Tungsten carbide (WC) is often induction welded to tougher and economical material, such as martensitic type 420 stainless steels (SS 420), to form a hybrid cutting tool stock. However, undesired softening in the SS 420 next to the fusion interface usually occurs. This softening is due to localized carbide precipitation in SS 420 matrix arising from heating during the induction brazing process. The aim of the present work is to investigate the soft zone of the SS 420 weldment by controlling the heat input during induction brazing. The result showed that cooling rate has a great effect on softening of the SS 420 weldment during induction brazing.