Development And Application Of A Special Turning Tool For Titanium Ingot

With good mechanical behavior like high weight to strength ratio, corrosive resistant and high temperature performance, titanium alloys are becoming the indispensable structure material in the modern industry. With the development of the industry, demand of titanium ingot increases sharply and requirements of the ingot quality are getting tougher and tougher, such as pure surface, homogeneous microstructure and low surface roughness. At present, peeling and face turning of the titanium ingot use carbide insert. However, this kind of heavy cutting usually causes rapid tool abrasion, mainly accompanied with non-normal broken of carbide insert, resulting in tungsten contamination, non-uniform material structure, stress concentration and low machining efficiency.To solve the problem, using titanium alloy cutting experiments and finite element analysis, a special cutting tool for titanium ingot is developed. This paper studied this special turning tool, which can meet the requirement of high impact resistance and abrasive performance. And tungsten contamination that is caused by tool wear and breakage in the cutting process can be avoided. The main content of this paper is as follow:1, Cutting experiments of titanium alloys are done by design of experiment. Aiming at tungsten contamination, tool wear morphologies, abrasive and breakage mechanisms of the tool during machining titanium are researched. Multiple regression models are developed to predict the surface roughness, iso-surfaces of surface roughness are established and cutting parameters are optimized by response surface methodology to improve surface quality and machining efficiency. Influences of cutting parameters to the cutting force are analyzed, which offered theoretical foundation for the development of advanced cutting tool.2, According to the characteristics of peeling and face turning of the titanium ingot, High performance tools are designed and produced considering tool material, tool edge strengthen and refinement, tool geometry, chip breakage and discharge, tool cutting surplus distribution and tool fixture. PCBN is selected as the substrate material, combined a circular turning blade and a square turning blade, the turning tool with two cutting blade is developed. In the peeling process, the tool can satisfy the large depth of cut of single process and greatly improve tool life. The turning tool with a declination of 45°single cutting blade is developed which can face turning and cylindrical peeling.3, Tool edge refinement design method of the special tool for titanium ingot is proposed. The cutting force, cutting temperature and index of equivalent stress to the edge structure parameters models are set up by finite element analysis and design of experiment. Effects of tool edge structure parameter on cutting process are analyzed. Accordingly, to improve tool life, tool edge parameters are optimized. Tool rake angle and relief angle are optimized considering the effect of each other. And the optimal machining parameters suitable for the special turning tool are obtained.