The effect of microstructural and texture evolutions during thermomechanical treatment on corrosion resistance of 310s austenitic stainless steel

Abstract

In this study, the evolution of the microstructure and texture during thermomechanical treatment and its effect on corrosion properties of 310s austenitic stainless steel were investigated. This stainless steel was cryo-rolled at 50 and 90% thickness reductions, and then the 90% cryo-rolled sample was annealed at 750 °C for 5 and 30 minutes. SEM and optical microscope images were used to examine the microstructure of the samples. Fritoscopy test was also used to calculate the volume fraction of the martensite phase. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and cyclic potentiodynamic polarization tests were performed in the 3.5 wt. % NaCl solution to investigate the corrosion behavior of the studied steel. The results showed that the cryo-rolling process caused the reduction of grain size, texture strengthening and transformation of austenite to strain-induced αʹ-martensite phase. Decreasing grain size and increasing texture components containing dense planes are beneficial factors and the formation of the αʹ-martensite phase is a harmful factor for corrosion resistance. It was observed that annealing at 750 °C for 30 min caused the grain growth and texture weakening, while a favorable condition is developed in the annealed sample for 5 min. After 90% cryo-rolling and subsequent annealing at 750 °C for 5 min, the corrosion resistance was significantly improved compared to the as-received sample and reached 37 kΩ.cm2. Formation of the sub-micron microstructure along with the high volume fraction of Brass and Goss texture components were the main reasons for improving corrosion resistance at 750 °C-5 min.

Design of Heterogeneous Lamella Microstructure of 316L Austenitic Stainless Steel and Effect of Aging on Its Mechanical Behavior and Corrosion Properties

“…[ 71 ] Therefore, appropriate heat treatment following cold deformation can improve the corrosion resistance of ASS. For example, Heidari et al [ 72 ] discovered that annealing at 750 °C for 5 min can enhance the reverse phase transformation of ‐martensite in cold‐rolled 310S ASS. The presence of a high‐volume fraction of UFG structure, Gauss texture, and brass texture contributes to the improved corrosion resistance of the stainless steel.…”