What are the common defects of pipeline steel pipe welding

What are the common defects of pipeline steel pipe welding?
1. Air bubbles, air bubbles mostly occur in the center of the weld bead. Hydrogen is still hidden in the weld metal in the form of air bubbles. The main reason is that the welding wire and flux have moisture on the surface. In the process, the current is small, the welding speed is too fast, and this will also happen with accelerated solidified metals.

2. Undercut, undercut is the appearance of a V-shaped groove along the center line of the weld at the edge of the weld, mainly due to inappropriate conditions such as welding speed, current, voltage, etc. It is more likely to cause undercut defects than unsuitable current.

3. Hot cracks of pipeline steel pipe. The cause of hot cracks is when the stress of the weld is very large, or when the SI silicon element in the weld metal is very high, there is also a sulfur crack, the blank is a strong sulfur segregation zone Cracks caused by sulfides entering the weld metal during the welding process of sheet metal (which belongs to soft boiling steel).

4. Welding penetration is insufficient, the overlap between the internal and external weld metal is insufficient, and sometimes it is not fully penetrated.

The above is about the common defects of pipeline steel pipe welding. Hope it is helpful to you.