Effect of Deep Cryogenic Treatment on the Dimensional Stability of Aisi 440c Bearing Steel

摘要

The interest of realizing cryogenic treatment on various materials has been increased recently. The dimensional stability of Shallow Cryogenic Treated (SCT) and Deep Cryogenic Treated (DCT) AISI 440C bearing steel compassion with Conventionally Heat Treated (CHT) have been investigated in this paper. Thermo mechanical analysis is carried out using a dilatometer. The temperature of the CHT, SCT and DCT specimens were increased upto 810 oC (1083k) with a constant rate of 5oC/min from atmospheric temperature. By using Linear Variable Differential Transformer (LVDT) the change in length of the specimens during the experiment is measured. By using these data, Coefficient of Linear Thermal Expansion (α) has been found for all the specimens, and DCT specimen has 8.7% lower than SCT and 14% lower than CHT specimen.