Study For Cutting Performance Of ZrN Coated Tools

ZrN is a sort of material with very good performance.It has high hardness,high melting point,very good stabilization and high wear resistance.If we make use of it as tool coated material,it will have a good development.In the article,the research object is ZrN coated tools(DZ,GZZ,FZT).The cutting performance,wear properties and mechanisms,cutting process of the ZrN coated tools were detailed studied.The cutting performance of ZrN coated tools was studied,and compared with YT15 cemented carbide and CN25 coated tool.The results indicate that the cutting force and temperature of coated tools were all smaller than those of YT15 uncoated tools in dry machining of 45# and 40Cr hardened steel with the same condition.The workpiece surface roughness had small difference.The GZZ coated tool had the smallest cutting forces and temperature.The GZZ coated tool has the best cutting performance.The cutting process and the cutting model of ZrN coated tools were established by finite element method(FEM).The influences of cutting speed on cutting force, cutting temperature field,stress field were studied.The resarch indicate that the cutting forces of coated tools were smaller than that of YT15 uncoated tools.In the initial stage of the cutting process,the cutting temperature of the coated tools was smaller than that of YT15 tools.But the the cutting temperature of the substrate maybe equals to that of YT15 tool or even higher.The thermal barrier effect of coated tool was evident in the intermittent high-speed cutting.All the tool stress had the similar changes trend and the stress of the coated tool very smaller than that of YT15 tool.The thickness had small difference on the stress of the coatings.The wear properties and mechanisms of ZrN coated tools were studied by experiment and theoretic.In addition,the wear properties and mechanisms of ZrN coated tools were compared with YT15 cemented carbide and CN25 coated tool.The results indicate that the rate of flank wear in descending order is YT15＞FZT＞DZ＞GZZ when cutting 45# hardened steel.The GZZ's flank wear is smaller than that of CN25 during the process of cutting 40Cr hardened steel.Different modes of tool failure including abrasive wear,adhesive wear and coating breakage were observed when machining in this study.Among these wear patterns,abrasive wear was found to be the main mode of flank wear,while adhesive wear was the main rake face wear type.It is common that several tool wear patterns may appear simultaneously at the same time and have an effect on each other.