Description
Factory-Direct HDG Sharp-Corner Tubes — Q235B and Q345B hot-dip galvanized sharp-corner rectangular steel tubes produced on our own ERW lines and shipped with full mill test certificates to 50+ countries.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B / Q345B HDG Sharp-Corner Rectangular Steel Tube |
| Product Type | Sharp-Corner (Right-Angle) Rectangular Steel Tube |
| Steel Grade | Q235B, Q345B |
| Standard | GB/T 6728; equivalent grades per EN 10219 / EN 10210 / ASTM A500 / JIS G3466 / AS1163 |
| Section Shape | Square / Rectangular (Sharp-Corner / Right-Angle) |
| Side Length | 150–625 mm |
| Length | 5–15 m (standard 5.8 m / 6 m / 12 m available) |
| Technique | ERW |
| Surface Treatment | Hot-Dip Galvanized (HDG) |
| Tolerance | ±1% |
| Ends | Plain / Beveled on request |
| Application | Steel structures, glass curtain walls, architectural facades, machinery frames |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & EPC | Building frames, bridge support structures, industrial plant steelwork |
| Facade & Curtain Wall | Architectural facade framing, glass curtain wall mullions and transoms |
| Machinery Manufacturing | Conveyor structures, crane booms, equipment base frames |
| Infrastructure | Sound barrier frames, solar mounting structures, utility gantries |
Where Hot-Dip Galvanizing Meets Sharp-Corner Geometry on a Facade Order
Standard rectangular tubes with rounded corners (R≥2t) leave visible gaps at facade joints — our patented sharp-corner forming delivers true 90° angles while the HDG coating survives tropical humidity without peeling.
On a curtain wall project in Southeast Asia, a batch of HDG rectangular tubes arrived with zinc coating that passed mill paperwork but peeled at the corners within weeks. The galvanizing line had not properly pre-treated the sharp edges before dipping. That shipment sat in a yard for months while the buyer, contractor, and galvanizer argued over liability. Ever since, I personally check every HDG order’s corner prep and coating uniformity before it leaves Jinan. Procurement teams ordering a Q235B Q345B HDG sharp-corner rectangular steel tube supplier often face three hidden risks: corner zinc thinning that accelerates rust in coastal environments, tolerance stacking that misaligns facade mullions, and missing EN equivalence that blocks EU customs clearance [NEED_CITE: EN 10219 cold-formed hollow section requirements].
How True Right-Angle Corners Match Curtain Wall Framing Demands
Facade engineers specifying a Q235B Q345B HDG sharp-corner rectangular steel tube supplier need corners that sit flush against glass clamp plates without filler shims. Our patented cold-forming process produces corners with R≈0, eliminating the rounded-edge gap that forces contractors to grind or weld on-site. The hot-dip galvanized coating — applied after forming — covers all four corners uniformly, giving curtain wall frames in coastal cities the corrosion margin that pre-galvanized tubes cannot match.
Structural Compliance and Certification Pathways for Global Projects
Load calculations for facade framing and steel structures typically reference EN 1993 or AISC 360, both of which accept cold-formed hollow sections meeting EN 10219 dimensional tolerances [NEED_CITE: EN 10219 cold-formed hollow section requirements]. For EU projects, Lloyd’s CE certification to EN 10210/EN 10219 is mandatory for structural hollow sections — without it, customs holds the shipment regardless of mill paperwork. North American buyers need ASTM A500 equivalence, which our Q345B grade satisfies through documented mechanical property correlation. On-site, the ±1% tolerance and 5–15 m length range allow direct cutting to design lengths, reducing secondary welding and preserving the galvanized layer at cut points when cold-saw methods are used.
Q235B vs. Q345B: Yield Strength, Formability, and Galvanizing Response
Q235B offers lower yield strength suited to non-load-bearing facade elements and light machinery frames, while Q345B provides higher yield capacity for primary structural members and bridge components. Both grades respond well to hot-dip galvanizing because their carbon equivalents stay within the range that prevents zinc-iron brittleness at the coating interface. The ERW welding process produces a longitudinal seam that, after galvanizing, becomes visually indistinguishable from the parent metal — critical for exposed architectural applications. Sharp-corner forming on these grades relies on controlled bend-radius sequencing; our 41 invention patents cover the die geometry that prevents corner cracking while maintaining R≈0 angles [NEED_CITE: steel grade equivalence between EN and ASTM standards].
