Residual stress analysis in robotically welded plates using phased array ultrasonics with validation through neutron diffraction and hole-drilling methods

This paper explores Residual Stress (RS) measurement in two robotically welded, S275 plates using Phased Array Ultrasonics for Residual Stress Measurement (PAURS) and Neutron Diffraction (ND), with the Incremental Hole Drilling (IHD) method employed for validation. Pogo ultrasonic simulation was used to model the Longitudinal Critically Refracted (LCR) wave and design the ultrasonic setup. Ultrasonic arrays operating at 5 MHz (8 elements) measured RS at a depth of ∼1.25 mm. Results show qualitative agreement among PAURS, ND, and IHD, with RS symmetrically distributed on both sides of the plates, validating the effectiveness of phased array probes for qualitative measurement. However, discrepancies in precise numerical values were observed across methods. As PAURS is a novel technique for welded samples, the paper highlights areas for improvement to enhance its quantitative measurement capabilities.