中文摘要：

选用不同涂层刀具进行高速切削300M钢试验,利用工具显微镜和电子扫描显微镜（SEM）观察刀具磨损形貌,并利用线扫描进行元素扩散分析,揭示刀具失效机理。研究结果表明：金属陶瓷基涂层刀具高速切削时,切削速度不宜超过240m/min;硬质合金基涂层刀具可在300m/min以上高速切削300M钢,其中CVD-Ti CNAl2O3厚涂层的高速切削性能更高,切屑塑形变形较小;涂层刀具切削300M钢的主要磨损形式是前刀面磨损和后刀面磨损,涂层剥落、崩刃、微裂纹、粘结磨损、磨粒磨损、氧化磨损、扩散磨损是刀具失效的主要原因。

英文摘要：

A series of experiments areconducted in high - speed cutting of high strength steel 300M with different coa- ted tools. The tool failure mechanisms arerevealed by observing tool wear morphology using microscopy and scanning electron microscopy（SEM）and analyzing element diffusion using line scanning. The results indicate that the speed of cutting 300M should not exceed 240m/min with cermet coating tools. Cemented carbide based coatings tools can be used under the speed o- ver 300 m/min in the cutting of 300M steel. The performance of CVD -TiCN -A1203 thick coatingismore superior,which has a small chip shape deformation. The main wear forms arethe rake wear and the flank wear. Coating flaking, chipping,micro- crack ,adhesive wear, abrasive wear,oxidative wear and diffusion wear arethe mainreasons of the tool failure.