Mechanical Reliability

CHarWeld – Influence of case hardening on the fatigue strength of welded joints

The project is financed by the Forschungsvereinigung Automobiltechnik e. V. (FAT) on behalf of the Verbandes der Automobilindustrie e. V. (VDA) via Forschungsvereinigung der Arbeitsgemeinschaft der Eisen und Metall verarbeitenden Industrie e. V. (AVIF)


The objective of this research project is to develop a methodology for the reliable evaluation of welded joints that are case-hardened after welding. In the project, the fatigue strength-increasing influence of the compressive residual stresses induced by case-hardening is induced by case hardening will be determined and quantified experimentally under different loading scenarios. In addition, the influence of the increase in hardness is identified separately from the residual stress state. Based on the experimental results a design concept and, based on this, design recommendations will be developed, which take into account the compressive residual stresses induced during case hardening and the high hardness in the weld. Two stages are planned: On the one hand, a simple-to-use linear-elastic evaluation, with which a conservative design is possible. On the other hand, elastic-plastic evaluation is being developed, which requires a higher calculation effort, but which calculation effort, but with which the reliability of the design can be further increased.

Matthias Hecht, M.Sc.
Phone.: +49-6151-705-431