Description
Factory-Direct Square Hollow Sections — S255JR square steel tubes rolled and welded in-house, shipped with original mill test certificates to over 50 countries.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S255JR Square Steel Tube |
| Product Type | Square Steel Tube / Square Hollow Section (SHS) |
| Steel Grade | S255JR, Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Square |
| Size Range | 19 mm × 19 mm – 800 mm × 800 mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8 m / 6 m / 11.8 m / 12 m / Random Length |
| Technique | ERW Welded / Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction Structure / Building / Curtain Wall / Support Tubes / Structure Pipe / Fertilizer Tube |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building & Construction | Steel frames for warehouses, high-rise curtain wall mullions, column bracing |
| Industrial Infrastructure | Equipment support frames, conveyor structures, industrial platforms |
| Agricultural & Fertilizer | Greenhouse skeleton tubes, fertilizer distribution piping |
| General Structural | Scaffolding uprights, machine base frames, load-bearing brackets |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on S255JR square steel tubes keeps fabrication crews from re-cutting or re-welding on site.
I have stood on job sites where a full container of square tubes arrived with wall thickness deviations exceeding 15%. The third-party inspector flagged every piece, the contractor refused acceptance, and the entire shipment had to be pulled out of the container and re-sorted. That kind of failure does not come from the steel grade — it comes from suppliers who ship by theoretical weight instead of measured dimensions. When you source an S255JR square steel tube supplier who controls tolerance at the mill, the tubes fit the connection plates the first time [NEED_CITE: EN 10219 cold-formed structural hollow section dimensional tolerances].
Matching S255JR Square Tubes to Structural Frame Loads
S255JR square steel tubes in the 100 × 100 mm to 300 × 300 mm range with wall thickness above 6 mm serve as primary load-bearing members in portal frames and mezzanine structures. The ERW welded process keeps unit cost lower for non-pressure applications, while seamless options handle higher point loads where weld-line integrity matters. Galvanized finish is specified for outdoor exposure — warehouse eaves, agricultural sheds — where black-painted tubes would corrode within months.
Engineering Compliance and Surface Selection
Structural frames designed under EN 1993-1-1 or AISC 360 require traceable mill certificates confirming chemical composition and yield behavior. S255JR conforms to EN 10025-2 and maps directly to ASTM A500 Grade B and GB Q235B, simplifying cross-standard procurement [NEED_CITE: steel grade equivalence between EN 10025 and ASTM A500]. For corrosion-prone environments, hot-dip galvanized coating extends service life without field painting. Custom cut-to-length at 5.8 m or 6 m reduces on-site welding and waste.
Steel Grade and Process Selection for Square Hollow Sections
S255JR delivers minimum 255 MPa yield strength, suitable for general structural frames where high-strength grades are not specified. Moving to S355 increases load capacity for the same cross-section, reducing self-weight on long-span structures. The ERW welded process forms the tube from coil through continuous rolling and longitudinal welding — cost-effective for standard structural sizes. Seamless tubes, produced by piercing solid billets, eliminate the weld seam entirely and are preferred for critical connections or dynamic loading. Surface treatment choice depends on environment: bare or varnished for indoor use, black painted for temporary outdoor protection, galvanized for permanent exterior exposure.
Hidden Costs of Sourcing the Wrong Square Tube
Ordering S255JR square steel tubes without verified mill certificates risks customs rejection in markets requiring CE or SGS documentation. Negative tolerance beyond acceptable limits means the tubes carry less steel than paid for — reducing load capacity and triggering structural re-calculation. Missing heat-number traceability blocks project handover documentation. These failures do not show up in the purchase price; they surface during inspection, at the port, or after the frame is erected [NEED_CITE: structural hollow section compliance requirements for CE marking].
Why Project Buyers Source S255JR Square Steel Tubes from XJY Plate
Every S255JR square steel tube leaving our facility carries an original mill test certificate with heat number, chemical composition, and mechanical test results — verified by our in-house metallurgical laboratory before shipment. We stock the full range from 19 × 19 mm to 800 × 800 mm across S255JR, S355, and allied grades, so mixed-size container orders ship without waiting for mill rolling. Third-party inspection by SGS or BV is arranged on request, with reports issued before container sealing. Our loading team specializes in heavy, long-length square tubes — using open-top containers and break-bulk methods that prevent edge damage and overweight penalties. ISO 9001:2015 and CE certification back every order, with full traceability from coil to finished tube.
Documentation & Compliance
- Mill test certificate documenting S255JR chemical composition and mechanical properties per EN 10025-2, with heat number traceability
- CE certificate confirming conformity to EN 10219 for cold-formed structural hollow sections
- ISO 9001:2015 quality management certificate covering production and inspection processes
- SGS or BV third-party inspection report issued before shipment, covering dimensional and visual checks
- Material traceability sheet linking each bundle to its heat number and coil origin
- Full customs documentation set: packing list, bill of lading, certificate of origin
Packaging, Loading & Delivery
- S255JR square tubes bundled with steel strips and edge protectors to prevent zinc coating damage on galvanized finishes
- Black-painted tubes wrapped in waterproof paper before bundling to preserve surface during ocean transit
- 6 m and 11.8 m lengths loaded in open-top containers or flatbed trailers to avoid bending and edge crush
- Custom cut-to-size orders marked with heat number and steel grade on each piece for site identification
- FOB, CIF, and DDP shipping terms available, with professional heavy-cargo logistics to port or project site
Getting Your S255JR Square Tube Quote Started
Send your size schedule — outer dimension, wall thickness, length, steel grade, and quantity — along with the destination port. We return a detailed quotation within 12 hours, including material cost, any cutting fees, and shipping terms, plus a sample mill test certificate for your quality team to review before deposit.
Request Your S255JR Square Steel Tube Quotation Today
Submit your specification sheet to receive pricing, mill test certificates, and shipping options within one business day.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjyplate.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjyplate.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How does S255JR compare to ASTM A500 Grade B and Q235B?
A: S255JR, ASTM A500 Grade B, and Q235B are closely matched in yield strength and chemical composition, making them interchangeable for general structural applications. We supply all three designations and provide cross-reference documentation for customs and engineering approval.
Q: Can I get a mill test certificate before shipment?
A: Yes. We provide original mill test certificates showing chemical composition and mechanical properties for every S255JR square steel tube order, available for your review before or at the time of shipment.
Q: What is the minimum order quantity for custom cut-to-size tubes?
A: The minimum order is 5 tons. We can cut to non-standard lengths and dimensions within the 19 × 19 mm to 800 × 800 mm range, with processing fees quoted separately.
Q: Should I choose galvanized or black-painted finish?
A: Galvanized finish is recommended for permanent outdoor exposure — building frames, agricultural structures, infrastructure. Black painting suits indoor or temporary outdoor use where cost is the priority. Bare tubes are available for projects that apply their own coating system.
Q: How are long-length square tubes loaded to avoid damage?
A: Tubes at 6 m and 11.8 m are loaded in open-top containers or on flatbed trailers with timber separators and edge protectors. Our loading team has specific experience with heavy square hollow sections to prevent bending, coating damage, and overweight penalties.
