Ductile tearing in austenitic stainless steel weldments

The UK Technical Advisory Group on the Structural Integrity of Nuclear Plant (TAGSI) was asked to respond to a Question that was submitted by the Ministry of Defence (MoD) on the use of tearing resistance data and the interaction with fatigue crack growth, including the effects of thermal or residual stresses, in austenitic stainless steel weldments. The TAGSI response was initially prepared in 2000, but the basic response is still considered relevant and timely. Additional comments on more recent developments are included. TAGSI concluded that for single loading conditions, material resistance curve data can be used to produce an integrity justification with up to Delta a(t) = 2 mm of tearing. Further work would be required to justify an increase in this limit, but for applications in thick sections it would be prudent to test 50-mm thick specimens as well as standard 25-mm thick specimens. For combined tearing/fatigue conditions, TAGSI considers that the results it has reviewed are encouraging in supporting linear summation of tearing and fatigue components to assess margins. TAGSI considers that it would be prudent to include secondary loading due to welding residual stresses as well as that due to thermal loading in any prediction of stress conditions up to the crack growth limit of 2mm for applications of the type considered. The paper discusses a number of restrictions and limitations to the general conclusions outlined above. (C) 2008 Elsevier Ltd. All rights reserved.