±1% ensures that the theoretical weight calculation matches actual delivered weight, preventing disputes over invoicing by actual weight. Our proprietary sharp-corner rectangular tube process produces corner radii as small as 1.0× wall thickness, compared to the industry-standard 2.0×–2.5×, enabling flush connections in architectural exposed structures. [NEED_CITE: hot dip galvanizing metallurgical bond formation per ASTM A123]
Hidden Costs of Procuring Without Verified Coating and Grade Documentation
Ordering a Hot Dip Galvanized Square and Rectangular Steel Tube without requiring an original MTC per heat number exposes the buyer to three failure modes: zinc coating below contractual minimum triggering site rejection, steel grade substitution passing visual inspection but failing structural load testing, and missing CE or SGS documentation causing customs holds at the destination port. Each failure mode carries a cost that exceeds the unit price difference between a verified factory-direct source and an unverified trader. Engineering codes such as EN 10219 and ASTM A500 require traceable mill test certificates for structural acceptance — without them, the project inspector has grounds to reject the entire batch regardless of physical quality. [NEED_CITE: structural hollow section acceptance criteria per EN 10219]
Procurement Confidence Built on Factory Controls
Every Hot Dip Galvanized Square and Rectangular Steel Tube we ship is produced on three dedicated lines covering 2,800+ specifications, with wall thickness up to 33 mm and outer dimensions up to 660 mm. Our in-house physical and chemical laboratory tests every heat for composition and mechanical properties before the tube enters the galvanizing bath — the MTC you receive is generated from actual test data, not a template. We hold 41 invention patents including the sharp-corner rectangular tube process that fills specification gaps unavailable from standard catalog suppliers. All products carry ISO 9001:2015 certification, CE marking under EN 10210/EN 10219 for EU markets, and Singapore FPC for Southeast Asian projects, with SGS and BV third-party inspection available before shipment. Custom non-standard dimensions and special steel grades are produced with a 1 Ton MOQ, and our logistics team prepares container loading plans optimized for square and rectangular profiles to maximize payload per 20ft and 40ft units.
Documentation & Compliance
- Mill Test Certificate documenting Q235B or S355JR chemical composition and mechanical properties per EN 10219 or ASTM A500, traceable to heat number
- CE Certificate of Conformity under EN 10210 (hot-finished) or EN 10219 (cold-formed) for EU customs clearance and structural project handover
- ISO 9001:2015 quality management system certificate covering the full production and galvanizing process
- SGS or BV third-party inspection report verifying zinc coating thickness, adhesion, and dimensional tolerance before container loading
- Material traceability sheet linking each bundle to its heat number, steel grade, and galvanizing batch record
- Full customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Hot dip galvanized tubes bundled with steel straps and edge protectors to prevent zinc coating abrasion during ocean freight
- Pre-galvanized and hot dip galvanized surfaces coated with anti-fingerprint passivation to resist white rust formation during humid transit conditions
- Container loading plans optimized for 6 m and 12 m square and rectangular tubes, maximizing payload within 20ft GP and 40ft HC units
- Custom cut-to-length service available for 5.8 m, 6 m, 11 m, and 12 m requirements, with saw-cut ends deburred and protected
- Each bundle tagged with heat number, steel grade (e.g., Q345, S355JR), outer dimensions, wall thickness, and gross/net weight
- Shipment terms supported include FOB, CIF, and DDP with door-to-door logistics coordination to 50+ countries
Securing Your Quote with Complete Technical Requirements
To receive an accurate quotation and Mill Test Certificate for your Hot Dip Galvanized Square and Rectangular Steel Tube requirement, submit your specification sheet including outer dimensions, wall thickness, steel grade, total tonnage, surface treatment preference (hot dip or pre-galvanized), and destination port. Our team responds within 12 hours with unit pricing, production lead time, applicable certification scope, and container loading recommendations. For non-standard dimensions or sharp-corner rectangular tubes, we provide a custom feasibility assessment and sample arrangement before contract commitment.
Frequently Asked Questions
Q: How do Q235 and Q345 map to ASTM A500 and EN 10219 steel grades?
A: Q235 corresponds roughly to ASTM A500 Grade A and EN 10219 S235JR in yield strength range, while Q345 aligns with ASTM A500 Grade B and EN 10219 S355JR. Exact equivalence depends on chemistry and elongation requirements specified by the project engineer, and we provide a grade cross-reference sheet with every inquiry.
Q: How can I verify the galvanized zinc coating thickness before shipment?
A: We provide the Mill Test Certificate with coating weight data for each batch, and third-party inspection through SGS or BV is available to measure zinc layer thickness using magnetic gauge testing per ASTM A123 or EN ISO 1461 before container sealing.
Q: Can you produce sharp-corner rectangular tubes in non-standard dimensions?
A: Yes. Our patented sharp-corner rectangular tube technology produces corner radii down to 1.0× wall thickness, and we manufacture custom non-standard sizes across 2,800+ specifications with a minimum order quantity of 1 Ton.
Q: Do your CE certificates ensure smooth EU customs clearance?
A: Our CE marking under EN 10210 and EN 10219 is issued by Lloyd’s Register and covers the full scope of hot-finished and cold-formed structural hollow sections, meeting EU Construction Products Regulation requirements for customs and site acceptance.
Q: How do you optimize container loading for square and rectangular tubes?
A: Our logistics team prepares a loading plan based on your specific dimensions and lengths, nesting rectangular profiles to maximize container payload and securing bundles with timber cradles and steel straps to prevent transit damage to the galvanized coating.
Request Your Hot Dip Galvanized Square and Rectangular Steel Tube Quotation
Submit your dimensions, steel grade, quantity, and destination port to receive a factory-direct price with Mill Test Certificate and certification scope within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd | Mobile/WhatsApp/WeChat: +86 188 5315 7756 | Email: admin@sdxjysteel.com | Website: www.sdxjysteel.com
