Erosion corrosion is the combined effect of corrosion and erosion, which is caused when a rapid turbulent fluid passes through the metal surface , which are already corroded by pits. The pits are formed because of the breakage of the oxide layer of the metal. A combination of erosion and corrosion can lead to very high pitting rates. The joint action of the erosion and corrosion is known as erosion-corrosion, which is encountered prominently in chemical processing industries like oil and gas and power plants. The joint effect of erosion and corrosion is significantly very much higher than that of the effects of erosion and corrosion when it acts separately. Thus erosion and corrosion have a synergetic effect on each other, which is why the phenomenon is often grouped together as one. A critical fluid velocity must be exceeded for a given material for the erosion corrosion to occur. The fluid which impacts on the material causes disruptive shear stresses or pressure variations on its protective surface film, which causes the mechanical damage of the material. Erosion corrosion is accelerated at pipe elbows where there is sudden change in geometry of the pipe design, tube constrictions and wherever the fluid flows are changed or on anything which results in the turbulent increase.
2. Erosion Corrosion mechanism in Steam Pipe Lines
Erosion-corrosion is produced by the impingement of liquid droplets on the metal at high velocity. The impingement of