Description
Factory-Direct Rectangular Hollow Sections — Every Q235 rectangular hollow section rolls off our own ERW lines in Jinan, shipped with original mill test certificates and no broker markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Rectangular Hollow Section |
| Product Type | Rectangular Steel Tube (Welded / ERW) |
| Steel Grade | Q235, Gr.B, S235, S275, S355, S355J2H, S355J0H, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091, EN 10219, EN 10210 |
| Section Shape | Rectangular |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW / Welded (Seamless available) |
| Surface Treatment | Black Painting / Hot-dip Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain End |
| Application | Steel structures / Construction frames / Curtain wall systems / Machinery supports / Building frameworks |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, curtain wall supports, column bracing, roof trusses |
| Machinery & Equipment | Conveyor structures, crane booms, equipment base frames |
| Industrial Fabrication | Scaffolding systems, fertilizer plant pipe racks, warehouse portal frames |
What Wall-Thickness Tolerance Costs on a Q235 Rectangular Hollow Section Order
A ±1% tolerance on a 700×800×30mm section means the difference between passing structural inspection and failing load calculations.
When buyers source a Q235 rectangular hollow section from fragmented suppliers, wall thickness often drifts into negative tolerance beyond acceptable limits. The result: theoretical weight invoicing diverges from actual mass, structural engineers recalculate load-bearing capacity, and project timelines slip while replacement tubes are sourced. On a 200-ton structural frame order, even minor tolerance stacking across hundreds of members compounds into rework costs that dwarf the initial price saving. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Rectangular Geometry to Structural Connection Details
A Q235 rectangular hollow section from 15×20mm up to 700×800mm covers everything from light-gauge curtain wall purlins to heavy column sections in portal frames. The flat faces of rectangular geometry provide direct bearing surfaces for gusset plates and moment connections — no flat-spot grinding required on round tubes. For corrosion-prone environments such as coastal infrastructure or fertilizer plants, hot-dip galvanized finish extends service life without field painting. Our ERW lines produce these sections in lengths up to 12m, reducing on-site splice joints and welding labor.
Engineering Compliance Across Q235, S235, and ASTM Grade Equivalents
Structural designers specifying Q235 rectangular hollow sections often need cross-references to EN or ASTM systems for international projects. Q235 corresponds broadly to S235JR in yield strength, while Gr.B under ASTM A500 serves North American structural codes. For projects requiring low-temperature impact toughness, S355J2H or S355J0H grades meet EN 10210 requirements for sub-zero service. CE certification under EN 10219 and EN 10210 ensures customs clearance across EU member states, while mill test certificates document chemical composition and mechanical properties per heat number. [NEED_CITE: steel grade equivalence between GB/T, EN, and ASTM structural standards]
ERW Welding Process and Surface Treatment Selection
ERW (Electric Resistance Welded) rectangular hollow sections offer cost efficiency for structural applications where internal pressure is not a design factor. The weld seam runs along the longitudinal axis, and modern high-frequency ERW processes produce weld integrity comparable to the parent metal. For outdoor or corrosive environments, hot-dip galvanizing applies a zinc coating that sacrificially protects the base steel — coating thickness verified by SGS report before loading. Black painting or varnish suits indoor applications or sections destined for field coating. Bare finish works for welding-ready fabrication where surface prep will occur on-site.
The Hidden Cost of Unverified Steel Grade on Structural Projects
Ordering a Q235 rectangular hollow section without original mill test certificates creates downstream risk: material traceability breaks, third-party inspectors flag uncertified batches, and customs authorities hold shipments pending chemical analysis. The re-galvanizing cost for a 40-foot container of non-compliant galvanized tubes exceeds the original price differential between verified and unverified suppliers. Structural engineers cannot sign off on load calculations without documented yield strength and elongation values per heat number. [NEED_CITE: importance of mill test certificates for structural steel procurement]
Why Global Buyers Source Q235 Rectangular Hollow Sections from Xin Jiyuan
Our Jinan facility operates three dedicated ERW lines producing rectangular hollow sections in Q235 and higher grades, with factory-direct pricing that eliminates broker margins. Every shipment includes original mill test certificates documenting chemical composition and mechanical properties — not photocopies or generic templates. We maintain ready stock across 2,800+ specifications, enabling split shipments and urgent fulfillment without waiting for production slots. For European projects, our CE certification under EN 10210 and EN 10219 satisfies notified body requirements. Third-party inspection by SGS or BV is available on request, with reports attached to the shipping documentation package.
