Correlation of Microstructure and Corrosion Behavior of Martensitic Stainless Steel Surgical Grade AISI 420A Exposed to 980-1035oC
Martensitic stainless steels have been extensively used for their good corrosion resistance and better mechanical properties. Heat treatment was suggested as one of the most excellent ways to this regard; hence, it affects the microstructure, mechanical and corrosion properties of the steel. In the current research work the microstructural changes and corrosion behavior in an AISI 420A stainless steel exposed to temperatures in the 980-1035oC range were investigated. The heat treatment is carried out in vacuum furnace within the said temperature range. The quenching of the samples was carried out in oil, brine and water media. The formation and stability of passive film was studied by Open Circuit Potential, Potentiodynamic polarization and Electrochemical Scratch Tests. The Electrochemical Impedance Spectroscopy results simulated with Equivalent Electrical Circuit suggested bilayer structure of outer porous and inner barrier oxide films. The quantitative data showed thick inner barrier oxide film retarded electrochemical reactions. Micrographs of the quenched samples showed sigma and chromium carbide phases which prove the corrosion resistance of steel alloy.
 S.K. Bhambri, Journal of Material Science 21 (1986) 1741–1746.
 9th Edition, Metals Handbook, Vol. 9, Wrought Stainless Steels, ASM, Metals Park, OH, 1980, p. 285.
 D.A. Porter, Phase Transformation in Metals and Alloys, 2nd ed., Chapman & Hall, Von Nostraned Reinhold, 1981.
 M.C. Tsai, C.S. Chiou, J.S. Du, J.R. Yang, Material Science and Engineering A, 332 (2002) 1–10.
 P. Gympel, N. Arlt, in: Les Acier Inoxidables, Tech. Et Documentation Lavoisier, Paris, 1990, p. 26–32.
 L. Columbier, J. Hochman, in: Acier Inoxidables Acier Refractaries, Dinod, Paris, 1965, p. 29–49.