Effect of Solution Treatment on the Microstructure and Performance of S31254 Super Austenitic Stainless Steel

Abstract

The second phases in the S31254 super austenitic stainless steel is easily precipitated, and the solution treatment plays an important role on the microstructure and performance. In this work, the solution treatment is performed on S31254 steel at 1180, 1200, and 1220 °C for 1, 2, and 4 h, respectively. Given the grain size and precipitation of second phase, the 1200 °C for 4 h or 1220 °C for 2 h may be suitable as the solid‐solution parameters. The corrosion resistance and impact toughness of the steel after solution treatment at 1200 °C are further investigated by means of microstructural analysis and electrochemical experiments. The sample after solution treatment for 4 h, where no second phase can be observed, exhibits a lower corrosion rate and a better mechanical properties, compared to that after annealed for 1 or 2 h. The electrochemical impedance spectroscopy, Mott–Schottky, and XPS results indicate that the passive films of the samples, with a significantly decreased donor and acceptor densities and increased Cr2O3 and Mo‐riched oxides, may be responsible for the improvement of corrosion resistance. The impact toughness results show that the samples after solution treatment for 4 h has the highest impact energy among the studied samples.