汽轮机轮盘热处理残余应力分析

百万核电汽轮机红套低压转子工作环境的蒸汽参数较低，各级轮盘均处于湿度较大的工作区域，易产生应力腐蚀，引起裂纹萌生和扩展．为提高轮盘的抗腐蚀能力，降低工作应力是一个有效的方法．通过热处理方法，在轮盘表面形成预压应力以抵消部分旋转拉应力是可行的方法，而产生适当深度和大小的预压应力则需对热处理过程进行谨慎的设计．本文以汽轮机轮盘为研究对象，建立轴对称有限元模型，通过对ABAQUS软件的二次开发，实现对轮盘热处理过程的温度场及应力场进行数值模拟．计算综合考虑了非线性的材料热物性参数、力学性能参数、表面换热系数及不同材料组织转变的相变潜热、热物性参数和力学参数，通过对不同热处理方法得到的残余应力场的比较，获得了较合理的水冷方式，为热处理工艺确定提供参考．

Residual Stresses Analysis of Heat Treatment Process of Steam Turbine Disk

The work environment of millions nuclear power steam turbine has a low steam parameter, and all levels of the turbines are under the influence of highly humid environment, which easily leads to stress corrosion cracking and crack propagation. Operating stress reduction of steam turbine is an effective method to improve turbine’s resistance to corrosion. One possible way to minimize the operating stresses in critical regions of components is to induce compressive residual stresses in the disk surface through special water-spraying treatment process. To form sufficient magnitude and depth of surface with compressive residual stresses, the heat treatment process is necessitated to be carefully designed. In the present work, further program-developing over ABAQUS software was carried out. The steam turbine disk was selected and an axisymmetric finite element model was thus established. Simulation of temperature and stress field during heat treatment process was elaborated, by incorporating nonlinear material thermal and mechanics parameters, surface heat transfer coefficient and internal heat generation which was associated with phase transformation. The numerical results were compared with the compressive residual stresses obtained from different heat treatment ways, therefore an effective water-cooling process was concluded, which provides a reference for heat treatment design of disk.