Study on total oxygen content and micro inclusion of bearing steel GCr15 during RH vacuum process

The influence of RH vacuum processing time on the total oxygen content and micro inclusion removal of bearing steel GCr15 was discussed. The results show that total oxygen content and micro inclusion amount will be decreased further by prolonging vacuum processing time, deoxidization during the RH process is caused by micro inclusion removal, and the relationship between the total oxygen content and RH vacuum processing time is in agreement with the relationship between the micro inclusion amount and vacuum processing time. After 25 min of the RH vacuum process, total oxygen content and micro inclusion amount are decreased by about 60%, which is 13% less than those after 14 min of the RH vacuum process. It is found that the deoxygenation coefficient is -0.036 min^-1 under the RH production condition of bearing steel GCr15 in Xingtai Iron & Steel Corporation. The average total oxygen content of 147 heats bearing steel is 6.7×10^-6 after process optimizing.