高速铣削淬硬钢表面细观结构表征与损伤演化机制研究

High speed milling has become mainstream processing technology for automobile panels' hardened steel mould; The researches about influencing law of hardened steel surface condition under high speed milling on service performance as well as the mapping principle between high speed milling conditions and surface service performance are comparatively weak, and the surface integrity evaluation indexes are imperfect, which can't effectively guarantee its service life and performance. Therefore, multi-high filed coupling acting mechanism of hardened steel surface formation under high speed milling is researched in this project, and the thermal distribution model of manufactured surface is established; meanwhile, microscopic reconstruction and characteristics identification of surface Meso-structure is made, and the surface meso-structure characterization model is established; macro-meso analysis of surface damage evolution process is analyzed, and relationship coupling matrix between surface meso-structure and surface service performance is constructed; surface meso-structure is taken as middle variable, surface meso-structure evaluation index is confirmed, and the mapping relationship between the conditions of high speed milling and surface service performance is researched, accordingly the optimal conditions of high speed milling is put forward. The purpose of this research is to illustrated surface damage evolution mechanism of hardened steel under high speed milling, and to reveal mapping law among the three: high speed milling surface conditions - surface meso structure - service performance, in order to lay the foundation for improving high speed milling technology level and service performance as well as life time of Automobile panels' hardened steel mould.

高速铣削已成为汽车覆盖件淬硬钢模具的主流加工技术。由于在淬硬钢高速铣削加工的表面状态对服役性能影响规律、高速铣削条件与表面服役性能映射规律等方面研究比较薄弱，表面完整性的评价指标与控制方法不够完善，无法有效保证其寿命与服役性能。本项目研究高速铣削淬硬钢表面形成的多强场耦合作用机制，建立已加工表面热力分布模型；进行表面细观结构的显微重构与特征识别，建立表面细观结构表征模型；进行表面损伤演化过程的宏细观分析，建立表面细观结构与表面服役性能关系耦合矩阵；以表面细观结构为中间变量，确定表面细观结构评价指标，研究高速铣削条件与表面服役性能映射关系，提出优化的高速铣削条件。研究旨在阐明淬硬钢高速铣削表面的损伤演化机制，揭示高速铣削条件-表面细观结构-表面服役性能三者之间的映射规律，为提高汽车覆盖件淬硬钢模具的高速铣削技术水平、服役性能与寿命奠定基础。

高速铣削已成为汽车覆盖件淬硬钢模具的主流加工技术。由于在淬硬钢高速铣削加工的表面状态对服役性能影响规律、高速铣削条件与表面服役性能映射规律等方面研究比较薄弱，表面完整性的评价指标与控制方法不够完善，无法有效保证其寿命与服役性能。项目针对淬硬钢高速铣削加工，依据汽车覆盖件淬硬钢模具加工特点，建立了已加工表面细观结构表征模型，分析了已加工表面细观结构的承载特性和接触变形；建立了球头铣刀铣削的刀工接触关系模型和变切削厚度正交切削模型，通过淬硬钢铣削过程数值模拟和高速铣削试验研究，分析了淬硬钢高速铣削过程中力热特性及其对表面残余应力、加工硬化的影响规律，阐明了切削参数对已加工表面形成影响的热力耦合作用机制；针对不同切削参数形成的加工表面进行了服役过程数值模拟与冲压试验研究，获得了服役过程中已加工表面受力分布、磨损分布，建立了切削参数与表面服役性能映射关系；基于细观损伤力学，根据表面缺陷统计分析获得的损伤参数，进行了服役过程中表面损伤演化数值模拟，预测了表面损伤演化趋势。研究旨在阐明淬硬钢高速铣削表面的损伤演化机制，揭示高速铣削条件-表面细观结构-表面服役性能三者之间的映射规律，为提高汽车覆盖件淬硬钢模具的高速铣削技术水平、服役性能与寿命奠定基础。