论文部分内容阅读
首先根据不同应变率阶段金属材料的塑性变形机制,分析工件材料强度和塑脆性随切削速度提高的变化规律,通过理论计算说明这种变化对切屑锯齿化的作用机制,揭示不同切削速度下产生不同形态切屑的控制机理;然后,在40~7000m/min切削速度范围对Inconel718,AerMet100,7050-T7451进行直角切削实验,分析切屑形态及工件材料脆化现象,验证随切削速度提高工件材料脆化及相应的切屑形态;最后,根据切削速度与切屑形态的对应规律,提出基于切屑形态的切削速度阶段划分方法.研究表明:随切削速度提高,材料强度提高、塑性降低,使得主变形区材料易于发生热塑性剪切失稳和断裂失效而使切屑锯齿化;对一般塑脆性金属材料,随切削速度提高,第一变形区材料热塑性剪切失稳的发生早于断裂失效的发生;对同一种工件材料,可根据切屑形态将切削速度划分为普通切削速度阶段、高速切削速度阶段、超高速切削速度阶段.
Firstly, according to the plastic deformation mechanism of metal materials in different strain rate stages, the variation law of the material strength and plasticity and brittleness with the increase of cutting speed is analyzed. The mechanism of this change on chip sawing is explained by theoretical calculation to reveal the difference between different cutting speeds Then the cutting experiments of Inconel718, AerMet100 and 7050-T7451 were carried out at 40 ~ 7000m / min, the chip shape and material embrittlement were analyzed, and the embrittlement of the workpiece material was verified with the cutting speed. The corresponding cutting pattern is put forward.Finally, according to the corresponding rule of cutting speed and chip shape, the cutting speed phase division method based on chip shape is put forward.The research shows that the material of the main deformation zone tends to occur with the increase of cutting speed, the increase of material strength and the plasticity Thermoplastic shear instability and fracture failure make the chip sawtooth; for general plasticity brittle metal material, with the cutting speed increases, the first deformation zone material thermoplastic shear instability occurred earlier than the fracture failure; the same kind of workpiece material , The cutting speed can be divided into common cutting speed stage according to the chip shape, Fast cutting speed stage, super-fast cutting speed stage.