Thermal Phenomena on the Front Surface of Tools with PcBN during Turning of Hardened Steel

Abstract—

The paper presents the results of determining the temperature at flash spots on the front surface and the cutting temperature when turning hardened steel with a tool made of PcBN of the BH group. Based on the experimental data on the dimensions of the chip-tool contact area, its topographic characteristics, and the level of loads on the tool’s front surface, a theoretical calculation of the flash point temperature in the tool contact zone was performed. It was found that the change in temperature at the flash spots with increasing cutting speed is extreme: at a cutting speed of 2 m/s, the temperature at the flash spots exceeds 2000°C on the plastic and 1000°C on the elastic parts of the contact area. Using an experimental and computational approach, the level of cutting temperature was determined, which increases with increasing cutting speed and reaches 1200°C. It is proved that, in accordance with the decrease in the temperature at the flash spots when machining at a cutting speed of more than 2 m/s, the intensity of the increase in the cutting temperature, which characterizes the average temperature at the contact area of the tool, decreases.