Barkhausen Noise Emission in AISI 321 Austenitic Steel Originating from the Strain-Induced Martensite Transformation

Abstract

This paper investigates the sensitivity of the Barkhausen noise technique against strain-induced martensite in AISI 321 austenitic stainless steel. Martensite transformation was induced by the uniaxial tensile test, and a variable martensite fraction was obtained at different plastic strains. It was found that Barkhausen noise emission progressively increases with plastic straining, while its evolution is driven by the martensite fraction in the deformed matrix. This study also demonstrates that the uniaxial tensile stressing produced a certain level of stress and magnetic anisotropy in the samples. The number of strong Barkhausen pulses increased for more developed strains, whereas the position of the Barkhausen noise envelope remained less affected. This study clearly demonstrates the good sensitivity of the Barkhausen noise technique against the degree of martensite transformation in austenitic stainless steel. Moreover, this technique is sensitive to the direction of the exerted load.

Keywords

• austenitic steel
• plastic deformation
• Barkhausen noise
• martensite