Research on the correlation between impact toughness and corrosion performance of Cr13 Super martensitic stainless steel under deferent tempering condition.

• DL-EPR was used to describe the precipitation of carbides in super Cr13 stainless steel. • The main reason for the decrease in impact toughness is the precipitation of continuous Cr-rich carbides (M23C6) along the interface. • Solution treatment before quenching and tempering treatment can improve the impact toughness. • The impact tough of the steel can be predicted by DL-EPR. Super martensitic stainless steel (SMSS) is characterized by improved mechanical properties and corrosion resistance. However, during production the impact toughness will be significantly reduced under certain heat treatment regimes (tempering at 873 K followed by quenching at 1213 K and tempering at 913 K). Double loop electrochemical potentiokinetic reactivation (DL-EPR) were used to investigate the mechanism for the reduction of impact toughness in this experiment. It was found that the primary cause for the decrease was precipitation of continuously distributed Cr-rich carbides (M 23 C 6) along martensite lath boundaries. The Ra value obtained by DL-EPR is positively correlated with the amount of Cr-rich carbide precipitation. As Ra increases, impact toughness increases first and then decreases rapidly, which indicates that it is reasonable to use Ra to qualitatively predict the impact toughness of the steel. [ABSTRACT FROM AUTHOR]