Influence of active cooling on microstructure and mechanical properties of wire arc additively manufactured mild steel

Abstract

Additive manufacturing (AM) of metals attracts attention because it can produce complex structures in a single step without part-specific tooling. Wire arc additive manufacturing (WAAM), a welding-based method that deposits metal layer by layer, is gaining popularity due to its low cost of operation, feasibility for large-scale part fabrication, and ease of operation. This article presents the fabrication of cylindricalshaped mild steel (ER70S-6) samples with a gas metal arc (MIG)—based hybrid WAAM system. A mechanism for actively cooling the substrate is implemented. Deposition parameters are held constant to evaluate the impact of active cooling on deposition quality, inter-pass cooling time, and internal defects. Surface and volume defects can be seen on the cylindrical sample fabricated without an active cooling setup. Defect quantification and phase analysis are performed. The primary phase formed was α-iron in all samples. Actively cooled deposition cross section showed a 99% decrease of incomplete fusion or porosity, with temperature measured 60 s after deposition averaging 235°C less than non-cooled. Microstructural analysis revealed uniformity along the build direction for actively cooled deposition but non-uniform microstructures without cooling. Hardness decreased by approximately 22HV from the first layer to the final layer in all cases. Property variation can be attributed to the respective processing strategies. The current study has demonstrated that active cooling can reduce production time and porosity while maintaining uniform microstructure along the build direction. Such an approach is expected to enhance the reliability of WAAM-processed parts in the coming days.

Non-transferring arc and wire additive manufacturing: microstructure, mechanical properties and bulk texture evolution of deposits

“…Rodrigues et al (2022) also reported that the formation of fine-grained structures in the top layer is mainly attributed to the fast cooling rate. Similar microstructural evolution was also attained in the scientific studies of Ahsan et al (2020), Dash et al (2023) and Rodrigues et al (2021) during WAAM of low-carbon steel parts. The elemental composition observed at different sections (Figure 19) is almost aligns with the wire electrode composition (ER70S-6).…”

“…Wire, single bead and multi-layered structure exhibits ferrite diffraction planes, namely, {110}, {200}, {211} and {220}. These reported results are matched with the WAAMed deposits of low-carbon steel (Dash et al , 2023; Nemani et al , 2020; Pattanayak et al , 2022; Raut and Taiwade, 2022). Only in the initial wire sample additional copper diffraction planes are identified ({111} and {200} at 50.3° and 59.2°).…”

“…A similar study was also conducted by Silva et al (2020). In a recent study, Dash et al (2023) designed a heat exchanger with continuous coolant flow (20.5°C). The build plate was attached over this heat exchanger to dissipate heat during GMAW-WAAM.…”

“…Metal additive manufacturing (AM) has become a promising technology in the manufacturing industries due to the capability of fabricating large-scale products under high deposition conditions that cut off production time (Raut and Taiwade, 2022). Directed energy deposition (DED) is one of the metal-based AMs, where the feedstock is introduced either in the form of powder or in wire (Dash et al , 2023). Laser, electron-beam based process and wire arc AM (WAAM) are the common DED processes available for metal AM.…”

Enhancment of Wire Arc Additive Manufacturingproduction of Aluminum Part

“…Запроваджені сучасні методи вирішення проблем адитивного виробництва з використанням технології електродугового зварювання [1][2][3][4] вказують на те, що проведення автоматизованого друку потребує подальшого вдосконалення. Для покращення якості процесу виробництва використовуються сучасні методи контролю за температурою [5][6][7], проте й вони не є автоматизованими. Однією з проблем під час адитивного виробництва є перекриття валиків [8][9], параметри якого залежать так само й від розповсюдження тепла між ними [10][11][12].…”