Examination of the influence of heat treatment on the corrosion resistance of martensitic stainless steels

Martensitic stainless steels are commonly used in cutlery fabrication requiring high hardness and sufficient corrosion resistance. The heat treatment process affects the mechanical and electrochemical behavior of martensitic stainless steels due to the precipitation of chromium carbides. Depending on the heat treatment the corrosion resistance of these steels can vary strongly, and improper heat treatment parameters can lead to a weak pitting corrosion resistance. The aim of this work is to identify heat treatment parameters influencing the corrosion resistance of martensitic stainless steels by using three different electrochemical testing methods. To this purpose, five different heat treatments were applied to the alloys 1.4116 and 1.4034. In addition to the determination of the critical pitting potentials and the modified double-loop electrochemical potentiodynamic reactivation tests (DL-EPR) a new KorroPad indicator test was used assessing the pitting corrosion behavior. The results showed that all methods used were in good agreement for verifying the influence of the various heat treatment parameters on the corrosion behavior and to identify the effect of heat treatment conditions on the pitting corrosion resistance.