High temperature mechanical properties of cast billet of CCr15 bearing steel (0.98%C
1.51% Cr) have been tested by using Gleeble-3500 thermal simulation test machine to get that zero plastic temperature (ZDT)of GCr15 steel- 1400 ℃
zero strength temperature- 1450 ℃
optimum plastic temperature range of billet - 1250~950 ℃ and Ⅱ brittle temperature range-950~600 ℃. The fracture morphology of billet at plastic temperature range and brittle temperature range was analyzed by SEM. The study results show that the straightening temperature of cast billet should be controlled ≥950 ℃.