فهرست نشریات علمی دسترسی آزاد ایران

This study explores using CeO2 flux with Ar and Ar+5%N2 shielding gases to enhance the welding process of 2507 super duplex stainless steel through active TIG welding. It discusses their impact on weld geometry, microstructure, pitting corrosion, and passive film in a 3.5% NaCl solution, using scanning electron microscopy, cyclic polarization curves, electrochemical impedance spectroscopy, and Mott-Schottky analysis. The results indicate that the proportion of austenite phase in the microstructure resulting from A-TIG welding with CeO2 flux and Ar gas increased to 49.1%, compared to 42.1% in conventional TIG welding, aligning well with the phase balance in the base metal. The microstructure of A-TIG welding with cerium oxide flux and shielding gas mixture, with increased austenite with quasi-spherical shapes, has created a morphology similar to the base metal. When utilizing CeO2 flux for welding in conjunction with a shielding gas mixture, a significant reduction in grain size occurs, which becomes about four times smaller than the base metal. Moreover, it modifies the shape, size, and distribution of inclusions. This increased corrosion resistance and significantly reduced Icorr and Ipass by approximately 22 times. Additionally, EIS and Mott-Schottky tests indicated decreased point defects in the passive film and a greater propensity to form a dense protective film with higher chemical stability in A-TIG welding, mainly when using a shielding gas mixture. These findings demonstrate the crucial role of cerium in enhancing the welding of super duplex stainless steel, potentially representing a significant breakthrough in the industry.