【作者】 张丽霞；

【导师】 方敏；

【作者基本信息】 中北大学 ， 材料加工工程， 2007， 硕士

【摘要】 本文以五孔式氧枪喷头底座挤压成形为研究对象,对该零件的挤压成形过程及其模具的工作状况进行了数值模拟,制定了该挤压件的成形工艺,并对模具进行了失效分析,这对于保证成形件的质量及提高模具使用寿命均具有积极的意义。首先,根据模拟分析的需要,建立了模具的几何模型以及模拟过程的刚塑性有限元模型,并对模拟中边界情况的定义、材料性能的施加、设备速度的选取和网格的划分等关键问题进行了分析,为模拟和仿真的顺利进行打下了基础。应用有限元数值模拟方法,对氧枪喷头底座挤压过程进行了三维数值模拟。讨论了坯料大小、变形温度、变形速度和摩擦条件对变形过程中等效应变、等效应力以及挤压力的影响,确定了合理的变形工艺参数。模拟结果显示:在坯料直径为340mm,挤压温度为850℃,挤压速度为5mm/s时,有利于该零件的成形。在数值模拟结果分析的基础上,制定了氧枪喷头底座挤压成形的工艺方案,并进行了生产试制。实验结果表明,用挤压工艺代替传统工艺生产该零件,有效地提高了材料利用率,降低了生产成本。经过批量生产后,挤压凸模表面出现裂纹,导致模具失效。本文采用有限元数值模拟软件对凸模挤压过程中的应力场、温度场进行了分析,找出其失效的主要原因,并提出改进方案。更多还原

【Abstract】 Take the extrusion of the pedestal of 5-hole spray nozzle of oxygen lance as the research object, the numerical simulation of forming process and working condition of die are studied in this paper. The technology of the extruded part has been stipulated, and the failure analysis has been studied. Those are in favor of increasing the part and the service life of die.Firstly, the geometric model of die and rigid-plastic finite element model of simulation are built according to the demand of simulation analysis. The definition of interface condition between die and workpiece, the adding of material parameters, forming velocity of machine and mesh, is also done. it is the base of the following computer simulation.Through numerical simulation of finite element method (FEM), the course of extrusion of the spray nozzle of oxygen lance is simulated. The forming of the blank, deformation temperature, deformation rate and friction are discussed which impact equivalent strain, equivalent stress and extrusion force. The analysis showed that it is beneficial to forming when the diameter of blank is 340mm, the extrusion temperature is 850℃, and the extrusion speed is 5mm /s.Based on the result of the FEM simulation,the extruded forming technology of the spray nozzle of oxygen lance has been stipulated, and the physical experiment is achieved. The result shows that it is feasible to produce the spray nozzle of oxygen lance with extrusion in place of the traditional technology, which improved the utilization of material and reduced the production cost effectively.Through quantity production, the surface of extruded die of the spray nozzle of oxygen lance appeared crack. It resulted in the ineffectiveness of die. The stress and temperature field of die in the extrusion processes is analyzed using simulation software of finite element method. The main reason of ineffectiveness of die is found, and the improving project is put forward.更多还原