Material for slewing ring bearing rollers is generally entirely-quenching carbonchromium, No. steel Cr15SiiMn or steel GCr15. Surfice-quenching steel is used on the bearing sleeve. If there is no special requirements on the slewing ring bearing materials, usually use 50Mn steel, but sometimes in order to satisfy main machine needs in some special application occasions, select steels in other No.s surface-quenching steels based on users’ specific needs, such as 42CrMo and 5CrMnMo.