Non-Destructive Testing of Components Produced via Wire-Arc Additive Manufacturing

Additive Manufacturing allows the manufacturing of high-value, complicated, and tailored metallic components that would not have been achievable with conventional methods. Powder bed fusion methods, such as electron beam melting and selective laser melting, provide remarkable layer-by-layer production capabilities by selectively melting the metal powder with a moving electron or laser beam. Wire Arc Additive Manufacturing (WAAM), on the other hand, is based on arc-welding techniques, in which metal wire is fed into a welding nozzle at the tip of a robotic arm, which melts the metal and deposits it in layers according to a computerized 3D design. Any material in the form of welding wire, such as steels, Al-, Ti-, and Ni-alloys, can be utilized for WAAM.
With its flexibility, simplicity, and faster deposition rate than most other AM methods, WAAM can build completely dense parts with massive dimensions and create structures that can be extended to several meters in length while increasing manufacturing efficiency and decreasing production costs. Furthermore, the functional component design can be accomplished by changing the material type during the process. It is also useful for repairing and maintaining damaged components. However, post-heat treatment is occasionally used to improve strength and reduce anisotropy, and, the as-built product is reworked by multi-axial machining to ensure precision.
WAAM processes have difficulties managing a larger molten pool, complex metallurgical phenomena, and high internal stresses. Inconsistencies in material composition, unstable process parameters, and fluctuations in conditions can readily create discontinuities in the product that might harm structural integrity, functionality, performance, and durability. Thus, the acceptance criteria of WAAM components necessitate extensive tests. Non-destructive testing (NDT) techniques have critical roles in the WAAM for the real-time monitoring of material deposition and quality control of as-built components. Detection and evaluation of changes in optical, thermal, sonic, and electromagnetic signals provide a base for NDT of WAAM processes. An overview of the NDT techniques used in WAAM will be presented in this talk.

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Biography

Prof. Dr. C. Hakan Gür received his BSc (1st rank among the department graduates in 1986), MSc, and PhD (1995) degrees from the Department of Metallurgical Engineering of Middle East Technical University (METU, Ankara). He performed research studies at BAM-Berlin between 1991-1993. He is the editor of the Handbook of Thermal Process Modeling of Steels (2009 CRC-Press). In 2010, he was appointed a Fellow of the International Federation of Heat Treatment and Surface Engineering. He served as the chair of the Department of Metallurgical and Materials Engineering between 2012-2022 and as the director of the Welding Technology and Non-destructive Testing Center between 2007-2024 at METU. He has level 3 certificates in UT, RT, MT, and PT methods from the German NDT Society. His research topics include non-destructive testing and materials characterization, heat treatment, and residual stress. He has 70 international journal articles and more than 150 conference articles.