Documentation & Compliance
- Mill test certificate documenting Q235 chemical composition (C, Mn, Si, P, S) and yield strength per GB/T 3091 or equivalent standard
- CE certificate confirming compliance with EN 10219 for cold-formed welded structural hollow sections
- ISO 9001:2015 quality management system certificate covering production and inspection processes
- SGS or BV third-party inspection report verifying dimensional tolerance, surface coating thickness, and weld quality
- Material traceability by heat number linking each bundle to its original slab and rolling record
- Customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235 rectangular hollow sections bundled with steel strips and edge protectors to prevent coating damage during ocean transit
- Hot-dip galvanized tubes wrapped in waterproof paper with desiccant to preserve zinc finish in humid container environments
- Container loading optimized for 6m and 12m lengths to maximize payload per 20ft and 40ft open-top or standard dry van
- Random length or cut-to-order sections available for 5.8m container-loading efficiency on 20ft equipment
- Heat number and steel grade stenciled on each bundle for site identification and traceability verification
- FOB Qingdao, CIF destination port, or DDP door-to-door logistics with real-time tracking
Request Your Q235 Rectangular Hollow Section Quotation
Submit your specification sheet — including section dimensions, wall thickness, steel grade, surface treatment, quantity, and destination port — and receive a factory-direct quotation within 12 hours, complete with mill test certificate samples and container loading plans.
Start Your Procurement Inquiry
Email your requirements to admin@sdxinjiyuan.com or message via WhatsApp at +86 188 5315 7756 for pricing, certification confirmation, and delivery scheduling.
Frequently Asked Questions
Q: How do Q235, S235, and ASTM A500 Gr.B compare for rectangular hollow sections?
A: Q235 (GB/T 3091) and S235 (EN 10219) share similar yield strength levels around 235 MPa, making them interchangeable for many structural applications. ASTM A500 Gr.B specifies minimum yield strength of 290 MPa for rectangular sections, offering slightly higher load capacity. We supply all three grade systems and provide cross-reference documentation for international projects.
Q: Can I obtain third-party inspection before shipment?
A: Yes. SGS and BV inspection services are available on request for every Q235 rectangular hollow section order. Inspectors verify dimensional tolerance, weld quality, surface coating thickness (for galvanized finish), and witness loading. Inspection reports are included in the shipping documentation package.
Q: What is the minimum order quantity for non-standard rectangular sizes?
A: Standard sizes from our ready stock carry a 5-ton MOQ. Non-standard dimensions outside 15×20mm to 700×800mm range or custom wall thickness require production runs with typical lead times of 15–25 days depending on specification complexity.
Q: How do I choose between hot-dip galvanized, black painted, and bare finish?
A: Hot-dip galvanized finish suits outdoor or corrosive environments — coastal construction, chemical plants, infrastructure exposed to weather. Black painting provides temporary protection for indoor applications or sections destined for field coating systems. Bare finish works for welding-ready fabrication where surface preparation occurs on-site before final coating.
Q: How does Xin Jiyuan optimize container loading for mixed-size orders?
A: Our logistics team plans container loading to maximize payload while protecting surface finish. Heavy-wall sections load on the bottom, light-gauge tubes nest on top. Edge protectors prevent zinc coating damage. For 6m and 12m lengths, we optimize 20ft and 40ft container selection to minimize freight cost per ton.
Get Factory-Direct Pricing on Q235 Rectangular Hollow Sections
Send your specification sheet to admin@sdxinjiyuan.com or WhatsApp +86 188 5315 7756 for quotation, mill test certificate samples, and container loading confirmation.
