齿轮轴热锻组织与流动形态模拟及模具磨损分析

发布时间：2018-09-10 11:22

【摘要】：齿轮轴是机械传动中不可或缺的部件之一,具有传动效率高、结构紧凑和使用寿命长等一系列优点。传统的齿轮轴的切削加工生产方式已逐步被精密锻造成形工艺取代,并取得了良好的效果。根据齿轮轴的工况要求,在锻造生产中提高齿轮轴锻件的力学性能与尺寸精度是改进产品质量的重要手段。锻造过程中,在保证齿轮轴锻件成形性的前提下,研究内部组织形态的变化,并改进工艺方案以获得更加均匀细小且分布合理的微观组织,是提高锻件性能的有效措施。同时,减小锻造过程中模具磨损,也是提高锻件精度,节约模具成本的重要方法。本文应用三维有限元数值模拟技术研究齿轮轴的精锻成形,获得了变形过程中的流动规律,温度变化,应力应变等参数,并且通过结合不同的模型计算,得到了齿轮轴锻件内部微观组织与成形模具磨损的分布,并提出工艺改进方法。对单工步及多工步成形方案进行模拟,基于Yada动态再结晶理论公式,分析坯料初始温度、压下速度及摩擦系数等因素对热锻过程中的锻件内部再结晶的影响规律,比较了不同成形方案的内部组织演化过程。使用Deform软件中Flownet功能,模拟不同工艺条件锻造流线分布。为改善成形中材料流动均匀性,提出局部控温工艺,并分析了控温后的材料流动形态。基于改进后的Archard模型磨损公式,对Defrom软件二次开发,分析不同工艺下齿轮轴热锻模具的影响,同时模拟了采用浮动模结构的工艺过程,得出浮动模移动速度对模具磨损的影响规律。综合比较,齿轮轴热锻多工步成形在改善组织分布、流线形态及模具磨损方面比单工步成形取得了更理想的效果。根据数值分析结果,进行齿轮轴热锻成形实验,选取内部材料分析金相组织,并制作锻造流线样本,对比模拟结果,验证了数值模拟结果的可靠性。在数值模拟和实验研究的基础上,对实用化工艺提出指导建议。
[Abstract]:Gear shaft is one of the indispensable parts in mechanical transmission. It has a series of advantages, such as high transmission efficiency, compact structure and long service life. The traditional production mode of gear shaft cutting has been replaced by precision forging technology, and good results have been obtained. According to the requirements of gear shaft working conditions, it is an important means to improve the product quality to improve the mechanical properties and dimensional accuracy of gear shaft forgings in forging production. In the process of forging, on the premise of ensuring the formability of gear shaft forgings, it is an effective measure to improve the properties of forgings by studying the change of internal microstructure and improving the technological scheme to obtain more uniform and well-distributed microstructures. At the same time, reducing die wear in forging process is also an important method to improve forging precision and save die cost. In this paper, the three-dimensional finite element numerical simulation technique is used to study the precision forging of gear shafts. The flow law, temperature change, stress strain and other parameters in the process of deformation are obtained. The microstructure of gear shaft forging and the distribution of wear of forming die were obtained, and the process improvement method was put forward. Based on the theoretical formula of Yada dynamic recrystallization, the effects of the initial temperature of the blank, the speed of pressing and the friction coefficient on the internal recrystallization of the forging are analyzed. The internal structure evolution process of different forming schemes was compared. The distribution of forging streamline under different technological conditions is simulated by using Flownet function in Deform software. In order to improve the uniformity of material flow, a local temperature control process was proposed, and the material flow pattern after temperature control was analyzed. Based on the improved Archard model wear formula, the influence of the hot forging die of gear shaft under different processes is analyzed by the second development of Defrom software. At the same time, the process of adopting floating die structure is simulated. The influence of moving speed of floating die on die wear is obtained. Compared with simplex forming, the multi-step forming of gear shaft is more effective than simplex forming in improving the structure distribution, streamline shape and die wear. According to the results of numerical analysis, the hot forging experiment of gear shaft was carried out, the metallographic structure was analyzed by selecting internal materials, and the forging streamline sample was made, and the simulation results were compared to verify the reliability of the numerical simulation results. On the basis of numerical simulation and experimental research, some suggestions for practical process are put forward.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH133.2;TG316

【引证文献】