Patent ID: 10202678

Abstract:
Method for heat treating a steel component (28, 36) comprising the steps of: a) carbonitriding the steel component (28, 36) at a temperature of 930-970° C., b) cooling the steel component (28, 36), d) re-heating the steel component (28, 36) to a temperature of 780-820° C. and d) quenching the steel component (28, 36). The method comprises the step of either e) performing a bainite transformation at a temperature just above the martensite formation temperature, transforming 25-99% of the austenite into bainite at the temperature and then increasing the temperature to speed up the transformation of the remaining austenite into bainite, or f) holding the steel component (28, 36) at an initial temperature (T1) above the initial martensite formation temperature (Ms), and lowering the initial temperature (T1) to a temperature (T2) that is below the initial martensite formation temperature (Ms) but above the actual martensite formation temperature during the bainite transformation.