Effects of cryogenic treatment on residual stresses of AISI D2 tool steel

Positive effects of cryogenic treatment on residual stresses of AISI D2 cold work tool steel were studied in this article. Samples were exposed to the cryogenic treatment at -145 degrees C for short and long holding durations (4 and 24 h, respectively). Alteration in residual stress distribution was correlated with the microstructure, hardness and surface roughness examinations of the samples. Results showed that cryogenic treatment reduced the residual surface stresses in comparison to the conventional heat treatment. There was no significant difference in hardness values and retained austenite contents. However, more dense and homogeneous carbide precipitation was observed mainly for the cryo-treated sample for 24 h. Surface roughness was found better for cryo-treated samples. In general, holding duration of 24 h represented preferable conditions, and this case was achieved by using the improved microstructure.