Wear Behavior and Mechanism of Coated Carbide Tools in Face Milling Ti40 Burn Resistant Titanium Alloy

Face milling experiments on Ti40 titanium were conducted using coated carbide tools in two kinds of cooling modes,i.e. oil cooling and cryogenic pneumatic mist jet impinging cooling (CPMJC). The wear patterns of tool and its corresponding mechanism,milling temperature and milling force were investigated. By analyzing experimental results,it is found that wear patterns of coated carbide tools included rake face wear and flank wear in face milling Ti40 burn resistant titanium alloy. The former was crater wear and the latter was boundary groove wear. The damage morphologies were conchoidal coating spallation,fatigue crack and micro-chipping of cutting edge. Wear mechanisms were synergistic interaction among adhesion wear,abrasion wear,oxidation wear and fatigue damage. The experimental results demonstrate that high milling temperature was the leading factor that affected life of tool in face milling Ti40 titanium. CPMJC mode could reduce milling temperature drastically,alleviate adhesion and oxidation,and simultaneously restrain the groove wear development. Therefore,CPMJC improved tool life remarkably.