Assessment of welding residual stresses by employing Instrumented Indentation Technique

Abstract

This thesis investigates the applicability of the Instrumented Indentation Technique (IIT) for evaluating residual stresses in welded S355 steel joints. The study focuses on adapting a methodology originally developed for nanoindentation system to a macro-scale portable indentation device. Experimental measurements were performed across base material, heat-affected zone, and weld metal regions of structural steel weld joint, and the results were analysed using indentation-based models. The obtained residual stress values were compared with literature data derived from X-ray diffraction and hole-drilling methods. The results show higher stress values and increased data scatter, highlighting the influence of device resolution and measurement conditions on the reliability of IIT for heterogeneous welded structures.