Idemitsu Kosan Company, Limited

Toyota Jidosha Kabushiki Kaisha

Makoto Takeishi

Katsumi Ichitani

Yasuyuki Fujiwara

Masahiro Kobessho

Yoshimi Aoyama

Yasuyuki c/o Toyota Jidosha Kabushiki Fujiwara

Yoshimi c/o Toyota Jidosha Kabushiki Aoyama

The heat-treating oil composition of the present invention is characterized by comprising a mixed base oil containing a low-boiling base oil having a 5% distillation temperature of from 300 to 400&#xb0; C. in an amount of not less than 5% by mass but less than 50% by mass, and a high-boiling base oil having a 5% distillation temperature of 500&#xb0; C. or higher in an amount of more than 50% by mass but not more than 95% by mass. There is provided a quenching oil composition capable of exhibiting a less fluctuation in hardness or quenching distortion of a metal material treated therewith even when a large number of the metal materials are quenched therewith at the same time.

Heat treatment oil composition

A quenching oil for reduced pressure quenching which comprises a base oil having a kinematic viscosity at 40&#xb0; C. of 40 mm/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.

Quenching oil for reduced pressure quenching and method for quenching

Provided is a quenching method capable of producing quenched articles having little distortion and having a desired hardness. The quenching method with a coolant is specifically so controlled that the surface of the quenching bath is kept under pressure all the time throughout the step of cooling the articles being processed therein.

Quenching method

A heat treatment oil composition comprising a mixed base oil containing 50-95 weight % of (A) a low viscosity base oil with kinematic viscosity of 5-60 mm/s at 40&#xb0; C., and 50-5 weight % of (B) a high viscosity base oil with kinematic viscosity of more than 300 mm/s at 40&#xb0; C. is proposed. By the use of this heat treatment oil composition for hardening of metallic material, it enables to generate little cooling unevenness, to assure the hardness of hardening processed product, and to reduce quenching distortion.

Growing community of inventors

Chiba, Japan

Makoto Takeishi