On the identification of eigenstrain sources of welding residual stress in bead-on-plate inconel 740H specimens.

The main source of welding residual stress is identified by investigating the distribution of permanent plastic strains in as-welded and post-weld heat treated specimens of Inconel 740H. For this purpose, inverse eigenstrain problem is solved using experimental displacement data obtained by high precision coordinate measuring machine measurements from the surface of transversal wire-cut of electric discharge machining. A new multi-component iterative inverse eigenstrain model is developed and, in total, three different inverse eigenstrain models are analysed to get a high-quality fit with experimental data and have a reasonable prediction of residual stresses in the whole body of nonuniform bead-on-plate specimen design. In order to determine the boundaries of permanent plastic strains, which are the main source of welding residual stress, eigenstrain distribution size is analysed in terms of mean squared error using three models. The distribution size that provides the best match between the calculated displacements and the measured deplanation on the surface of cut is determined. The multi-component iterative eigenstrain reconstruction model validated itself by providing a good agreement with experimentally determined displacement and residual stress profiles, and this model is used to predict residual stress distribution in the whole body. [ABSTRACT FROM AUTHOR]