Description
Factory-direct pricing, no middlemen — Every S355JR square and rectangular steel tube leaves our Jinan mill at base price, with full EN 10219 / ASTM A500 documentation included in the quote.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B / S355JR ERW Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q235, Q235B, Q355, S235JR, S355JR, S355JOH, S355J2H, STK400, SS400, C250, C350, C460, St37, St52, ASTM A500 Grade A/B/C/D |
| Standard | ASTM A500, EN 10219, EN 10210, JIS G3466, AS1163, GB/T 6728 |
| Section Shape | Square & Rectangular |
| Size Range | Square 12×12 mm – 800×800 mm; Rectangular 10×20 mm – 800×1000 mm (extended up to 1000×1000 mm / 1100×800 mm) |
| Wall Thickness | 0.5 – 25 mm (extended up to 60 mm) |
| Length | 1 – 12 m (up to 24 m extended) |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Bare, Oiled, Black Painting, Hot Rolled, Galvanized (zinc coating 30 – 550 g/m²), Color Painting |
| Tolerance | ±1% dimensional; diameter tolerance ≤0.12%, deflection <1/2000, ovality <1% |
| Ends | Plain End |
| Application | Steel structures, construction frames, scaffolding, fencing posts, brackets, shelving, guard bars, furniture, greenhouse structures, handrails, industrial platforms |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC & Construction | Structural frames for high-rise buildings, bridge support columns, scaffolding uprights, industrial platform beams |
| Machinery & Equipment | Conveyor system frames, automation machine bases, heavy-duty shelving uprights, crane boom sections |
| Infrastructure & Civil | Guard rail posts, sound barrier supports, highway sign gantries, utility pole foundations |
| Agriculture & Commercial | Greenhouse skeleton tubes, fencing posts, furniture frames, handrail systems, parking structure bracing |
Where Missing Mill Test Certificates Stall EU Customs Clearance
An S355JR square and rectangular steel tube without EN 10204 3.1 documentation cannot clear European ports — regardless of actual material quality.
Procurement teams regularly discover this after production is complete. The tubes arrive at Rotterdam or Hamburg, customs holds the container, and the project faces demurrage charges while the supplier scrambles to produce paperwork that should have traveled with the cargo. Fragmented sourcing makes this worse: pipes from one vendor, plates from another, fabrication from a third — each with different certificate formats, missing heat numbers, or no third-party verification at all. [NEED_CITE: EN 10219 cold-formed hollow section certification requirements for EU import]
Matching Hollow Section Dimensions to Structural Load Paths
When specifying a S355JR square and rectangular steel tube for structural frames, the section modulus and moment of inertia determine whether the member carries the design load without excessive deflection. Our ERW process holds dimensional tolerance at ±1% with deflection under 1/2000, meaning the as-delivered geometry matches the engineer’s calculation input. For conveyor integrators and machinery builders ordering 2,800+ specification combinations, this precision eliminates on-site shimming and re-welding. The proprietary sharp-corner rectangular tube technology — one of our 41 patented processes — produces corner radii tight enough for flush gusset plate connections without gap-filling weld metal.
Engineering Compliance Across EN, ASTM, and JIS Frameworks
Structural projects in Europe require CE marking under EN 10210 or EN 10219, while North American EPC contractors specify ASTM A500 Grade B or C. A single S355JR square and rectangular steel tube order can include multiple grades meeting different regional codes, provided the mill maintains separate chemical composition records and mechanical test reports for each heat. [NEED_CITE: steel grade equivalence mapping between EN 10219 S355JR and ASTM A500 Grade B] Galvanized finish with 30–550 g/m² zinc coating addresses corrosion class C3–C5 environments per ISO 12944, while bare or oiled tubes suit indoor structural applications where field painting follows erection. Custom cut-to-length up to 24 m reduces on-site welding joints and accelerates erection schedules.
Decoding ERW Weld Integrity and Grade Selection for Hollow Sections
The ERW (Electric Resistance Welded) process forms the tube by rolling steel strip into shape and fusing the seam through resistive heating — no filler metal, no slag. For S355JR and higher grades, the weld zone undergoes online ultrasonic inspection to confirm full penetration without inclusions. The “JR” designation indicates Charpy impact testing at room temperature (20°C), while “J2H” specifies testing at −20°C for cold-climate structural applications. Q355B serves as the Chinese GB/T 1591 equivalent to S355JR, and both meet EN 10219 chemical composition limits when sourced from certified mills. Wall thickness from 0.5 mm to 60 mm covers everything from light-gauge furniture frames to heavy structural columns — but thinner walls demand tighter tolerance control to prevent ovality exceeding 1% during the forming stage.
The Hidden Cost of Tolerance Drift in Fabricated Steel Frames
When a 200×200×10 mm S355JR square tube arrives with actual wall thickness at the low edge of negative tolerance, the section modulus drops — and the structural engineer’s safety margin shrinks accordingly. Worse, if the mill cannot provide traceable heat numbers linking each bundle to its original slab chemistry, the entire shipment fails third-party inspection and the contractor faces re-procurement delays measured in weeks, not days. [NEED_CITE: consequences of negative tolerance exceedance in structural hollow sections per EN 10219] Missing CE certificates compound the problem: EU customs does not release construction steel without EN 10210/10219 compliance documentation, regardless of the material’s actual fitness for purpose.
