390MW定子线圈TU2铜接头焊接预热失效分析
Failure Analysis of TU2 Copper Joint of 390 MW Stator Coil in Preheating Process
迟永强1， 李学浩1， 焦雅丽2， 林娜娜2
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作者单位：（1.镇江四洋特种金属材料制造有限公司，江苏 镇江212003；2.江苏科技大学 材料科学与工程学院，江苏 镇江212003）
中文关键字：铜接头； 起泡； 氢气病； 沿晶裂纹
英文关键字：copper joint; blistering; sickening hydrogen; intergranular crack
中文摘要：390MW汽轮发电机定子线圈TU2铜接头在焊接前的预热过程中产生表面起泡现象，经过分析表明：在中频感应预热后产生表面起泡的失效原因是390MW定子线圈TU2铜接头材料含有一定量的氧和热锻工艺采用水煤气(H2+CO)加热所致。为消除由“氢气病”引起的起泡现象，应采用含氧量更低的无氧铜用于390MW定子线圈TU2铜接头上，或者是将铜接头的热锻加热方式改为电阻炉加热。
英文摘要：TU2 copper joint of 390MW turbo generator stator coil generates surface blistering in the preheating process before welding. The analysis results show that a certain amount of oxygen being in the TU2 copper joint material of 390 MW stator coil and using water-gas （H2+ CO） in the hot forging process are the main reasons for surface blistering after preheating in medium frequency induction furnace. To eliminate the blistering caused by “sickening hydrogen”, the oxygen- free copper with lower oxygen should be used in the TU2 copper joint of 390MW stator coil, or the hot forging heating approach of copper joint should be changed into resistance furnace heating.