The round plates with arc shaped butt-welded joints were used for stopping sone tube holes which were moved away to another proper positions in the pipes.
采取有弧度的圆形镶块，以对接接头的形式堵补部分管孔，将其移位到管道上的合适位置。
2
The status of the radiographic technology for the butt-welded joints in small diameter tubes are re-viewed briefly. The key points are discussed for the development of radiographic technology.
简要评述小直径管对接焊缝射线照相的特点、方法以及现行技术规定。
3
Having been practiced for several years, a new butt method for spiral welded pipe, the two spots tack-weld butt was made out.