Font Size: 

Assessing a flaw acceptability in a welded structure by means of afailure assessment diagram (FAD) can be difficult when accurate data (Kmat , localbehaviors) on the heterogeneous materials of the weld are not available. The aim ofthis work is to demonstrate that the coarse grained heat affected zone (CGHAZ) isthe critical microstructure of the studied weld and to study the behavior mismatchof the different materials. Therefore bending tests on as received weld blanks wereconducted and showed failure initiation in the CGHAZ. This microstructure was reproducedusing a GLEEBLE 1500 thermal simulator. Charpy V-Notch tests on weldmetal (W-M), base metal (B-M) and simulated CGHAZ were made showing the brittlenessof the CGHAZ and the mismatch diminution with increasing sy. Smooth tensiletests on B-M and W-M showed the same mismatch evolution.