Effects of Annealing Parameters on the Microstructure of Galvannealed Coating on DP590 Steel

Galvannealed coated sheet steels are extensively used in the automotive industry due to its good corrosion resistance, excellent spot weldability and paintability. However, galvannealed coated sheet steels generally present different forming behaviors, which mainly depend on the amount, orientation and distribution of different Fe-Zn intermetallic phases in the coating. This paper deals with the characterizations of experimentally produced galvannealed coatings using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and Glow Discharge Optical Emission Spectroscopy (GDOES). The effects of annealing parameters on the microstructure of galvannealed coating on DP590 steel were discussed. As a result, the proper annealing temperature and time for this dual phase steel are put forward.