Description
Factory-Direct Rectangular RHS Supplier — ASTM A500 GR.B welded hollow sections produced in-house with 2,800+ specification coverage and full mill test documentation.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 GR.B Rectangular Steel Tube |
| Product Type | Welded Rectangular Steel Tube / RHS Hollow Section |
| Steel Grade | GR.B, A53(A, B), S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Rectangular |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | Welded (ERW) |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction Structure / Building Pipe / Curtain Wall Pipe / Support Tubes / Structure Pipe / Scaffolding |
| MOQ | 5 Tons |
| Origin | China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & EPC | Building frames, column supports, roof trusses, scaffolding structures |
| Architectural Facade | Glass curtain wall龙骨, exposed structural framing, decorative rectangular profiles |
| Machinery & Industrial | Equipment support bases, conveyor frames, platform structures, machine guards |
| Infrastructure | Bridge handrails, sound barrier posts, solar panel mounting structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on 30mm wall rectangular tube means ±0.3mm — enough to shift load calculations on heavy-duty frames.
When procurement teams source ASTM A500 GR.B rectangular hollow section supplier products from multiple vendors, wall thickness inconsistency creates cascading problems: structural engineers recalculate load capacity, fabricators adjust weld parameters mid-production, and inspectors flag dimensional deviations during final acceptance. Off-standard sizes compound the issue — most mills only produce popular specifications, leaving projects to wait weeks for custom runs or accept substitution grades that require re-engineering. [NEED_CITE: dimensional tolerance requirements for structural hollow sections]
How 1-30mm Wall Thickness Serves Different Structural Loads
The 1-30mm wall thickness range in ASTM A500 GR.B rectangular hollow section supplier inventory covers everything from lightweight non-load-bearing partitions to heavy industrial column supports. Thin-wall sections (1-3mm) work for curtain wall framing where weight matters more than load capacity, while medium-wall (4-10mm) handles typical building frames and machinery bases. Heavy-wall sections (11-30mm) serve bridge components and high-rise structural cores where concentrated loads demand maximum section modulus. The ERW welding process maintains consistent wall thickness around the entire perimeter — critical when rectangular tubes face multi-directional loading in moment frames.
Meeting EN 10219 and ASTM A500 Compliance for Global Projects
Structural rectangular tubes exported to EU markets require CE certification under EN 10210 (hot-finished) or EN 10219 (cold-formed) standards, while North American projects specify ASTM A500 GR.B or GR.C grades. The steel grade equivalence between these systems — S275 to GR.B, S355 to GR.C — determines whether mill test certificates satisfy both the engineer’s specification and customs documentation. [NEED_CITE: steel grade equivalence between EN and ASTM standards] Missing the correct EN standard reference on certificates blocks EU imports entirely, regardless of whether the physical product meets requirements. Surface treatment selection (black painted for indoor use, hot-dip galvanized for outdoor exposure) must align with the project’s corrosion category per ISO 12944.
Understanding ERW Welding and Steel Grade Selection
ERW (Electric Resistance Welded) rectangular tubes form from coiled steel strip through continuous rolling and high-frequency welding — a process that produces consistent dimensional accuracy at lower cost than seamless alternatives for structural applications. The weld seam undergoes online ultrasonic testing and heat treatment to match base metal properties. Steel grade selection follows load requirements: GR.B provides 290 MPa minimum yield strength for general construction, while S355 delivers 355 MPa for heavier structural frames. The Q-series (Chinese GB standard), S-series (EN standard), and ASTM system represent equivalent performance tiers — GR.B roughly corresponds to S275JR in yield strength, though chemical composition limits differ slightly. [NEED_CITE: ERW welded hollow section manufacturing process quality control]
Hidden Costs of Incorrect Grade or Missing Certification
Ordering the wrong steel grade — specifying GR.B when the engineer requires GR.C — means the entire shipment fails structural review, triggering return freight and replacement production that delays projects by weeks. Missing CE marks on EN 10219-certified products destined for Europe results in customs rejection; the tubes physically meet requirements but lack documentation proving compliance. Negative tolerance abuse (wall thickness consistently below nominal) reduces actual load capacity below design calculations, creating safety liability even if the product passes visual inspection. Third-party inspection reports from SGS or BV verify both dimensional accuracy and material properties before shipment, preventing these hidden costs. [NEED_CITE: structural steel certification requirements for international construction projects]
Why Source ASTM A500 GR.B Rectangular Hollow Section from Us
Our factory produces ASTM A500 GR.B rectangular hollow section supplier products across 2,800+ specifications — including off-standard sizes that typical mills refuse to run — with wall thickness up to 30mm and ±1% tolerance verified by in-house physical and chemical laboratories. We hold 41 invention patents including China’s first sharp-corner rectangular tube technology, delivering true right-angle corners (R≤1.5t) for architectural facades where standard rounded corners (R≥2t) look unfinished against glass curtain walls. Full international certifications — ISO 9001:2015, Lloyd’s CE (EN 10210/10219), Singapore FPC, SGS/BV verified — ensure customs clearance across 50+ export destinations. Custom non-standard sizes, cutting to length, and professional container loading with anti-damage measures prevent the bending and surface scratches that cause site rejection. Every shipment includes mill test certificates documenting chemical composition and mechanical properties per heat number, with third-party inspection available before loading.
