The problem is raised that in some scanning quenching applications, the step axis undergoing proper austenitizing may appear soft at the inner Angle of the diameter transition.
Solution: Sometimes, when the quenched stepped shaft is scanned, it may be difficult to spray quenching to reach certain areas of the shaft shoulder. As a result, inadequate local quenching, low hardness, or upper phase change products may occur at the inner corner of the step. Therefore, it is important to know that there may be a better scanning Angle. In the case of an unsatisfactory scan Angle, the spray quenching impact may miss the smaller diameter near the shoulder, which may lead to under hardening and soft spots. Therefore, if the spray quenching impact Angle is too small, increasing the impact Angle will help to better quench the inner Angle of the transition part of diameter. There is a limit, however, because an excessive increase in the impact of Angle may cause the quencher to spill back into the heating coil, resulting in a pattern of speckled hardness. It may also be helpful to use a quenching follower with an appropriate spray impact Angle.