镦粗工艺理论与技术的进展

Advance of the Upsetting Technology Theory and Technique in a Hydraulic Press

提出了普通平板间镦粗圆柱体高径比H／D＞1时刚塑性力学模型的拉应力理论和高径比H／D＜1时的静水应力力学模型的剪应力理论．前者打破了传统工程塑性力学中所阐述的镦粒体内部总处于三向压应力之说．后者圆满地解释了大型饼类锻件中常出现的“夹馅饼”缺陷问题．平板镦粗新理论已被定性物理模拟和定量数值模拟、广义滑移线解、力学分块法和生产解剖试验所证实．在该新理论基础上．进一步提出了方柱镦粗的两个新力学模型、锥形板镦粗的新工艺及其力学原理．

In tension stress theory of a rigid-plastic mecbhanical model when the ratio of height to diameter (H/D) larger than 1 and the shearing stress theory if ahydrostatic stress mechanical model when H/D less than l are advanced for the problem of upsetting a cylinder between common flat platens,The former breaks the saying described in the traditiional engineering plastic mechanics that there always exist three-dimensional compressive stresses in the interior of an upsetting body． The latter perfectly interprets the problem that there often present the flaws with meat pie in the heavy forgings,The new theory of the flat platen upsetting has been testified by the qualitative physical simula tion，the quantitiative numerical simulation,the generalized slip-line solution,the mechanical slab method and the dissecting test in production.Two new mechanical model for upsetting a square bdy and the new technology and its mechanical principl of upsetting between the cone-shaped platens are further proposed on the basis of the new theory.