Development of UT procedure for SCC crack depth sizing by phased array UT in Ni-based alloy weld

Abstract

The advanced phased array UT technique for SCC crack depth sizing in Ni-based alloy weld was developed. In previous study, authors proposed to the UT procedure for defect depth sizing by phased array UT in the inside inspection. The UT procedure was applied to the defect depth sizing in Ni-based alloy weld specimen with EDM notches. From these results, superior performance for defect depth sizing by phased array UT technique was shown. However, it is not clarified the performance of SCC crack depth sizing. And then, it is not established the fabrication method of Ni-based alloy weld specimen with artificial SCC crack. In this paper, the investigated results of fabrication method of Ni-based alloy weld specimen with axial SCC crack are shown. Furthermore, phased array UT technique for crack depth sizing was applied to the Ni-based alloy weld specimen with axial SCC crack. From the experimental results, good accuracy of SCC crack depth sizing by phased array UT in the inside inspection was shown. Therefore, it was clarified the effectiveness of the UT procedure for defect depth sizing in Ni-based alloy weld. Furthermore, main factors of crack depth sizing error were investigated, and then countermeasure for the decrease of those errors was also investigated.