本文分析了锥形模镦锻变形的三个阶段,提出了二次稳定镦锻的概念,给出了金属变形过程中几个瞬态的数学模型。在此基础上,提出了不产生空间螺旋弯曲的原始坯料长径比ψ_(nkp),并绘出了ψ_(nkp)-φ临界曲线,进而得出了为设计模具用的三条限制曲线。通过试验分析,提出了在长径比很大时镦锻模膛设计的限制曲线,并在生产中取得了满意的效果。 In this paper, three stages of upsetting forging of conical die are analyzed. The concept of quadratic stable upsetting is proposed. Several transient mathematical models are given during the deformation of metal. On this basis, the ψ - (nkp) of the original blank without spatial helical bending was proposed and the critical curve of ψ_ (nkp) - φ was drawn. Three limiting curves for designing the die were obtained. According to the experimental analysis, the limit curve of upsetting die cavity design is proposed when the aspect ratio is very large, and satisfactory results are obtained in the production.