Our study deals with rain erosion of metal, which concerns aeronautic industries. The erosion resistance of AISI301 and MLX17, austenitic and martensitic stainless steels respectively, has been appraised thanks to a pulsated water jet device. Moreover, the influence of hardness has been evaluated thanks to hard-rolling plates. The tests of erosion are 10 million impacts for each material with 225m/s impact velocity to obtain sufficient wear volume. The kinetics has been assessed by stopping the test every million impacts, making possible replicas of defects with fast precision resin. An in-service eroded sample has been analysed for comparison purpose. Finally, the best erosion resistance among the tested materials was shown by the hard-rolled austenitic stainless steel, since erosion resistance increases with work hardening. Sample MLX17 was not as resistant as hard-rolled AISI301 despite better mechanical properties. This would be due to a more brittle behaviour of martensite than that of austenite. Surface observations of tested samples reveal inter-granular cracks and fatigue defects similar to those observed in-service. Finally the erosion mechanisms consist of plastic deformation, work hardening, initiation and growing of cracks and, finally, fatigue spalling.