The paper present and analyze the results obtained by testing to cavitation erosion four stainless steels samples, containing maximum 0.1% carbon, 13% chromium, and variable quantities of nickel (between 0 and 6%). The purpose of the experimental work is to clarify the effect of Nickel upon microstructure and cavitation erosion resistance of the material, having in mind the final goal to obtain an improved alloy for manufacturing hydraulic turbine