Abstract: The effects of Si content on combinations of important properties such as hardness, hardenability, and weldability in addition to strength increment were systematically investigated to develop a Mo and V free low alloy cast steel for automobile cold pressing die insert. For the evaluation of the applicability as the die insert, the mechanical properties were measured after spheroidization annealing (SA), quenching and tempering (Q/T), and flame hardening (FH) treatments, respectively. The developed 0.8%–1.6%Si containing Mo and V free alloy cast steels showed excellent matrix strengthening effect, hardenability, and weldability, fulfilling the industrial criterion of the mechanical properties for the die insert.

Key words: Low alloy cast steel, Cold pressing die, Die insert, Matrix hardening, Flame hardening