Residual stress measurement in a repair welded header in the as-welded condition and after advanced post weld treatment

Measurements of the residual stresses in a type 316H stainless steel steam header were made using the deep hole drilling (DHD) technique to characterise the through thickness residual stress distribution in a circumferentially repaired weld in the as-welded condition and after an advanced post weld treatment (APWT) had been applied. The measured residual stress field was compared with finite element (FE) predictions. Overall there was a good correlation between the DHD measurement results and the FE results in the as-welded condition. The results highlighted the generation of high residual stresses due to repair welding. After APWT, there were noticeable differences between the measurements and the FE predictions. The study also demonstrated the feasibility of performing an APWT procedure on components and its significant effect on the redistribution of residual stresses. In particular, it was demonstrated that APWT promoted a finite volume of compressive stresses near the critical area of the header, thus providing increased confidence in the component integrity.