This paper presents the mechanism of corrosion of austenitic steel in the presence of copper. It has been found that when corrosion occurs, the presence of copper in the corrosive solution in the neighbourhood of austenitic steel results in the intensification of the corrosion processes. In the macroscopic scale, austenitic steel constitutes a cathode, but since copper precipitates can deposit on it, the steel can locally pass to the active state and become an anode in the places where copper deposited, which leads to its local corrosion due to galvanic corrosion.