Review certificate records, scope and current status. Confirm order-specific documentation and inspection requirements with the export team.
What Is S350GD Structural Galvanized Steel Coil?
S350GD is a structural grade designation under EN 10346, indicating a minimum yield strength of 350 MPa. The “GD” stands for “Galvanized Drawing,” though this grade is primarily used for structural rather than deep drawing applications. When combined with a zinc coating like Z275 (275 g/m² total both sides), the S350GD structural galvanized steel coil delivers exceptional resistance to atmospheric corrosion. The hot dip galvanizing process ensures a metallurgical bond between the steel substrate and the zinc layer, preventing spalling during forming or bending.
Common LSI keywords associated with this product include GI coil, zinc coating Z60 Z120 Z275, hot dip galvanized coil, and galvanized steel supplier. The material is frequently specified for purlins, roofing sheets, wall panels, and structural framing in industrial and commercial buildings. The zinc coating weight directly influences service life—Z275 offers robust protection in moderate to aggressive environments, while lighter coatings like Z60 or Z120 are suitable for indoor applications.
Mechanical Properties and Chemical Composition
The steel base of S350GD is micro-alloyed to achieve high strength without sacrificing formability. Typical mechanical properties include:
- Yield strength: 350 MPa minimum
- Tensile strength: 420–520 MPa
- Elongation: 18% minimum (A80)
- Zinc coating: Z60, Z120, Z180, Z275 (specify per order)
- Surface finish: Regular spangle, minimized spangle, or zero spangle
Chemical composition is tightly controlled with low carbon (≤0.20%) and small additions of manganese, phosphorus, and silicon to achieve the strength requirements. The hot dip galvanized coil undergoes continuous annealing and galvanizing in a single line, ensuring uniform mechanical properties across the entire coil length.
Why Choose S350GD+Z275 Over Standard Grades?
Compared to lower-strength grades like DX51D or S250GD, the S350GD structural galvanized steel coil offers a superior strength-to-weight ratio. This allows engineers to reduce material thickness by 15–30% while maintaining structural performance, leading to significant cost savings in transportation and erection. The Z275 coating provides 275 g/m² of zinc, delivering approximately 15–20 years of maintenance-free service in rural environments and 8–12 years in industrial or coastal areas.
For projects requiring enhanced corrosion resistance, ChinaCNU Steel can supply GI coil with Z350 or even Z600 coatings. However, Z275 remains the most cost-effective choice for structural applications where both strength and durability are critical. Our galvanized steel supplier team provides detailed coating weight certifications with every shipment, ensuring compliance with EN 10346 and ASTM A653 standards.
Comparison of Coating Weights and Applications
| Coating Designation | Total Zinc Mass (g/m²) | Typical Service Life (Years)* | Recommended Applications | Relative Cost |
|---|---|---|---|---|
| Z60 | 60 | 3–5 | Indoor dry environments, temporary structures | Lowest |
| Z120 | 120 | 6–10 | Roofing, wall cladding (moderate exposure) | Low |
| Z180 | 180 | 10–15 | Agricultural buildings, exterior panels | Medium |
| Z275 | 275 | 15–20 | Structural framing, purlins, bridges | Optimal |
| Z350 | 350 | 20–25 | Marine environments, chemical plants | High |
*Service life estimates based on rural atmosphere; actual performance varies with environment.
Applications of S350GD Structural Galvanized Steel Coil
The high strength and corrosion resistance of S350GD make it suitable for a wide range of structural applications. In the construction industry, it is commonly used for cold-formed steel sections such as C-purlins, Z-purlins, and steel studs. These components form the backbone of modern steel-framed buildings, warehouses, and industrial sheds. The hot dip galvanized coil can be roll-formed, punched, and cut without damaging the zinc coating, enabling efficient prefabrication.
In the energy sector, S350GD is specified for solar panel mounting structures, wind turbine towers, and electrical enclosures. The material’s ability to withstand cyclic loading and environmental stress makes it a reliable choice for renewable energy projects. Additionally, the automotive industry uses this GI coil for chassis components, brackets, and reinforcement parts where weight reduction is essential.
Certificate records — Review the certificate holder, scope and current verification status. Confirm the documents applicable to your order.
Quality Assurance and Certifications
Every coil produced at our Boxing, Binzhou facility undergoes rigorous testing to verify mechanical properties, coating thickness, and surface quality. Our quality control lab performs tensile tests, bend tests, and salt spray tests to ensure the S350GD structural galvanized steel coil meets EN 10346 and ASTM A653 requirements. We provide mill test certificates (MTC) with each shipment, including heat numbers and coating weight analysis.
Review certificate records, scope and current status. Confirm order-specific documentation and inspection requirements with the export team.
Frequently Asked Questions (FAQ)
1. What is the difference between S350GD and S250GD?
S350GD has a minimum yield strength of 350 MPa, while S250GD has 250 MPa. The higher strength allows S350GD to be used in thinner gauges for load-bearing applications, reducing overall material weight and cost. Both grades are galvanized, but S350GD is preferred for structural framing and purlins.
2. Can I order S350GD with different zinc coating weights?
Yes, ChinaCNU Steel offers S350GD with coating weights from Z60 to Z600. The most common for structural use is Z275, but we can adjust based on your environmental exposure and budget. Contact our team to discuss your specific requirements for GI coil.
3. What is the standard MOQ for S350GD structural galvanized steel coil?
Our standard MOQ is 25 tons per specification (thickness, width, and coating weight). For mixed containers or smaller trial orders, we can accommodate sample quantities. For large projects, we offer volume discounts and flexible delivery schedules.
4. How does FOB pricing work for coils from factory in Boxing, Binzhou?
FOB Tianjin pricing includes the cost of the steel coil, inland transport to the port, and export documentation. We provide a full FOB quotation with estimated shipping costs to your destination port. Payment terms are typically T/T or L/C at sight for first-time buyers.
5. Is S350GD suitable for marine environments?
For marine or highly corrosive environments, we recommend S350GD with a heavier zinc coating such as Z350 or Z600, combined with additional protective measures like paint or sealants. The base steel’s strength remains beneficial, but the coating weight must be increased to resist salt spray and humidity.
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