Effect of austenitizing heat treatment on microhardness and corrosion resistance of 1.4116 martensitic stainless steel

Abstract Martensitic stainless steels are utilized in applications requiring high hardness, low wear, and elevated corrosion resistance. Owing to their high alloying element content, they can be hardened through heat treatment. To achieve the desired mechanical properties and corrosion resistance, heat treatment parameters must be appropriately selected; the ratios of martensite, carbide, and retained austenite in the microstructure should be balanced. In this study, temperature and time parameters in the austenitizing heat treatment of 1.4116 (X50CrMoV15) martensitic stainless steel, commonly used in the knife manufacturing industry, were experimentally investigated to obtain an optimal microstructure, maximum hardness, and high corrosion resistance. Temperature values of 1,000 °C, 1,020 °C, 1,040 °C, 1,080 °C, 1,100 °C, and 1,120 °C, as well as durations of 180 s, 210 s, and 260 s, were examined. At lower temperatures, insufficient hardness was achieved due to incomplete austenite transformation and partial dissolution of carbides. At higher temperatures, grain coarsening and retained austenite formation led to a decrease in hardness. At the optimal temperature of 1,080 °C, significant carbide dissolution occurred, complete austenite transformation was achieved, and high-carbon martensite was formed, resulting in maximum hardness. In the time-based experiments, an increase in duration led to a reduction in retained austenite in the microstructure and an increase in hardness. From a corrosion resistance perspective, samples with higher hardness exhibited lower corrosion resistance; however, with increasing duration, corrosion resistance improved due to the activation of diffusion mechanisms.