Description
Factory-Direct Rectangular Hollow Sections — 3 production lines running simultaneously with 20,000+ tons monthly capacity, delivering Q195 through S355JR grades at bulk pricing without middleman markups.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | S355JR Rectangular Hollow Section |
| Product Type | Rectangular Steel Tube / Rectangular Hollow Section (RHS) |
| Steel Grade | Q195, Q235, Q345, S235JR, S275JR, S355JR |
| Standard | ASTM |
| Section Shape | Rectangular |
| Size Range | 20×20mm – 50×50mm (20×20, 40×40, 40×60, 40×80, 50×50mm) |
| Outer Diameter | 0.8 – 15 inches |
| Length | 6m / 6.4m / 12m |
| Technique | Hot Rolled |
| Surface Treatment | Black / Oiled (as requirement) |
| Tolerance | ±1% |
| Ends | Plastic Pipe Cap (End protector) |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Application | Steel structures / Construction frames / Building frameworks / Ornamental and decorative designs / Indoor and outdoor structural use |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frameworks, structural columns, roof trusses, mezzanine floor supports |
| Architectural Design | Ornamental facades, decorative screen walls, canopy structures, interior feature frames |
| Industrial & Machinery | Equipment base frames, conveyor support structures, platform guardrails, machine guarding enclosures |
| Commercial Buildings | Retail display structures, warehouse racking uprights, parking structure bracing |
What Negative Tolerance Actually Costs on a 40×80 Structural Frame Order
A 15% wall-thickness deviation on a container load of rectangular tubes means two tons of missing steel — and an air-freight bill that dwarfs the material cost.
I spent three months on a warehouse project in Lagos where 40×80 rectangular hollow sections arrived with wall thickness running 15% below nominal. The third-party inspector flagged it at port. The client rejected the entire lot. By the time replacement pieces flew out, the air freight cost more than the steel itself. This is not an isolated story. Global buyers sourcing S355JR rectangular hollow section steel tube supplier shipments from fragmented vendors face the same pattern: inconsistent grade traceability, missing mill certificates that stall customs, and negative tolerance that only shows up after cutting begins on site. [NEED_CITE: impact of negative tolerance on structural steel invoicing and load-bearing capacity]
How Hot-Rolled RHS Matches Structural Frame Requirements
The hot-rolled process produces rectangular hollow sections with uniform corner radius and consistent wall distribution across the 20×20mm to 50×50mm size range. For structural frames in building frameworks and industrial supports, this means predictable load paths at connection points — welds sit on material that has not been cold-worked into stress concentrations. The black finish with optional oiling handles indoor environments and short-term outdoor exposure during construction phases, while the ±1% dimensional tolerance keeps fabrication drawings accurate. As a S355JR rectangular hollow section steel tube supplier running three production lines, we hold ready stock in 6m and 12m lengths that ship within standard lead times, so site crews do not wait for custom rolling schedules.
Structural Compliance and Grade Selection for Engineering Projects
Rectangular hollow sections in S355JR and Q345 grades meet the yield strength requirements for load-bearing frames under ASTM standards, where structural engineers specify minimum section modulus and moment of inertia for beam and column design. [NEED_CITE: ASTM A500 structural hollow section grade requirements] The S-series grades (S235JR, S275JR, S355JR) align with EN 10219 cold-formed specifications, giving EPC contractors a single procurement source for projects spanning both European and North American design codes. Surface treatment selection matters: black oiled RHS works for interior structural use and painted finishes, while projects in coastal or high-humidity zones should specify galvanized coating to prevent corrosion undercut at welded joints. Fixed 6m and 12m lengths reduce on-site cutting waste, and the plastic pipe cap end protectors prevent damage during container loading and ocean transit.
Understanding Steel Grade Equivalence Across Standards
The Q-series (Q195, Q235, Q345) follows Chinese GB standards where the number indicates minimum yield strength in MPa. The S-series (S235JR, S275JR, S355JR) follows EN standards with JR denoting room-temperature impact toughness at 27J. [NEED_CITE: steel grade equivalence between GB Q-series and EN S-series standards] For buyers specifying ASTM A500, Q345 and S355JR both deliver higher yield strength suitable for primary structural members, while Q195 and S235JR serve lighter secondary structures and ornamental applications. Hot-rolled rectangular hollow sections in these grades offer better corner integrity than cold-formed alternatives for welded connections, since the material has not undergone the severe bending that creates residual stresses at the corner radii. The ±1% tolerance on the 40×80 and 50×50 sizes ensures that theoretical weight invoicing matches actual delivered mass within acceptable engineering margins — a critical factor when container loads are billed by calculated weight rather than weighbridge.
