In this study, AISI O2 tool steel was subjected to conventional quenching, conventional quenching followed by tempering, double quenching, and double quenching followed by tempering heat treatments. The effects of microstructural changes caused by these treatments on hardness, impact toughness, and wear resistance were examined. Microstructures were analyzed using a scanning electron microscope. Martensite lath and carbide sizes were measured with ImageJ software, and phase analysis was performed via X-ray diffraction. Hardness was measured using the Rockwell C scale. Charpy impact and dry sliding wear tests were conducted. Double quenching decreased martensite lath size, carbide size, and retained austenite. It improved hardness, impact toughness, and wear resistance by approximately 30 percent. Tempering increased impact toughness but slightly reduced hardness and wear resistance.
Çivici et al. (Thu,) studied this question.