Description
Vertically Integrated Mill & Fabrication — 2,800+ specifications of square and rectangular hollow sections produced and fabricated under one quality system, covering ASTM A500 Gr.B from 20×20 mm to 500×500 mm.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Gr.B Square Steel Tube |
| Product Type | Square / Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q235, Q355, S235JR, S355JR, ASTM A500 Grade A/B/C, ASTM A53 Grade A/B, A36, STK400, SS400, ST42.2 |
| Standard | ASTM A500, ASTM A53, ASTM A36, EN 10219, EN 10210, GB/T 6728, JIS G3466 |
| Section Shape | Square / Rectangular |
| Size Range | Square: 20×20 mm – 500×500 mm; Rectangular: 20×40 mm – 300×500 mm |
| Wall Thickness | 1.2 – 20 mm |
| Length | 3 – 12 m (random / cut to size) |
| Technique | Hot Rolled / ERW (Welded) |
| Surface Treatment | Pre-galvanized (40–80 g/m²) / Hot-dip galvanized (200–600 g/m²) / Black (as rolled) |
| Tolerance | ±1% |
| Ends | Plain / Beveled (per request) |
| Application | Steel structures, construction frames, solar support structures, fence posts, greenhouse frames, machinery frames, building materials |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| General Contracting & EPC | Building skeleton frames, column-beam assemblies, platform structures, stairway stringers |
| Renewable Energy & Agriculture | Solar panel support structures, greenhouse arches, mounting rails |
| Infrastructure & Civil Works | Fence posts, highway sign gantries, noise barrier frames |
| Machinery & Industrial | Conveyor frames, equipment bases, machine guards, mezzanine structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A 12% negative tolerance deviation on a 75×75 mm square tube cost one container over two tons of short-weight — and nearly triggered a client claim.
Overseas buyers sourcing ASTM A500 Gr.B square steel tube from China regularly encounter wall thickness inconsistencies that slip past visual inspection. When fabricators source raw material from third-party mills without integrated quality control, heat number traceability breaks down, and EN 10219 / ASTM A500 compliance becomes a paperwork exercise rather than a production reality. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements] Missing or falsified mill test certificates then surface only at destination port re-inspection, forcing costly rejections or emergency re-procurement mid-project.
Matching Hollow Section Profiles to Structural Load Paths
Square and rectangular hollow sections in ASTM A500 Gr.B distribute bending and torsional loads more evenly than open profiles, making them the default choice for column-beam frameworks in warehouse and industrial building construction. The closed geometry also simplifies bolted and welded connections at node points, reducing fabrication time on site. For solar support structures and greenhouse frames exposed to continuous atmospheric moisture, hot-dip galvanized coating at 200–600 g/m² provides corrosion resistance aligned with C3–C4 environment classifications. Our mill produces these sections in Q235 and Q355 grades mapped directly to S235JR and S355JR equivalents, ensuring ASTM A500 Gr.B square steel tube orders ship with consistent chemistry across every heat.
Engineering Compliance and Certification Requirements
Structural hollow sections destined for European projects must carry CE marking under EN 10210 (hot-finished) or EN 10219 (cold-formed), with Declaration of Performance documentation traceable to the production heat. [NEED_CITE: CE marking requirements for structural steel hollow sections under CPR Regulation] North American projects specify ASTM A500 Gr.B with supplementary Charpy impact testing for low-temperature service. Wall thickness tolerance of ±1% ensures that theoretical weight calculations match actual over-pipe weight, preventing shipping disputes and customs weight discrepancies. Cut-to-length capability up to 12 m reduces on-site welding joints, while beveled ends prepare tubes for full-penetration butt welds in moment-resisting frames.
Steel Grade Selection and Manufacturing Process
The ASTM A500 Gr.B square steel tube we produce covers a grade spectrum from Q195 through Q355, each mapping to international equivalents: Q235 aligns with S235JR and A36 for general structural use, while Q355 corresponds to S355JR and ASTM A500 Gr.C for higher-load applications. ERW (Electric Resistance Welded) production suits wall thicknesses from 1.2 mm to 20 mm with consistent weld seam integrity, while hot-rolled hollow sections serve heavier structural demands where forming stresses must be minimized. Surface treatment selection follows environmental exposure: pre-galvanized at 40–80 g/m² handles indoor or temporary outdoor conditions, whereas hot-dip galvanizing at 200–600 g/m² protects structural frames in coastal or industrial atmospheres for decades. The ±1% wall thickness tolerance matters because even small deviations compound across hundreds of tons — a 5% negative tolerance on a 500×500×16 mm tube reduces load-bearing capacity and triggers structural engineer rejection. [NEED_CITE: steel grade equivalence mapping between GB/T, EN, and ASTM standards]
Hidden Costs of Non-Conforming Hollow Section Procurement
Purchasing ASTM A500 Gr.B square steel tube without verified mill test certificates or third-party inspection creates downstream risks that dwarf the initial price saving. Material arriving at port with wall thickness below specified tolerance fails dimensional inspection, triggering full-container rejection or costly sorting operations. Missing CE documentation blocks customs clearance in EU member states, stranding cargo in bonded warehouses while penalties accumulate. [NEED_CITE: structural steel non-conformance costs in international construction projects] Welding procedures qualified against assumed base metal chemistry produce defective joints when actual composition deviates, forcing joint removal and re-welding that delays critical-path schedules.
