Effect of substructure and carbide phases on strength and tempering resistance of low-carbon pearlitic steels

Results of investigating 15 KhMFA and 15KhNMFA steels after initial heat treatment and additional long-term high-temperature tempering are presented. The ratio between the structure element sizes and forming as a result of tempering substructure of low-carbon pearlitic steels, at which instead of typical for such cases loss of strength hardening and increase of steel tempering resistance take place, is determined. The carbide phases forming during tempering (Me7C3, Me2C, MeC) increase the steel stability heat resistance