The distribution of C

Si

Mn and Cr elements in cross sections of Φ450 mm continuous casting round billet and Φ130 mm round steel of high hardenability bearing steel GCr15SiMn was analyzed by original position statistic distribution analysis(OPA)and borehole chemical analysis.The contact fatigue life of the material was tested by the thrust plate con-  tact fatigue testing machine.The results show that the segregation tendency of C element in bearing steel GCr15SiMn continuous casting round billet is large

and it is easy to produce center positive segregation

while the segregation tendency of Cr

Si and Mn element is small.The central carbon segregation in casting bloom was improved by adopting stable low superheat casting and

three-stage strong electromagnetic stirring.After(1240±20)℃×5 h high temperature diffusion and large deformation rolling with primary pass deformation ≥90 mm

the carbon segregation of φ130 mm round steel can be further improved. The rated contact fatigue life L

10

of the test steel under 5.3GPa high stress load reaches 3.58×10

6

times

which is close to the level of ESR steel.