Characterization of the Galvanizing Behaviors Depending on Annealing Conditions in 22MnB5 Steel and the High Temperature Phase Evolution of Zn Coatings with Hot Press Forming

摘要

The characteristics of the formation of inhibition layers of galvanized iron (GI) in association with selective oxidations by the change of annealing conditions in 22MnB5 grade steel and the corresponding high temperature phase evolution of Zn coatings during hot press forming have been studied using a combination of various analytical techniques. The annealed and also galvanized samples were prepared by galvanizing simulator. It was shown that the chemistry and oxide morphology of selective oxidations controlled by annealing conditions are crucial to the growth of inhibition layers. Selective oxidations were formed by the alloying elements of Mn, Si, B, and Al. The initial Zn coating was changed to an oxide layer at surface, and a Zn-Fe intermetallic layer and/or a Fe-Zn layer in reacted coating after hot press forming. The corresponding coating structures by the high temperature phase development after hot press forming were influenced by the characters of inhibition layers.