Description
Factory-Direct Rectangular GI Pipe — 2,800+ specifications in S275 and S355 grades shipped from our own mill to 50+ countries with no trading markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500/A53/S275/S355 Rectangular GI Steel Pipe |
| Product Type | Rectangular Steel Tube (Welded) |
| Steel Grade | Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Rectangular |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | Welded / Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction Structure / Building Pipe / Curtain Wall Pipe / Support Tubes / Structure Pipe / Fertilizer Tube |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Steel structure frameworks for industrial plants and warehouse portals |
| Construction Companies | High-rise building columns, curtain wall support frames, scaffolding uprights |
| Machinery Manufacturers | Equipment base frames, conveyor system supports, automation rig structures |
What Negative Tolerance Actually Costs on a Galvanized Rectangular Frame Order
A ±1% wall thickness tolerance sounds tight on paper, but on a 700×800mm S355 column it can mean the difference between passing structural inspection and tearing down a finished floor.
Procurement teams ordering ASTM A500 S355 rectangular GI steel pipe often discover the gap between catalogue weight and actual delivered weight only after the steel reaches the job site. When wall thickness drifts below the nominal minus tolerance allowed by EN 10219, the load-bearing capacity drops — and the engineer’s signature on the approval form disappears with it. [NEED_CITE: EN 10219 cold-formed structural hollow section tolerance requirements] Add inconsistent zinc coating thickness on top of that, and you face a second rejection at the galvanizing inspection stage. Fragmented sourcing from separate pipe and galvanizing suppliers makes traceability nearly impossible when the inspector asks for the heat number.
Matching Wall Thickness and Zinc to Structural Exposure Conditions
When specifying ASTM A500 S355 rectangular GI steel pipe for a curtain wall support system, the 1–30mm wall thickness range covers everything from lightweight purlin braces to heavy transfer girders. The hot-dip galvanized surface handles coastal and industrial atmospheres where black-painted alternatives would corrode within a single wet season. Our proprietary sharp-corner rectangular tube process — one of 41 patented technologies — produces corners that seat flush against gusset plates and connection brackets, eliminating the gap-filling welds that slow down erection crews on high-rise projects.
Structural Code Compliance and Certification Pathways
Rectangular hollow sections used in load-bearing frames must satisfy both material and dimensional requirements under EN 1993-1-1 or AISC 360, depending on the destination market. [NEED_CITE: steel grade equivalence between EN 10219 S355 and ASTM A500 Grade C] The S355 grade delivers higher yield capacity than S275 or Gr.B, allowing section size reduction in heavily loaded columns — but only if the mill test certificate confirms the chemistry and mechanical properties match the declared standard. CE certification under EN 10210/10219 is mandatory for EU-bound shipments; Singapore FPC clearance opens doors across Southeast Asian infrastructure tenders. Random-length cutting to exact erection dimensions reduces on-site waste and avoids the secondary cutting costs that erode project margins.
Understanding S-Series and ASTM Grade Equivalence in Rectangular GI Pipe
The S235, S275, and S355 designations follow the European EN system where the number indicates minimum yield strength in MPa — S355 outperforms S275 in load-bearing applications, while S235 suits lighter framing. ASTM A500 Gr.B maps roughly to S275 in yield terms, though the chemical composition limits differ. [NEED_CITE: steel grade equivalence between EN and ASTM standards for structural hollow sections] STK400, a Japanese JIS grade, appears in projects sourced for Southeast Asian and Pacific markets. Welded rectangular tubes produced under GB/T 3091 serve domestic-standard projects, while the same production lines can shift to EN 10219 or ASTM A500 depending on the purchase order specification. Hot-dip galvanizing adds a zinc layer that sacrificially protects the base steel; coating thickness must meet the project specification — typically 60 microns minimum for structural applications in corrosive environments.
The Hidden Price of Unverified Galvanized Rectangular Tubes
Ordering ASTM A500 S355 rectangular GI steel pipe without third-party inspection or a verifiable mill test certificate creates risk at three points: customs clearance, structural approval, and long-term corrosion performance. [NEED_CITE: EN 10219 cold-formed hollow section requirements] A shipment with zinc coating below the specified threshold passes the port inspection but fails the client’s on-site adhesion and thickness test — triggering a full re-galvanizing cycle at the destination, where labor and logistics costs dwarf the original savings. Missing heat-number traceability means the structural engineer cannot sign off, stalling the project schedule. Certification gaps — no CE mark for EU entry, no SGS report for Middle Eastern tenders — result in cargo held at port, accruing demurrage charges that erase any factory-direct price advantage.
