Description
Factory-Direct Sharp-Corner RHS — Q235B and Q345B sharp corner rectangular steel tubes rolled on three dedicated lines with wall thickness up to 40 mm, shipped with in-house lab-verified MTC to 50+ countries.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B / Q345B Sharp Corner Rectangular Steel Tube |
| Product Type | Sharp Corner Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q235B, Q345B |
| Standard | GB/T 6728; EN 10219 / EN 10210 / ASTM A500 available upon request |
| Section Shape | Rectangular (Sharp Corner) |
| Size Range | Up to 500 × 1000 mm; customizable non-standard sizes |
| Wall Thickness | Up to 40 mm |
| Length | 5.8 m / 6 m / 12 m; customizable 5–15 m |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Bending, Cutting, Decoiling, Punching, Welding |
| Application | Steel structures, construction frames, industrial buildings, machinery frames, infrastructure |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Steel structure procurement for industrial plants, pipe racks, equipment support frames |
| Construction Companies | High-rise building frames, bridge components, infrastructure formwork |
| Machinery Manufacturers | Conveyor frames, automation equipment bases, precision structural supports |
| System Integrators | Industrial racking, modular platform structures, conveyor system fabrication |
What Tolerance Drift Costs on a Sharp-Corner Frame Order
A ±1% tolerance on a sharp-corner rectangular steel tube is not a paperwork detail — it decides whether your beam flanges sit flush or need re-cutting on site.
When wall thickness drifts beyond tolerance, the sharp 90° inner radius deforms into a rounded corner, and weld joints misalign during assembly. I once shipped a batch of oblique-angle rectangular tubes to a steel structure project in Mexico City — the wall negative tolerance was pushed to the limit, and the whole container had to be re-cut on site. After that, every batch from our sharp corner rectangular steel tube supplier lines goes through our in-house physical and chemical laboratory before shipment, and nothing leaves until the MTC data checks out. [NEED_CITE: EN 10219 cold-formed structural hollow sections tolerance requirements]
How Sharp-Corner Geometry Matches Structural Connections
Standard ERW RHS produces rounded inner corners that create gaps at moment connections and bolted joints. The proprietary sharp-corner forming process delivers a true 90° inner radius, allowing beam-to-column connections to sit flush without filler plates — critical for EPC contractors assembling steel structures where every millimeter of misalignment compounds across a multi-story frame. As a sharp corner rectangular steel tube supplier, we hold 41 invention patents including the sharp-corner technology that fills gaps in global specifications, with 2,800+ models covering non-standard sizes that standard catalogs cannot reach.
Engineering Compliance and Certification Pathways
Structural frames designed to EN 1993 require hollow sections conforming to EN 10219 or EN 10210 — and customs authorities in the EU will not clear shipments without the CE certificate referencing these standards. For North American projects, ASTM A500 Grade B or C equivalence must be documented on the mill test certificate. Our sharp corner rectangular steel tube supplier facility holds CE certification under EN 10210 / EN 10219, Singapore FPC, and ISO 9001:2015, with SGS and BV third-party inspection available at buyer’s request. [NEED_CITE: steel grade equivalence between Q235B and S235JR / ASTM A36] Hot rolled surface finish arrives ready for painting or galvanizing, avoiding the adhesion problems that occur when mill scale is left unremoved.
Q235B vs Q345B: Selecting the Right Grade for Load and Environment
Q235B is the workhorse carbon structural steel for general fabrication — adequate for non-critical frames, scaffolding, and light industrial buildings where yield strength requirements are moderate. Q345B delivers higher yield strength for heavy-load applications: crane beams, bridge components, and high-rise structural frames where weight-to-strength ratio matters. Both grades are fully weldable using standard ERW processes, and the ±1% tolerance ensures consistent mechanical properties across the full wall thickness range up to 40 mm. The ERW welding seam undergoes full integrity testing, and hot rolled surface treatment provides a clean base for downstream coating systems in corrosive environments. [NEED_CITE: Q235B Q345B mechanical properties comparison for structural applications]
Hidden Costs When Certification or Tolerance Fails
Ordering a sharp corner rectangular steel tube supplier without verified CE documentation means the container sits at EU customs — demurrage charges accumulate while the mill scrambles to produce retroactive paperwork. Material that fails tolerance checks on site forces re-cutting, delays the erection schedule, and triggers structural engineer re-approval. Steel grade misidentification — receiving Q235B when Q345B was specified — creates latent safety risks that only surface during load testing or inspection audits. [NEED_CITE: consequences of missing mill test certificates in structural steel procurement]
Why Procurement Teams Source Sharp-Corner RHS From Xin Jiyuan
Three dedicated production lines with in-house physical and chemical laboratories mean every heat number is tested before shipment — no outsourcing QC to third-party labs that add weeks to lead time. Factory-direct pricing eliminates trading company margins, and 2,800+ specifications in stock reduce the “sorry, that size requires a new tooling run” delay that fragments sourcing across multiple suppliers. The proprietary sharp-corner technology — a domestic and international first among sharp corner rectangular steel tube supplier facilities — produces true 90° corners that standard roll-forming cannot achieve. Professional loading plans optimize container utilization for 12 m lengths, and door-to-door logistics coordination handles FOB, CIF, and DDP terms to 50+ countries.
