Description
One-Source Rectangular GI Tube Supply — From raw steel coil to finished ASTM A500 S355 rectangular GI steel tube, every step runs under one roof and one quality system.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 / A53 / S275 / S355 Rectangular GI Steel Pipe |
| Product Type | Rectangular Hollow Section (RHS) |
| Steel Grade | GRB, A53 (A, 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 (ERW) / Seamless |
| Surface Treatment | Galvanized / Black Painting / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction structures, building frames, curtain wall supports, structural pipe, scaffolding, machinery frames |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building column and beam frames, mezzanine structures, roof truss supports |
| Industrial Facilities | Factory warehouse portals, crane runway beams, equipment support platforms |
| Curtain Wall & Façade | Vertical and horizontal mullion systems, bracket supports for cladding |
| Scaffolding & Access | Load-bearing scaffolding uprights, cross-brace tubes, temporary structural frames |
| Infrastructure & EPC | Bridge handrail posts, solar panel mounting frames, conveyor support structures |
What Galvanized Coating Thickness Decides on a Structural Tube Order
A zinc layer that fails third-party inspection turns a delivered shipment into a rejected one.
When overseas buyers source ASTM A500 S355 rectangular GI steel tube from separate material suppliers and fabricators, the galvanizing step often becomes the weakest link. Coating thickness drops below specification during transit handling or gets applied over poorly prepared surfaces, and the problem only surfaces at the destination port — after ocean freight and customs clearance costs are already sunk. [NEED_CITE: hot-dip galvanized coating thickness requirements per ASTM A123]
Buyers who consolidate raw steel production and galvanizing under one quality system avoid this gap entirely. Every rectangular GI steel tube leaving the mill carries coating thickness data traceable to the original heat number, so site engineers can verify compliance without waiting for third-party re-testing.
How Rectangular GI Tube Matches Structural Frame Demands
Rectangular hollow sections carry bending loads efficiently in both axes, making them the default choice for building frames and column systems where bidirectional loading is expected. The galvanized surface protects against atmospheric corrosion during construction staging and extends service life in industrial environments where moisture and chemical exposure are routine. Our ASTM A500 S355 rectangular GI steel tube rolls from the same steel we produce in-house, so the base material chemistry and the zinc coating both fall under a single mill test certificate — no gaps between material source and surface treatment.
Engineering Compliance and Certification Requirements
Structural frames designed to EN 1993 or AISC standards require hollow sections that meet dimensional tolerance and material certification thresholds. Rectangular GI steel tube in S275 and S355 grades must carry EN 10219 or ASTM A500 marking, with mill test certificates showing chemical composition and mechanical properties per heat number. For EU-bound projects, CE marking under EN 10219 is mandatory for customs clearance; for North American projects, ASTM A500 Grade B or C certification applies. [NEED_CITE: EN 10219 cold-formed structural hollow sections certification requirements] Galvanized coating thickness must comply with ASTM A123 or EN ISO 1461 depending on the destination market, and third-party inspection reports from SGS or BV are often required before shipment release.
Steel Grade Selection and Welding Process Explained
The jump from S235 to S275 to S355 represents increasing minimum yield strength, which directly affects how much load a rectangular section can carry before permanent deformation. For heavy structural frames and multi-story buildings, S355 reduces section size while maintaining load capacity — saving weight and connection costs. ASTM A53 Grade B serves similar roles in North American-spec projects, while STK400 covers Japanese-standard structural applications. ERW welded production suits standard wall thicknesses up to moderate sizes, while seamless processes handle heavier walls and higher-pressure applications. Hot-dip galvanizing after forming provides full external and internal coating coverage, critical for hollow sections exposed to humid or corrosive environments. [NEED_CITE: steel grade equivalence between ASTM A500 and EN 10219 standards]
Negative tolerance on wall thickness is standard industry practice, but excessive negative tolerance reduces actual load-bearing capacity below design calculations. Our ±1% tolerance specification keeps dimensional deviation tight enough for structural engineering precision without inflating theoretical weight invoicing.
Hidden Costs of Sourcing GI Tube from Disconnected Suppliers
When rectangular GI steel tube comes from a trader who subcontracts galvanizing to a separate processor, coating adhesion and thickness consistency become unpredictable. Projects fail acceptance inspection when zinc layers measure below specification, forcing either costly re-galvanizing at destination or complete material rejection. Missing or inconsistent mill test certificates delay customs clearance and trigger port storage fees. Welding procedures qualified on one heat of steel may not transfer to another, creating requalification costs and schedule delays on site. [NEED_CITE: structural steel fabrication quality control requirements per AWS D1.1]
Why Procurement Teams Consolidate GI Tube Orders Here
We run our own steel production lines alongside the fabrication workshop, so the rectangular GI steel tube you order starts as coil we rolled and ends as a finished section we galvanized and inspected. This vertical integration means one mill test certificate covers base material and coating, one quality manager signs off on dimensional checks and welding records, and one point of accountability handles any technical query from inquiry through delivery. Our facility holds 2,800+ specification slots in inventory, so standard sizes in S275 and S355 ship from stock while custom lengths and non-standard sections run on dedicated production schedules. CE certification under EN 10219, ISO 9001 quality management, and third-party inspection partnerships with SGS and BV cover EU, Middle East, and Southeast Asian project requirements. Professional loading teams handle oversized rectangular sections with specialized lashing to prevent coating damage during ocean transit.
