基于有限元分析的汽车用大法兰螺母冷镦成形技术

Cold heading technology on automotive large flange nut based on finite element analysis

以车用大法兰螺母为研究对象,通过结构分析,提出两种冷镦成形工艺方案。首先,研究了40CrNiMoA钢在室温条件下的变形特性,以建立其准确的材料模型;其次,采用Deform-3D软件对两种方案的前4个工位分别进行有限元建模和成形模拟,并对比了模具的填充、材料的变形、等效应力的分布以及各工位的成形载荷情况,确定了更加可行的冷镦成形方案;最后,根据该可行方案对各工位的模具结构进行设计与制造,并装入6工位冷镦机中进行试模。结果显示:该冷镦成形工艺稳定,生产速度快,并且制造的大法兰螺母外形完整、质量好,无折叠和开裂等严重缺陷,使用性能满足厂家的需求。

For automotive large flange nuts,two cold heading process schemes were proposed by structural analysis.Firstly,the deforma-tion characteristics of 40CrNiMoA steel at room temperature were studied to establish an accurate material model.Secondly,finite element modeling and forming simulation on the first four stations of the two schemes were conducted by software Deform-3D,respectively,and the filling of mold,the deformation of material,the distribution of equivalent stress and the forming load of each station were compared to de-termine a more feasible cold heading scheme.Finally,according to the feasible scheme,the mold structure of each station was designed and manufactured,and a mold testing was carried out by a 6-station cold heading machine.The results show that the cold heading process is stable,the production speed is fast,and the manufactured large flange nuts have complete shape,good quality and no serious defects such as folding and cracking,and the performance meets the requirements of manufacturer.