VT22 titanium alloy: study of the cutting tool geometry effect on output parameters of turning process

Abstract

The aim of the present work consists in studying the effect of the g rake angle (in the range from -8° to +10° with a constant a relief angle of +6°) of a VK8 hard material turning tool on the output parameters (cutting force, roughness, wear of the cutting edge at the rake and flank surfaces) in turning a VT22 titanium alloy billet. In order to determine the cutting forces, a dynamometric analysis was performed using the STD. 201-1 laboratory bench. The turning of the billet was carried out at a constant cutting speed of 50 m/min, a cutting depth of 3 mm and feed values of the tool movement along the billet equal to 0.11, 0.15 and 0.21 mm/rev. A TR200 profilometer and Micro Vu-Sol-1 measuring machine were applied for determining the roughness and wear of the cutting edge, respectively. The highest value (2000 N) of the tangential cutting force was established to be achieved with a 0.21 mm/rev feed, while the largest difference (400 N) of the tangential cutting force was recorded depending on the g value variation in the range from -8° to +10°. For a feed rate of 0.11 and 0.15 mm/rev, this difference amounted to 300 and 100 N, respectively. The roughness measured at specified feed values lies within the acceptable range of surface cleanliness corresponding to 8-9 grade (except for g = +10°). Based on the results, the following mode selection algorithm for turning of a VT22 titanium alloy billet is proposed according to various criteria: fixed tangential cutting force - 0.11 mm/rev feed rate (g = +10°); roughness values - 0.11 and 0.21 mm/rev feed rate (for all selected g values) or 0.15 mm/rev (for g = -4, 0, +4, +8°); wear of the cutting edge - feed rate of 0.11 mm/rev at g from -8° to -2°, 0.15 mm/rev (at g = -4°, 0°, 2°, 4°, 8°, 10°), 0.21 mm/rev (at g = -4°, -2°, 2°, 4°, 6°, 8°, 10°).