Investigations of the high-temperature deformation behaviour and fatigue mechanisms of cemented carbide inserts during cutting 508III steel

Cutting heat is one of the major factors affecting the cutting performance and service life of cemented carbide inserts. During the milling of water-chamber heads, periodic thermal and mechanical loading can lead to failure in round cemented carbide inserts, significantly reducing both their service life and their cutting efficiency. This paper describes high-temperature deformation experiments and analyses of both metallic material and YT15 cemented carbide; by conducting these experiments, we were able to determine the thermal expansion coefficient of the cemented carbide within a certain temperature range, as well as provide suitable parameters for the thermal deformation calculation and cutting simulation of cemented carbide. We then conducted water-chamber head field milling experiments, from which we discovered that failures of the round inserts are generally attributable to wear and fracture. We used the thermal expansion coefficient, material properties of the inserts, and billets and cutting parameters to simulate the process of cutting water-chamber heads (508III steel) with a round insert. In combination with the simulation result, we assessed the influence of cutting force, cutting heat, and insert deformation on insert failure, and we also investigated the insert failure mechanism while cutting water-chamber heads. Ultimately, we were able to analyze the influence of different milling conditions on insert failure. We tested the cutting performances of five types of inserts so as to optimize the insert structure and coating. The results of this research can provide a foundation for improving the anti-failure performance and service life of inserts, which are often used in water-chamber head cutting.