Effects of Cooling Rate on Metallographic Structure and Hardness of Bearing-B Steel

Effects of cooling rate on metallographic and hardness of bearing-B steel were investigated in present research. The results showed it consists of ferrite and pearlite formed in the initial stage of the transformation in the studied bearing-B steels cooled at 0.5 °C/s. For the higher cooling rate than 10°C/s, it consisted of bainite and martensite formed in the initial stage of the transformation. All the results showed that the hardenability of this alloy was sufficient to avoid any elevated temperature transformation which steel sheet was expected to be cooled at rates from 0.5 to 20 °C/s. The hardness of specimens was rapidly increased for the higher cooling rate than 10°C/s. The peak value of the hardness was captured corresponding to the cooling rate of 20°C/s though its invariant then.