Metallurgical Failure Analysis
3568 Caminito El Rincon, #93
San Diego, California, 92130
209 367-1398 - Email: firstname.lastname@example.org
Mark Douglas Bell, PE
Consulting Metallurgical Engineer
|Pitting corrosion is highly localized. Stainless steels, copper and some aluminum alloys are subject to pitting. Localized corrosion will occur when there is a potential difference from one area to another on the same component, (a galvanic cell). The small anode will rapidly corrode in order to protect the surrounding metal. The pitting is rapid and sometimes undetected until the wall has been penetrated. Debris on the bottoms of stainless steel tanks will initiate the galvanic cell. Also a lack of oxygen to replenish the protect chromium oxide film will allow some stainless steels to pit.
Alloy selection, avoiding stagnant, oxygen deprived water, and not allowing debris to settle will control pitting corrosion.