"Evaluation and control technique of cooling unevenness by quenching oil"

In the heat treating process, it is important for parts to be cooled uniformly in order to reduce distortion while obtaining target hardness. However, it is difficult to cool the parts uniformly due to the vapor blanket stage in oil quenching.

In this study, we investigated the influences of cooling unevenness in various heat treatment conditions, such as the types of oils which have different vapor stage lengths, and varying agitation rates. We found that cooling unevenness was decreased by changing the quenching oil with a shorter vapor blanket stage length. Additionally, the cooling unevenness was decreased by agitation compared to quenching without agitation.

In conclusion, we found that to select the quench oil which has short vapor blanket stage length, and agitation were effective in reducing the distortion of parts after oil quenching.