This paper reviews factors that contribute to stress relief and reheat cracking in weldments. In particular we consider the influence of thermo-mechanical history on the relaxation of triaxial residual stresses, typical of those observed in the 316H austenitic stainless steel thick section attachment welds. 316H austenitic stainless steel parent material has been subject variously to thermo-mechanical pre-treatments and a critical microstructure encountered within the heat affected zone of the thick section weldments has been simulated. Through thickness residual stress fields induced by a spray water quenching technique and their relaxation as a result of high temperature exposure have been characterised using neutron diffraction. The rates of relaxation are correlated with microstructure. The susceptibility of grain boundary to brittle fracture at a temperature of -196°C is shown to be a function of inter-granular M23C6 carbides and phosphorous segregation at grain boundaries. The influences of the thermo-mechanical history on creep deformation resistance and the potential susceptibility to grain boundary creep cavitation are discussed.
|Translated title of the contribution||Relaxation of residual stresses and grain boundary fracture in 316H stainless steel (Keynote paper)|
|Title of host publication||International Symposium on Structural Integrity, Shanghai|
|Editors||Shan-Tung Tu, Zhengdong Wang, George C Sih|
|Publisher||East China University of Science and Technology Press|
|Pages||41 - 50|
|Number of pages||10|
|Publication status||Published - 2010|