Abstract
10 kW laser beam welder was installed in the continuous annealing and pickling line for hot coil (H-APL), and welding characteristics was researched. As a result, the following conclusions are obtained. The maximum penetration depth was obtained at the focal point of 2 mm below the surface. The HAZ width of a laser weld was approximately 0.3 mm, and the number of bending repetition and the HAZ width were mutually related.
The deterioration in ZnSe lens was caused by adhesion of fumes, spatters and dusts of welding to the lens surface, or residual strain of lens occurred as the number of welding passes increased. The thermal effect occurred by using deteriorated lens. For prevention of the thermal effect, the parabolic mirror could be used instead of ZnSe lens, since the penetration depths of parabolic mirror and the ZnSe lens were almost equal.
