Welding seam is one of the main connection ways of steel structure, and its welding quality directly affects the installation quality. It is found that the common quality defects in steel structure welding are as follows:
First, crack: usually have hot crack and cold crack. The main reasons for this phenomenon are poor crack resistance of raw materials, poor quality of welding materials, improper selection of welding process parameters, improper welding structure design, improper weld arrangement, no preheating before welding, rapid cooling after welding and so on. The solution is to drill out the crack stop metal at both ends of the crack, or eliminate the crack on the crack stop metal, repair welding.
Two, slag inclusion: the main reason for slag inclusion is poor solder quality, welding current is too small, welding speed is too fast, multi-layer welding slag is not removed, the treatment method is to remove the welding metal at the slag inclusion, and then welding.
Three, not fusion: the main reason for not fusion is welding current is too small, welding speed is too fast, groove clearance is too small, improper operation process, etc. The treatment method of unfusion is to shovel the weld metal at the end of fusion, and then welding repair.
Four, weld deformation: the main reason for weld deformation is improper selection of welding process parameters, poor operation technology, improper placement of welding parts. Use shovel, file, grinding and other manual or mechanical methods to remove accumulated excess metal.
