A Member Company mill has purchased second hand batch digesters made from 317L stainless steel. PAPRICAN was asked to assess the corrosion resistance of the alloy, and to determine if the alloy would undergo excessive corrosion in the kraft process at the mill. A number of tests were done to determine the corrosion rates of 317L under different conditions. Electrochemical tests (polarization curves, potentiostatic
tests and time to repassivation tests), were done to assess the corrosion resistance of the alloy to the range of liquors in the digester. Samples were also examined in the scanning electron microscope to determine the relationship, if any, between the corrosion rate and the corrosion morphology of the samples.