Microstructural Characterization of Different Steels Using Barkhausen Noise Measurement

摘要

Magnetic Barkhausen Noise (MBN) measurements have been used to characterize microstructure of die steel, mild steel, high speed steel and ferritic stainless steel. Metallographic samples of different steels were prepared to characterize the microstructural features of different steels. Metallographic examination indicated distinguished difference in microstructural features of different steels. High frequency Barkhausen Noise measurements were carried out to observe the shift in peak position of Barkhausen Noise signal profile with respect to microstructural features. High frequency Barkhausen Noise analysis showed single peak profile for all steel samples and influence of magnetically hard feature (martensite) and magnetically soft feature (ferrite) on motion of magnetic domain walls. It is observed that magnetically soft feature (ferrite) require low magnetic field strength to move the domain walls across it and magnetic field of higher strength is required for moving domain walls across the magnetically hard feature (martensite). Barkhausen Noise analysis clearly revealed that peak position shifts towards higher magnetic field strength with increase in carbon content and demonstrated the applicability of this technique for microstructural characterization of ferromagnetic materials.