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What Is ASTM A653 CS Type B Galvanized Coil?
ASTM A653 is the standard specification for steel sheet, zinc-coated (galvanized) by the hot-dip process. The “CS Type B” designation refers to commercial steel with a specific chemical composition optimized for general forming and moderate drawing. Unlike structural steel (SS) or deep drawing steel (DS), CS Type B provides a reliable balance of strength and elongation for applications like ductwork, automotive components, and electrical enclosures.
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Key Properties of CS Type B
- Excellent formability for bending, roll-forming, and light stamping
- Minimum tensile strength: 310 MPa (45 ksi)
- Minimum yield strength: 170 MPa (25 ksi) typical
- Elongation in 2 inches: 20% minimum for thicknesses ≥ 0.023 in (0.58 mm)
- Zinc coating adhesion: passes 180-degree bend test without flaking
Zinc Coating Weights: Z60, Z120, Z275 – Which One to Choose?
The choice of zinc coating weight directly affects the corrosion resistance and service life of the GI coil. Heavier coatings like Z275 provide longer protection in harsh environments but reduce formability slightly. Lighter coatings like Z60 are suitable for indoor applications where cost is a priority.
| Coating Designation | Coating Weight (g/m², triple-spot) | Typical Application | Relative Corrosion Resistance |
|---|---|---|---|
| Z60 | 60 | Indoor ducting, light electrical boxes | Low |
| Z120 | 120 | General construction, roofing, wall panels | Medium |
| Z275 | 275 | Agricultural buildings, marine environments | High |
For ASTM A653 CS Type B galvanized coil, we recommend Z120 as the standard choice for most structural and fabrication applications. Z275 is available for projects requiring extended outdoor exposure. Our factory can supply any coating weight from Z60 to Z350, with strict adherence to ASTM A653 tolerances.
Why Choose ChinaCNU Steel as Your Galvanized Steel Supplier?
With 15+ years dedicated to manufacturing and exporting hot dip galvanized coil, ChinaCNU Steel has built a reputation for consistent quality and reliable delivery. Our factory in Boxing, Binzhou operates multiple continuous galvanizing lines with annual capacity exceeding 200,000 metric tons. Every coil is tested for mechanical properties, coating thickness, and surface quality before shipment.
We export to over 50 countries, including the United States, Canada, Germany, Australia, and Southeast Asia. Our logistics team handles all documentation, including mill test certificates, packing lists, and bills of lading. We offer FOB Tianjin pricing, CIF to major ports, and door-to-door delivery for container orders. The MOQ of 25 tons makes it easy for both large distributors and medium-sized fabricators to start a trial order.
Quality Certifications
Applications of ASTM A653 CS Type B Hot Dip Galvanized Coil
This grade is widely used in industries requiring a balance of strength and formability. Common applications include:
- Automotive components: brackets, reinforcements, floor panels
- HVAC systems: ductwork, plenums, air handler housings
- Electrical enclosures: junction boxes, switchgear panels, cable trays
- General fabrication: shelving, storage racks, furniture parts
- Construction: purlins, girts, light structural framing
The galvanized steel supplier must ensure the material can withstand roll-forming and bending without cracking the zinc coating. Our CS Type B coil passes the standard bend test with a radius equal to the thickness (1T) for thicknesses up to 0.060 in (1.5 mm). For heavier gauges, we recommend a 2T bend radius to maintain coating integrity.
How to Order ASTM A653 CS Type B Galvanized Coil
Ordering from ChinaCNU Steel is straightforward. Provide the following specifications in your inquiry:
- Thickness (mm or gauge): 0.3 mm to 3.0 mm
- Width (mm or inches): 600 mm to 1500 mm
- Coating weight: Z60, Z120, Z275, or custom
- Surface treatment: chromated, oiled, or dry
- Quantity (metric tons): minimum 25 tons
- Delivery port and preferred shipping method
We respond within 24 hours with a detailed quotation including FOB price, lead time, and shipping options. For large projects, we offer volume discounts and staggered delivery schedules. Our technical team can also recommend the optimal coating weight for your specific environment.
Frequently Asked Questions
1. What is the difference between ASTM A653 CS Type B and SS Grade 33?
CS Type B has lower yield strength (170 MPa typical) compared to SS Grade 33 (230 MPa minimum). CS Type B offers better formability for bending and light drawing, while SS Grade 33 is used when higher strength is required without sacrificing ductility. Both are hot dip galvanized under the same ASTM A653 standard.
2. Can you supply coils with Z275 coating for outdoor use?
Yes, we supply Z275 coating on ASTM A653 CS Type B galvanized coil. Z275 provides 275 g/m² of zinc on both sides, offering excellent corrosion resistance for outdoor applications. We recommend this for agricultural buildings, fencing, and coastal constructions. The MOQ is 25 tons.
3. How do you ensure the zinc coating adhesion meets ASTM standards?
Every production lot undergoes a bend test per ASTM A653, where the coated steel is bent 180 degrees around a mandrel equal to the sheet thickness. The coating must not flake or peel. We also perform coating weight tests using the gravimetric method (ASTM A90) to verify the specified Z-class.
4. What is the typical lead time for a 25-ton order?
For standard thicknesses and coating weights, the lead time is 15-20 working days from order confirmation. For non-standard dimensions or special surface treatments, please allow 25-30 working days. We ship from Tianjin Xingang port, and FOB pricing includes all export documentation.
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