Abstract
The quenching effects of several kinds of commercial mineral oil were examined using test piece A (0·7%C steel, 11·5_??_×20mm). Further, the quenching effects of various fatty oils, fatty acid ethyl esters and fatty acids were tested. The following conclusions were obtained:
(1) The quenching effect of oil must be studied from the point of view of its boiling point, the intensity of polarity and contents of some hydrocarbons having higher boiling points.
(2) The phenomena observed during quenching are closely related to the composition of mineral oils. Generally, the duration of gas film adhering to the specimen during quenching is shorter for the oil in which the thermal cracking of hydrocarbons takes place remarkably.
(3) Quenching effects of rape seed oil and soya bean oil are almost the same, so all fatty oils having higher molecular weight will give the same quenching effect.
(4) Castor oil gives more marked quenching effect, because of its thermal instability.
(5) The esters and the fatty acids have almost the same quenching effects, which are lower than those of fatty oils.