Procurement Confidence Through In-House Testing and Full Documentation
Every S355JR square and rectangular steel tube shipped from our Jinan facility passes through an in-house physical and chemical laboratory before release — incoming raw material verification, in-process weld seam inspection, and final dimensional checks. We issue original EN 10204 3.1 Mill Test Certificates documenting chemical composition and mechanical properties per heat number, and welcome SGS or BV third-party inspection at our facility before container sealing. With 2,800+ specifications covering side lengths up to 1000×1000 mm and wall thickness to 60 mm, plus custom non-standard profiles using our patented sharp-corner technology, we consolidate what typically requires three or four separate suppliers into a single purchase order. CE certification under EN 10210 and EN 10219, ISO 9001:2015 registration, and Singapore FPC approval ensure customs clearance across 50+ destination countries without documentation disputes.
Documentation & Compliance
- Mill Test Certificate (EN 10204 3.1) documenting S355JR chemical composition, yield strength, and tensile properties per heat number per EN 10219
- CE Declaration of Conformity covering EN 10210 and EN 10219 hollow section standards for EU market customs clearance
- ISO 9001:2015 quality management system certificate validating production process controls and inspection protocols
- SGS or BV third-party inspection report available upon request, conducted at our facility before shipment sealing
- Full material traceability linking each bundle to its original heat number, slab chemistry, and rolling records
- Export customs documentation including packing list, ocean Bill of Lading, and Certificate of Origin
Packaging, Loading & Delivery
- ERW S355JR square tubes bundled with high-tensile steel strips at intervals matched to 6–12 m lengths, preventing bundle separation during crane handling
- Galvanized hollow sections (30–550 g/m² zinc) wrapped with edge protectors and moisture-barrier film to preserve coating integrity during ocean transit
- Custom container loading plans distributing heavy-wall (up to 60 mm) and large-section (up to 1000×1000 mm) tubes to maximize 20ft and 40ft payload without exceeding port weight limits
- Cut-to-length service available from 1 m to 24 m, with plain ends deburred and marked with heat number, steel grade, and dimensional specification
- Shipment terms FOB Qingdao port, CIF destination port, or DDP door-to-door with real-time container tracking across 50+ countries
Securing Your Quote with Complete Technical Documentation
Submit your specification sheet — including section dimensions, wall thickness, steel grade (S355JR / Q355B / ASTM A500), surface treatment preference, quantity, and destination port — and receive a detailed quotation within 12 hours covering unit price, production lead time, payment terms, and applicable certification scope. For non-standard dimensions or sharp-corner rectangular profiles, our engineering team provides custom feasibility assessment and tooling timeline before you commit to production.
Request Your S355JR Square and Rectangular Steel Tube Quotation
Send specifications via email to admin@sdxjysteel.com or contact our international team via WhatsApp at +86 188 5315 7756 to receive pricing, Mill Test Certificate samples, and container loading plans.
Frequently Asked Questions
Q: How do S355JR, Q355B, and ASTM A500 Grade B compare for the same structural application?
A: All three grades occupy similar yield strength ranges and serve equivalent structural roles, but they originate from different standard systems — EN 10219 (European), GB/T 1591 (Chinese), and ASTM A500 (North American). We produce all three grades in our ERW lines and issue separate Mill Test Certificates confirming compliance with each standard’s chemical and mechanical requirements, allowing you to specify the code your project engineer requires.
Q: Can SGS or BV conduct pre-shipment inspection at your facility?
A: Yes. Our Jinan mill welcomes third-party inspection agencies to witness dimensional checks, witness mechanical testing, and verify surface treatment quality before container sealing. We coordinate the inspection schedule with your nominated agency and include their report in the shipment documentation package.
Q: What is the minimum order quantity for custom non-standard dimensions or sharp-corner rectangular tubes?
A: Standard catalog sizes (within our 2,800+ specification range) carry no special MOQ beyond normal commercial quantities. Custom non-standard profiles and sharp-corner rectangular tubes using our patented technology require project-specific evaluation — we assess tooling requirements and provide MOQ guidance during the quotation stage based on your dimension and quantity combination.
Q: When should I specify galvanized finish versus bare or painted for my project environment?
A: Galvanized coating (30–550 g/m² zinc) suits outdoor exposure, coastal environments, or applications where field painting after erection is impractical — greenhouse structures, fencing, guard rails, and marine-adjacent infrastructure. Bare or oiled finish works for indoor structural frames where site painting follows erection. Black painting or color coating provides aesthetic finish for architectural applications with moderate corrosion exposure.
Q: Do your CE certificates cover all S355JR sizes shipped to European markets?
A: Our CE certification under EN 10210 and EN 10219 covers the full production range of ERW square and rectangular hollow sections manufactured at our facility, including all S355JR / S355JOH / S355J2H grades across our size spectrum from 12×12 mm to 1000×1000 mm. The certificate accompanies each shipment and satisfies EU customs requirements for construction steel imports.
