Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Analysis of Copper Addition by Electrolysis on the Microstructure and Corrosion Resistance of Laser Welded Super-Duplex Stainless Steel
Submission Author:
Bruna Berbel Seloto , SP
Co-Authors:
Bruna Berbel Seloto, Eli Cruz Junior, Leonardo Vilela de Menezes Carvalho, Vicente Afonso Ventrella
Presenter: Bruna Berbel Seloto
doi://10.26678/ABCM.COBEM2021.COB2021-1923
Abstract
Duplex and super duplex stainless steels receive this denomination due to their microstructure composed of austenite and ferrite, which contributes to good mechanical resistance and corrosion, however, subjecting them to the welding process; it results in a weld bead with a predominantly ferritic structure, with distinct properties of the base metal. Thus, Nd: YAG pulsed laser welding presents a good alternative for these materials, since it offers low thermal input, with energy concentrated in the weld bead and, consequently, small heat affected zone. Even though this process presents good quality in the welding of super-duplex stainless steels, the unbalance of the phases in the fusion zone is still present. Some alloying elements contribute to the formation of austenite, such as copper. Thus, the present work sought to add this element in the form of electrodeposition with a time of 60, 80 and 100 minutes, current density 2 A / dm², temperature of 50ºC, and pH 1.0, with the use of acidic solution of CuSO4, in plates of 3mm thick UNS S32750 super-duplex stainless steel. Subsequently, they were welded with a Nd: YAG pulsed laser welding process with the following fixed parameters: welding speed 1mm/s, peak time 5ms, frequency 9Hz, pulse energy 10J, peak power 2kW and argon shielding gas with a flow rate of 20L / min. The analysis of the effects of copper addition occurred through the evaluation of the microstructure, microhardness and corrosion tests of Open Circuit Potential (OCP) and Potentiodynamic Polarization on the weld bead. The results demonstrate that the copper deposition formed a uniform, adherent orange-colored coating. The macrographic and micrographic images indicate that there was a formation of austenite predominantly in the grain boundaries, insoluble copper islands, cracks along of the weld bead and porosity. Regarding corrosion, among all the analyzed samples, there was no significant disparity in the difference in potential of the Open Circuit tests and the pitting potential.
Keywords
Nd:YAG pulsed laser welding, Super-duplex Stainless Steel, Copper Addition
