Studying the effects of preheat temperature on the turning process of CK45 steel

In many industries that are related to machining processes, the basic factor to reduce the overall cost of production is the selection of ideal machining conditions. The piece temperature is a very effective factor in machining processes, and in this study, the effect of this parameter on the behavior of the chip and the forces on the tool in the machining of CK45 steel has been investigated. Three preheating temperatures of 25, 70, and 100°C were used to preheat the part before turning, and the variables of chip formation were investigated. Also, by developing a finite element model (FEM) of the process, the machining of the part and the formation of chips in the material were simulated, which shows a good agreement with the experimental tests. After FEM validation, the amount of machining force, thermal stresses and wear in the process was evaluated with the help of FEM. Based on the obtained results, it was found that the maximum curvature of the chip occurs at the preheat temperature of 70 degrees Celsius. Also, the maximum deformed thickness of the chip was at a preheat temperature of 25 degrees and the lowest value was at a preheat temperature of 70 degrees Celsius. The forces applied on the tool in the Y and X directions increased with the decrease in temperature, but the heating rate of the tool tip increased up to the machining temperature of 70 degrees Celsius, and after that, due to the reduction of friction, it has been significantly reduced to about 60%.