Interrupted quenching is used to modify the rate of cooling of an alloy in heat treatment. An example of interrupted quenching is found in the treatment of an axle after repair by welding. A specific time in oil will cool the surface rapidly enough to suppress the transformation to a given depth below the surface. In interrupted quenching, if immersion time is sufficiently short, there will be enough heat in the interior of the axle to raise the temperature of the exterior layer, effecting a tempering treatment. Subsequent tempering is unnecessary, and the highly stressed condition caused by full quenching is avoided.
