The influence of Cr content on the high-temperature oxidation behaviour of bearing steels

High-temperature oxidation experiments were conducted on GCr6 and GCr9 bearing steels with varying Cr contents using the discontinuous weighing method. The oxidation experiments were carried out in the temperature range of 700–1100°C for 40 min, at 900°C and 1050°C for 10–60 min. And the composition of the oxide layer at 800, 900, 1000 and 1100°C was analysed by XRD. The results indicate a similar increasing trend in the unit area oxidation weight gain curves for GCr6 and GCr9 bearing steels. Furthermore, the unit area oxidation weight gain of GCr6 bearing steel consistently exceeds that of GCr9 bearing steel under the same conditions. The unit area oxidation weight gain for specimens exhibits a parabolic relationship with holding time, showing a positive correlation with the square root of the holding time. Cr 2 O 3 was detected in the oxide layer of the specimens starting from 900°C, and CrO 3 was detected at 1100°C.