Ultrasonic Impact Study on Strain Hardening of Thread Profile Surface Layer

Abstract

The paper presents the experimental results of various types of ultrasonic vibrations impact on the strain hardening of a thread profile surface layer when cutting the thread. The research results have shown the effectiveness of using a progressive method of cutting threads in tough titanium alloys with the introduction of ultrasonic vibrations into the cutting zone. The analysis of publications on this issue showed that many authors also note the viability and economic efficiency of using ultrasonic technologies in the industry. This paper also presents the results of a comprehensive study of ultrasonic vibrations impact, varying in directions, on the quality formation of the surface layer of a thread, namely the important indicator affecting the performance of thread pieces, that is, strain hardening. The attention is drawn to the fact that the formation of the surface layer on different parts of the thread profile occurs in different ways. Accordingly, the effect of ultrasonic vibrations in different areas manifests itself in various ways, as the research findings have shown. From the obtained regularities, it has been established that the use of tangential ultrasonic vibrations leads to a decrease in strain hardening on the side surface of the thread and the root, while processing with axial vibrations, an increase in the micro-hardness on the side surface occurs, and when cutting with radial vibrations, the side surface and the root of the thread are subjected to hardening.