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

Metals

Anibal de Andrade Mendes Filho¹  Guilherme dos Santos Vacchi²  Rodrigo Silva²  Cristie Luis Kugelmeier²  Isabela Dainezi²  Claudio Beserra Martins Júnior²  Carlos Alberto Della Rovere²  José Henrique Alano³  Wislei Riuper Ramos Osório⁴ 

[1] Engineering, Modeling and Applied Social Sciences Center (CECS), Federal University of ABC, Avenida dos Estados 5001, Santo André 09210-580, SP, Brazil;Munir Rachid Corrosion Laboratory, Department of Materials Engineering, Federal University of São Carlos, Rodovia Washington Luis Km 235, São Carlos 13565-905, SP, Brazil;School of Engineering, Federal University of Rio Grande, Rio Grande 96203-900, RS, Brazil;School of Technology, University of Campinas, Limeira 13484-350, SP, Brazil;

关键词: cast nickel alloy;    welding;    microstructure;    polarization;    pitting corrosion;   

DOI  :  10.3390/met11081286

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown