液压机上镦粗与拔长新理论与新工艺的研究

在镦粗工艺理论方面 ,提出了圆柱体镦粗的刚塑性力学模型的拉应力理论和静水应力力学模型的切应力理论 ,设计了锥形板镦粗的新工艺。在拔长工艺理论方面 :应用方柱体镦粗的两个新力学模型与拔长的刚端影响问题 ,论证了只有砧宽比一个工艺参数的不足 ,而应补充一个新的工艺参数——料宽比 ,才能正确描述拔长体中心区域的应力状态与有效控制锻件质量 ;并进一步解决了该拔长理论工艺参数量值的合理匹配与确定 ;在“锻造条件对毛坯内部空洞闭合的影响”研究中 ,提出了增加料宽比对横向拉应力控制的“新 FM(Free from Mannesmann effect)锻造法”;并在此基础上提出了横向无拉应力锻造法。用上述理论指导工艺生产 ,可大幅度提高锻件的质量

Research for New Theories and New Technologies of Upsetting and Stretching in a Hydraulic Press

In the upsetting technology theory,a tension stress theory of a rigid-plastic mechanical model and a shearing stress theory of a hydraulic stress mechanical model are proposed for upsetting a cylinder between flat platens,and a new type technology for upsetting between cone-platens is advanced.In the stretching technology theory,based on the two new mechanical models for upsetting a square body and the rigid influence problem,it is demonstrated that only a new technology parameter-blank width ratio is complemented besides the technology parameter-tool width ratio,can the stress state in the central zone of stretching body be correctly described and the forging quality be effectively controlled.The technology parameters of stretching technology theory are correctly matched and determined.In the research for the influence of forging conditions on closing the internal pores in blanks,New FM method with which the transverse tension stress is controlled by the complemented blank width ratio is promoted. The forging method without transverse tension stress is advanced.With the above theories directing production,the forging quality can be improved effectively.