Experimental investigation on deposits of ER70S-6 wire on SiO2 substrate using non-transferred arc-based wire arc additive manufacturing

Abstract

Recent trends in additive manufacturing (AM) are to produce geometrically complex structures at minimal wastage of material, time and cost, without sacri cing part quality, mechanical performance and to introduce ease in processing and part removal. Here a non-transferred arc (NTA) based wire arc additive manufacturing (WAAM) system has been developed to achieve the above objectives, where arc is only generated between tungsten electrode and consumable ller wire. No electrical contact with substrate facilitates deposits even on non-conductive substrate surface that helps in easy removal of nal deposits. In uence of deposition parameters (welding current, voltage, wire feed speed (WFS), and travel speed) on response characteristics (bead uniformity, height deviation, droplet diameter, droplet transfer frequency) is studied on multi-performance level using grey relational analysis (GRA). Then single and multi-bead layer is fabricated over SiO 2 substrate for ease in part removal after complete fabrication. WFS is referred as a key deposition parameter which have in uence on all deposition characteristics. It has been observed that NTA based WAAM results high bead uniformity with minimal spatter and bead height difference between start and exit arc point. Complete ferrite microstructure with few pearlites is observed on the deposits with similar elemental composition on top, bottom and interface surface. X-ray diffraction (XRD) study reveals ferrite diffraction planes ({110}, {200}, {211}, and {220}) with no intermetallic formations on deposits. Also, compressive residual stress with less variation in crystallite size, stress, strain and microhardness among top, bottom, and lateral surface of deposit indicates isotropic nature of the fabricated part.

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

“…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°).…”

“…Only in the initial wire sample additional copper diffraction planes are identified ({111} and {200} at 50.3° and 59.2°). It could be due to the copper coating on the wire electrode but their intensities are minimal compared to ferrite peaks (Pattanayak et al , 2022).…”

“…The presented XRD data sets are further analysed to evaluate the crystallite size (CS) and lattice strain (LS) according to the detailed procedure provided by Kumar et al (2020) and Pattanayak et al (2022). Kumar et al (2020) reported that the Williamson Hall approach (W-H plot) was best suited for calculating the CS and LS, owing to their combinational dominance over peak broadening.…”

“…Here, the arc is formed between two electrodes, consisting of a tungsten electrode and filler wire, which are connected to the -ve and 1ve terminals of a 250 A GMAW machine. Compared to our previously reported study (Pattanayak et al, 2022), a change has been accommodated in the electrode arrangements (as shown in Figure 1) to reduce the tungsten electrode wear rate and spatter. An 80°angle is made between the 3 mm tungsten electrode and 1.2 mm AWS A5.18 ER70S-6 filler wire (as presented in Figures 1-2).…”