Influence of alloying elements on precipitation behavior of VCN in middle carbon steels

For lightening the hot forged automotive components such as connecting rods, crank shafts etc. the increase in their yield strength is an important technical issue. Recent developments indicate that it is a promising way to increase the yield strength of the components using the ferrite-pearlite microstructure strengthened by precipitation hardening of VC. In this study, the influence of alloying elements, cooling rate and aging temperature on the precipitation hardening behavior of V containing middle carbon steels was investigated. The precipitation hardening is very sensitive to cooling rate and aging temperature. The addition of Si reduced the sensitivity of the cooling rate. The deformation in the austenite region slightly decreases the precipitation hardening. From a detailed analysis, it was found out that the precipitation hardening is strongly influenced by the γ→α transformation behavior, which indicates that the interphase precipitation plays a significant role for the precipitation hardening.