Description
Factory-direct ERW square tubes — 2,800+ specifications in stock with wall thickness up to 30mm for structural and architectural orders.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube |
| Steel Grade | ASTM A500 Gr.B, S235JR, S275JR, S355JR, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Square |
| Size Range | 19×19mm – 800×800mm |
| Wall Thickness | 1 – 30mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain / Beveled (upon request) |
| Application | Steel structures / Construction frames / Curtain wall framing / Support tubes / Building structures |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, bridge handrail structures |
| Architectural Facades | Glass curtain wall framing, exposed structural grids, facade mullions |
| Industrial & Machinery | Equipment bases, conveyor support frames, platform structures |
| Steel Fabrication | Welded assemblies, truss members, bracing tubes for steel structures |
What Corner Tolerance and Mill Certification Cost You on an ASTM A500 Gr.B Welded Square Steel Tube Order
Inconsistent corner radii and missing EN 10204 3.1 certificates are the two most common reasons welded square tubes get rejected at destination ports.
Procurement teams ordering ASTM A500 Gr.B welded square steel tube from overseas suppliers frequently discover dimensional deviations only after containers arrive — corners out of tolerance mean facade framing does not align, and absent mill test certificates block customs clearance in regulated markets. When multiple sizes are sourced from different mills, grade equivalence between ASTM, EN, and JIS systems creates ordering errors that surface during fabrication. [NEED_CITE: EN 10219 cold-formed welded hollow section dimensional tolerance requirements]
How 1–30mm Wall Thickness Range Serves Structural and Architectural Frames
An ASTM A500 Gr.B welded square steel tube spanning 19×19mm to 800×800mm covers both light gauge curtain wall mullions and heavy-duty column members in a single procurement cycle. The 1mm to 15mm wall range handles typical facade and bracing work where weight and weldability matter, while 15mm to 30mm sections carry primary structural loads in industrial buildings and infrastructure. ERW welding produces a consistent longitudinal seam that passes ultrasonic inspection across the full thickness range, and ±1% dimensional tolerance ensures that bolted or welded connections fit without on-site reaming.
Structural Code Compliance and Surface Protection for Export Orders
Engineering specifications for welded square hollow sections typically reference EN 1993-1-1 for load-bearing design and ASTM A500 for North American structural applications — the steel grades S235JR through S355JR and ASTM A500 Gr.B both conform to these frameworks when supported by proper mill documentation. [NEED_CITE: steel grade equivalence mapping between ASTM A500 and EN 10219] For outdoor or humid environments, hot-dip galvanized coating provides long-term corrosion resistance, while black painted or varnished finishes suit indoor structural frames where appearance is secondary. Beveled ends facilitate full-penetration butt welding on-site, and random or fixed lengths of 5.8m to 12m reduce field cutting waste. Lloyd’s CE certification under EN 10219 and EN 10210 ensures that tubes shipped to EU markets clear customs without documentation disputes.
Steel Grade Selection and ERW Welding Process Explained
The ASTM A500 Gr.B welded square steel tube is available in multiple grade designations that serve different structural demands. ASTM A500 Gr.B targets North American projects requiring minimum 290 MPa yield strength in square hollow sections, while S235JR, S275JR, and S355JR follow the EN 10025 incremental yield system — S355JR delivering higher load capacity for heavy frames without increasing section size. STK400 aligns with JIS G3466 for Japanese-spec structural work. ERW welding forms the tube from coiled steel strip through continuous forming and high-frequency electric resistance welding, producing a clean internal bead suitable for fluid conveyance at low pressure and excellent dimensional consistency for structural use. Surface treatment selection depends on the destination climate: galvanized coating resists coastal and tropical humidity, black painting provides short-term rust prevention during transit, and bare tubes suit projects where the buyer applies custom coating systems. [NEED_CITE: ERW versus seamless versus SSAW manufacturing process comparison for structural tubes]
The Hidden Cost of Specifying the Wrong Grade or Accepting Negative Tolerance Beyond Standard
Ordering ASTM A500 Gr.B welded square steel tube without verifying that the supplier’s mill test certificate matches the specified grade can result in material that fails structural inspection upon arrival — a common scenario when certificates are forged or borrowed from unrelated heats. Excessive negative tolerance reduces actual wall thickness below design assumptions, compromising load-bearing capacity and triggering rejection during third-party inspection. Missing CE marks or incorrect EN standard references on documentation cause customs holds in European ports, delaying projects by weeks. [NEED_CITE: consequences of non-compliant steel imports in EU construction regulations]
Why SD XJY Pipe Delivers Consistent Quality on Every ASTM A500 Gr.B Welded Square Steel Tube Shipment
SD XJY Pipe operates three dedicated production lines covering over 2,800 specifications in square and rectangular welded tubes, with wall thickness reaching 30mm — eliminating the need to source small and large sizes from separate suppliers. An in-house physical and chemical laboratory tests every heat for composition, yield strength, and dimensional accuracy before release, and full mill test certificates are issued per batch. Lloyd’s CE certification under EN 10219 and EN 10210, Singapore FPC, and SGS/BV third-party verification are maintained as standard, ensuring smooth customs clearance across 50+ export destinations. Professional container loading plans with internal bracing and edge protection prevent the bending and surface damage that plague poorly packed tube shipments. Custom non-standard sizes and cut-to-length services are available with low MOQ of 5 tons, and the company’s 41 invention patents include China’s original sharp-corner rectangular tube technology for architectural applications requiring true 90-degree corners.
