AP1000核电主管道支管嘴径向镦挤模具设计及应力分析

Radial upset-extruding die design and stress analysis on branch pipe of nuclear power AP1000 main-pipe

针对AP1000核电主管道支管嘴,提出一种新的局部径向镦挤工艺。该工艺以挤压管坯为基础,直接在管坯的局部成形支管嘴。基于这种新工艺,设计了具有垂直合模、水平镦挤功能的多向模锻特点模具。模具结构主要包含模腔结构、合模导向结构、芯轴结构、芯棒结构及镦挤轴结构等部分。对各主要模具的结构设计进行了详细阐述,并对承载能力要求高的模腔结构利用有限元方法进行应力与变形分析。缩比模型镦挤试验结果表明,设计的模具结构可行,强度和刚度满足试验要求。应用该模具成功挤出碳钢和316 LN不锈钢1∶5试验件,为实施1∶1尺寸主管道镦挤工艺提供了模具设计基础。

For the forming of branch pipe of nuclear power AP1000 main-pipe,a novel partial radial upset-extruding（ PRUE） process was developed,which produces the branch pipe directly in the part of a pipe billet based on an extruding pipe billet. According to the PRUE process,a multi-ram forging die which could close dies vertically and upset-extruding the billet horizontally was designed. The structure includes die cavity structure,closing guide structure,mandrel structure,mandril structure and upset-extruding shafts,etc. The design of the above structures was presented in detail,and the stress and the distortion of the die cavity structure under the heavy load were analyzed by FEM. The experimental results from the reduced scale model show that the structure is applicable,and its strength and stiffness meet the requirement of experiments. The test parts are successfully extruded with the scale of 1 to 5 of carbon steel and stainless steel 316 LN,which can be the design foundation in the PRUE process of real size main-pipe.