Abstract: The theoretical models of geometrical characterization were analyzed, including segmented degree, serration frequency and serration step pitch. The cutting tests of GH4169 nickel-based superalloy was carried out with PCBN tools under high-pressure cooling，and the chips were prepared and polished to analyze the morphology and geometrical characterization of serrated chips under different conditions of cutting parameters and coolant pressures. The change laws of geometrical characterization of serrated chips were analyzed under different cutting parameters. The experimental results show that with the increases of cutting speeds, feed rates and cutting depths, the segmented degree and the serration step pitch of chips increase, on the contrary, the serration frequency of chips decreases. With the increases of coolant pressures, the segmented degree of chips decreases, the serration frequency of chips increases, and the serration step pitch firstly increases and then decreases. The chip breaking ability of the chips is improved under high pressure cooling, and the chip breaking effectiveness further improves as the coolant pressure increases.

Key words: serrated chip, geometrical characterization, high-pressure cooling, polycrystalline cubic boron nitride（PCBN）tool, superalloy

摘要： 理论分析了锯齿化程度、锯齿化频率与锯齿化步距等几何表征模型；在高压冷却条件下进行了聚晶立方氮化硼（PCBN）刀具切削GH4169镍基高温合金试验，并对不同切削用量与冷却液压力下的切屑进行试样制备及抛磨，以分析锯齿形切屑的形貌及表征；分析了不同切削参数下锯齿形切屑几何表征的变化规律。试验结果表明：随着切削速度、进给量和背吃刀量的增大，切屑的锯齿化程度和锯齿化步距增大，而锯齿化频率减小；随着冷却液压力的增大，切屑的锯齿化程度降低，锯齿化频率增大，锯齿化步距先增大后减小；在高压冷却条件下切屑的断屑能力得到了提高，且随着冷却液压力的增大，断屑效果进一步提高。

关键词: 锯齿形切屑, 几何表征, 高压冷却, 聚晶立方氮化硼刀具, 高温合金