Galvanic Corrosion Study on Stainless Steel Cartridge Design

A new ammunition design incorporates stainless steel as the cartridge case, a copper alloy bullet jacket, and an aluminum plug insert for structural support. The dissimilar materials in the new design will be physically connected electrical contact and may be exposed to environments that result in an electrolyte connection. Therefore, a study on the possible galvanic corrosion issues of the new ammunition design was conducted. Several different representative galvanic couples were tested. Aggressive environments were used to accelerate the reactions in an attempt to predict future corrosion issues. Testing included atmospheric exposures, constant immersion, and electrochemical analysis. At the conclusion of each test, the specimens were examined visually and microscopically to determine the extent of damage in each individual material. The results of the study did not show any significant cause for redesign, but galvanic reactions were present.