Abstract: The invention is directed to a method for hardening a metallic part by shot blasting. In prior art hardening processes, debris from the projectiles is frequently encrusted on the surface of the part and forms indents whose bottom is often sharp and which may constitute a starting point for rupture caused by metal fatigue. The inventive process allows hardening without damaging the surface of the part. Prior to shot blasting, a metallic protection film which may, for example, be made of nickel or a nickel-base alloy, is electrolytically deposited on the part. The protection film is thick enough to adhere to the metallic part throughout the shot blasting step but thin enough to allow the shot blasting to work harden the part and to impart a residual compressive stress thereto. After the shot blasting is completed, the protection film is removed.