Distortion control in laser welding of ultra high strength steels (LaserLight)
Purpose and goal
The project has developed process planning tools for minimisation of distortion during laser welding of different steel types including UHSS. Three types of tools were developed based on FE-simulation of different degrees of complexity. The most complex simulations of course show best agreement with experiments. Different methods to reduce distortions during laser welding were studied. The most effective ones are to reduce energy per weld length by increasing laser welding speed or by using stitch welding.
Expected results and effects
Effective simulation tools have been developed for prediction of distortions during laser welding. They show good agreement with experimental trials. Methods have also been developed to minimize distortions by process control. In summary these results mean that it is possible to use a high proportion of laser welds to join a body in white. This is an important contribution to the creation of light weight car bodies. With the new simulation tools the process planning can be made significantly faster than with todays methods based on trial-anderror.
Planned approach and implementation
In the project three simulation methods were developed and at the same time verified with experimental trials. The trials were made for idealized type cases and on real A-pillars of a car. Real distortions and predictions were compared so that the reliability or the simulation techniques could be established. The idealized type cases have also been used to find ways to reduce distortions and a number of ways have been found to generate this reduction.