Performance of the INCONEL 625 alloy weld overlay obtained by FCAW process

Abstract

Nickel-based weld overlays (cladding) are commonly used in oil & gas industry to extend the life of equipment under corrosive environment, as it improves the corrosion resistance without a significant increase in the manufacturing cost, when compared to a full nickel-based alloy equipment. Although there are extensive literature involving overlays applied by SMAW, GMAW or GTAW processes, works about the use of FCAW process are limited. Consequently, an investigation of the performance of the overlays deposited by this process, which provides a higher productivity in comparison to the processes usually used, can be an interesting option for this application. The present work evaluates the mechanical and microstructural properties of the nickel-based superalloy 625 weld overlay deposited on a ASTM A516 Grade 70 carbon steel plate by the flux cored arc welding process (FCAW), both in as welded and heat treated conditions. Bending and microhardness tests were performed in order to verify possible effects of welding thermal cycles on the mechanical properties. The microstructure was evaluated through both optical (OM) and scanning electron microscopy (SEM), with the use of electron backscatter diffraction (EBSD) technique. Corrosion tests were conducted on samples removed from the top layer of the weld overlay according to ASTM G 48 Method A. All results obtained with this welding process, in both as welded and heat treated samples, were considered satisfactory.

Microstructural Evolution And Mechanical Properties of FCAW Joints In 9% Ni Steel Prepared With Two Types of Ni-Based Weld Metals

“…The compositional analysis reveals that the interdendritic regions are relatively rich in Mo and Nb (Table 4). These results suggest the liquid segregation of Mo and Nb during the weld joint solidi cation [8,13]. The compositional analysis of the interdendritic precipitates reveals that the Nb-enriched phase is NbC.…”

Corrosion Behavior of CW6MC Nickel Cast Alloy (Inconel 625) Welded by Shielded Metal Arc Welding

“…From the EDS results, it can be noted that the intermetallic particles have a characteristic core-shell structure; where the shell is enriched with Nb, Mo and Si, while the core is composed mainly of Nb. The shell intermetallics, rich in Nb, Mo and Si, are Laves phases (points 1 and 3), whereas the core particles, rich in Nb (points 2 and 4), are NbC-type carbides, as reported in the literature [9,34,[42][43][44]. Additionally, in good agreement with the mentioned literature, the XRD patterns (Figure 5) of the BM and WM microstructure show the presence of NbC-type carbides and Laves phases in both regions.…”

Thermal Deformation Analysis Methodology Development for Inconel Overlaying

“…Both carbon steel CSF71S and Inconel Supercore 625p welding electrode of diameter 1.2 mm were used. The effect of weld quality was studied with reference to input parameters like voltage, current, and height of the torch tip to the base metal [6][7][8][9][10] . Welding was carried out considering the following input parameters described in Table 1 and Table 2.…”