基于楔横轧预制坯的中空气门终锻凸模设计

对中空气门楔横轧-模锻成形工艺终锻成形过程中的凸模形状尺寸进行研究。根据预成形毛坯终锻过程的成形特点，设计3种不同初始尺寸的终锻成形凸模，采用实验与模拟相结合的方法研究其对预成形毛坯终锻成形过程的影响。模拟结果表明，终锻成形过程中凸模芯轴太短，将出现凸模芯轴前端聚料的现象，导致无法成形出终锻件的盘部型腔尺寸；而实验结果表明，凸模芯轴太长会在实际生产中导致成形后终锻件难以脱模。通过综合模拟与实验结果的分析，获得了凸模芯轴的设计原则，确定了合适的凸模芯轴长度，并且依据该凸模设计原则，进行终锻成形，获得了形状尺寸合理的终锻件。

Design of final forging punch for hollow valve based on cross wedge rolling preformed blank

The punch’s shape size in the process of cross wedge rolling and final forging of the hollow valve was studied. According to the characteristics of the performed blank in final forging process, three kinds of final forging punches with different initial dimensions were designed, and the influences of the punches on the final forging process of preformed blank were studied by combining experiment with numerical simulation. The simulation results show that if the punch mandrel is too short in the final forging process, the front end of the punch mandrel appears the phenomenon of material gathering, and the cavity dimensions of the final forging cannot be formed. However, the experimental results show that the over-long punch mandrel will lead to the difficulty of unmold in final forging in the actual produc-tion. According to the analysis on results of both simulation and experiment, the design principle of the punch mandrel was obtained and the appropriate length of the punch mandrel was determined. Based on above research, the reasonable shape and size of the final forging was obtained by the designed punch.