Intergranular corrosion and stress corrosion tests

This post was last edited by Wang Wei2 on 2021-12-5 at 13:13. We know that stress corrosion is a failure phenomenon that occurs when materials are subjected to both static stress (mainly tensile stress) and corrosion. Intergranular corrosion is a type of local corrosion that propagates inward along the boundaries between metal grains. Stress corrosion: If the selected equipment is subject to stress corrosion in a corrosive environment, and there is no prior record of such equipment being used in that same environment, then it is necessary to conduct a assessment of stress corrosion based on the specific operating conditions. Intergranular corrosion: Similarly, intergranular corrosion is a type of local corrosion, and it can occur without the presence of stress. Whenever equipment operates in environments where conditions for intergranular corrosion exist, such as in nitric acid solutions, sulfuric acid-copper sulfate solutions, hydrofluoric acid-65% nitric acid solutions, and sulfuric acid-copper sulfate solutions, intergranular corrosion is likely to occur in many cases. Similarly, there is no basis for reference regarding its use in actual operating environments; therefore, intergranular corrosion tests must be conducted to obtain such a basis. One solution is to choose the metal material properly ； Second, anti-corrosion coatings can be considered as a barrier layer. The method to be chosen can be determined based on the specific usage conditions and environment.

Under normal circumstances, the casing of a centrifugal pump isn’t subjected to excessive stress. As for intergranular corrosion, it depends on the medium being pumped; it won’t occur when pumping water under normal conditions. For pumping certain specific media, corrosion-resistant pumps are used instead. In the case of seawater, there’s no need to test for these two factors