Determination of welding residual stresses with help of the micromagnetic measurement method

The micromagnetic measurement method is a well known technique for a qualitative estimation of residual stresses in ferromagnetic materials. The application due to the advantages of a fast and manageable use is hindered by the high complexity of the calibration procedure for the quantitative residual stress determination when additionally a changing microstructure influences the measured signals. Therefore basic investigations were performed for the residual stress determination of welded joints by the micromagnetic method. A multi-parameter approach by using different micromagnetic techniques was evaluated by a linear regression analysis. For each structural steel a regression polynomial can be calculated for the residual stress determination of differently welded specimens. The accuracy of the prediction depends on the magnetization direction. The experimental results show, that this strategy enables a useful possibility of an easier method for the determination of residual stresses in welded joints.