油の焼入効果の検討方法ならびに炭素鋼の焼入性と油の焼入効果との関係について

油の焼入効果に関する研究-I

抄録

This paper deals with a study on some properties of oils required for the quenching of steels. Some experiments were carried out on several oils having different properties, using carbon tool steels and low alloy structural steels. This study also treats some remarkable phenomena observed during the quenching as well as the cooling actions of quenching oils.
The experimental methods are described in detail, together with a preliminary study on the relationship between the hardenability of carbon tool steel and the quenching effects of oil. The following conclusions are obtained:
(1) The cooling behaviour of carbon tool steels during quenching varies remarkably depending on occurrence or none of pearlite transformation in the steel.
(2) The presence of gas film generated during quenching is long when pearlite transformation takes place in the surface layer of the test piece.
(3) The pearlite transformation occurring in the surface layer of a test piece affects remarkably the degree of its hardening.
(4) The quenching effects of oil on a carbon tool steel differ greatly depending on its hardenability.
(5) The quenching effects of oil should be examined with respect to steels having different hardenabilities. Proper evaluation of the quenching effects of oil is not obtained using a carbon tool steel having high hardenability.