Inconel 625 is nickel-based superalloy strengthened by solid-solution due to incorporation of niobium and molybdenum refractory metals in an austenitic FCC ³ matrix. This material is a widely used engineering material owing to its excellent resistance to corrosion, high temperature strength and weldability. Due to these characteristics this alloy is widely used in coating pipes for oil extraction. Requirements in Inconel 625 for uses in petroleum industry restrict Fe amounts to 5 or 10 wt.% Fe, depending on its application. Higher content of Fe is usually related to lowering the corrosion resistance of this alloy. Currently, the domestic industry uses the TIG (Tungsten Inert Gas) welding process for superalloy deposition on steels. This method presents a large amount of heat input, which can have important and detrimental effects on the microstructure, mechanical properties and corrosion resistant of the material. In this study, single bead and multiple beads samples of Inconel 625 wire will be cladded on the surface of ASTM A182 F22 steel under optimized process conditions. The morphologies, compositions, phase formed, mechanical properties and corrosions performances of cladded area will be investigate for observed using optical microscopy (OM), scanning electron microscopy (SEM) and analyses were made by X-ray diffractometry (XRD). Open-circuit potential (OCP) vs time measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques will be carried out. The corrosion behavior of the alloys was evaluated in NaCl 3.5 wt.% and ferric chloride solution in the same concentration as ASTM-NACE 48G. The present research proposal intends to provide technical content for decision-making in relation to the standards and procedures performed during the production of the tubes for oil extraction using the coating. Detailing the effect of the content of iron in the mechanical properties and corrosion resistance of this component, as well as to evaluate an alternative to the welding process currently used to obtain the Inconel 625 deposit.
News published in Agência FAPESP Newsletter about the scholarship: