Relative performance of two cast irons and two stainless steels under erosion-corrosion conditions

Erosion-corrosion is one of the most challenging material degradation processes that occur in engineering components that handle slurries. Materials that can withstand a combination of corrosive fluid with suspended particles are required to extend the service life of hydraulic equipment. High chromium cast irons are favorable for these applications as the chromium carbides improve the wear resistance and usually, good corrosion resistance is obtained. In this study, two white cast irons (a 37%Cr - austenitic matrix and 27%Cr - martensitic matrix) were evaluated along with an austenitic stainless steel (UNS S31600) and a martensitic stainless steel (UNS S42000). The experiments were carried out using a submerged jet apparatus in a testing medium of 3.5% NaCl containing sand particles with and without cathodic protection. The most notable finding was that the relative performance of the tested materials varied by altering the testing conditions. The role of hardness in the performance of the different materials was also investigated.