The Coating Fragile Phase Thickness Measure Methods of Galvannealed Steel Sheet

Powdering and desquamation is prone to happen when galvannealed sheet steel is stampinged and Powdering or desquamation often happens at the fragile phase where Fe content is high. The fragile phase thickness of the coating of galvannealed steel sheet is correlative nearly to the coating anti-pulverization ability. So it is very important to measure the fragile phase thickness with the research of galvannealed sheet steel process. The fragile phase thickness of the same batch galvannealed sheet steel made by some steel plant is about 560 similar to 590nm when it is measured by glow ischarge spectrometer, fracture observation methods by SEM and metallographic microscope, the error is very little.