Corrosion Behavior of CW6MC Nickel Cast Alloy (Inconel 625) Welded by Shielded Metal Arc Welding
Guilherme dos Santos Vacchi,
Rodrigo Silva,
Cristie Luis Kugelmeier,
Claudio Beserra Martins Júnior,
Isabela Dainezi,
José Henrique Alano,
Anibal de Andrade Mendes Filho,
Wislei Riuper Ramos Osório,
Carlos Alberto Della Rovere
Affiliations
Guilherme dos Santos Vacchi
Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil
Rodrigo Silva
Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil
Cristie Luis Kugelmeier
Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil
Claudio Beserra Martins Júnior
Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil
Isabela Dainezi
Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil
José Henrique Alano
School of Engineering, Federal University of Rio Grande, Rio Grande 96203-900, RS, Brazil
Anibal de Andrade Mendes Filho
Engineering, Modeling and Applied Social Sciences Center (CECS), Federal University of ABC, Avenida dos Estados 5001, Santo André 09210-580, SP, Brazil
Wislei Riuper Ramos Osório
School of Technology, University of Campinas, Limeira 13484-350, SP, Brazil
Carlos Alberto Della Rovere
Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil
The aim of this study concerns the effect of multi-pass shielded metal arc welding (SMAW) on the corrosion behavior of CW6MC cast nickel alloy. Using optical and SEM techniques the welded joint is analyzed. Vickers microhardness mapping and potentiodynamic polarization in NaCl and H2SO4 solutions are also evaluated. Both the Laves phase and NbC-type carbides are identified in the base metal (BM) and weld metal (WM) regions. The main microstructural difference observed between these regions is the morphology aspect and fineness of the dendritic arrays. The welding process promotes the finer columnar grains formation with refined intermetallic particles in the WM than equiaxed grains of the BM, which in turn results in higher microhardness values in the former region. However, no substantial changes were observed in the corrosion behavior between the BM and WM regions, considering both acid and saline media. Nevertheless, during the multi-pass SMAW process, some non-metallic micrometric inclusions (Mo and S-rich regions) can be constituted to occur in the WM region. This is associated with a significant drop in the corrosion performance of this region when the electrochemical tests are evaluated.
