The piece to be hardened is wholly austenitized and after that quenched in a lead of salt bath held at a temperature simply above at that martensite would begin to form. This is maintained at this temperature till its temperature becomes uniform throughout that is inside and outside temperatures do not stay different and is after that water quenched to form entire bainite formation and martensite structure is prevented. From the austenite-martensite expansions such procedure successfully separates the cooling contraction and hence prevents quench cracking in large articles. The procedure of martempering is illustrated in following figure.
Figure: Martempering represented on the TTT Curve
The steel can be tempered to low temperatures for additionally refine the structure.
Table no. illustrates a few properties obtained from martemper, austemper and quenchtemper treatments.
Elongation % (on 25 min gl)
Water quench, Temper