Description
Factory-direct ERW tubes, no trading markup — SS400 rectangular steel tubes produced on our own ERW lines with in-house lab testing and original mill test certificates for every heat.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | SS400 Rectangular Steel Tube |
| Product Type | Rectangular Steel Tube |
| Steel Grade | SS330, SS400, SS490, SPCC, SPCD, SPCE, Q195, Q235, Q345, S235JR, S355JR, ST37, ST42, ST52, SPHC, DC01, QSTE, SAPH |
| Standard | JIS |
| Section Shape | Rectangular |
| Size Range | 10mm×30mm – 600mm×800mm (Rectangular); 15mm×15mm – 800mm×800mm (Square) |
| Wall Thickness | 0.5mm – 20mm |
| Length | 1m – 16m or Customized |
| Technique | ERW |
| Surface Treatment | Bared / Black Painted (Varnish Coating) / Galvanized / Oiled / Shop Primer and Shot Blasting |
| Tolerance | ±1% |
| Processing Service | Bending, Cutting, Decoiling, Punching, Welding |
| Application | Steel structures, Construction frames, Machinery, Electric bicycle frames, Agricultural machinery, Construction machinery |
| Invoicing | By Actual Weight |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Industrial plant frames, pipe rack supports, solar mounting structures |
| Construction Companies | Building columns, mezzanine beams, scaffolding uprights |
| Machinery Manufacturers | Conveyor frames, agricultural equipment chassis, electric bicycle body structures |
| Infrastructure Developers | Bridge handrails, signage gantries, utility pole bases |
What ±1% Tolerance Means When Bolts Must Align on Site
A 3mm deviation on a 6-meter SS400 rectangular steel tube turns a bolted connection into a rework order.
On a photovoltaic racking project in Riyadh, a container of rectangular tubes arrived with cut-end deviations exceeding 3mm. Every base plate hole missed its mark. The entire shipment had to be re-drilled locally, delaying the project by weeks and adding unplanned labor costs. Tolerance is not a catalog footnote — it is the difference between bolting up on day one and burning through a contingency budget. Global buyers sourcing a JIS SS400 rectangular steel tube manufacturer often discover this only after the container opens [NEED_CITE: JIS G3466 dimensional tolerance requirements for structural hollow sections].
Matching JIS SS400 Rectangular Steel Tube to Structural and Machinery Frames
SS400 sits in the mild carbon range where formability meets adequate load capacity for non-pressure structural applications. The ERW process produces a consistent weld seam suited to rectangular and square profiles from 10mm×30mm up to 600mm×800mm, covering everything from electric bicycle frames to heavy construction machinery chassis. Our ERW lines hold the ±1% tolerance across wall thicknesses from 0.5mm to 20mm, which matters when a JIS SS400 rectangular steel tube must slide into a jig or accept a pre-punched connection plate without force-fitting.
Engineering Compliance and Surface Protection Choices
Structural frames in seismic or wind-loaded zones require traceable material properties backed by mill test certificates showing chemical composition and tensile data per JIS standards. For outdoor or humid environments — solar farms, coastal infrastructure, agricultural machinery — surface treatment selection becomes a service-life decision: hot-dip galvanized coatings resist corrosion for decades, while shop primer with shot blasting provides a weldable base for final painting. Projects targeting EU markets may need EN 10219 conformity documentation even when ordering JIS-grade material, and our in-house lab issues certificates that satisfy both origin and destination inspectors [NEED_CITE: EN 10219 cold-formed structural hollow sections dimensional and technical requirements].
Steel Grade Logic: SS400 Within the JIS Family and Beyond
SS400 is a general structural steel under JIS G3101, defined primarily by tensile strength range rather than strict chemical composition — making it versatile for welded frames where formability matters more than precise alloy content. SS330 offers lower strength but superior ductility for tight bending radii, while SS490 steps up for heavier load paths. When buyers request equivalence mapping, SS400 roughly aligns with GB Q235 and EN S235JR in yield behavior, though chemical boundaries differ slightly. The ERW welding process suits all three grades, producing a longitudinal seam that undergoes ultrasonic inspection inline. Wall thickness from 0.5mm to 20mm covers thin-gauge machinery guards through to heavy structural columns, and the ±1% tolerance applies uniformly regardless of grade selection.
