摘要
Bottom dross obtained from zinc bath and the typical bottom dross defects on galvanized and galvannealed coating were metallographically investigated.Galvannealing simulations with different holding time were conducted,and the bottom dross transformation behavior during the galvannealing process was revealed.The fast diffusion between bottom dross particles and the surrounding zinc occurs during the galvannealing process,resulting in the formation of an Al-containing Zn-Fe intermetallic outburst structure at the defect position.The thicker and harder coating will cause a shiny spot on the coating surface and a deep dent on the substrate after being temper rolled.
