大型汽轮机低压转子轴颈裂纹生成分析及处理

针对某200MW汽轮机低压转子轴颈上出现的裂纹和硬化带，进行金属测试分析和车削检查，查清了裂纹和硬化带的分布，揭示了汽轮机的断油烧瓦（缺油或少油）运行故障可能导致抽颈生成表面深度裂纹和硬化带的事实。通过对油系扭振强度计算，科学及时地作出了更换主轴的决定，并适当加大了新主轴轴颈直径。对本机型轴系设计及现场汽轮机栓修提出了指导性建议。

Analysis and Treatment for the Crack on Bearing Collar of Low Pressure Rotor of Large Turbine

To the crack on appearing bearing collar of low pressure rotor of a 200MW turbine,some metal tests were completed so as to find the distribution of the crack and harden area. The fact that op- eration fault of oil lack and bearing bush burn-out may result in deep crack and harden area on the bearing collar face is opened out. By means of calculating the shafting torsional strength,a decision of replacing the main shaft by new one,whose bearing diameter is increased,was made reasonably and duly. A series of instructional proposal was presented aimed at shafting design of this unit and spot re-pair of turbine set.