Abstract
One of the ways to improve formability of Advanced High Strength Steel grades is by modifying the surface during downstream production process. In this study, Galvannealed DP980 grade was selected to understand the impact of a change in the annealing furnace atmosphere before hot-dip coating on product attributes such as diffusible hydrogen content in the steel, bendability, etc. Results showed that an increase in the dew point in the furnace resulted in an increase in surface decarburization which correlates with an improvement in bendability. Along with a decarburized layer, changes in diffusible hydrogen amounts were also observed with furnace atmosphere changes. This paper will also discuss the relationship between hydrogen diffusivity and delayed fracture (DF) susceptibility associated with the presence or absence of a decarburized layer.