Why Project Procurement Teams Source Rectangular GI Pipe From Our Mill
We operate three dedicated production lines covering 2,800+ specifications in rectangular, square, and round profiles — meaning your S355 rectangular GI tubes, S275 round pipes, and custom-cut plates come from a single mill with unified quality control. Our in-house physical and chemical laboratory tests every heat before release, and the original mill test certificate travels with the shipment. The proprietary sharp-corner rectangular tube technology — a domestic and international first among our 41 patents — delivers geometric precision that standard roll-forming cannot achieve. CE EN 10210/10219, ISO 9001:2015, Singapore FPC, and third-party verification through SGS and BV cover certification requirements across EU, North American, and Asian markets. Professional loading plans optimize container fill for mixed-size orders, and door-to-door logistics reach 50+ countries with full documentation.
Documentation & Compliance
- Mill test certificate documenting S355JR chemical composition and yield strength per EN 10219, traceable to heat number
- CE certificate confirming compliance with EN 10210/EN 10219 for structural hollow sections exported to EU markets
- ISO 9001:2015 quality management certificate covering the full production and inspection process
- SGS or BV third-party inspection report verifying zinc coating thickness and dimensional tolerance on request
- Material traceability sheet linking each bundle to its heat number, steel grade, and production date
- Customs documentation package including packing list, bill of lading, and certificate of origin for destination clearance
Packaging, Loading & Delivery
- Galvanized rectangular tubes bundled with steel strips and edge protectors to preserve the zinc coating during ocean transit
- Surface protection via anti-rust oil on bare or black-painted ends to prevent white rust formation on galvanized surfaces during humidity exposure
- Container loading plans optimized for mixed-size orders combining 15×20mm small sections with 700×800mm large rectangular profiles in 20ft and 40ft containers
- Cut-to-length service available for 5.8m, 6m, 11.8m, and 12m standard lengths, reducing on-site waste for construction projects
- Heat number and steel grade stenciled on each bundle tag for site-level traceability during erection
- FOB, CIF, and DDP shipping options with real-time tracking to ports and project sites across 50+ countries
Getting Your Rectangular GI Pipe Quote Moving
Submit your specification sheet — section dimensions, wall thickness, steel grade, surface treatment, quantity, and destination port — and receive a detailed quotation within 12 hours, including unit pricing, applicable certifications, and estimated production timeline. For non-standard dimensions outside the 15×20mm to 700×800mm range, our engineering team provides custom feasibility assessments and MOQ guidance.
Start Your ASTM A500 S355 Rectangular GI Steel Pipe Inquiry
Send your specifications, steel grade, and destination to receive a quotation with mill test certificate preview and certification confirmation.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjysteel.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjysteel.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How does S355 compare to ASTM A500 Gr.C and Q345B in rectangular GI pipe applications?
A: S355 (EN system), ASTM A500 Gr.C, and Q345B (GB system) share similar minimum yield strength levels, making them functionally equivalent for most structural rectangular tube applications. The chemical composition limits and testing methods differ slightly between standards, so the mill test certificate should confirm compliance with the specific standard named in your purchase order.
Q: Can you provide third-party inspection for zinc coating thickness on galvanized rectangular tubes?
A: Yes. SGS and BV third-party inspections are available for every shipment. The inspection report documents zinc coating thickness, adhesion test results, and dimensional measurements against your specified tolerance, providing independent verification for your project quality requirements.
Q: What is the minimum order quantity for non-standard rectangular GI pipe dimensions?
A: The standard MOQ is 5 Tons. For non-standard dimensions outside the 15mm×20mm to 700mm×800mm range, our engineering team reviews the specification and confirms feasibility, production timeline, and any adjusted MOQ based on the required rolling setup.
Q: How do you select between galvanized, black painted, and bare surface treatment for rectangular steel tubes?
A: Hot-dip galvanized treatment suits outdoor, coastal, and industrial environments where corrosion resistance is critical. Black painting provides moderate protection for indoor or temporary exposure conditions. Bare tubes are specified when the project includes field-applied coating systems or when the tubes will be embedded in concrete where galvanizing is unnecessary.
Q: Do you handle container loading optimization for mixed-size rectangular GI pipe orders?
A: Yes. Our logistics team prepares detailed loading plans that maximize container utilization for orders combining multiple section sizes and lengths. This reduces per-ton freight costs and ensures the galvanized coating remains protected through proper bundling and separation during transit.
