Changes in pH value have an impact on the corrosion of stainless steel
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A decrease in the pH value of the solution increases stress corrosion susceptibility and shortens the rupture time. As underscale corrosion creates closed cells, the high concentration of chloride ions within these pores leads to accelerated corrosion due to acidification, a phenomenon known as \"autocatalytic acidification,\" resulting in a significant decrease in the pH level inside the pores. Although the pH on the water side of the shell side is slightly alkaline, the pH inside the scale-induced blocked cell is very low. Furthermore, once a leak occurs and causes CO2 from the tube-side process gas to leak into the water side, creating an acidic environment, it also accelerates corrosion.
Changes in pH value have a significant impact on the corrosion of stainless steel. As the pH value of the solution decreases, the stress corrosion sensitivity of stainless steel increases, and its failure time shortens. The closed cells formed by underscale corrosion lead to high concentrations of chloride ions within the pores, thereby accelerating acidification and reducing the pH value in those pores. Although the pH value on the external water side may be neutral or slightly alkaline, the pH value in the environment beneath the scale can be very low. Furthermore, if CO2 from the process gas on the tube side leaks to the water side, it will lead to the formation of an acidic environment, further exacerbating corrosion. .