Induction hardening of heat treated gear teeth which includes the steps of
rough and finish cutting the gear teeth, or alternatively cutting the gear
teeth to their final configuration utilizing a one cut method, carburizing
the gear and in particular, the gear teeth, slow cooling, or alternatively
drawing back the gear so the gear teeth are not hard, and induction
hardening the gear teeth heating only the surface of the gear teeth. This
results in improved strength for the gear teeth as a result of increased
residual compressive stresses therein. Induction heating of only the
surface of the gear teeth results in an relatively low case depth in the
root of the gear teeth. Since the residual compressive stresses increase
as the case depth decreases, the fatigue life of such a gear will be
improved as compared to gears produced using known prior art methods which
utilize the case depth from the carburizing process which results in a
relatively deeper case and, therefore, lower residual compressive stresses
in the gear teeth and a less than desirable fatigue life.