摘要
分析厚壁管无芯棒开式冷挤压的变形特点,运用场论及流体动力学的理论,建立包含坯料几何参数的运动学许可速度场。分析已知零件尺寸时,能成形该零件的坯料集合特点,根据所建立的运动学许可速度场,利用上限法原理,建立坯料逆向预测的方法。针对特定零件,利用先确定坯料内孔尺寸,再进行外径预测的方法,得出该零件可以由一组不同的挤压前坯料(坯料集合)获得。坯料集合与零件的关系曲线表明,对于外径相同内径不同的零件,随着内孔直径d0增大,零件壁厚减小,坯料集合的D1/d1整体减小;对于同一零件,能成形该零件的坯料集合中,坯料的内外径比值不是简单线性关系,随着坯料内孔直径d1的增大,D1/d1减小。根据预测结果设计试验,对模型进行验证,预测结果与试验结果误差在2%以内。
The forming feature of open die extrusion without mandrel for thick wall tube is analyzed.Based on the concepts of hydrodynamics and field theory the kinematically admissible velocity field is established.The peculiarity of the billet to form given part is analyzed.Based on upper bound method the prediction of the billet to form given part by open-die cold extrusion of thick wall pipe is constructed.The billets set can be obtained by determining the diameter of the inner hole firstly and predicting outer diameter.The billets set is the group of different billets can be extruded for the specific part.The curve of the relationship between the billets set and the parts shows wall thickness and D1/d1 decrease with the inner hole diameter d0 increasing for the parts whose outside diameter is same and inner diameter is different; For the same part,the billet＇s inner and outer diameter ratio is not a simple linear relationship among the billets set.The D1/d1 reduces with the inner hole diameter d1 increasing.The experiment is finished based on the he prediction.And the prediction results and the experiment results are contrasted and analyzed.Prediction error is less than 2％.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第10期98-102,共5页
Journal of Mechanical Engineering
关键词
厚壁管
开式冷挤压
流函数
上限法
坯料集合
工艺逆向预测
thick wall pipe
open die extrusion
stream function
upper bounding theory
billets set
prediction of reversed process
