SHANGHAI RUICHAO INDUSTRIAL
SHANGHAI RUICHAO INDUSTRIAL
Galvanized (GL) steel is a zinc-coated carbon steel known for outstanding rust resistance. The zinc layer, typically applied via a hot-dip process, corrodes first—protecting the underlying steel and extending its life. Common uses span from construction (roofing, structural frames, pipelines) and transportation (vehicle parts, guardrails, shipping containers) to everyday household items like appliances, fencing, and outdoor furniture. Its durability and weather resistance make it essential in both heavy industry and daily life.
Specification Parameters
| Parameters of Galvanized Steel (GL Steel) | |||
| Parameter Category | Specific Parameter | Typical Value/Description | Importance/Effect |
| Base Steel Properties | Grade/Type | Commercial Quality (CQ), Forming Quality (FQ), Structural Grade (e.g., S350GD+Z) | Determines mechanical properties (yield strength, formability) for applications like roofing, automotive, or structures. |
| Yield Strength (YS) | 140–700 MPa (varies by grade) | Provides structural integrity; higher grades used for load-bearing components. | |
| Surface Preparation | Clean, scale-free, pickled surface | Ensures uniform zinc adhesion and coating quality. | |
| Zinc Coating Properties | Coating Mass/Weight | Code Designation: | Directly correlates to corrosion resistance. Higher mass = longer service life. |
| • G90 (∼275 g/m² total) | |||
| • G60 (∼183 g/m²) | |||
| • G30 (∼100 g/m²) | |||
| Coating Thickness | ∼5–85 µm (per side) | Measured via magnetic gauges; thicker coatings offer better durability. | |
| Coating Structure | Pure zinc outer layer + zinc-iron alloy layers (metallurgical bond) | Provides sacrificial protection; zinc corrodes first to protect steel. | |
| Spangle Size | Regular, minimized, or spangle-free | Aesthetic preference; minimized spangle often preferred for painting. | |
| Performance & Testing | Adherence/Bend Test | 180° bend around mandrel; coating must not flake (per ASTM A525) | Ensures coating durability during fabrication and forming. |
| Uniformity Test | Preece Test (CuSO₄ dip): Coating must withstand multiple dips without copper deposition. | Checks for bare spots or thin areas. | |
| Corrosion Resistance | Salt Spray Test (ASTM B117): Hours to white rust (zinc oxide) and red rust (steel). G90: ∼30 years in rural atmospheres. | Predicts service life; zinc sacrificially protects even scratched areas. | |
| Standards | Governing Standards | ASTM A653 (Sheet Steel), ASTM A123 (Structural), EN 10346 (Continuous hot-dip coated) | Defines coating classes, mechanical properties, and testing requirements. |
