Abstract: An ultrasonic strengthening method for improving the fatigue life of a metal work-piece and its application, by clamping the metal work-piece on the ultrasonic machining lathe, ultrasonic machining of the surface of the metal work-piece with ultrasonic machining tool. The present invention focuses on presetting the compressive stress on the surface of the metal work-piece by adjusting the pressure of the ultrasonic machining tool on the surface of the metal work-piece, to eliminate the residual stress and to improve the fatigue life of the work-piece eventually. Meanwhile, the present ultrasonic strengthening method can refine the surface grain of the metal work-piece, improve the surface microhardness, wear resistance, and corrosion resistance of the surface of the metal work-piece, eventually to improve the fatigue life of the metal work-piece.

Abstract: An ultrasonic machining method to improve the wear resistance of locomotive wheels includes ultrasonic machining by ultrasonic machining tool head on the wheel rim and/or surface of the tread that is rotated along the main axis. The ultrasonic machining method mentioned in the invention can not only process the locomotive wheel just after leaving factory, but also repair the worn locomotive wheel. After machining the rim and/or tread of the locomotive wheel with ultrasonic machining, the surface tensile stress of the rim and/or the tread surface will become compressive stress, the surface roughness will be greatly reduced, and the ideal compressive stress will be preset on the surface.