Experimental investigation of CMT discontinuous wire arc additive manufacturing of Inconel 625

Abstract

Additive manufacturing (AM) is a progressive technology which holds promise for manufacturing of heat resistant super alloys. One of the most productive methods is wire arc additive manufacturing (WAAM). In this article, an alternative WAAM strategy is investigated. Experimental clads and material tests were performed to evaluate the material properties obtained through a cold metal transfer (CMT) discontinuous WAAM of Inconel 625 alloy. Using the modern terminology of Fronius Gmbh this method is called CMT cycle step. The difference is that it is automatically controlled by the welding source. CMT discontinuous WAAM has lower productivity and a higher consumption of shielding gas. However, it excels in low heat input and precise material cladding in comparison with a standard CMT continuous WAAM. It enables fabrication of finer details even on thin-walled components or in sections with problematic heat dissipation. Samples manufactured using this strategy were also compared with samples manufactured through a standard CMT continuous WAAM. Two sets of manufactured samples were thus tested. The following material tests were performed: (i) metallographic analysis, (ii) x-ray tomography, (iii) SEM analysis, (iv) hardness, (v) tensile strength (20 °C, 650 °C) and (vi) pin-on-disc (20 °C, 650 °C). The results show that the CMT discontinuous WAAM led to improved material properties in the Inconel 625 samples. Ultimate tensile strength improved by 15% at 20 °C and by 4% at 650 °C. Wear resistance at 650 °C was about two times higher. This paper concludes that the CMT discontinuous WAAM for Inconel 625 is definitely suitable for manufacturing of complex shapes, fine details and thin-walled components.

A review on microstructure and mechanical properties of Inconel 625 alloy fabricated using wire arc additive manufacturing process

“…Hardness measurements revealed no differences in hardness between samples from the CMT continuous WAAM strategy and those from the CMT discontinuous WAAM strategy. The results of the tensile strength tests unequivocally demonstrated that the mechanical properties of specimens from the CMT discontinuous WAAM strategy outperformed those from the CMT continuous WAAM strategy (Votruba et al , 2022).…”

“…Hardness measurements revealed no differences in hardness between samples from the CMT continuous WAAM strategy and those from the CMT discontinuous WAAM strategy. The results of the tensile strength tests unequivocally demonstrated that the mechanical properties of specimens from the CMT discontinuous WAAM strategy outperformed those from the CMT continuous WAAM strategy (Votruba et al, 2022). Table 6 indicates that different characteristics of corrosion behavior of Inconel 625 and the alloy have excellent hot corrosion resistance, fatigue resistance, wear resistance, weldability and high strength at elevated temperatures making it widely used in the aerospace, chemical, petrochemical, marine and high-temperature and corrosion applications industries (Kannan et al, 2021).…”

Wire ARC Additive Manufacturing of Functional Metals - A Review

“…The microstructure is porefree in both the as-deposited and heat-treated conditions. Owais Mansoor Inconel 625 [7] was deposited with good forming quality by using a layer-by-layer deposition strategy. Different microstructures were identified at the different layers of the specimen, with the bottom layers consisting mainly of fine primary cellular structures.…”

Processing of Bimetallic Inconel 625-16Mo3 Steel Tube via Supercritical Bend: Study of the Mechanical Properties and Structure

“…During welding, temperature variations in welds and parent metals have important effects on material characteristics and residual stresses, as well as on the dimensional and shape accuracies of welded products [6,7]. The CMT method has been effectively used for the welding and cladding of Inconel, Aluminum, Titanium alloys, steels, and other materials [8][9][10][11][12].…”