TiCN涂层硬质合金刀具铣削性能研究

Cutting Properties of TiCN Coated Carbide Cutter in Milling

采用Kistler三向压电铣削测力仪测试了刀具切削45钢过程中的切削力,利用超景深显微镜、扫描电镜和能谱仪观察分析刀具切削后的磨痕宽度、形貌和成分,获得了未涂层刀具HSS、TiN和TiCN涂层刀具的切削时间与磨痕宽度关系图,探讨了刀具的切削失效机理。采用XRD分析了涂层刀具铣削前的相结构,结果表明:TiN与TiCN涂层均表现为fcc-TiN相结构,TiCN具有明显的(111)择优取向,TiN择优取向不明显。切削试验表明:在磨痕宽度达到0.3mm时,TiCN涂层刀具的切削时间比TiN涂层刀具切削时间约长2.5倍,同时整个切削过程中TiCN比TiN具有更低的切削力。这可能是因为TiCN涂层比TiN涂层具有更高的硬度和耐磨性,并且切削过程中TiCN涂层中固溶的C能析出至晶界处,起到润滑作用,降低刀具与工件材料之间的摩擦,减小切削力,延长刀具使用寿命。SEM和EDS分析表明:TiN涂层刀具磨损失效机理为磨料磨损和粘着磨损,而TiCN涂层刀具失效以磨料磨损为主。

A three-dimensional piezoelectric dynamometer is used to measure the cutting force during dry cutting 45 steel.The width,morphologies and compositions of the cutting zone are characterized by microscope,scanning electron microscope and energy disperse spectroscopy.The relationship between the wear track width and cutting time of the high speed steel,TiN and TiCN cutting tools is obtained and the wear mechanism is analyzed.The main phase of the TiN and TiCN coatings is fcc-TiN obtained by XRD diffractometer.The preferential orientation of TiCN coating is(111)crystal plane,while the TiN coating has no distinct preferential orientation.The cutting experiment result shows that the cutting time of the TiCN coating is 2.5 times longer than that of TiN coating when the cutting width reaches 0.3mm.Besides,the cutting force of TiCN coating possesses is lower than TiN.This might be due to the TiCN coating possesses have higher hardness and wear resistance than the TiN coating,and C would precipitate from the TiCN phase to the grain boundaries acting as lubricant which can reduce the friction between the cutting tool and work-piece resulting in lower cutting force and longer cutting life.According to the SEM and EDS analysis,the wear mechanism of the TiN coating is abrasive wear and adhesive wear,while the wear mechanism of the TiCN coating primarily is abrasive wear.