Bake hardening mechanism in steels

The steels used in modern automotive sector are faced with inherent compromise of formabilityfor desired increase in strength. During the last two and half decades. bake hardenable (BH) steels were developed to reduce the weight by decreasing the sheet thickness of autobody panels without deteriorating the strength properties. BH steels are characterized by excellent formability and low yield strength in delivery conditions from the plant and hence can be readily used for outer panels of automotive bodies. A sincere attempt is made to elucidate the core of contemporary mechanisms for bake hardening under different conditions of prestrain and temperature in two distinct stages. A worthwhile mention of some mathematical models is made to simulate the phenomena at atomic level and to reason some of the attributes of bake hardening mechanism. Finally, the ultimate increase in yield strength due to bake hardening process is abridged in an empirical relationship. The current paper is framed to unravel the 'Bake hardening mechanism. which serves as the grass root feature of the bake hardenable steels.