But in the backingwelding, columnar grain-growth will be appeared in the direction of crystal direction, it effects the welding quality seriously.
但是单面焊打底层焊缝中出现的沿焊缝柱状晶结晶方向的柱状气孔，严重地影响着船舶焊接质量。
2
Welding methods and technology of narrow gap quirk backing weld were discussed. Indirect quirk backing weld using manual hydrogen arc welding is considered as the best result.
讨论了窄间隙深槽打底焊焊接方法和工艺，认为用手工氩弧焊进行单面深槽打底焊效果最好。
3
They cause all the welding of double tubes, joint boxes and gas-collecting tubes to realize the backing weld of TAW-P. The quality of the double tube waste heat boilers have been improved.