1. Bubbles
Bubbles mostly occur to the center of the weld bead. Hydrogen is still hidden in the weld metal in the form of bubbles. The main reason is that the welding wire and flux have moisture on the surface. They are used directly without drying, and the current is relatively high during the welding process. If the welding speed is too fast, it will also happen to the accelerated solidified metal.
2. Undercut
The undercut is a V-shaped groove at the edge of the weld along the centerline of the weld. The main reason is that the welding speed, current, voltage, and other conditions are inappropriate. The welding speed is too high than the current is not suitable. Easily cause undercut defects.
3. Hot cracks
The cause of thermal cracking is when the stress of the weld is very high, or when the SI silicon element in the weld metal is high, there is also sulfur cracking. The blank is a sheet with a strong sulfur segregation zone (belonging to soft boiling Steel), in the welding process, sulfide enters the weld metal and produces cracks.
4. Insufficient penetration
The overlap between the inner and outer weld metal is not enough, and sometimes the weld is not penetrated.
Post time: Dec-05-2023