Description
Direct Mill Supply, No Middlemen — ASTM A500 Gr.B rectangular hollow sections produced and galvanized under one roof, with full material traceability from billet to finished tube.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500 Gr.B Rectangular Steel Tube |
| Product Type | Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Gr.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 | ERW / Welded or Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures / Construction frames / Curtain wall / Support tubes / Building structures / Machinery |
| MOQ | 10 Tons |
| Origin | China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building columns, beam frames, mezzanine structures |
| Industrial Facilities | Factory roof trusses, crane support beams, equipment platforms |
| Curtain Wall Systems | Mullion frames, facade support grids, architectural structural elements |
| Infrastructure | Bridge handrails, sound barrier supports, lighting pole bases |
| Machinery Manufacturing | Conveyor frames, machine bases, hydraulic support structures |
When Galvanizing Thickness Fails Third-Party Inspection at Destination Port
Coating weight variance between production batches creates rejection risk at overseas customs.
Sourcing ASTM A500 Gr.B galvanized rectangular steel tube from disconnected suppliers means the galvanizing line is often a subcontractor — not the tube mill. That separation creates gaps in process control: zinc bath temperature fluctuates between batches, draining time varies by operator, and coating thickness reports rarely travel with the mill test certificate. Buyers discover the problem only when SGS or BV inspectors measure 45μm against a contract requirement of 80μm minimum. The entire container gets held at the destination port, rework costs multiply, and project schedules collapse. [NEED_CITE: hot-dip galvanized coating thickness requirements per ASTM A123]
How Wall-Thickness Tolerance Affects Structural Load Calculations
Rectangular hollow sections in 50×100 mm through 200×400 mm sizes serve as primary load-bearing members in portal frames and mezzanine floors. The ±1% wall thickness tolerance specified for ASTM A500 Gr.B rectangular steel tube means a nominal 6mm wall can measure between 5.94mm and 6.06mm. For structural engineers calculating moment capacity and deflection limits, this tolerance band determines whether the section meets design requirements or falls short. Consistent tolerance control across production runs ensures that shop drawings approved by the engineer match the material arriving on site — no field substitutions, no RFI delays.
Corrosion Protection Selection for Different Service Environments
Galvanized ASTM A500 Gr.B rectangular steel tube provides sacrificial zinc protection suitable for C2 and C3 corrosion categories per ISO 12944 — typical indoor industrial environments and mild outdoor exposure. For C4 coastal or industrial atmospheres, additional paint systems over galvanized substrate extend service life. Black painted or varnished finishes suit interior applications where corrosion resistance is secondary to appearance. Bare tubes require site-applied coating systems specified by the project engineer. Each surface treatment option carries different lead times and cost structures that affect total project procurement planning. [NEED_CITE: corrosion category classification per ISO 12944-2]
Steel Grade Equivalence Across ASTM, EN, and JIS Standards
ASTM A500 Gr.B rectangular steel tube specifies minimum yield strength of 42 ksi (290 MPa) for rectangular sections. European projects often specify S355 per EN 10219, which requires 355 MPa minimum yield — a higher strength grade. Japanese projects reference STK400 per JIS G3466 with 235 MPa minimum yield. Understanding these equivalences matters when a single fabrication shop serves multiple international markets. Our production covers Gr.B, S235, S275, S355, and STK400 across the full 15×20 mm to 700×800 mm size range, allowing engineers to specify their preferred standard while sourcing from one material system. ERW welded production suits most structural applications up to 30mm wall thickness, while seamless options address high-pressure or critical load requirements. [NEED_CITE: steel grade equivalence tables between ASTM A500 and EN 10219]
Hidden Costs of Unverified Material Certification
Purchasing ASTM A500 Gr.B galvanized rectangular steel tube without verified mill test certificates creates downstream risk. Material arriving without EN 10204 3.1 certification cannot be legally installed in CE-marked structures across the European Union. Chemical composition outside the Gr.B specification range compromises weldability — welders following approved WPS procedures discover cracking during production. Coating thickness below contract minimums triggers rejection at destination port inspection, forcing either return shipment or local rework at the buyer’s expense. These failures trace back to procurement decisions prioritizing unit price over documentation completeness. [NEED_CITE: EN 10204 inspection document types for steel products]
Integrated Production Controls Material Quality From Billet to Finished Tube
Vertically integrated production eliminates the material traceability gaps that plague fragmented supply chains. Our own steel mill produces the raw rectangular hollow sections, then our fabrication workshop handles galvanizing, cutting, drilling, and surface treatment — all under one quality management system. This integration means the mill test certificate for ASTM A500 Gr.B rectangular steel tube travels with the material through every processing step. Heat numbers remain traceable from the original steelmaking heat through galvanizing bath records to final dimensional inspection reports. With 2,800+ specifications in stock and production capacity for medium-to-large structural steel projects, we serve general contractors and EPC firms who need reliable fabrication partners with complete accountability. CE marking compliance per EN 10210 and EN 10219 supports European project requirements, while ISO 9001 certification documents our quality management system. Third-party inspection through SGS, BV, or TÜV verifies coating thickness, dimensional accuracy, and material properties before shipment.
