Description
Factory-Direct S255JR Supply — Every S255JR square steel tube rolls from our own ERW and seamless lines, shipped with original mill test certificates and no trading markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S255JR Square Steel Tube |
| Product Type | Square Steel Tube |
| Steel Grade | S255JR, Gr.B, S235, S355, S275, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091, EN 10219, EN 10210 |
| Section Shape | Square |
| Size Range | 19mm × 19mm – 800mm × 800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW / Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain / Beveled |
| Processing Service | Bending / Welding / Cutting |
| Application | Steel structures / Construction frames / Curtain wall / Support tubes / Machinery / Scaffolding / Fertilizer equipment |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Industrial plant frameworks, pipe rack supports, equipment skid bases |
| Construction Companies | High-rise building columns, curtain wall mullions, scaffolding uprights |
| Machinery Manufacturers | Conveyor frames, agricultural equipment chassis, hydraulic support columns |
| Infrastructure Developers | Bridge handrail posts, sound barrier supports, solar panel mounting structures |
What Negative Tolerance Really Costs on a 90×90 Structural Frame Order
A 15% wall-thickness deviation on S255JR square steel tube turns a 50-ton order into a customs rejection and a two-ton weight shortfall.
I once watched a client in Ho Chi Minh pull calipers off the truck and measure every single 90×90 piece we delivered. The negative tolerance had drifted past 15%, and the theoretical weight versus actual weighbridge figure diverged by nearly two tons. The S255JR third-party inspection report came straight back rejected. Since then, I check wall thickness before I check chemistry. Every S255JR square steel tube leaving the mill now gets measured and weighed individually, with figures printed on the packing list. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections]
Matching S255JR Square Steel Tube to Structural Frame Loads
S255JR square steel tube in the 90×90 to 200×200 range with 4–10 mm wall thickness handles typical building frame and machinery base loads where yield strength matters more than extreme pressure resistance. The ERW process keeps unit cost lower than seamless for these structural applications, while the ±1% tolerance holds section modulus within design calculations. For corrosive environments such as coastal scaffolding or fertilizer plant frames, hot-dip galvanized S255JR square steel tube extends service life without repainting cycles.
Engineering Compliance and Certification Requirements
Structural frames designed to EN 1993 require hollow sections conforming to EN 10219 or EN 10210, and S255JR meets the S-series non-alloy structural grade specification. For projects shipping to the EU, Lloyd’s Register CE certification under EN 10210/EN 10219 decides whether the container clears Rotterdam or gets held for document review. In North America, ASTM A500 Gr.B equivalence applies, and our mill test certificates cross-reference both standards. [NEED_CITE: steel grade equivalence mapping between EN 10219 S255JR and ASTM A500 Gr.B] Fixed lengths of 6m and 12m align with standard container loading, while beveled ends reduce on-site welding preparation time for moment connections.
S255JR Grade and ERW Process Explained
S255JR belongs to the EN 10025 S-series non-alloy structural steel family, where the “255” indicates minimum yield strength at 16 mm thickness and “JR” specifies 27J Charpy impact energy at room temperature. Compared to S235, S255JR provides higher load-bearing capacity for the same cross-section; compared to S355, it offers better weldability and lower cost for moderate-load frames. The ERW welding process forms the square section from hot-rolled coil through continuous forming and high-frequency welding, producing a consistent weld seam suitable for structural applications up to moderate pressure. Seamless S255JR square steel tube, available in thicker walls up to 30 mm, serves higher-load columns and machinery bases where weld seam integrity becomes critical. Black painted surface protects during transit and fabrication; hot-dip galvanizing adds 45–85 μm zinc coating for outdoor or humid environments; bare finish suits indoor machinery frames where painting follows on-site.
Hidden Costs of Buying the Wrong Grade or Missing Certificates
Specifying S235 when the structural engineer calculated for S255JR means the frame deflects beyond allowable limits under design load — discovered only after erection, when replacement means dismantling and re-welding. Shipping S255JR square steel tube to the EU without EN 10219 CE marking triggers customs holds that delay project timelines by weeks, with storage and demurrage costs added. Wall thickness below the specified tolerance reduces section modulus, forcing the structural engineer to either reject the batch or redesign the connection details. [NEED_CITE: consequences of dimensional non-compliance in structural steel procurement] Missing mill test certificates mean the material cannot be traced to heat number, and third-party inspectors will not sign off on the installation.
