机械自紧工艺控制参量的实验研究

机械自紧技术在超高压容器和身管制造过程中得到广泛采用,但国内尚无完整的设计方法和工艺规范。采用实验方法来研究机械自紧问题,设计了自紧冲头,搭建由液压泵站提供动力的机械自紧实验装置,建立应变、冲头行程及推力测量系统。对厚壁圆筒试件进行机械自紧实验后,获得了冲头挤进过程中推力的变化数据,结合实验结果和经验公式归纳了机械自紧冲头推力计算公式,得到的推力与实验测量值的误差在±10%以内。测量了机械自紧过程中的重要工艺控制参量外表面应变、残余应变和冲头位移-外表面应变曲线。机械自紧后进行稳定化、机械加工对再屈服压力影响的实验。

Experimental Study of Process Control Parameters in Swage Autofrettage

Swage autofrettage has been widely used in the production of high-pressure vessel and barrel.There are no complete design and process specifications so far.With the help of literature and empirical data,the specimen of the thick-walled cylinder and the mandrel was designed.A hydraulic pump drives the experimental device,and the test system measures strain,mandrel displacement and mandrel push force.Formulas of the push force were summarized according to the experimental data and empirical formulas.The formulas′ absolute error is less than ±10% in comparison of the calculated values with measured values.Residual strain and external surface strain-mandrel displacement variation curves were also tested.After low-temperature thermal treatment and machining,changes in the re-yield pressure of thick-walled cylinders were given.