Documentation & Compliance
- Mill test certificate documenting ASTM A500 Gr.B chemical composition (carbon, manganese, phosphorus, sulfur) and mechanical properties (yield strength, tensile strength, elongation) per heat number
- CE certificate confirming EN 10210/EN 10219 compliance for structural hollow sections in European Union construction projects
- ISO 9001 quality management system certificate covering the integrated production process from steelmaking through galvanizing and finishing
- SGS or BV third-party inspection report verifying galvanized coating thickness, dimensional tolerances, and surface quality for ASTM A500 Gr.B rectangular steel tube
- Material traceability documentation linking each tube bundle to the original heat number, galvanizing batch record, and final inspection report
- Complete customs documentation package including packing list, bill of lading, and certificate of origin for ASTM A500 Gr.B galvanized rectangular steel tube
Packaging, Loading & Delivery
- Galvanized ASTM A500 Gr.B rectangular steel tube bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit
- Surface protection applied per treatment type: galvanized tubes receive anti-fingerprint passivation, black painted tubes get interleaf paper separation, bare tubes receive rust preventive oil
- Container loading optimized for 6m and 12m lengths of 50×100 mm through 200×400 mm rectangular sections, maximizing payload within 20GP and 40HC containers
- Custom cutting to project-specific lengths from standard 5.8m, 6m, 11.8m, and 12m stock, with cut ends deburred and protected
- Heat number and steel grade identification marked on each tube bundle, with color coding per ASTM A500 Gr.B specification for rapid site identification
- FOB, CIF, and DDP shipping terms available with professional oversized cargo loading plans for 700×800 mm large-section rectangular tubes
Start Your Procurement With Complete Technical Documentation
Share your project drawings in PDF or DWG format along with required steel grade, surface treatment preference, and quantity. We respond within 24 hours with a detailed quotation including material cost, galvanizing cost, packaging, and shipping to your destination port — plus mill test certificate samples and production timeline. Confirm your ASTM A500 Gr.B galvanized rectangular steel tube requirements and receive shop drawing support for connection details.
Request Your Quotation With Mill Test Certificate
Submit your specifications and receive a complete quotation with material certification documentation within 24 hours.
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: What is the difference between ASTM A500 Gr.B and EN 10219 S355 for rectangular hollow sections?
A: ASTM A500 Gr.B specifies minimum yield strength of 290 MPa for rectangular sections, while EN 10219 S355 requires 355 MPa minimum yield. Both standards cover rectangular hollow sections produced by ERW welding, but they differ in chemical composition limits, tolerance requirements, and testing procedures. European projects typically require EN 10219 with CE marking, while North American projects specify ASTM A500. Our production covers both standards across the full size range from 15×20 mm to 700×800 mm.
Q: How do you ensure galvanized coating thickness meets project specifications?
A: Galvanized coating thickness for ASTM A500 Gr.B rectangular steel tube is controlled through zinc bath temperature management, immersion time, and draining speed parameters. Each production batch receives coating thickness measurement using magnetic induction gauges per ASTM A123 standards. Results are documented in the inspection report accompanying the mill test certificate. Third-party inspection through SGS or BV can verify coating thickness before shipment if required by the contract.
Q: Can you provide custom lengths and non-standard sizes for rectangular steel tubes?
A: Yes, we produce ASTM A500 Gr.B rectangular steel tube in custom lengths beyond standard 5.8m, 6m, 11.8m, and 12m options. Non-standard sizes outside the 15×20 mm to 700×800 mm range can be quoted based on order quantity and production feasibility. Custom fabrication services including cutting, drilling, welding, and bending are available through our integrated fabrication workshop. Share your project drawings for specific size and length requirements.
Q: What documentation do you provide for customs clearance and project compliance?
A: Each shipment of ASTM A500 Gr.B galvanized rectangular steel tube includes mill test certificate per EN 10204 3.1 format, CE certificate for European projects, ISO 9001 quality system certificate, packing list, bill of lading, and certificate of origin. Third-party inspection reports from SGS, BV, or TÜV are available upon request. Material traceability documentation links each tube to the original heat number through galvanizing batch records.
Q: What is the minimum order quantity for galvanized rectangular steel tubes?
A: The minimum order quantity for ASTM A500 Gr.B galvanized rectangular steel tube is 10 tons. This MOQ applies across all sizes within the 15×20 mm to 700×800 mm range and 1-30mm wall thickness range. Mixed size orders are acceptable within the 10-ton minimum. Larger projects benefit from consolidated shipping and reduced per-ton logistics costs.
