Improving the impact toughness properties of high carbon powder metallurgy steels with novel spherical cementite in the bainitic matrix (SCBM) microstructures

Spherical cementite in the bainitic matrix (SCBM) microstructures in the high carbon powder metal steels having 1.5 wt% C were achieved in specimens with the spherical cementite in the ferritic matrix microstructures by isothermal annealing in a salt bath at 350 °C after annealing at 750 °C. The toughness properties of the specimens with SCBM microstructures were compared with pearlitic plus primary cementite, fully martensitic plus tempering,...