Study on influence of the PTA-P welding process parameters on corrosion behavior of Inconel 625 coatings

Resumo

In the present work, PTA welding process was used to investigate the influence of welding parameters on the
dilution, microhardness and corrosion resistance of Inconel 625 alloy coatings on the API 5L X70 grade
steel. The electrochemical impedance spectroscopy (EIS) and linear potentiodynamic polarization (LPP)
measurements were used to study the protection properties of the deposited layer when immersed in a 3.5%
NaCl solution. The results of EIS and LPP have shown that the corrosion resistance results were more satisfactory
for coatings with higher dilution index. The results also showed that the dilution values D (%)varied
from 15.33% to 4.39% at the maximum (18.99 kJ/cm) and the minimum (8.34 kJ/cm) welding energy levels.
The most relevant dilution value obtained was 4.39%.
Keywords: Plasma transferred arc-welding; coatings; dilution; corrosion.