Heat treatment quenching oil aging

Causes of aging of heat treatment quenching oil and maintenance work

Heat treatment of steel parts quenching oil is usually divided into two categories, vegetable and mineral oil, in the long-term quenching process, the rise of oil viscosity, oil generated in dross or debris, cause the loss of the quenching cooling capacity, referred to as the "aging" phenomenon of oil, will cause the workpiece hardness inconsistent or difference is very big, can't meet the technical requirements, according to its working process analysis, the reasons are as follows:

1. The oil comes into contact with the surface of hot steel parts at high temperature, and the oil will decompose, heat polymerization and coking after being heated;

2. When the oil is heated, it will contact with the oxygen in the air to produce oxidation;

3. When the parts are quenched and cooled, the salt residue, dirt, oxides, rust agents on the fixtures and fixtures are brought in to promote the oil to produce oxidation polymerization;

4. During the long-term use of oil, the oil temperature increases after quenching, resulting in the volatilization of some oil and the increase of viscosity.

According to the above reasons of "aging" of heat treatment quenching oil, combined with its specific working conditions, in order to ensure the stability of heat treatment product quality, the following maintenance work should be done:

It is necessary to check the actual working oil temperature of quenching oil regularly to avoid the reduction of cooling capacity or fire caused by excessive oil temperature. Keep the oil temperature within the specified range, and make the oil circulate in the oil tank, with filtration and cooling devices; Avoid water into the quenching oil, too much water, not only make the oil easy to aging, but also easy to make the heat treatment parts appear defects; Often remove oil residue and oxide peel.