高压冷却下高温合金加工切削力特性及刀具磨损研究

发布时间：2019-01-30 12:15

【摘要】：高温合金作为航空航天、船舶、原子能、车辆工业关键零部件中的重要材料,对国家制造业起着重要作用。随着我国制造业日新月异的发展,对高温合金的加工需求也逐渐提高,但其材料的难加工性是制造中的难点,主要表现在切削过程中存在切削力大、刀具磨损严重及切削温度高等现象。针对以上问题,采用高压冷却是改善加工效果的一种有效途径。本文通过高压冷却下PCBN刀具加工高温合金试验,分析切削力及刀具磨损规律,探索高温合金加工质量改善和加工效率提高的理想方案。首先,建立高压冷却条件下的切削力数学模型。根据直角切削理论,对斜角切削过程中的相关参数进行简化计算,建立斜角切削力系数模型;通过对高压冷却相关理论及冷却润滑过程的研究,探讨高压冷却下切削力变化原因及摩擦系数计算方法,将其与常规切削力模型结合,完成高压冷却下切削力系数模型的构建,为高压冷却下切削力预测及刀具磨损分析提供支撑。其次,对高压冷却下镍基高温合金车削过程及PCBN刀具磨损过程进行有限元仿真分析。通过Third Wave Advant Edge软件对切削过程进行仿真,在切削力仿真结果基础上,分析预测高压冷却下的切削力变化规律;利用DEFORM仿真软件对刀具磨损过程进行仿真,分析刀具磨损的渐变过程,为刀具磨损形貌研究提供参考。再次,进行高压冷却下镍基高温合金切削试验。根据试验结果,分析冷却条件、切削参数与切削力的变化关系,对高压冷却下切削力系数模型进行完善和修正,并建立切削力经验模型,验证模型准确性,为切削参数优化提供支持;建立多目标切削参数优化模型,运用遗传算法并结合试验结果,优化高压冷却下的切削参数。最后,对高压冷却条件下PCBN刀具磨损情况进行研究。通过高压冷却下的刀具磨损试验,在分析刀具磨损形貌的基础上,对PCBN刀具的失效原因进行探讨;研究切削加工条件对刀具磨损的影响,获得高压冷却下的刀具磨损规律,并结合切削力试验结果,对高压冷却下考虑刀具磨损时的切削参数选择进行分析,为提高刀具寿命和加工效率提供建议及参考。
[Abstract]:As an important material in aerospace, ship, atomic energy and vehicle industry, superalloy plays an important role in the national manufacturing industry. With the rapid development of manufacturing industry in our country, the processing demand of superalloy is increasing gradually, but the difficulty of material processing is the difficulty in manufacturing, which is mainly manifested in the cutting process of large cutting force. The tool wear is serious and cutting temperature is high. In view of the above problems, high-pressure cooling is an effective way to improve the processing effect. In this paper, the cutting force and tool wear law are analyzed through the experiment of PCBN tool machining superalloy under high pressure cooling, and the ideal scheme to improve the machining quality and efficiency of the superalloy is explored. Firstly, a mathematical model of cutting force under high pressure cooling condition is established. According to the theory of right angle cutting, the relative parameters in the process of oblique cutting are simplified and the model of cutting force coefficient of inclined angle is established. Through the research on the theory of high pressure cooling and the process of cooling lubrication, the reason of cutting force change and the calculation method of friction coefficient under high pressure cooling are discussed. The model of cutting force coefficient under high pressure cooling is constructed by combining it with the conventional cutting force model. It provides support for cutting force prediction and tool wear analysis under high pressure cooling. Secondly, the turning process and PCBN tool wear process of nickel base superalloy under high pressure cooling are simulated by finite element method. The cutting process is simulated by Third Wave Advant Edge software. Based on the simulation results of cutting force, the law of cutting force variation under high pressure cooling is analyzed and predicted. The process of tool wear is simulated by DEFORM software, and the gradual process of tool wear is analyzed, which provides a reference for the study of tool wear morphology. Thirdly, the cutting test of nickel base superalloy was carried out under high pressure cooling. According to the experimental results, the relationship among cooling conditions, cutting parameters and cutting forces is analyzed, and the model of cutting force coefficient under high pressure cooling is improved and modified, and the empirical model of cutting force is established to verify the accuracy of the model. To provide support for the optimization of cutting parameters; The optimization model of multi-objective cutting parameters is established, and the cutting parameters under high pressure cooling are optimized by genetic algorithm and experimental results. Finally, the wear of PCBN tool under high pressure cooling condition was studied. Based on the tool wear test under high pressure cooling and the analysis of tool wear morphology, the failure reasons of PCBN tool are discussed. The influence of cutting conditions on tool wear is studied, and the wear law of cutting tool under high pressure cooling is obtained. In combination with the results of cutting force test, the selection of cutting parameters considering tool wear under high pressure cooling is analyzed. Suggestions and references are provided to improve tool life and machining efficiency.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG506.7

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