INCREASED HARDENABILITY OF STEEL BY AN EXTERNAL ELECTRIC-FIELD

The effect of an external dc electric field of 1 kV/cm on the hardenability of two steels (02 and 4340) was investigated. The experiment consisted of making the specimen one electrode of an electrostatic circuit and applying a potential during austenitizing and/or quenching in several media representing a range in cooling rates. The electric field produced an increase in hardness at intermediate cooling rates, the effect being much larger for the 02 steel. Further, the influence of the field was much larger when applied only during the quench compared to only during austenitizing. The results suggest that the effect of the field is to cause a shift in the cooling transformation (CT) diagram to longer times. The mechanisms by which this might occur are discussed. © 1990.