残余应力对焊接接头裂尖蠕变性能的影响

Effects of Residual Stress on Creep Properties of Welded Joints

核电一回路安全端焊后冷缩过程极易产生残余应力,并且长时间处在高温、高压恶劣环境中,会导致力学性能降低,对核电安全产生严重的影响。因此,以紧凑拉伸试样为研究对象,借助ABAQUS有限元分析软件模拟焊接接头冷缩过程中产生的残余应力对裂尖蠕变性能的影响。结果表明:残余应力的存在导致蠕变后裂尖处的Mises应力、等效蠕变量均增大,并且在蠕变初始阶段蠕变速率较大,缩短了裂纹的起裂时间,使得结构构件更易发生失稳破坏,影响核电运行安全。

The residual stresses are easily produced during the cold shrinkage process after welding in a nuclear power circuit safe end,and the nuclear power circuit safe end serves at high temperature and in high pressure for a long period of time,which results in sharp decrease of mechanical properties and has a serious impact on nuclear safety.Taking the compact tensile specimen as the research object and the effect of residual stress generating in the cold shrinkage process on creep properties of crack tip was simulated using ABAQUS.The results show that the Mises stress,equivalent creep amount at the crack tip increase due to the residual stress,and the creep rate is bigger at the initial stage of creep,which shortens the crack initiation time,makes the structural members more prone to destabilize and damage and affects the safety of nuclear power operation.