Investigation of the Strain Behaviour of Laser-Beam and High-Frequency-Welded Seams of Tailored Blanks Using Electronic Laser Speckle Interferometry

Because of local modifications of the grain structure in the heat-affected zone of the welding as well as a different chemical composition of the weld metal as compared to the base material the various areas of a welding exhibit a different deformation- and strain behaviour. To evaluate the influence of the material behaviour and the process behaviour of the joining procedure on the strain behaviour of the welding the application of laser-optical sensoring offers a new source of information. In particular, results of investigations of weldings made of sheet metals will be presented. As a welding process for tailored blanks, high frequency welding is particular emphasized in this presentation apart from the process of laser beam welding. The investigations also have the purpose to be a basis for the verification of FEM calculations and to develop appropiate material models.