Abstract: The following process is used to produce wheel medium carbon bearing steel S55C: 120 t BOF smelting—► LF refining—► RH vacuum treatment —► 240 mm x 240 mm continuous casting billet—►Φ55 mm and Φ60 mm bar rolling. Catch carbon practice is used in BOF smelting to control end [C] \0. 10% , and the slagging-off detection system is e- quipped. The basicity of slag is controlled within 4.0 ~ 6.5 during LF refining. The cyclic degassing in RH is carried out under the condition of high vacuum degree ≤66. 7 Pa, and die soft blowing time after degassing is not less than 40 min. Protective casting is carried out in the whole casting process, and M-EMS and F-EMS as well as light reduction technology is applied, the control rolling and control cooling technology are adopted in the rolling process to control finishing rolling at 880 -950 ℃. The measuring results show that the oxygen content in product is ≤ 0.001 0% , and the titanium content is ≤ 0.001 5%. The internal quality of the bars meets the ultrasonic grade A； and there are no macro defects and large inclusions； and the longitudinal material fatigue life exceeds 10 ⁷ times.

Key words:  , S55C Bearing Steel for Wheel Hub, Cleanliness, Fatigue Life