TIG and laser beam welded joints – simplified numerical analyses

Abstract

Regardless of the welding method, a new joint and the surrounding area are inevitably subjected to thermo-physical perturbation. The paper presents analyses of many different issues involved in welding and potential solutions including adoption of simplifying assumptions, application of numerical algorithms and development of reliable representative models. The Finite Element Method is used to determine residual stress distribution, using results from thermo-physical tests and widely known mechanical properties of metals subjected to welding processes. Experimental and numerical methods for determining residual stress are compared for welds generated using both TIG (Tungsten Inert Gas, Gas Tungsten Arc Welding) and a laser beam. This data reveals that it is necessary to precisely define location of the analyzed welded fragment to correctly determine thermal boundary conditions.

Fatigue Life of Austenitic Steel 304 Bolts Strengthened by Surface Treatment with Graphene Oxide Layer and Surface Shot Peening

“…Modification of the surface layer of machine components can have a significant effect on improving their mechanical properties [1][2][3][4][5][6][7]. One important factor in the initiation and development of fatigue cracks concerns structural and geometric notches, which cause local accumulation of stresses favoring the weakening of the structure [7].…”

“…They showed that the surface crushing created by surface peening leads to compressive stresses in the subsurface layers affecting crack development. In non-surface-strengthened specimens, crack initiation usually occurs at the bottom of structural or geometric notches, whereas the introduction of a state of subsurface compressive stresses can shift the crack initiation site to the point of maximum material stress below the surface [5,15] and, most importantly, increase fatigue life.…”