Effect of Different Heat Treatment Procedures on the Corrosion Behavior of High-Manganese Austenitic Steels

Abstract This study investigates the effects of different heat treatment procedures on the corrosion behavior of high-manganese austenitic steel containing molybdenum. Five samples were prepared, including as-cast and heat-treated specimens, with varying processes such as tempering, single and double solution annealing, and aging. The study focuses on microstructural changes, carbide dissolution, and the formation of protective molybdenum-rich oxides. Microstructural analysis using scanning electron microscopy and X-ray diffraction was conducted to understand phase distribution. At the same time, corrosion resistance was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy. The results reveal that double solution annealing leads to the most homogeneous microstructure and significantly enhances corrosion resistance by forming stable molybdenum oxide layers, underscoring the crucial role of molybdenum oxides in surface protection. Among the samples, the corrosion resistance ranked from best to worst is as follows: double solution-annealed (Ht-5), solution-annealed (Ht-3), aged after solution annealing (Ht-4), tempered (Ht-2), and as-cast (Ht-1). This highlights the crucial role of molybdenum oxides in surface protection. The findings demonstrate the effectiveness of advanced heat treatments in improving the corrosion resistance of high-manganese austenitic steels for industrial applications.