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COBEF 2023
12th Brazilian Congress on Manufacturing Engineering
Impact of deposition procedures on 410L multilayer Plasma transferred arc processing
Submission Author:
Otávio Lima , PA
Co-Authors:
Otávio Lima, Gustavo Scheid Prass, Ana Sofia D'Oliveira
Presenter: Otávio Lima
doi://10.26678/ABCM.COBEF2023.COF23-0330
Abstract
Additive manufacturing (AM), Directed Energy Deposition (DED) technology is an important industrial manufacturing tool to produce mechanical parts without the use of expensive molds with functionalities otherwise not possible. AM can be carried out to fabricate new components or on maintenance of operations to rebuild the geometry of worn parts. Another benefit these manufacturing processes is the high efficiency use of material, increasing the competitiveness and reducing the carbon footprint of the process. Plasma Transferred Arc (PTA) is a low-cost, high-quality deposition technique that brings significant advantages in AM, and it was used to process multilayers of AISI410L. This study is part of an on-going study that addresses the impact of the deposition direction, bidirectional and unidirectional, and the mass flows (Qm) , 6 g/min and 9 g/min, on the solidification microstructure of multilayers. Walls were build using the four processing conditions and characterized in two different regions exposed to a larger and a small number of thermal cycles. Multilayers exhibited an epitaxial solidification structure with a growth direction that depended on the processing parameters used. Results pointed out that regions exposed to a large number of thermal cycles, exhibited larger ferritic grains with an acicular structure at the grains boundaries and a uniform hardness varying between 180 HV and 200 HV. As the deposition height increased, the thermal cycles become smoother at the center of the multilayer walls. In contrast, the top region of multilayers exposed to a smaller number of thermal cycles revealed changes to the microstructure and hardness profile. The later exhibiting lower values at the last deposited layers varying between 150 HV and 185 HV (up to 5 thermal cycles) where larger grains formed followed by an increase up to 230 HV after 8 thermal cycles and the onset of the acicular structure. The low mass flow used allow for good finishing of the multilayers nevertheless the increase in mass flow resulted on an increase in hardness at the different regions and more significant changes at the top layers.
Keywords
Additive manufacturing, stainless steels, Thermal Cycle, Multilayer Walls, Microstructure
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