It is applied to oil or Air hardened tool steels directly from the heating bath in a molten AAM TEMP– 9902 bath for MarQuenching and Tempering within the temp. range of 150°C - 540°C. MarQuenching and Tempering alloy steels after hardening and reheating within 780°C - 820°C.
Typical parts which are tempered are low alloy transmission steels, gears, punching & cutting tools, die casing & forging dies, ball and roller bearing, reamers, spindles, taps and dies, mandrels etc. parts are first heated to normal hardening temp. in a salt bath and then quenched into a molten bath of AAM TEMP – 9902.For high alloy steels and at lower temp. for low alloy steels.
While tempering of low alloy tool steels, the tempering bath should be kept in a state of agitation by providing an agitator or stirrer in the bath, so that heat is spread uniformly. For the steels of controlled grain size and low alloy. Steels such as EN 34, 35, 352, 353, 354 tempering is done at the temp. range of 200°C - 250°C.
It is mainly used to minimize distortion & to relieve hardening strains.