The Hidden Cost of Unverified Material and Negative Tolerance Abuse
Ordering a JIS SS400 rectangular steel tube manufacturer without requiring original mill test certificates risks receiving off-grade material that fails inspection at destination customs or during structural audits. Worse, some producers exploit negative tolerance allowances — delivering wall thickness at the lower boundary while invoicing by theoretical weight, effectively charging for steel that is not there. The consequences compound: rejected shipments, re-order delays, and in load-bearing applications, potential structural safety concerns that no amount of rework can fix [NEED_CITE: steel grade equivalence and tolerance standards between JIS and EN systems].
Why Buyers Choose Our ERW Lines for SS400 Rectangular Profiles
We operate three dedicated ERW production lines with in-house physical and chemical laboratories, meaning every heat is tested before it leaves the mill — no third-party lab scheduling delays. Our 2,800+ specification range covers the full 10mm×30mm to 600mm×800mm rectangular scope plus square profiles up to 800mm×800mm, so a single order for mixed structural sizes ships from one source. The proprietary sharp-corner rectangular tube technology — holding 41 patents — delivers tight radii that fit flush against gusset plates without gap-filling welds. Every shipment includes original mill test certificates, and we arrange SGS or BV third-party inspection for buyers who require independent verification. Professional loading plans optimize container weight for heavy rectangular tubes, and we handle FOB, CIF, and DDP terms to 50+ countries.
Documentation & Compliance
- Mill test certificate documenting SS400 chemical composition and tensile properties per JIS G3101, issued per heat number
- CE certificate conforming to EN 10210/EN 10219 for projects requiring European structural hollow section compliance
- ISO 9001:2015 quality management certificate covering ERW production and in-house laboratory testing
- SGS or BV third-party inspection report available upon request for independent material verification
- Full material traceability from coil input to finished tube, linked to heat number stamped on each piece
- Customs documentation package including packing list, bill of lading, and certificate of origin for destination clearance
Packaging, Loading & Delivery
- SS400 rectangular tubes bundled with steel strips and edge protectors to prevent coating damage during ocean transit, especially for galvanized and oiled surface finishes
- Custom cut-to-length service available from 1m to 16m, with cut ends deburred and marked with heat number and steel grade for site identification
- Container loading plans optimized for rectangular profile nesting, maximizing payload for 600mm×800mm heavy-wall sections while respecting port weight limits
- Galvanized tubes wrapped with waterproof paper and plastic sleeves to preserve zinc coating integrity during humid climate shipping
- Heat number and JIS SS400 grade stenciled on each bundle for traceability from mill to installation site
- FOB, CIF, and DDP shipping terms available with real-time tracking to ports across EU, North America, Middle East, Southeast Asia, and beyond
Start Your SS400 Rectangular Tube Procurement
Send your specification sheet — dimensions, wall thickness, steel grade, surface treatment, quantity, and destination port — and receive a detailed quotation within 12 hours, including delivery timeline and applicable certification documentation.
Request a Quotation with Mill Test Certificate
Submit your JIS SS400 rectangular steel tube requirements via email or WhatsApp, and our team will return pricing, certification details, and loading plans tailored to your project.
Email: admin@sdxjysteel.com
WhatsApp: +86 188 5315 7756
Frequently Asked Questions
Q: How does JIS SS400 compare to GB Q235 and EN S235JR for structural applications?
A: SS400, Q235, and S235JR share similar yield strength ranges for general structural use, though chemical composition boundaries differ slightly. We provide grade equivalence guidance and issue mill test certificates that satisfy destination inspectors regardless of which standard your project specifies.
Q: Can you provide mill test certificates for customs clearance and project compliance?
A: Yes. Every shipment includes original mill test certificates documenting chemical composition and mechanical properties per JIS G3101, linked to heat numbers traceable from raw coil to finished tube. Third-party inspection via SGS or BV is also available.
Q: What are the MOQ requirements for non-standard rectangular tube dimensions?
A: We produce over 2,800 specifications in-house, covering 10mm×30mm to 600mm×800mm rectangular and 15mm×15mm to 800mm×800mm square profiles with wall thickness from 0.5mm to 20mm. Custom non-standard sizes are available — contact us with your drawing for MOQ and lead time confirmation.
Q: Which surface treatment is best for outdoor structural applications?
A: For long-term outdoor exposure, hot-dip galvanized coating provides decades of corrosion resistance. For structures requiring final painting, shop primer with shot blasting offers a clean, weldable base. Oiled or bare finishes suit indoor or temporary applications where cost optimization takes priority.
Q: How do you handle container loading for heavy rectangular tubes?
A: Our logistics team prepares professional loading plans that nest rectangular profiles efficiently, maximizing container payload while respecting weight limits. We coordinate port delivery, provide real-time shipment tracking, and support FOB, CIF, and DDP terms to over 50 countries.
