INFLUENCE OF MODIFICATION AND HEAT TREATMENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF LOW ALLOY CASTING STEEL

Abstract

Influence of Al and Ti addition combined heat treatment on microstructure and mechanical properties of the low alloy casting steels is presented in this article. In this research, the samples were modified by Al and Ti then heat treatment as follows: heated and held at 650^oC for 2 hours, then continued heating to 920^oC for 3 hours before quenching in water; after that, they were tempered at 250^oC for 06 hours. The results indicate that the highest values of impact strength and hardness were 57.5J/cm² and 50 HRC. The microstructure of the sample was bainite and residual austenite with grade 4 of the particle size.