某汽轮机缸壁补焊变形量预测

某汽轮机下半缸铸造后产生尺寸偏差，隔板定位面螺栓孔轴向错位，造成上下缸无法直接组装运行，急需进行补焊返修.为了评估补焊工艺的可行性，采用数值计算的方法，对汽轮机下半缸多道多层补焊过程进行了三维数值模拟，预测了缸壁补焊后关键部位的变形量.结果表明，采用18道焊缝分区跳焊的工艺，补焊后中分面平整度在2 mm内；汽封轴向尺寸偏差小于1 mm；汽封开档尺寸从喉口到出口先膨胀后收缩，最大变形量为0.886 mm；变形量的预测为制定和评估正确的补焊工艺提供理论依据和技术支持.

Deformation prediction of repair welding on steam turbine's cylinder wall

Because of size deviation and bolt hole axial misalignment after casting, the upper and lower cylinder of the steam turbine can''t be assembled directly, it must be repaired. In order to evaluate the feasibility of repair welding technology, this paper simulated the multi-layer and multi-passed welding process and predicted the deformation of main size in the lower cylinder wall. Calculation results show that the mid-surface smoothness was within 2 mm after partition jump welding, the axial alignment tolerance of steam sealing was less than 1 mm, and its open size expanded first and then shrunk from throat to outlet and the maximum deformation was 0.886 mm. Repair welding deformation forecast provides the theoretical basis and technical support for making and evaluating the correct repair welding technology.