气门热锻模具的优化设计和性能研究

发布时间：2018-06-14 22:14

本文选题：气门 + 3Cr2W8V　；参考：《华南理工大学》2015年硕士论文

【摘要】：气门是发动机关键部件之一,目前国内气门的主要成形方法有两种,一是电镦模锻法,二是挤压模锻法。在气门模锻成形工艺过程中,热锻模具普遍寿命较短。其模具报废,不仅会造成气门的生产中断,而且会浪费大量时间用于更换模具及试模,其用于试模的气门也将作为废品处理。所以,气门模具的寿命不仅关系到气门的制造成本,还密切影响了气门生产工艺的连续性。本文通过对气门毛坯的终锻成形过程进行数值模拟和分析,发现模具R位存在金属的流动剧烈,其R位摩擦作用大,受力变形也大;同时模具与工件接触时间长,尤其是R位始终都与模具接触,造成模具局部温度高,这些是导致出现R位失效的主要原因。并对实际生产中终锻模具的失效形式进行分析,终锻模具失效主要为圆角R位磨损、R位微细裂纹、整体断裂、R位表面拉伤等几种方式,并针对产生失效的具体原因,提出了相应的解决策略。本文就目前市场常用的热作模具钢H13、HM3、HM1、3Cr2W8V、RM2,分别从高温韧性、高温抗拉强度、高温下耐磨性、热疲劳性能以及回火稳定性上做了对比。并特别针对HM1、H13和3Cr2W8V三种常用的气门热作模具钢,分别对比了其生产寿命,HM1热作模具钢具有较为明显的优势。其次,以市场上广泛应用的3Cr2W8V作为实验材料,从热处理淬火、回火的不同温度方面进行了详细的比较,说明了热处理对气门模具的寿命的重要性。之后,通过对模具的设计改进、机械加工、润滑等几个方面,进行了生产试验,其设计成组合模具、更高的加工精度以及良好的润滑效果,都对气门模具的使用寿命有一定的提高,且大大节省了模具材料的使用,有效的降低了生产成本。
[Abstract]:Valve is one of the key components of engine. At present, there are two main forming methods of valve in China, one is electric upsetting die forging method, the other is extrusion die forging method. In the process of valve die forging, the life of hot forging die is short. Not only the production of valve will be interrupted, but also a lot of time will be wasted to replace the mould and test the mold. The valve used for the mold test will also be treated as a waste product. Therefore, the life of valve die not only relates to the manufacturing cost of valve, but also affects the continuity of valve production process. Through numerical simulation and analysis of the final forging process of the valve blank, it is found that the metal flow in the R position of the die is intense, the friction action at the R position is large, the deformation of the force is also large, and the contact time between the die and the workpiece is long. Especially, the R bit is always in contact with the mould, which results in the high local temperature of the mould, which is the main reason for the failure of R bit. The failure forms of the die in actual production are analyzed. The failure of the die is mainly caused by micro-cracks at R position and micro-cracks at R position, and the surface tension at R position is broken as a whole, and the specific reasons for the failure are pointed out. The corresponding solutions are put forward. In this paper, the hot work die steel H13 / HM3 / HM1 / 3Cr2W8 / RM2 is compared in terms of high temperature toughness, high temperature tensile strength, wear resistance at high temperature, thermal fatigue property and tempering stability. Especially for HM1H13 and 3Cr2W8V hot working die steels, the advantages of HM1 hot work die steel are compared with those of HM1H13 and 3Cr2W8V hot working die steels. Secondly, using 3Cr2W8V widely used in the market as experimental material, the importance of heat treatment to the life of valve die is explained by comparing the different temperatures of heat treatment quenching and tempering. After that, by improving the design of the die, machining, lubrication and other aspects of the production test, it is designed into a combination die, higher machining accuracy and good lubrication effect. Both of them can improve the service life of valve die, save the use of mould material, and reduce the production cost effectively.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG315.2

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