Documentation & Compliance
- Mill Test Certificate documenting Q235B / Q345B chemical composition and mechanical properties per GB/T 6728, with heat number traceability
- CE certificate under EN 10210 / EN 10219 for EU market compliance and customs clearance
- ISO 9001:2015 quality management system certificate covering the full production process
- SGS or BV third-party inspection report available at buyer’s request before shipment
- Material traceability report linking each bundle to heat number, production date, and lab test results
- Customs document package: packing list, Bill of Lading, Certificate of Origin, and commercial invoice
Packaging, Loading & Delivery
- Hot rolled Q235B / Q345B sharp corner rectangular steel tubes bundled with steel strips and edge protectors to prevent corner damage during ocean transit
- Surface protection with anti-rust oil applied to hot rolled finish, preserving the mill scale-free surface for downstream painting or galvanizing
- Container loading plans optimized for 6 m / 12 m standard lengths, with custom 5–15 m cut-to-size bundles consolidated for full-container shipments
- Heat number and steel grade stenciled on each bundle, with packing lists cross-referenced to MTC for site verification
- FOB / CIF / DDP terms with door-to-door logistics coordination to ports in EU, North America, Southeast Asia, and Middle East
Request a Quote With Mill Test Certificate
Submit your sharp corner rectangular steel tube specifications — section size, wall thickness, steel grade, quantity, and destination port — and receive a detailed quotation including unit price, delivery time, payment terms, and applicable certifications within 12 hours. For non-standard sizes outside the 2,800+ catalog, our engineering team provides custom tooling feasibility and lead time confirmation before you commit.
Start Your Sharp-Corner RHS Inquiry
Send your specifications to admin@sdxjysteel.com or WhatsApp +86 188 5315 7756 to receive pricing and MTC samples.
Frequently Asked Questions
Q: What is the difference between a sharp-corner rectangular tube and standard ERW RHS?
A: Standard ERW rectangular hollow sections have rounded inner corners formed by conventional roll-forming. Sharp-corner rectangular tubes use a proprietary forming process that produces a true 90° inner radius, allowing flush-fit connections at beam-to-column joints without filler plates or re-cutting.
Q: Can Q235B be used as an equivalent to S235JR or ASTM A36?
A: Q235B, S235JR, and ASTM A36 are broadly equivalent in carbon structural steel applications, with minor differences in chemical composition and testing standards. For EU projects, we can supply sharp corner rectangular steel tube products certified to EN 10219 with S235JR designation; for North America, ASTM A500 equivalence is available upon request.
Q: What is the minimum order quantity for custom non-standard sizes?
A: Standard sizes from the 2,800+ catalog have no minimum order quantity beyond one bundle. Custom non-standard sizes outside catalog specifications require tooling setup, and MOQ depends on the section dimensions and wall thickness — contact our team with your drawing for a feasibility assessment.
Q: How do you ensure wall thickness tolerance on sharp-corner tubes?
A: Every production batch undergoes incoming, in-process, and final inspection in our in-house physical and chemical laboratory. Ultrasonic thickness testing verifies the ±1% tolerance across all four corners and flat surfaces, and the original mill test certificate documents results before shipment.
Q: What certifications are included for EU customs clearance?
A: EU shipments include CE certificate under EN 10210 / EN 10219, mill test certificate per EN 10204 3.1, packing list, Bill of Lading, and Certificate of Origin. SGS or BV third-party inspection reports are available at buyer’s request for additional compliance verification.
