Time quenching,Time quenching,Time quenching,Time quenching,Time quenchingTime quenching is used when the cooling rate of the part being quenched needs to be abruptly changed during the
cooling cycle. The change in cooling rate may consist of either an increase or a decrease in the cooling rate depending on
which is needed to attain desired results. The usual practice is to lower the temperature of the part by quenching in a
medium with high heat removal characteristics (for example, water) until the part has cooled below the nose of the timetemperature-
transformation (TTT) curve, and then to transfer the part to a second medium (for example, oil), so that it
cools more slowly through the martensite formation range. In some applications, the second medium may be air or an
inert gas. Time quenching is most often used to minimize distortion, cracking, and dimensional changes.
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