Evolution of M s Temperature as a Function of Composition and Grain Size

Martensite transformation was studied in 16 steel compositions with various C, Mn, Si, Al, and Cr contents. Different annealing treatments were performed on the elaborated steels to obtain different prior austenite grain sizes (PAGSs) and M s temperatures. This permitted the concomitant evolution of M s temperature as a function of chemical composition and PAGS. The experimentally built database allowed the decorrelation of the effects of chemical composition and PAGS, and a new empirical equation to predict M s temperature was proposed. The obtained experimental results and equation are discussed, and some future improvements are proposed.