A report is given of our experience with electrochemical potentiodynamic reactivation
(EPR) measurements conducted in industrial installations operating at elevated
temperatures. The sensitization behavior after four to five years' service of austenitic
welded pipes working at temperatures within the range of 340-600°C was investigated. In
situ measurements were carried out on different 150-460 mm diameter pipes during plant
shutdown periods. Welded joints, heat affected zones as well as pipe and flange materials
were tested. An on-site measuring cell setup was used. A new testing system has been
developed to overcome problems encountered with standard instrumentation. New
approaches to EPR measurements are recommended based on the new mobile setup.
A comprehensive interpretation of the experimental results is given taking into account the
C and Mo contents as well as the stabilization and phase transformation relationships.