The heat treatment and quenching process provides tremendous advantages for the steels by modifying the mechanical properties and affecting phase change in the structure of steel. So we perform this heat treatment process in various quenching medium to test the EN8 steels. Few specimen of EN8 steel were studied and analyzed after heating them in the Muffle Furnace between 750 °C and 950 °C followed by quenching in different medium. Oil, Water, and Air are used as different quenching medium. Using the Rockwell hardness equipment the mechanical properties such as hardness are measured, and the hardness of the quenched material is significantly greater than the parent material. The samples are then subjected to Charpy impact testing and Rockwell hardness testing after heat treatment. The sample was crated for Charpy test as per ASTM-E23, and for Rockwell hardness test as per ASTM-E18.In this work EN8 a grade of medium carbon steel is used. The composition of this EN8 steel is shown in the table below. The specimen was taken in the form of square bars 14 × 14 mm cross section which was then machined on lath machine by facing to the cross section of 10x10 mm and then cut. The final dimension of the specimen was 10x10x55 mm as per ASTM-E23. A U - notch of 2 mm depth was cut at the centre for impact testing.