Adaptive compensation for in-process ultrasonic cladding inspection

Throughout the early 21st century, the rise in manufacturing costs has led to economic and industrial drivers to develop novel solutions to tackle the increasing costs of high-integrity manufacturing. A key driver to reduce costs is to implement product quality conformance inspections, such as Non-Destructive Testing (NDT) at the point of manufacture, rather than at the end of the process, reducing manufacturing rework, improving schedule certainty, and increasing manufacturing throughput within industrial facilities. Welding is a highly utilised process deployed in the manufacture of high-value components such as nuclear pressure vessels, which are then clad with a corrosion-resistant alloy, with preferential attributes onto a cheaper base material to reduce the cost of manufacture. Traditional code-compliant ultrasonic inspection methodology commonly requires the machining of any non-planar surfaces prior to inspection, preventing the inspection of cladding methods during manufacture. Until now, in-process inspection has not been applied to weld cladding applications with non-planar surface profiles. This paper presents a novel approach to optimising ultrasonic imaging through the as-clad surface, consisting of multiple angled transmission and reception beams. Representative cladding trials, with artificial ultrasonic reflectors representing typical cladding defects, were introduced to assess the sensitivity of the ultrasonic inspection to defects under various non-planar surfaces. The approach demonstrated a reduction in variability of defect amplitude due to surface profile compensation alone, from 9.42 dB to 1.37 dB, demonstrating the methodology that can be applied agnostically of complex ray-tracing methods.