某VCR发动机齿板热锻成形参数研究

Research on hot forging parameters of a VCR engine rack

对某VCR (Variable Compression Ratio,可变压缩比)发动机齿板热锻成形进行参数影响和优化研究,可为锻件质量控制提供理论依据。基于DEFORM-3D,建立了该过程的有限元仿真模型,研究了坯料始锻温度和上模下压速度等参数对金属填充模腔情况、成形载荷、终锻件温度和等效塑性应力分布等的影响。结果表明:在研究的参数范围内,金属填充模腔完整,无折叠缺陷;当坯料始锻温度升高或上模下压速度加快时,各工步所需载荷和终锻件的最大等效塑性应力均减小,终锻件温度升高。最终获得了较优参数,即坯料始锻温度为1050℃、下压速度为50 mm·s^(-1)时,终锻件温度分布合理、填充饱满、无折叠和表面过度氧化缺陷,且锻件应力和成形载荷小,并对较优参数进行了实验验证。

Researching on influence and optimization of parameters in hot forging of a VCR(Variable Compression Ratio) engine rack can provide a theoretical basis for forging quality control. Therefore,a finite element model of the process was established based on DEFORM-3D,and the influences of the initial forging temperature of blank and the loading speed of upper die on the metal filling,forming load and temperature and equivalent plastic stress distributions of finish forging were studied. The results show that the metal filling in the finish forging die cavity is full without folding defects in the range of parameters studied. As the initial forging temperature of blank or the loading speed of upper die increases,the loadings required for each forming step and the maximum equivalent plastic stress of finish forging both decrease,and the temperature of finish forging rises. Furthermore,the optimized parameters are obtained,and when the initial forging temperature of blank is1050 ℃ and the loading speed is 50 mm·s^-1,the temperature distribution of finish forging is reasonable,the metal filling is full without folding and excessive oxidation,and the stress and forming load are small. Finally,the optimized parameters were verified by the experiments.