Description
Factory-Direct Bulk Supply — Shandong Xin Jiyuan Special Steel Tube Co., Ltd operates 3 production lines with 2,800+ specifications in ready stock, delivering ASTM A36 Q235 S355 galvanized square rectangular steel tube directly from our Jinan facility to ports worldwide.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A36 Q235 S355 Galvanized Square and Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q195, Q235, Q345, S235, S355, ASTM A36, A53 Grade A/B, 10#, 20#, 45#, 16Mn, St37, St42, St52 |
| Standard | BS EN 10219, BS EN 10210, ASTM A500, ASTM A53, GB/T 6728, JIS G3466, DIN EN 10219 |
| Section Shape | Square / Rectangular / Round |
| Size Range | 10 mm – 1000 mm |
| Wall Thickness | 0.6 – 28 mm |
| Length | 1 – 12 m |
| Technique | ERW (Hot Rolled / Cold Rolled) |
| Surface Treatment | Galvanized (Zinc Coating 30–275 g/m²), Black, Oiled, Color Painted, 3PE, PVC |
| Ends | Plain / Beveled / Threaded with Couplings or Sockets; Plastic Caps and Steel Rings available |
| Application | Steel structures / Construction frames / Fencing / Machinery / Warehouse / General engineering structure / Cars / Bridges / Ships / Boilers / Pressure vessels |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, warehouse structures, scaffolding systems, fencing panels, bridge support members |
| Industrial & Machinery | Machinery frames, conveyor structures, pressure vessel supports, boiler frameworks |
| Energy & Utilities | Solar panel mounting structures, wind farm access platforms, utility pole bases |
| Transportation | Truck chassis frames, ship bulkhead stiffeners, railway station canopy structures |
Where Zinc Coating Weight Decides Project Acceptance on a Galvanized Square Rectangular Steel Tube Order
A 35μm zinc reading against a 60μm contract specification means the entire container gets rejected at the project gate.
I watched this happen on a Middle East infrastructure job — 50×100 galvanized square tubes arrived at the site, the consultant pulled out a coating thickness gauge, and the numbers did not match the purchase order. Every pipe had to be unloaded, re-inspected, and the replacement shipment delayed the steel frame erection by weeks. The root cause was not the steel grade or the welding — it was a supplier who quoted hot-dip galvanized but delivered pre-galvanized material with a fraction of the coating weight. [NEED_CITE: hot-dip galvanizing coating thickness requirements per ISO 1461] When procurement teams source galvanized square and rectangular tubes across multiple vendors, coating consistency becomes the single largest variable between smooth project handover and costly on-site disputes.
Matching Structural Frame Requirements Across Corrosive and Load-Bearing Environments
The ASTM A36 Q235 S355 galvanized square rectangular steel tube covers projects where both structural load capacity and atmospheric corrosion resistance matter simultaneously. In coastal industrial zones, zinc coating at 275 g/m² provides long-term barrier protection for exposed scaffolding and fencing, while indoor warehouse frames may only need 30–60 g/m² for cost efficiency. The ERW welding process produces consistent seam integrity across wall thicknesses from 0.6 mm to 28 mm, and the square or rectangular cross-section delivers predictable moment of inertia for column and beam applications. Our production lines run standard sizes from 10 mm to 1000 mm side length, with custom non-standard dimensions available for projects where off-the-shelf catalogs fall short.
Engineering Compliance and Certification Requirements for Structural Hollow Sections
Structural hollow sections used in load-bearing frames must comply with dimensional tolerances defined in EN 10219 for cold-formed welded sections or EN 10210 for hot-formed finished hollow sections. [NEED_CITE: EN 10219 cold-formed structural hollow section dimensional tolerances] For projects in the European market, CE certification under EN 10210/EN 10219 is mandatory for customs clearance and consultant approval. North American procurement typically specifies ASTM A500 Grade B or C, while Middle East and African tenders often accept Q235 or S235 with mill test certificates traceable to heat numbers. The steel grade selection — whether Q235 for general construction, S355 for higher load requirements, or ASTM A36 for North American spec compliance — directly determines whether the material passes third-party inspection at destination. Our in-house laboratory tests chemical composition and mechanical properties per batch, and SGS or BV third-party inspection is arranged before shipment for clients who require independent verification.
Steel Grade Equivalence and ERW Welding Process Explained
The Q-series (Q195, Q235, Q345), S-series (S235, S355), and ASTM series (A36, A53) represent three different national standard systems, but they overlap significantly in chemical composition and mechanical behavior. Q235 and S235 share similar yield strength ranges and are both widely used for general structural frames; S355 offers higher yield strength for heavy-load columns and crane beams; ASTM A36 serves as the default carbon structural grade in North American specifications. [NEED_CITE: steel grade equivalence between EN and ASTM standards] The ERW (Electric Resistance Welding) process forms the tube from hot-rolled or cold-rolled coil, welding the seam through electrical resistance heat without filler metal — this produces a smooth exterior surface ideal for galvanizing and consistent dimensional accuracy across long production runs. Hot-rolled ERW tubes suit thicker wall applications above 3 mm, while cold-rolled ERW delivers tighter tolerances and smoother finishes for thinner walls down to 0.6 mm. The galvanized surface treatment — zinc coating ranging from 30 g/m² for indoor use to 275 g/m² for harsh outdoor or marine environments — is applied after forming, ensuring full coverage on both exterior and interior surfaces.
