Improvement of surface properties of alloy constructional steel with ultrasonic composite strengthening modification

Abstract

The key components of the automatic gun are subjected to the severe working condition of high temperature, transient state and continuous strong impact load in the shooting process, the surface of which using the alloy constructional steel is prone to fatigue cracks and gradual expansion, resulting in the fracture of the key components and the fault of the automatic gun. To improve the lifespan of the automatic gun, ultrasonic composite strengthening modification treatment (UCSM) was employed to improve the surface properties of alloy constructional steel in the present work. The three aspects of surface roughness, surface hardness and friction-wear properties, in comparison with those of the traditional dry cutting and advanced ultrasonic-rolling surface modification (AURSM), were characterized. The results show that the surface roughness of the samples after the ultrasonic composite strengthening modification fluctuates by about 0.31 μm, and the surface hardness increases by about 23.5% when compared with the cutting hardness, and the friction-wear properties of the samples has been increased by more than 75%. Ultrasonic composite strengthening modification can increases the local residual compressive stress on the material surface, which endows the material with better surface properties.