Stress Build-Up during Multilayer Welding with Novel Martensitic Filler Materials

摘要

Controlling the level of mostly detrimental residual stresses already during the welding process would be highly attractive as time and cost consuming post processing may be prevented. Innovative Low Transformation Temperature (LTT-) filler materials are specially designed for controlling weld residual stresses by means of adjusted martensite formation already during welding. Numerous publications can be found on this issue, but they provide only little insight into the interaction between martensite formation and resulting welding residual stresses. Within this study a component weld test was performed in a special large-scale testing facility. In-situ load analysis revealed that the amount of stress reduction during deposition of the individual weld runs is dependent on the weld volume undergoing phase transformation related to the shrinking volume. The residual stresses found after welding show that the desired residual stress control by using LTT alloys is sensitive to welding boundary conditions (i. e. weld geometry, plate thickness) and to be evaluated separately for varying weld scenarios.