Abstract
Investigating inclusively the beginning curves for all kinds of mineral oils, the approximate calculation method of quenching properties was explained without measuring the quenching curves. Addition of the oil soluble substances of high molecular weight and surfactant agents particularly improved the quenching properties.
When the initial temperature of test pieces is T°C, the later temperature t°C, and the time τsec., the formula of quenching curves are as follows:
At (I) t+T-T1/τ1τ=T
At (II), (III) (τ-τ1) tk1=k2
or (t-te)τn1=n2
but k1, k2, n1 and n2 are constant, and te is the temperature when the oil temperature is idential with the metal temperature.
