Laser welding has an undercut problem:
The combination of the weld and the base metal is not good, there is a groove, the depth is greater than 0.5mm, and the total length is greater than 10% of the weld length, or greater than the length required by the acceptance standard.
Causes:
A. The welding speed is too fast, and the liquid metal in the weld will not be redistributed on the back of the small hole, forming undercuts on both sides of the weld.
B. If the assembly gap of the joint is too large, the molten metal in the filling of the joint is reduced, and undercutting is also prone to occur.
C. At the end of laser welding, if the energy drop time is too fast, the small hole is easy to collapse, which will also cause local undercut.
Solution:
A. Control the laser welding machine to match the processing power and speed to avoid undercutting.
B. The undercut of the weld found in the inspection can be polished, cleaned and repaired to make it meet the requirements of the acceptance standard.