Why Engineers Source ASTM A500 Gr.B Square Steel Tube from Our Mill
Our facility integrates raw steel production with tube fabrication under a single quality management system, eliminating the material traceability gaps that occur when fabricators source from disconnected third-party mills. Every ASTM A500 Gr.B square steel tube we ship carries a mill test certificate with full heat number traceability, chemical composition, and mechanical properties verified by our in-house laboratory. The mill maintains over 2,800 specifications in stock across square and rectangular profiles, enabling single-source procurement for projects combining multiple section sizes. We hold CE certification for EN 10210 and EN 10219, ISO 9001 quality management, and arrange SGS or BV third-party inspection before shipment. Custom cut-to-length, non-standard dimensions, and special surface treatment requirements are processed through the same production line that serves our stock program, ensuring identical quality standards. Professional container loading plans maximize payload for 20ft and 40ft shipments, with seaworthy hexagonal bundling and edge protection preserving galvanized coatings during ocean transit.
Documentation & Compliance
- Mill test certificate documenting Q235 / Q355 / S235JR / S355JR chemical composition and mechanical properties per ASTM A500, EN 10219, or GB/T 6728, with heat number traceability
- CE certificate of conformity for EN 10210 hot-finished and EN 10219 cold-formed hollow sections, required for European market entry
- ISO 9001 quality management system certificate covering both steel production and tube fabrication operations
- SGS or BV third-party inspection report verifying wall thickness, coating weight, and dimensional tolerance before shipment
- Material traceability documentation linking each bundle to its production heat number and test certificate
- Complete customs documentation including packing list, bill of lading, and certificate of origin for destination port clearance
Packaging, Loading & Delivery
- Hot-dip galvanized ASTM A500 Gr.B square steel tube bundled in seaworthy hexagonal packs with steel strips and edge protectors to preserve zinc coating integrity during ocean transit
- Pre-galvanized and black finish tubes packed in compact rectangular bundles optimized for 20ft and 40ft container loading, maximizing payload per shipment
- Cut-to-length service available from 3 m to 12 m, with random length or fixed length options reducing on-site cutting waste for construction frame applications
- Each bundle labeled with heat number, steel grade (Q235 / Q355 / S355JR), section dimensions, and wall thickness for site identification and traceability
- FOB, CIF, and DDP shipping terms available with professional loading plans for oversized square sections up to 500×500 mm
How to Request a Quotation for Your Hollow Section Project
Submit your project drawings, section dimensions, steel grade requirements, and surface treatment preference to receive a detailed quotation including material cost, fabrication charges, coating fees, and ocean freight estimates. We provide shop drawing review, material optimization recommendations, and production scheduling within 24 hours of inquiry. Third-party inspection arrangements and mill test certificate preparation are confirmed before production begins.
Request Your ASTM A500 Gr.B Square Steel Tube Quotation
Send your specifications, quantity, and destination port to receive pricing, mill test certificate samples, and production lead time confirmation.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do Q235 and Q355 grades map to ASTM A500 and EN standards?
A: Q235 corresponds to S235JR (EN 10219) and A36 (ASTM A36) for general structural applications, while Q355 aligns with S355JR (EN 10219) and ASTM A500 Gr.C for higher-strength requirements. Our mill test certificates document the chemical composition and mechanical properties for each grade, and we provide grade equivalence documentation for international project compliance.
Q: Can you arrange third-party inspection before shipment?
A: Yes, we coordinate SGS, BV, or TÜV third-party inspection at our facility before container loading. The inspection covers wall thickness measurement, coating weight verification for galvanized products, dimensional checks, and visual surface inspection. Inspection reports are issued alongside mill test certificates for customs clearance and project documentation.
Q: What is the minimum order quantity for custom cut-to-length tubes?
A: The minimum order quantity is 1 ton for both stock sizes and custom cut-to-length requirements. We offer random length (3–12 m) or fixed cut-to-size service based on your project drawings, with non-standard dimensions available upon engineering review.
Q: How do you select between pre-galvanized and hot-dip galvanized surface treatment?
A: Pre-galvanized coating at 40–80 g/m² suits indoor applications or temporary outdoor exposure where cost efficiency is prioritized. Hot-dip galvanized coating at 200–600 g/m² provides long-term corrosion protection for outdoor structural frames, solar supports, and coastal environments. We recommend coating selection based on your project’s environmental exposure classification and design service life.
Q: What documentation do you provide for European market customs clearance?
A: We supply CE marking certification for EN 10210 and EN 10219 hollow sections, Declaration of Performance documents, mill test certificates with heat number traceability, and complete export documentation including packing list, bill of lading, and certificate of origin. These documents satisfy EU Construction Products Regulation requirements for structural steel imports.
Secure Your ASTM A500 Gr.B Square Steel Tube Supply
Submit your project specifications and quantity requirements to receive a detailed quotation with mill test certificate samples and production scheduling.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
