Cutting forces, chip formation, and tool wear in high-speed face milling of AISI H13 steel with CBN tools

High-speed face milling experiments of AISI H13 steel (46–47 HRC) with cubic boron nitride (CBN) tools were conducted in order to identify the characteristics of cutting forces, chip formation, and tool wear in a wide range of cutting speed (200–1,200 m/min). The velocity effects are focused on in the present study. It was found that, at the cutting speed of 800 m/min, which can be considered as a critical value, relatively low mechanical load, relatively low degree of chip segmentation, and relatively long tool life can be obtained at the same time. Both the cutting forces and the degree of chip segmentation firstly decrease and then increase with the cutting speed, while the tool life exhibits the opposite trend. By means of analyzing the wear mechanisms of tools tested under different cutting speeds, it was found that, as the cutting speed increases, the influences of fracture and chipping resulting from mechanical load on tool wear were reduced, while the influences of adhesion, oxidation, and thermal crack accelerated by high cutting temperature became greater. There exist obvious correlations among cutting forces, chip formation, and tool wear.