切削温度对刀具表面覆盖膜的影响

Influence of Cutting Temperature on the Film Covering Tool Surface

研究表明，用ＴｉＣ类硬质合金刀具切削Ｃａ－Ｓ易切不锈钢时．刀具表面覆盖膜的形成及分布规律．与前刀面切削温度及其分布规律有关；切屑－覆盖膜间温度达到覆盖膜主要成分─钙黄长石的软化挤出温度９００℃左右和覆盖膜－前刀面间温度达到粘结温度８５０℃左右时．至主切削刃距离ｘ＝０．２～０．６ｍｍ范围便形成致密的稳定覆盖膜；ｘ＜０．１ｍｍ范围温度低于钙黄长石的挤出温度无膜生成；ｘ＞０．６ｍｍ温度稍低于钙黄长石的挤出温度，仅有熔点较低的ＭｎＳ、ＣａＳ及ＦｅＳ为主的稀疏覆盖膜．

It was revealed that the formation and distribution of the film covering Tic carbede tool surface when cutting Ca-S free-cutting steel relate to temperature and its distribution. When the temperature of chip-film reaches about900℃. i. e. the extrudable softening temperature of gehlenite which is the main constituent of film. or the temperatureof film-surface reaches about 850℃ .i. e. the adhesion temperature. a dense and stable covering film forms at a distancex= 0. 2-0. 6 mm from the main cutting edge. but no film will form if x<0. 1 mm and the temperature is lower thanthe extrudable temperature. On the other hand. only a thin film mainly composed of MnS. CaS and FeS is found if x>0. 6 mm and the temperature is slightly lower than the extrudable temperature.