During recent years the trend in modern plant processes is in the direction of more severely corrosive conditions. To keep pace with this trend, greater emphasis is constantly being applied to factors influencing the service life of chemical equipment. Erosion-corrosion is one of the important and widely encountered factors because it often results in unexpected and rapid deterioration of chemical and other types of equipment.
As the name implies, erosion-corrosion is the deterioration caused by the combined effect of corrosion and the wear tendency produced by relative movement between the corrosive and the metal surface.
The rate of corrosion can be accelerated greatly when mechanical or abrasive conditions are present, such as liquids moving at substantial velocities, solids in suspension (slurries), marked turbulence, and impingement. Examples of equipment that may be subjected to erosion-corrosion are pumps, valves, centrifugals, measuring devices (such as an orifice), agitators, lines (particularly at elbows and...
