Heat treatment effect on the microstructural, hardness and thermal properties of XC48 steel

This work examines the effect of heat treatment parameters such as the cooling velocity and the quenching fluid nature on the structural, Rockwell hardness and thermal properties of XC48 steel. The studied specimen is a cylinder of 3 cm diameter and 10 cm length, and the used quenching fluids are oil, water and air. The investigation shows that the XC48 hardness varies from 18 to 58 HRC through the used quenching fluid and decreases along the length of the specimen contrary to the thermal conductivity and thermal diffusivity, which are primarily in the order of 36 W m −1 K −1 and 0.125 cm 2 s −1 respectively, and which increase with the quenching velocity. A correlation between these thermo-mechanical properties such as the hardness and the thermal conductivity is realized to obtain a new nondestructive technique permitting to determine the mechanical hardness without measuring it. This technique is of an overwhelming importance and can be used in the industrial and research fields.