Avaliação de revestimentos com ligas de níquel aplicados por soldagem em tubulações para o setor de petróleo e gás.

Abstract

This study aimed to evaluate the influence of welding parameters on the microhardness, dilution, microstructure and corrosion resistance of weld overlay based on Ni base superalloys, applied by welding in API 5L Gr. B steel pipe with 18 mm of thickness using the GMAW process and wire ERNiCrMo-3 (Inconel 625) as filler metals protected with Argon (Ar) pure. To evaluate the effect of welding parameters variation specimens with and without pre-heating to 523 K (250 °C) using voltage from 22 to 30 V and feed speed from 5 to 10 m/min were produced. The results indicated significant variations in the dilution, the microhardness of HAZ and weld metal, and localized regions partially diluted with hardness above 300 HV. The best results of the geometry. The lowest hardness values obtained with the welding parameters of 22 V was provided for pre-heating and feeding speeds of 5 and 7 m/min. The samples were submitted to corrosion electrochemical measurements using a conventional 3-cell electrodes in solutions of 1M NaCI at room temperature, and evaluated the influence of variation of welding parameters on the measures of potentiodynamic linear polarization (PLP) and impedance spectroscopy of each sample. The samples without preheating and with lower feed speed of wire showed the best corrosion resistance.