Cutting Performances Of Ceramic Tools In Dry Cutting Of Austenitic Stainless Steels

Ceramic tools materials have huge advantages in improving machining efficiency and tool life, because of its high hardness and well high-temperature performances. Therefore this kind of tool materials is promising in high-speed machining. Composite ceramic materials can be various in property, according to different design theorys,basic components and toughening mechanisms, in need of machining various workpiece materials. Austenitic stainless steels are difficult to machine, due to their high toughness,serious work hardening and bad thermal conductivity. They can easily result in tool wear and damage, reduce of tool life, especially in interrupted cutting and dry cutting. Cutting performances of Al₂O₃/SiCw(AS),Al₂O₃/(Ti,W)C(AT)and Si₃N₄/TiC(ST)ceramic tools in machining austenitic stainless steels were researched through dry cutting experiment, in the hope that it's valuable in developing property of ceramic materials and expand the scope of them. The influence of cutting parameters on cutting force,chip breaking and wear were also studied, to give suggestion on selecting cutting parameters of ceramic tools in machining hard-to-cut materials like austenitic stainless steels.The results of cutting forces of the orthogonal cutting experiment indicate that: feed rate and cutting depth have more significant effects on cutting forces than cutting velocity; Radial force is greater than main force occasionally while machining in low cutting parameters; Emprical formula of cutting force of two ceramic tools when machining austenitic stainless steels were created.Through the research on the shape of chips, found out that the performance in chip breaking is better when high parameters are selected whthin the bounds of cutting parameters, and feed rate has the most significant effect on chip breaking.Researched on the wear of ceramic tools in cutting austenitic stainless steels through experiment of single factor, the results indicate that, wear in tool nose and notch wear at depth of cut line are the major pattern of tools wear; Cutting velocity and feed rate have significant influence in the wear of tool nose; The predominant wear mechanism are abrasive,adhension and oxidation; AS and ST tools would be worn causing by the notch wear when machining in high velocity; Al₂O₃ based tools show better performance in resistance to wear than Si₃N₄ based tools.