湛江发电厂给水泵汽轮机隔板裂纹的分析及焊接修复

Analysis and repair welding for baffle cracks on feedpump-driving steam turbine in Zhanjiang Power Plant

直接指出湛江发电厂1号机组的给水泵汽轮机隔板分面出现裂纹的原因是:原铸钢件ZG20CrMo材质的铸型能力差,存在气孔、砂眼、缩孔、裂纹等缺陷;给水泵汽轮机隔板结构复杂,刚性不均匀,应力分布也不均匀,造成应力集中而出现裂纹。为此,针对给水泵汽轮机隔板所用ZG20CrMo材质的化学成分和力学性能,分析其焊接性,确定现场补焊方案及工艺。给水泵汽轮机隔板裂纹补焊修复后投入运行,一直未发现任何异常情况,说明补焊方案、工艺的正确合理。

This paper indicates the reasons of the baffle cracks on the feedpump-driving steam turbine of Unit 1 in Zhanjiang Power Plant: 1) The poor casting capability of steel ZG20CrMo for the baffle led to defects such as air holes, sand holes, cavitation and cracks; 2) The baffle is of complicated structure, uneven rigidity and stress distribution, thus causing concentrated stress and cracks. In view of the chemical composition and mechanical property of steel ZG20CrMo for the baffle, its weldability is analyzed and the on-site repair welding procedures determined. No abnormities have ever happened since the repair welding, which proves the rationality of the procedures.