Influence of Substrate Molybdenum on Galvannealing Kinetics of an Advanced High Strength Steel

Advanced high strength steels (AHSS) are used for car body applications in the automotive industry to improve passenger safety, improve fuel efficiency and to lower harmful carbon emissions. Galvannealed AHSS are used to provide corrosion protection. AHSS are alloyed with several elements such as Mn, Si, Al, P, Mo, etc. to achieve better mechanical properties. However, the knowledge of the effects of Mo on galvannealing behavior is limited. This investigation was conducted to study the influence of molybdenum in steel on galvannealing kinetics. Five dual-phase steels with Mo varying from 0 wt% to 0.4 wt% were used for this study. The results showed a delay in the galvannealing kinetics with an increase in the steel molybdenum content. No obvious improvement in the coating appearance was observed with increasing molybdenum.