Documentation & Compliance
- Mill test certificate documenting GR.B chemical composition (C, Mn, P, S limits) and mechanical properties (yield strength, tensile strength, elongation) per ASTM A500
- CE certificate under EN 10219 for cold-formed welded structural hollow sections, required for EU market entry
- ISO 9001:2015 quality management system certificate covering production process control and inspection procedures
- SGS or BV third-party inspection report verifying dimensional accuracy, surface quality, and material test results before shipment
- Material traceability documentation linking each tube to heat number, production date, and test sample location
- Export customs documents including packing list, bill of lading, and certificate of origin for destination country clearance
Packaging, Loading & Delivery
- ASTM A500 GR.B rectangular tubes bundled with steel strips at intervals matching 6m and 12m lengths, preventing bundle shift during ocean transit
- Black painted or varnished surfaces protected with edge guards and waterproof wrapping to prevent coating damage from moisture and handling
- Galvanized rectangular hollow sections separated by rubber spacers within bundles to preserve zinc coating integrity during transport
- Container loading optimized for 15×20mm to 700×800mm size range, with heavy-wall sections positioned at bottom and thin-wall on top to prevent crushing
- Heat number and steel grade marked on each tube end for site identification and traceability verification during installation
- FOB, CIF, and DDP shipping terms available with professional tube loading expertise preventing the bending damage that causes site rejection
Ready to Source ASTM A500 GR.B Rectangular Hollow Sections?
Submit your specification requirements — dimensions, wall thickness, steel grade, surface treatment, quantity, and destination port — to receive detailed pricing with mill test certificate samples and production lead time within 12 hours. We provide custom non-standard sizes, cutting services, and third-party inspection coordination for projects requiring verified compliance documentation.
Request Your ASTM A500 GR.B Rectangular RHS Quote
Send specifications to admin@sdxjypipe.com or contact via WhatsApp at +86 188 5315 7756 for pricing, mill test certificate samples, and delivery schedule.
Frequently Asked Questions
Q: How does ASTM A500 GR.B compare to S275 under EN 10219?
A: ASTM A500 GR.B and EN 10219 S275JR offer similar minimum yield strength (290 MPa vs 275 MPa), but differ in chemical composition limits and testing requirements. GR.B allows higher carbon content for improved weldability in some applications, while S275JR requires Charpy impact testing at 20°C. Both grades serve general structural applications, but project specifications dictate which standard applies — we supply both with appropriate mill test certificates.
Q: Can you produce non-standard rectangular sizes outside the 15×20mm to 700×800mm range?
A: Yes, our 3 production lines cover 2,800+ specifications including custom non-standard sizes beyond typical catalog ranges. MOQ for custom sizes remains 5 tons, with production lead time of 15-25 days depending on complexity. We hold 41 patents for specialized forming technology including sharp-corner rectangular tubes with true right-angle corners for architectural applications.
Q: What surface treatment works best for outdoor structural applications?
A: Hot-dip galvanized coating provides superior corrosion protection for outdoor rectangular hollow sections exposed to weather, offering 50+ year service life in moderate environments. Black painting suits indoor applications or projects where field painting occurs after installation. Bare tubes require immediate surface preparation and coating after delivery to prevent rust formation during storage.
Q: Which certifications are required for exporting rectangular hollow sections to the EU?
A: EU construction projects require CE certification under EN 10210 (hot-finished) or EN 10219 (cold-formed welded) standards, plus Declaration of Performance documentation. We hold Lloyd’s CE certification covering both standards, with mill test certificates formatted to EN 10204 3.1 requirements. Third-party inspection from SGS or BV provides additional verification for projects specifying independent quality control.
Q: How do you prevent rectangular tube damage during container loading?
A: Our loading team uses specialized techniques for rectangular hollow sections: heavy-wall sections positioned at container bottom, thin-wall on top; edge protectors prevent strap damage to corners; rubber spacers separate galvanized tubes to preserve zinc coating; wooden chocks secure bundles against shifting during ocean transit. This professional loading approach prevents the bending and surface damage that causes site rejection on architectural projects.
