A. R. Saheb Alam - Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi
M Kashefi
S. Kahrobaee - Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Sadjad
S Ghanei

Among different nondestructive magnetic methods, barkhausen noise is a the newest one in evaluation ofmetallurgical and mechanical properties such as grain size, hardness and microstructure assessment as well as determination of residue stress. The basis of the method is on the abruptmotions and rotation of domian walls in ferromagnetic materials, when magnetized under AC current. Difference in magnetic properties, due to variation in microstructure, results in the different behavior under magnetization. Barkhausen noise is related to materaills magnetization behavior, which this, in turn, may be used to separate various microstructures. In this research, analysing barakhausen signals, different microstructures (anneal, normale, quench and quench-temper in different temperatures) were examined. The comparsion were made for position and ampliutede of the MBN peaks in the voltagemagnetic diagram. The results indicate that the BN technique can be succsessfully used to separate the microstructure

Nondestructive test; Barkhausen noise; Microstructure; Heat treatment;