利用上限法，建立了管坯镦锻成外六角管头时，金属流动动可容的速度场及应变速率场，计算了管料变形时等效应变速率及总的功率消耗。利用最小功原理，导出了管坯镦锻成外六角管头的单位变形力，并确定了合理工艺参数 By using the upper bound method, the velocity field and strain rate field of metal flow can be set up when the tube is upset into the hexagonal tube head, and the equivalent strain rate and total power consumption of the tube material are calculated. Using the principle of least work, the deformation force of upsetting tube into hexagon head was deduced, and the reasonable process parameters