MEASUREMENT OF DEFORMATION-INDUCED MARTENSITE IN STAINLESS STEEL USING MAGNETIC CONTACT FORCE

Metastable austenitic stainless steels are attractive industrial materials with excellent corrosion resistance, mechanical properties, and formability. However, during plastic deformation, alpha'martensite can be formed. The volume fraction of that particular phase influences the mechanical and other properties (such as corrosion resistance) of these steels. Therefore, it is important to determine the amount of a'martensite in the obtained microstructures. Currently, the volume fraction of deformation-induced martensite in stainless steel is most commonly measured by the X-ray diffraction or magnetic permeability methods. In this study, a novel method of measuring deformation-induced martensite using magnetic contact holding force is proposed. Measurement trials were carried out using a prototype measuring system, and the results of measurements taken from SUS301 and SUS304 stainless steels are discussed in terms of deformation and martensite volume fraction.