Micromechanical Study of Heterogenous Deformation of Austenitic Stainless Steel Welded Joints at Different Temperatures

Heat-resistant austenitic stainless steels are widely used in the final stages of superheater and reheater new generation fossil fuel power stations, due to their high creep strength. Similar weld joints, fabricated using gas tungsten arc welding, for connecting different components made heat resistant usually suffer from premature failures at elevated temperature [1]. Experimental studies showed that cracks may nucleate affected zone or metal similar welded joints under service conditions. In order reveal physical origin unexpected a microstructure-based modelling work has been performed. Firstly, microstructure was experimentally characterised, then representative model digitally reconstructed Electron-Back-Scattered Diffraction (EBSD) finite element techniques. The stressstrain behaviour each region temperatures identified combination digital image correlation (DIC) techniques, uniaxial tensile microindentation tests. Dislocation density-based crystal plasticity models [2] formulated calibrated so as describe region. Crystal simulations were carried out based on generated study heterogenous distribution stress strain grain level. Local damage initiation mechanisms systematically analysed regions.