A Study of Reduced Activation Ferritic Martensitic Metal Core Wire for Wire Arc Additive Manufacturing
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Master of Science, Mechanical Engineering
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Thesis (open access)
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This work is licensed under a Creative Commons Attribution 4.0 License.
Department of Mechanical Engineering
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This study seeks to determine the technical feasibility of fabricating reduced activation ferritic martensitic (RAFM) steel parts, using a wire arc additive manufacturing (WAAM) process. The WAAM process, manufactures a part by depositing layers of metal onto a substrate to build a large scale near net shape part. RAFM alloy steels are next generation steels designed to resist radiation effects in the radiation intense working environments, such as nuclear reactors. To achieve this, process development and testing to design the WAAM production process with the custom RAFM filler wire was carried out. Several welding waveform modes were tested, and it was determined that Pulse waveform mode offers an acceptable weld parameter to successfully fabricate custom made RAFM metal cored wire. After successfully fabricating the first test walls hardness testing and metallography was conducted to categorize the steels microstructure by controlling the interpass temperature. The microstructure present is typical martensitic lath, and the presence of delta ferrite is inevitable. The settings were further tested with the addition of shielding gas experimentation to determine if porosity’s visible in the initial prints could be removed. The shielding gas results did aid in the porosity control, but introduced other issues arose. With a reduction in amperage input from the initial settings and the introduction of wait times to allow the equipment to cool, large scale prints were successfully fabricated. The mechanical properties of the deposited material were tested, such as impact toughness as well as macro and microhardness. These tests resulted in an average impact absorption energy of 6.25J and an average hardness across two-layer deposition interpass test samples of 423.74HV.
Reichenbach, Alexander L., "A Study of Reduced Activation Ferritic Martensitic Metal Core Wire for Wire Arc Additive Manufacturing" (2022). Electronic Theses and Dissertations. 2437.
Research Data and Supplementary Material