Hidden Costs of Procuring the Wrong Coating Weight or Uncertified Material
Ordering galvanized square rectangular steel tube without specifying zinc coating weight in the purchase contract leaves the buyer exposed to material that looks correct on the outside but fails coating thickness inspection at destination. Missing or incomplete mill test certificates cause customs holds in markets that require mandatory inspection — SONCAP in Nigeria, SASO in Saudi Arabia, PVOC in Kenya — and the delay costs far exceed the price difference between certified and uncertified material. Negative tolerance abuse on wall thickness reduces the actual load-bearing capacity below what the structural engineer calculated, creating safety risks that only surface during loading tests or, worse, during service. [NEED_CITE: structural hollow section tolerance requirements per EN 10219] Replacing rejected material after it has arrived at the project site involves double freight, demolition of already-installed sections, and schedule penalties that no supplier discount can offset.
Why Procurement Teams Source Galvanized Square Rectangular Steel Tube from Xin Jiyuan
Our factory-direct pricing eliminates trading company margins — you pay production cost plus reasonable profit, with volume discounts applied automatically for repeat orders. We hold 2,800+ standard specifications in ready stock at our Jinan warehouse, meaning urgent orders for common sizes ship within days rather than weeks. Every batch leaves our facility with original mill test certificates documenting chemical composition and mechanical properties, and we arrange SGS or BV third-party inspection at our cost for clients who need independent verification before container sealing. Our CE certification under EN 10210 and EN 10219, combined with ISO 9001:2015 quality management, satisfies European project compliance requirements without additional testing delays. For non-standard dimensions, custom steel grades, or special length requirements, our production team provides fabrication drawings and lead time confirmation within 48 hours of receiving your inquiry. Our export team handles container loading optimization — mixing multiple sizes in a single container to minimize freight cost per ton — and prepares complete customs documentation including packing lists, bills of lading, and certificates of origin.
Documentation & Compliance
- Mill test certificate documenting Q235, S355, or ASTM A36 chemical composition and mechanical properties per EN 10219 or ASTM A500, traceable to heat number
- CE certificate under EN 10210 / EN 10219 for European market structural hollow section compliance
- ISO 9001:2015 quality management system certificate covering full production and inspection process
- SGS or BV third-party inspection report verifying coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability report linking each bundle to heat number, production date, and test results
- Complete customs documentation package including packing list, bill of lading, certificate of origin, and destination-specific compliance certificates (SONCAP, SASO, PVOC as required)
Packaging, Loading & Delivery
- Galvanized square and rectangular tubes bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit
- Plastic caps installed on both ends of each tube to prevent moisture ingress and protect beveled or threaded ends
- Container loading plan optimized by our logistics team to maximize weight utilization — mixing 100×100, 50×100, and rectangular sections in a single 20ft or 40ft container
- Custom cut-to-length service available for orders requiring specific lengths between 1 m and 12 m, reducing on-site waste and cutting labor
- Heat number and steel grade stenciled on each bundle for site identification and traceability during installation
- FOB, CIF, and DDP shipping terms available from Qingdao port, with door-to-door delivery coordination for project sites requiring inland transport
Ready to Confirm Specifications and Receive a Bulk Quote
Submit your required dimensions, steel grade, zinc coating weight, quantity, and destination port — we respond within 12 hours with factory-direct pricing, production lead time, and available mill test certificate samples. For non-standard sizes or custom fabrication requirements, our technical team provides dimensional drawings and feasibility confirmation before you commit to a deposit.
Request Your Galvanized Square Rectangular Steel Tube Quote Today
Send your specifications to admin@sdxinjiyuan.com or contact us via WhatsApp at +86 188 5315 7756 to receive pricing, mill test certificate samples, and container loading optimization for your next bulk order.
Frequently Asked Questions
Q: How do Q235, S355JR, and ASTM A36 compare in terms of steel grade equivalence?
A: Q235 and S235 share similar yield strength ranges and are interchangeable for general structural applications. S355JR offers higher yield strength suitable for heavy-load columns and beams. ASTM A36 is the standard carbon structural grade in North American specifications. We supply all three grades and can provide equivalence documentation for your project consultant.
Q: Can you provide mill test certificates and arrange third-party inspection for customs clearance?
A: Yes. Every batch ships with original mill test certificates documenting chemical composition and mechanical properties. We arrange SGS or BV third-party inspection at our facility before container sealing, and we prepare destination-specific compliance documents including SONCAP, SASO, or PVOC certificates as required.
Q: What is the minimum order quantity for custom dimensions and special steel grades?
A: Our flexible MOQ starts from 1 ton for trial orders. Standard sizes ship from ready stock, while custom non-standard dimensions or special steel grades typically require typical production lead times. We accommodate split shipments for large projects with phased delivery schedules.
Q: When should I specify hot-dip galvanized versus pre-galvanized coating for my project?
A: Hot-dip galvanizing produces thicker zinc coating (typically 60–275 g/m²) suitable for outdoor, coastal, or industrial corrosion environments. Pre-galvanized tubes offer thinner coating (30–60 g/m²) at lower cost for indoor or temporary applications. We clarify the coating process and weight in our quotation so there is no ambiguity at site inspection.
Q: How do you optimize container loading for mixed-size bulk orders?
A: Our logistics team prepares a loading plan that nests smaller sections inside larger ones and distributes weight evenly to maximize container utilization. This reduces freight cost per ton and minimizes the number of containers needed for your full order.
