Deformation behavior of a low carbon steel in α+γ range under electric current heating

Abstract

The effect of electric current (EC) heating on deformation and phase transformation behavior is studied for plain low carbon steel. It is shown that EC heating does not sensibly influence the deformation resistance of austenite. During deformation at the upper temperatures of the α+γ range the EC-effect is positive (flow stress decreases upon application of EC) while at the lower temperatures of the α+γ range the EC-effect is negative. This is accompanied by variations in the work hardening rate of the same sign. The EC-effect in the α+γ range is more pronounced at lower strain rates when the contribution of the EC heating to the overall temperature of the specimen is higher. EC heating combined with deformation leads to an increase in the Ar3 temperature. The magnitude and the sign of EC-effects on deformation resistance and transformation behavior in the α+γ range are related to the differences in electric resistivity and deformation resistance between the emerging and the parent phases. A negative difference in electric resistivity and deformation resistance accelerates the phase transformation and leads to a positive EC-effect, and vice versa.