Abstract: The effects of Ti on the formation of austenite and carbides during solidification and cooling in Cr12 MoV die steel were investigated by calculating the solubility products of carbides such as Ti,V,Mo and Cr in different temperature ranges.The results show that TiC can be precipitated only when Ti content in the Cr12 MoV steel exceeds 0.108 4%,and the precipitated TiC may become the nucleation core of austenite.TiC precipitates in austenite earlier than VC during the cooling after solidification,which may acts as the nucleation core of VC,causeing VC particles coarser,and making it difficult for VC particles to dissolve uniformly in austenite during the quenching process,thereby affecting precipitation hardening effect of VC after tempering.