蠕墨铸铁铣削用刀片材质优化与失效机理探讨  

Material Optimization and Failure Mechanism of Vermicular Graphite Cast Iron Milling Insert

作　　者：赵毅湘 章伟 黄威武[1,2] 王社权 Zhao Yixiang;Zhang Wei;Huang Weiwu;Wang Shequan(Zhuzhou Cemented Carbide Cutting Tools Co.,Ltd.,Zhuzhou Hunan 412000,China;State Key Laboratory of Cemented Carbide,Zhuzhou Hunan 412000,China)

机构地区：[1]株洲钻石切削刀具股份有限公司,湖南株洲412000 [2]硬质合金国家重点实验室,湖南株洲412000

出　　处：《硬质合金》2023年第6期435-442,共8页Cemented Carbides

基　　金：国家科技重大专项(2018ZX04040-001)。

摘　　要：蠕墨铸铁因其独特的物理特性,切削加工过程中切削力较大、切削温度高、切削加工性能差。而刀片材质特性对蠕墨铸铁切削加工有着极其重要的影响。本文通过开展一系列的蠕墨铸铁铣削加工测试,对比了不同材质刀片切削蠕墨铸铁时的寿命差异,分析了基体硬度对刀片失效时的磨损形貌差异及产生的原因,并研究了切削初期刀片磨损状态对后续加工的影响特性。寿命对比测试结果表明:CVD涂层刀片寿命较PVD涂层刀片寿命更高,硬度为15.97 GPa的WC-5.5%Co细晶合金基体/MT-TiCN/Al_(2)O_(3)涂层的CVD涂层刀片,因为基体硬度适中,涂层耐磨性好,刀片寿命最高,更适合蠕墨铸铁的铣削加工。通过对比三种不同材质刀片失效形态可知,WC-5.43%Co超细晶合金基体/TiAlN涂层的PVD涂层刀片更易发生崩缺,WC-6%Co细晶合金基体/MT-TiCN/Al_(2)O_(3)涂层的CVD涂层刀片因磨损过快导致刃口微崩,WC-5.5%Co细晶合金基体/MT-TiCN/Al_(2)O_(3)涂层的CVD涂层刀片后刀面均匀磨损。通过磨损机理分析可知,铣削三种材质的刀片均以磨粒磨损和粘结磨损为主,其中,WC-5.43%Co超细晶合金基体/TiAlN涂层的PVD涂层刀片在切削初期就发生了涂层剥落与刃口微崩缺,失去了涂层的保护,裸露的基体更容易发生磨粒磨损和粘结磨损;两种CVD涂层在切削初期均存在涂层热裂纹,但是并未发生涂层剥落,特别是基体硬度相对更高的WC-5.5%Co细晶合金基体/MT-TiCN/Al_(2)O_(3)涂层的CVD涂层刀片,因基材对涂层的支撑作用更强,切削性能更好。Vermicular graphite cast iron has unique physical characteristics,such as high cutting force,high cutting temperature,and poor cutting performance during the cutting process.The material characteristics of the insert have an extremely important impact on the cutting process of vermicular graphite cast iron.This article conducted a series of milling WCtests on vermicular graphite cast iron,compared the tool life of different insert materials when cutting vermicular graphite cast iron,analyzed the differences in wear morphology and causes of insert failure caused by matrix hardness,and studied the impact characteristics of insert wear status on subsequent processing during the initial cutting stage.The results show that the tool life of CVD-coated inserts is longer than that of PVD-coated inserts.The hardness of CVD-coated inserts that are made of WC-5.5%Co fine-grained alloy matrix with MT-TICN/Al_(2)O_(3)coating with a matrix hardness of 15.97 GPa is moderate;the wear resistance of the coating is good,and the tool life of the insert is the highest.It is more suitable for milling vermicular graphite cast iron.By comparing the failure patterns of three kinds of inserts made of different materials,it is found that PVD-coated inserts that are made of WC-5.43%Co ultrafine-grained alloy matrix with TiAlN coating are more susceptible to breakage,and the CVD-coated inserts that are made of WC-6%Co fine-grained alloy matrix with MTTiCN/Al_(2)O_(3)coating wear too fast,resulting in micro-breakage at the cutting edge.In addition,the CVD-coated inserts that are made of WC-5.5%Co fine-grained alloy matrix with MT-TiCN/Al_(2)O_(3)coating have uniform wear in the flank.Through the analysis of the wear mechanism,it can be seen that the inserts made of three kinds of milling materials mainly have abrasive wear and adhesive wear.The PVD-coated inserts that are made of WC-5.43%Co ultrafine-grained with TiAlN coating have the coating exfoliation and micro-breakage at the cutting edge at the beginning of the cutting process.Without c

关 键 词：蠕墨铸铁 铣削 失效机理 粘屑 裂纹 

分 类 号：TG714[金属学及工艺—刀具与模具]