Influence of Al and Si on austenite formation in Cr–Ni–Mo steel in the intercritical temperature range

The effect of adding aluminum and silicon to 35XH1M2ΦA steel is investigated in order to analyze the influence of those elements on austenite formation. 35XH1M2ΦA steel, which is used in heavy industry and in power equipment, is selected for study because its mechanical properties—in particular, its plasticity and impact strength—require improvement. High-temperature structural analysis provides data regarding the ratio of α and γ phases in the steel. On the basis of the results, the critical points Ac1 and Ac3 are calculated. It is found that introducing aluminum in 35XH1M2ΦA steel expands the intercritical temperature range, whereas introducing silicon shifts the intercritical temperature range to higher temperatures. The lattice parameter of austenite is least at 740°C in 35XH1M2ΦA steel. Silicon and aluminum raise this temperature to 760 and 780°C, respectively. © 2015, Allerton Press, Inc.