Documentation & Compliance
- Mill test certificate documenting S355JR chemical composition and yield strength per EN 10219, with heat number traceability from raw coil to finished rectangular GI steel tube
- CE certificate confirming EN 10219 compliance for structural hollow sections destined for European Union construction projects
- ISO 9001 quality management certificate covering the full production chain from steelmaking through galvanizing and final inspection
- SGS or BV third-party inspection report verifying galvanized coating thickness, dimensional tolerance, and surface quality before shipment release
- Material traceability records linking each rectangular GI steel tube bundle to its original heat number, production date, and galvanizing batch
- Complete customs documentation package including packing list, bill of lading, certificate of origin, and commercial invoice formatted for destination port requirements
Packaging, Loading & Delivery
- Rectangular GI steel tube bundled with galvanized steel strips and edge protectors to preserve zinc coating integrity during handling and ocean transit
- Galvanized surface protected with plastic end caps and anti-rust paper wrapping to prevent white rust formation in humid container environments
- Container loading optimized for 5.8m and 6m lengths in 20-foot containers, with 11.8m and 12m sections loaded in 40-foot open-top or flat-rack containers for oversized rectangular profiles
- Custom cut-to-length service available for 15mm × 20mm through 700mm × 800mm sections, with saw-cut ends deburred and coated with zinc-rich paint to maintain corrosion protection
- Each bundle marked with heat number, steel grade (S275 / S355 / A53), size specification, and production batch for site identification and traceability
- FOB, CIF, and DDP shipping terms available with door-to-door logistics coordination for project sites across Middle East, Southeast Asia, Africa, and South America
How to Request a Quotation for Rectangular GI Steel Tube
Send your project drawings or specification list including section size, wall thickness, steel grade, total quantity, and destination port — we return a detailed quote covering material, galvanizing, packaging, and shipping within one working day. For non-standard sizes or custom lengths outside the 15mm × 20mm to 700mm × 800mm range, our engineering team reviews feasibility and provides a fabrication timeline. We confirm all certification and documentation requirements upfront so your customs clearance and site inspection proceed without surprises.
Frequently Asked Questions
Q: How do ASTM A500 and EN 10219 steel grades compare for rectangular GI steel tube?
A: ASTM A500 Grade B and C correspond roughly to S275 and S355 in the EN system, with similar yield strength ranges. We produce rectangular GI steel tube to both standards and provide mill test certificates showing compliance with whichever specification your project requires. For projects spanning multiple regions, we can supply mixed shipments with clear grade marking on each bundle.
Q: What galvanized coating thickness do you apply to rectangular GI steel tube?
A: Hot-dip galvanizing per ASTM A123 or EN ISO 1461 typically produces 65-85 micrometers on rectangular sections, depending on steel chemistry and immersion time. We conduct coating thickness testing on every production batch and include results in the mill test certificate package. For aggressive corrosive environments, we can specify heavier coating classes upon request.
Q: Can you supply rectangular GI steel tube in custom lengths beyond standard 6m and 12m?
A: Yes, our saw-cutting line handles random lengths from 1m to 12.5m for rectangular sections up to 700mm × 800mm. Custom lengths incur a small cutting fee but eliminate on-site waste and reduce connection counts in structural frames. We bundle custom-length tubes separately with clear size marking to prevent mixing at your site.
Q: Do you provide third-party inspection before shipment?
A: We coordinate SGS, BV, or other nominated inspection agencies for pre-shipment inspection covering dimensional checks, coating thickness measurement, visual surface quality, and documentation review. Inspection reports issue within 2-3 working days of the inspection date. We cover inspection coordination costs; third-party agency fees apply per their standard rates.
Q: What is the minimum order quantity for rectangular GI steel tube?
A: Our MOQ is 5 tons per order, which typically covers 10-15 tons for mixed-size shipments. For project procurement requiring multiple sizes in S275 and S355 grades, we consolidate production runs to meet total tonnage while keeping individual bundle sizes manageable for site handling.
Get Your Rectangular GI Steel Tube Quote with Mill Test Certificate
Send your size list, steel grade, quantity, and destination port — we return pricing and lead time within 24 hours, with full documentation package confirmed upfront.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile / WhatsApp / WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
