Abstract
In the present study, the following points were clarified with regard to the quenching effects of the blended oil, composed with fatty oil having large molecular weight and fatty acid ester having 20 carbon atoms:
(1) The mixture containing ester up to 90% in volume has a more remarkable quenching effect than the fatty oil used. The quenching effect is the larger with the more ester concentration.
(2) When the mixture contains ester over 90% in volume, its quenching effect becomes the less with the greater ester concentration. For carbon steel, having low hardenability, the above quenching effect is less than that of the fatty oil used.
(3) Under constant blending ratio, the quenching effect of the mixture is the larger with the greater molecular weight of the fatty oil, the larger polarity of the fatty acid ester and the lower boiling point of ester.
(4) The blended oil containing castor oil, generally, has a more remarkable quenching effect than other oil mixtures. It may depend on the thermal instability of castor oil. (5) The phenomena observed during quenching using fatty oil, fatty acid ethyl ester or fatty acid individually differ greatly from those observed in a blended oil of these ingredients.
