ABSTRACT
Understanding phase evolution and growth kinetics of Zn-coating during press-hardening is essential in predicting welding behaviour of press-hardened 22MnB5 steel. The results showed that during press-hardening, the initial δ and Γ-Γ1 phases in the coating transform into α-Fe(Zn), Γ, and ZnO phases. As heat-treating continued at a constant temperature, the α-Fe(Zn) thickness grew and the overall Zn-content decreased. This resulted in the full-penetration weld window shifting towards higher heat-inputs. However, when heat-treating at higher temperatures, severe oxidation and Fe-Zn inter-diffusion led to the reduction of Zn-content in the evolved coating. It was found that higher heat-treatment times resulted in wider weld beads, thereby increasing joint strength.
Acknowledgements
Authors would like to acknowledge the National Science and Engineering Research Council (NSERC) of Canada and ArcelorMittal Dofasco Inc. in Hamilton, Canada.
Disclosure statement
No potential conflict of interest was reported by the authors.