When the annular parts of a spaceflight apparatus were welded,the centre of the rotation of electron gun and the centre of the annular weld are usually not superposed.
英
美
- 在真空电子束焊接航天器件的圆形焊缝时,由于工装等原因,出现电子枪回转中心与焊缝圆心不同心现象。