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

Abstract

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%.

Influence of voltage, feed speed and CTWD on the corrosion resistance of Inconel 625 alloy coatings deposited by MIG

“…These results confirm the higher corrosion resistance of the experiment 5 . A similar result was obtained in a study on the anti-corrosion properties of the PTA-P welding process obtained coatings [31], where the authors also observed that the increase in the dilution in the coating reduces the corrosion resistance.…”

Efeito do tratamento térmico de alívio de tensão e do preaquecimento na microestrutura e microdureza da interface entre depósitos de inconel 625 e aços AISI 8630M e AISI 4130

“…Vale salientar que o modelo da tocha PTA-P tem quatro canais de alimentação do pó em torno do orifício constritor com ângulo de convergência de 60º. Para a determinação de parâmetros satisfatórios para a deposição dos cordões de solda dos amanteigamentos, foram observados valores já estudados por outros autores [13,14,17]. Esses parâmetros foram testados e sofreram pequenos ajustes para resultar em um perfil geométrico adequado, com uniformidade na largura (L) e altura (R), valor relativamente baixo da relação R/L e baixa diluição, determinada através da Equação 1.…”

“…No entanto, o processo Plasma Pó (PTA-P) vem ganhando destaque em aplicação de revestimentos devido à excelente qualidade das soldas e aos baixos níveis de diluição alcançados. [13,14] O processo PTA-P utiliza um eletrodo de tungstênio não consumível, situado no interior da tocha, um bico constritor, que restringe a área de atuação do plasma, um sistema de refrigerado com água, gás de proteção para a poça fundida e gás de plasma. Até aqui o PTA-P é semelhante ao processo PAW (Plasma Arc Weld).…”

Development and Evaluation of the Internal Cladding Process of API 5L X70 Risers with Nickel-based superalloy 625 via PTA Welding

“…These properties make it a material suitable for surface modification of oil and gas components, especially those made with high-strength and low alloy (HSLA) steel. The HSLA steels, as the API 5L X70, are the most widely used material in the manufacturing of pipelines due its good combination of high mechanical strength, with good toughness, ductility and weldability [12].…”

“…Besides these, the PTA process has as operational benefits the smoothness of the deposition of powder without causing oscillation in the melting pool, absence of spatters, independence between heat input and material deposition rate, besides the coaxiality of the powder injection, allowing a high control of the melting pool and the geometry and finish of the cladding [26,27]. In addition, PTA process can achieve very low dilution, 5% to 10%, if compared with other arc welding process, 20% to 25% [12]. This feature combined with high energetic efficiency of PTA leads to a single-layer thick coatings that exhibit microstructural properties characteristic of a bulk material, independent of the substrate properties, that is, the lower the dilution, the less Inconel 625 is necessary to obtain the same corrosion resistance [28].…”