Idemitsu Kosan Company, Limited

Hitoshi Uchida

Eiichi Nakamura

Saburo Koyama

Hideo Kanamori

Disclosed are a method for restoring a water-soluble quenching medium being used, of which the cooling characteristics have been deteriorated during use, to its original condition to have nearly the original cooling characteristics which the fresh medium has before use, and a water-soluble quenching medium thus restored to its original condition to have nearly the original cooling characteristics thereof. The method comprises adding to a quenching bath being used an aqueous solution comprising a water-soluble polymer (B) that has a larger weight average molecular weight than that of the water-soluble polymer (A) existing in the fresh water-soluble quenching medium to be in the fresh bath.

Method for recovering cooling characteristics of water-soluble quenching

The invention provides a water-soluble quenching medium suitably usable for quenching of metal, which can prevent quenching cracks and quenching ununiformity while having good hardenability. The medium comprises (A) a polyalkylene glycol having a weight average molecular weight of from 10,000 to 100,000 and/or its derivative, (B) a glycol ether having a weight average molecular weight of 1,000 smaller, and optionally (C) an alkylene glycol having a weight average molecular weight of 1,000 or smaller, (D) an alkali metal carboxylate, and (E) an organic amine compound having a weight average molecular weight of 1,000 or smaller.

Water-soluble quenching medium

Disclosed is a heat treating oil composition which comprises a base oil adjusted to have a total sulfur content of 3 to 1000 ppm comprising (A) at least one base oil selected from a mineral oil and a synthetic oil each having a sulfur content of not more than 300 ppm and (C) at least one member selected from a sulfur and a sulfur compound, and (B) at least one additive selected from an alkaline earth metal salt of sulfonic acid, that of a phenol, alkenyl succinic acid derivatives, fatty acid or its derivatives and phenol-based and amine-based antioxidants. The above-mentioned heat treating oil composition is suitable for quenching under a condition of a high oil temperature, and realizes a treated metal product having a excellent brightness and little distortion.

Heat treating oil composition

There is disclosed a heat treating oil composition which comprises (A) at least one base oil selected from a mineral oil and a synthetic oil each having a sulfur content of not more than 300 ppm and (B) at least one member selected from alkaline earth metal salts of salicylic acid. There is also disclosed a heat treating oil composition which comprises (I) a base oil having a sulfur content of 3 to 1000 ppm consisting of said (A) component and (C) at lease one member selected from a sulfur and a sulfur compound, along with (II) various additives for quenching. This heat treating oil composition is suitable for quenching under the condition of a high oil temperature and capable of obtaining a treated metal excellent in brightness and having a minimized distortion.

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Ichihara, Japan

Hitoshi Uchida