Nondestructive evaluation of carbon contents and microstructures in plain carbon steel bars by Barkhausen emission

Plain carbon steels with different carbon contents have been widely used in industry. There is a pressing need for the nondestructive inspection of st eel parts during their fabrication and when they are in service. Barkhausen emission (BE) is one of the nondestrucave testing methods that is being us ed. Recently, we find that the following parameters of the BE signals depen ded strongly on the carbon content in steel sample, namely, the rising slop e of the BE profile, the root-mean-square of the signals, and the half-maxi mum-width of the profile. The values of these parameters increase as the am ount of carbon in the sample increases. The dependence is similar to that o f the mechanical hardness on the carbon contents in the samples.