Pınar Çakar
METU
MECHANICAL AND TEMPERATURE ANALYSIS OF MACHINING TI6AL4V & INCONEL 718
By Assoc. Prof. Dr. Ismail Lazoglu
Koc University
Department of Mechanical Engineering
ABSTRACT
Ti6Al4V and Inconel 718 are widely used alloys in advanced engineering applications. Besides their superior properties such as high strength and corrosion resistance at elevated temperatures; machinability of both alloys is poor. The current study analyzed mechanical and thermal effects of process parameters. Different cutting conditions were tested in dry conditions.
PROCEDURE
The turning process was chosen to be elementary orthogonal cutting. The tests were carried out with conventional uncoated carbide tools. In the experiments, cutting forces were collected for three levels of cutting speed, feed rate and cutting tool rake-angle. Tool insert angles were prepared by grinding the rake and clearance face. After grinding, tool measurements were taken by using optical microscope. Sidespread and chip thickness evaluation were carried out by using optical microscope. The complete actual testing environment can be seen in Figure 1, 2 and 3.
Figure 1 - Experimental setup for measurement of cutting forces
Figure 2 - Experimental setup for measurement of cutting forces
Figure 3 - Cutting insert and the workpiece
CONCLUSIONS
Average temperatures on rake face and shear plane increase as the cutting speed increases. Cutting speed’s effect on temperatue rise is more than the effect of the feed rate. Lower rake angle values yield lower temperatures for both alloys especially in higher level of cutting speeds. For both alloys, it was observed that as the cutting speed increases resutant force at all rake angles and the feed rates. In Ti6Al4V experiments, the lowest resultant force values were obtained when the tools with higher rake angle are used at highest level of cutting speed. At those conditions, the highest average temperatures were obtained according to the temperature simulation results. For Ti6Al4V, shear angle values are higher and friction angle values are lower at those conditions when compared to the experiments that were carried out with the tools which have lower rake angles. For Inconel718, similar behavior observed with one exception. There is no considerable distinction between the experiments that were performed with two highest level rake angles.