Phased Array Ultrasonic Nondestructive Testing for Mechanical Integrity Assessment of Steel Welding

Abstract Variety of structures and components are using welding processes as the major method of joining. Various materials such as steels, aluminum alloys, nickel alloys, and cast iron are being welded regularly in industrial applications. Well-known methods of welding are available which being used depending on the type of the materials welded together and application requirement. Like any other sections of a manufactured component, welding parts need to be inspected for required level of quality and integrity. Welding inspection typically consists of a series of quality assessment actions carried out in a certain procedure. It ensures welded joints meet required levels of quality and are fit for a specified purpose. A range of nondestructive testing (NDT) techniques may be used for welding inspection which depends on several factors including geometry and configuration of the joints, material, thickness of the welded parts, and inspection environment. Among the variety of NDT methods, configurations of ultrasonic testing (UT) are identified as efficient and accepted techniques of inspection for welding. Many UT methods are based on traditional techniques. Despite the effectiveness of these techniques, the accuracy and repeatability of the UT can be significantly improved via advanced phased array technology. In this study, phased array UT (PAUT) is used to evaluate the quality of the welding in steel samples. In addition, mechanical properties of the samples were measured by tensile testing and monitored with acoustic emission technique. Results show that the phased array ultrasonic testing can provide localized quality information of the weld and correlate to the mechanical properties (e.g., strength) of the part in welding region.