Maximum and minimum critical rates of deformation in open die extrusion are discussed on the basis of the slip field theory and the upper bound theory of plane state plastic deformation.

• 采用平面塑性变形的滑移线理论和上限理论对开式挤压成形工艺中的临界最小和临界最大变形率进行了分析计算，给出了挤压模角与临界最小和临界最大变形率的对应关系；