Effect of an electric field applied during the quenching on hardness of carbon steel

It is found that application of an electric field during the quenching of 0.46% carbon steel in water increases its hardness. The hardness of the quenched surface increases with the strength of the electric field. The effect of the electric field on the hardness of the quenched surface is larger than that in the interior of the material. The quenching with an electric field gives a tinier martensite microstructure than the quenching without it. The possible mechanisms of electric field increasing the quenched hardness are: (a) the field reduces the critical radius of the martensite and the nucleation energy, and increases the nucleation rate; (b) the field reduces the vacancy concentration at the charged surface, thereby retarding the vacancy influence on the rate of pearlite formation.