Hidden Costs When Corner Prep or Certification Falls Short
Ordering sharp-corner tubes from a supplier without galvanizing expertise risks corner zinc thinning that fails salt-spray tests within months — replacement costs triple the original material spend. Missing CE documentation for EU-bound shipments triggers customs rejection, demurrage charges, and project delays that dwarf the steel price difference. Tolerance beyond ±1% forces on-site re-cutting, which exposes bare steel at cut points and voids the galvanized warranty. Engineering inspectors referencing EN 10219 will reject tubes without traceable heat numbers linked to mill test certificates [NEED_CITE: EN 10219 cold-formed hollow section requirements].
Why Procurement Teams Specify Xin Jiyuan for HDG Sharp-Corner Tubes
Our three ERW production lines cover 2,800+ specifications including the 150–625 mm side-length range in this product, so facade contractors source tubes and beams from a single mill rather than splitting orders across three vendors. The in-house physical and chemical laboratory tests every heat for composition and mechanical properties before galvanizing — I review coating thickness reports personally. Full international certifications (ISO 9001:2015, Lloyd’s CE to EN 10210/EN 10219, Singapore FPC, SGS/BV verification) clear customs in EU, North America, and Southeast Asia without supplementary paperwork. Custom non-standard sizes and定尺切割 enter production within typical lead times, and our container loading team uses edge protectors and anti-shift bracing to prevent HDG coating damage during ocean transit.
Documentation & Compliance
- Mill test certificate documenting Q235B/Q345B chemical composition and mechanical properties per GB/T 6728, traceable by heat number
- Lloyd’s CE certificate confirming EN 10219/EN 10210 compliance for EU structural hollow section imports
- ISO 9001:2015 quality management certificate covering the full ERW forming and HDG coating process
- SGS or BV third-party inspection report available before shipment for projects requiring independent verification
- Material traceability linking each bundle to its heat number, galvanizing bath temperature log, and coating thickness measurement
- Export customs documents including packing list, bill of lading, and certificate of origin formatted for destination-country clearance
Packaging, Loading & Delivery
- Q235B/Q345B HDG tubes bundled with steel strips and edge protectors to preserve the zinc coating at sharp corners during ocean transit
- Hot-dip galvanized surface inspected for coating uniformity before wrapping; bundles labeled with heat number, steel grade, and dimensional spec
- 150–625 mm side-length tubes loaded in containers with anti-shift bracing; 5.8 m / 6 m / 12 m standard lengths optimized for 20ft and 40ft open-top containers
- Custom cut-to-length service available for 5–15 m requirements; cut ends cold-sawed to avoid damaging the galvanized layer
- Shipping terms FOB/CIF/DDP with professional container loading plans that maximize payload while protecting HDG coating integrity
Getting a Quote for Your HDG Sharp-Corner Tube Project
Send your specification sheet — section dimensions, steel grade preference (Q235B or Q345B), total tonnage, and destination port — and receive a detailed quotation with unit pricing, typical production lead times, and shipping terms within 12 hours. Request mill test certificates and CE documentation upfront to confirm compliance with your project’s structural and customs requirements. For non-standard sizes or定尺切割 outside the 150–625 mm range, our engineering team will provide a custom feasibility assessment.
Frequently Asked Questions
Q: How do Q235B and Q345B compare to European and American steel grades?
A: Q235B correlates to S235JR per EN 10219 and ASTM A500 Gr.A/B; Q345B correlates to S355JR per EN 10219 and ASTM A500 Gr.C/D. We provide equivalence documentation for customs and engineering approval.
Q: What is the difference between sharp-corner tubes and standard rectangular tubes?
A: Standard rectangular tubes have rounded corners (R≥2t) from the forming process, while our patented sharp-corner technology produces true 90° angles (R≈0) for flush facade joints and cleaner architectural lines.
Q: Can you produce custom non-standard sizes and what is the MOQ?
A: Yes, we manufacture custom dimensions outside the 150–625 mm standard range. MOQ depends on the specification — contact us with your drawing for a detailed assessment.
Q: How do you ensure the galvanized coating survives shipping without damage?
A: HDG tubes are bundled with edge protectors at sharp corners, loaded with anti-shift bracing, and inspected for coating uniformity before container sealing. Our loading team has specific protocols for preserving zinc coating integrity during ocean transit.
Request Your HDG Sharp-Corner Tube Quotation
Submit your project specifications — dimensions, steel grade, quantity, and destination — to receive a detailed quotation with mill test certificates and compliance documentation.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
