通过合理制定热锻工艺来消除材料内部缺陷是材料加工领域的重要课题。本文应用商用有限元软件MARC ,模拟了圆柱体热镦粗时内部空洞的闭合过程 ,分析了空洞变形时的应力和应变以及影响空洞闭合和焊合的各种因素。模拟结果表明 ,变形过程中空洞边缘微小区域内会产生双向拉应力 ,直到闭合时拉应力才会变成压应力。压下方向的应变是绝对值最大的应变 ,主导着空洞的闭合过程。高温下的空洞闭合后能够立即完成再结晶过程 ,但空洞焊合需要一定的保温时间 It is an important issue in the field of material processing to eliminate the internal defects of materials by reasonably formulating the hot forging process. In this paper, the commercial finite element software MARC is used to simulate the closing process of the internal cavity when the cylinder is upset. The stress and strain in the cavity deformation and various factors that affect the cavity closing and welding are analyzed. The simulation results show that the biaxial tensile stress is generated in the tiny area near the cavity edge during deformation, and the tensile stress will not become compressive until closed. The strain in the direction of depression is the strain with the largest absolute value, which dominates the closing process of the cavity. After the cavity closed at high temperature to complete the recrystallization process immediately, but the hole welding requires a certain holding time