Quenching oil for quenching under reduced pressure and quenching method

摘要

A quenching oil for reduced pressure quenching which comprises a base oil having a kinematic viscosity at 40° C. of 40 mm2/s or more and a vapor blanket breaking agent; and a method for quenching wherein the quenching oil is used and quenching is carried out while adjusting the pressure on the surface of the oil. The method allows the achievement of cooling characteristics over a wide range from those conventionally achieved by a cold oil to those by a hot oil, by the use of a single quenching oil.