Why Procure S255JR Square Steel Tube From Our Mill
Our three dedicated production lines cover 2,800+ specifications in square and rectangular hollow sections, meaning your 90×90 S255JR order ships from the same facility that produces your 200×200 S355 beams — one contract, one quality system, one delivery schedule. The in-house physical and chemical laboratory tests every heat before rolling and issues original mill test certificates showing full composition and mechanical results. We hold 41 invention patents including proprietary sharp-corner rectangular tube technology, and our products carry Lloyd’s Register EU CE (EN 10210/EN 10219), ISO 9001:2015, Singapore FPC, plus SGS and BV verification. Custom non-standard sizes below 5 tons remain available through our dedicated short-run line. Professional loading plans optimize container fill for 6m and 12m lengths, and our export team coordinates FOB, CIF, or DDP delivery to 50+ countries.
Documentation & Compliance
- Mill test certificate documenting S255JR chemical composition (C, Mn, Si, P, S) and yield strength per EN 10219, traceable to heat number
- Lloyd’s Register CE certificate confirming EN 10210/EN 10219 compliance for EU market customs clearance
- ISO 9001:2015 quality management certificate covering the full production and inspection process
- SGS or BV third-party inspection report available upon request before shipment, covering dimensional and visual checks
- Material traceability sheet linking each bundle to heat number, production date, and test results
- Full customs document package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- S255JR square steel tubes bundled with high-tensile steel strips at six points, with wooden cradles at each end to prevent deformation during ocean transit
- Galvanized S255JR tubes wrapped with edge protectors and waterproof paper to preserve the zinc coating from moisture and salt spray
- 6m and 12m fixed lengths loaded in 20ft and 40ft containers with optimized nesting for 90×90 to 200×200 sections, maximizing weight per container
- Custom cutting to site-specific lengths available, with cut ends deburred and marked with heat number and steel grade
- Each bundle tagged with waterproof label showing steel grade S255JR, size, wall thickness, length, heat number, and gross/net weight
- FOB Jinan/Qingdao, CIF destination port, or DDP door-to-door delivery coordinated with forwarders experienced in heavy steel cargo
Request Your S255JR Square Steel Tube Quotation
Send your size, wall thickness, steel grade, quantity, and destination port, and receive a detailed quotation within 12 hours including unit price, mill test certificate confirmation, production timeline, and applicable certification documents. For non-standard dimensions or mixed-size orders, our technical team provides a custom production plan with MOQ and lead time.
Get Your S255JR Square Steel Tube Quote and Mill Test Certificate
Submit your specifications by email or WhatsApp to receive pricing, certification details, and delivery options.
Email: admin@sdxjysteel.com
WhatsApp: +86 188 5315 7756
Frequently Asked Questions
Q: What is the difference between S255JR, S235, and S355 square steel tube for structural frames?
A: S255JR offers higher minimum yield strength than S235 for heavier loads, while S355 provides even greater capacity for high-stress applications. S255JR balances strength and weldability for most building frames and machinery bases, and our mill produces all three grades on the same ERW and seamless lines.
Q: Can you provide mill test certificates and third-party inspection for S255JR square steel tube?
A: Yes, every shipment includes original mill test certificates showing chemical composition and mechanical properties per EN 10219 or ASTM A500, traceable to heat number. SGS or BV third-party inspection is available before shipment at your request.
Q: Do you produce non-standard sizes for S255JR square steel tube below the 5-ton MOQ?
A: Yes, our dedicated short-run production line handles custom non-standard dimensions and smaller quantities. Contact our technical team with your drawing or specification for a tailored production plan.
Q: Which surface treatment suits S255JR square steel tube for outdoor construction use?
A: Hot-dip galvanizing provides long-term corrosion protection for outdoor scaffolding, bridge supports, and coastal structures. Black painting suits indoor or temporary exposure, while bare finish works for indoor machinery frames that receive on-site painting.
Q: What certification do I need to clear S255JR square steel tube through EU customs?
A: Lloyd’s Register CE certification under EN 10210/EN 10219 is required for structural hollow sections entering the EU market. We provide the CE certificate, mill test certificates, and full customs document package with every shipment.
Secure Factory-Direct S255JR Square Steel Tube Pricing and Full Certification
Send your size, wall thickness, quantity, and destination port to receive a detailed quotation with mill test certificate confirmation within 12 hours.
Email: admin@sdxjysteel.com | WhatsApp: +86 188 5315 7756