Hidden Costs of Procuring Rectangular Hollow Sections Without Verification
Material that arrives without original mill test certificates creates a cascade of problems: customs authorities hold containers pending grade confirmation, structural engineers refuse to sign off on load calculations without traceable chemistry data, and project owners demand third-party retesting at the buyer’s expense. [NEED_CITE: documentation requirements for structural steel imports] Negative tolerance beyond contractual limits does not just affect weight — it reduces section modulus below design values, forcing engineers to either reject the material or redesign the structure. Certification gaps between EN 10210/10219 and ASTM A500 cause shipment rejections at destination ports, particularly in markets with mandatory pre-shipment inspection programs. The cost of replacing rejected steel after vessel departure includes not only replacement material and expedited freight but also project delay penalties and idle labor on site.
Why Project Buyers Source S355JR RHS From Xin Jiyuan
Our Jinan facility operates three simultaneous production lines covering the full 20×20mm to 50×50mm rectangular range in Q195 through S355JR grades, giving bulk buyers single-source procurement without splitting orders across multiple mills. Every batch ships with original mill test certificates documenting chemical composition and mechanical properties, and we arrange SGS or BV third-party inspection at the factory before container sealing — the same verification step that would have caught the Lagos wall-thickness problem before the vessel loaded. With 2,800+ specifications in ready stock, standard sizes ship on urgent timelines while custom orders follow typical production lead times. Our export team handles container loading optimization for 6m and 12m lengths, maximizing payload per shipment and reducing per-ton freight costs. Volume discount programs apply to recurring orders, and we consolidate multi-product shipments — rectangular tubes, square tubes, plates, and sections — into single containers for project buyers needing full-category supply.
Documentation & Compliance
- Mill test certificate documenting S355JR chemical composition and yield strength per ASTM standard, issued per heat number for full traceability
- CE certificate covering EN 10210/EN 10219 hollow section compliance for European market customs clearance
- ISO 9001:2015 quality management certificate covering production processes and inspection procedures
- SGS or BV third-party inspection report available on request, verifying dimensional tolerance and surface quality before shipment
- Material traceability by heat number stamped on each bundle, linking physical delivery to mill test certificate data
- Complete customs documentation package including packing list, bill of lading, and certificate of origin for destination port clearance
Packaging, Loading & Delivery
- Hot-rolled black rectangular tubes bundled with steel strips and edge protectors, preserving surface condition during ocean transit for Q195–S355JR grades
- Oiled surface treatment applied per buyer specification to prevent flash rust on S235JR and S355JR RHS during humid climate storage and shipping
- Container loading optimized for 6m and 12m fixed lengths in 20ft and 40ft containers, maximizing payload for 40×80 and 50×50mm rectangular sections
- Plastic pipe cap end protectors fitted on all cut ends to prevent damage and moisture ingress during handling and transit
- Heat number and steel grade markings stenciled on each bundle for site identification and inspection traceability
- FOB, CIF, and DDP shipping terms available with professional export documentation handling for 50+ destination countries
Getting Your Rectangular Hollow Section Quote Started
Submit your specification sheet with section dimensions, steel grade requirement, total tonnage, and destination port — we respond within 12 hours with bulk pricing, mill test certificate confirmation, and delivery timeline. For non-standard rectangular sizes outside the 20×20mm to 50×50mm range, share your drawing for custom rolling feasibility and lead time assessment. Confirm whether SGS or BV third-party inspection is required for your project compliance, and we will schedule factory verification before container loading.
Request Factory-Direct Pricing With Mill Test Certificates
Send your rectangular hollow section specifications, steel grade, quantity, and destination port to receive bulk pricing and delivery confirmation.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Email: admin@sdxinjiyuan.com
Tel: +86 531 8573 6315
WhatsApp: +86 188 5315 7756
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
