Abstract
<jats:p>Introduction. Due to the wide application of pure α-titanium in critical products, the intensification of its machining by cutting is an urgent task. Existing studies focus mainly on alloyed alloys, while the features of high-speed dry milling of pure α-Ti are not well understood. The aim of this work was to investigate the influence of milling modes on the wear of a CVD-coating (Al2O3/TiCN+TiN) on carbide inserts, chip morphology and deformation processes in the surface layer of Ti Grade 2 alloy. Methodology. The experiments were carried out using parallel milling in the range of cutting speeds v = 100–300 m/min, feed rates f = 50–100 mm/min and depths of cut aр = 0.2–0.4 mm without coolant. The condition of the cutting edges and the morphology of the chips were investigated using SEM and EDX. X-ray diffraction analysis was used to assess deformation changes. The data were processed using correlation and regression analysis methods. Results and discussion. It has been found that with increasing cutting speed, adhesion processes and thermomechanical stresses are intensified, leading to local scraping and delamination of the CVD coating on the rake surface. At a speed of 300 m/min, there is significant material buildup, forming an unstable built-up edge. The study of the chips revealed a transition from continuous to elemental form. A strong negative correlation (r = −0.81) between the cutting speed and the height of protrusions (h3) on the chip was found, as well as a moderate positive influence of the depth of cut on the continuity coefficient (r = 0.55). The results obtained are relevant for the optimization of high-speed dry machining of pure titanium products used in cryogenic engineering and heat exchangers. Conclusions. The dominant wear mechanisms are adhesion and thermomechanical degradation of the coating. The critical mode leading to intensive buildup is a combination of v = 300 m/min, f = 100 mm/min, aр = 0.4 mm. To reduce wear, it is recommended to control heat dissipation by optimizing cutting speed and depth of cut.</jats:p>