Documentation & Compliance
- Mill test certificate documenting ASTM A500 Gr.B chemical composition and mechanical properties per heat number, conforming to EN 10204 3.1 format
- Lloyd’s CE certificate covering EN 10219 cold-formed welded structural hollow sections and EN 10210 hot-formed sections for EU market compliance
- ISO 9001:2015 quality management system certificate covering the full production and inspection process of ERW welded square steel tubes
- SGS or BV third-party inspection report available upon request, verifying dimensional tolerance, surface quality, and coating thickness for galvanized ASTM A500 Gr.B welded square steel tube
- Material traceability report linking each bundle to its heat number, steel grade, and production date for project audit requirements
- Full export documentation set including packing list, bill of lading, and certificate of origin for customs clearance in destination countries
Packaging, Loading & Delivery
- ASTM A500 Gr.B welded square steel tubes bundled with high-tensile steel strips and seaworthy packaging, sized to match 5.8m, 6m, 11.8m, or 12m fixed lengths for efficient container stowage
- Galvanized square tubes packed with edge protectors and moisture-resistant wrapping to preserve the zinc coating during ocean transit to humid destination ports
- Container loading optimized by section size — smaller 19×19mm to 100×100mm tubes nested for maximum payload, while 400×400mm to 800×800mm sections loaded with timber separators to prevent contact damage
- Heat number and steel grade stenciled on each bundle for site identification, with plain or beveled ends protected by plastic caps to prevent edge deformation
- FOB, CIF, and DDP shipping terms available from Shandong port, with professional loading crews trained in tube and beam stowage to prevent shifting during voyage
Ready to Procure Your ASTM A500 Gr.B Welded Square Steel Tube
Submit your required section size, wall thickness, steel grade, surface treatment, quantity, and destination port to receive a detailed quotation within 12 hours, including unit pricing, production lead time, and available mill test certificates. Non-standard sizes and custom lengths are confirmed with drawing review, and third-party inspection arrangements can be finalized before production begins.
Request Your Quotation and Mill Test Certificate Today
Send your specifications to receive pricing, certification documents, and container loading confirmation for your next ASTM A500 Gr.B welded square steel tube order.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: What is the difference between ASTM A500 Gr.B, S355JR, and STK400 for welded square steel tubes?
A: ASTM A500 Gr.B is the standard grade for North American structural hollow sections, S355JR follows the European EN 10025 system with higher yield strength for heavy-load applications, and STK400 conforms to Japanese JIS G3466 for structural use. All three grades are available in the same size range of 19×19mm to 800×800mm with wall thickness from 1mm to 30mm, and grade equivalence documentation can be provided to support cross-standard specification.
Q: Can you produce non-standard sizes or custom lengths with a low minimum order quantity?
A: Yes, SD XJY Pipe covers over 2,800 specifications across its production lines and accepts custom non-standard sizes and cut-to-length requests. The minimum order quantity is 5 tons, which applies to both standard and custom dimensions, making it practical for project-specific procurement without excess inventory.
Q: Which surface treatment is recommended for outdoor structural use in coastal or humid climates?
A: Hot-dip galvanized coating provides the most durable corrosion protection for ASTM A500 Gr.B welded square steel tube exposed to moisture, salt air, or tropical conditions. Black painting offers short-term rust prevention during storage and transit, while bare tubes are suitable when the buyer plans to apply a custom painting or powder coating system after fabrication.
Q: How do you ensure corner quality and dimensional accuracy on ERW welded square tubes?
A: Each production line uses precision forming rolls and inline measurement systems to maintain ±1% dimensional tolerance across the full 19×19mm to 800×800mm size range. The in-house laboratory performs dimensional checks, weld seam inspection, and mechanical testing before shipment, and third-party inspection by SGS or BV can be arranged for buyer verification.
Q: What export certifications and documents are included for customs clearance in the EU and North America?
A: Every shipment includes mill test certificates per EN 10204 3.1, Lloyd’s CE certification under EN 10219 and EN 10210 for EU compliance, ISO 9001:2015 quality certificate, and a full export documentation set with packing list, bill of lading, and certificate of origin. SGS or BV third-party inspection reports are available upon request for additional verification.
