China Hot-Dip Galvanized Galvannealed Coil Suppliers - High-Quality Coating from Leading Factory

Galvannealed (GA) coils are produced through an advanced two-step process that involves hot-dip zinc coating followed by in-line annealing at temperatures between 500–550°C. This thermal treatment enhances the coating by diffusing iron into the zinc layer, resulting in a Zn-Fe intermetallic alloy with a Fe content of 7–15%. This unique composition not only provides superior weldability and abrasion resistance but also ensures durability. Our GA coils feature a matte-gray finish that complies with ASTM A653 Grade GA60-GA165, offering a phosphate-free surface that is perfect for paint adhesion. As a leading factory and supplier in China, we utilize a proprietary air-knife system to accurately control the coating weight within ±5 g/m², achieving a total coating range of 60–180 g/m² on both sides. Our products also exhibit microhardness levels of 250–350 HV, making them ideal for various applications.