Abstract
The cooling curves were measured with silver specimen as to several typical mineral oils having widely different viscosities and flash points with one another in order to correlate the properties of mineral oils with the quenching severity, H, derived from the cooling curves here obtained, and the examinations of the results presented in the 7 th report were also done with the findings in this experiment. The H values of mineral oils increase with oil temperature up to a point at which maximum value of H is reached and subsequently decrease. The maximum values of H, the temperature at which the H value rises to the maximum and the variation of H value with oil temperature are correlated with the flash points of oils. Paraffinic mineral oils have smaller values of H as compared with naphthenic ones and the H value decreases so much so that the degree of refining is elevated. It is also referred to the improving reagent of cooling ability of mineral oils.
