Influence of grain refinement on strength and corrosion resistance of 316LN steel welded joint

Abstract

The cost of repairs for corrosion damage can be decreased with corrosion prevention. All industries, including those in the oil and gas sectors, as well as the majority of human endeavors, are impacted by corrosion. Optimal corrosion management techniques may increase efficiency and cut costs when corrosion is taken into account along the entire value chain. The influence of smaller grains on sensitization microstructure, strength, and corrosion of TIG-welded 316LN SS joints was summarized in this investigation. The welded metal structure and electrochemical resistance of 316LN steel after TIG welding and appropriate heat treatment have been summarized by using Electron Back Scatter Diffraction and Tafel plot test methods. This study summarized the understanding of the effect of TIG welding and appropriate annealing on the deformed and welded structure of 316LN steel. The corrosion rate drastically increases after TIG welding (HAZ zone) of forged samples as compared to base metal (un-welded zone) samples. The mechanism behind the reduction of corrosion resistance is the Depletion of the chromium oxide film. From the results findings, the corrosion rate decreased after TIG welding of forged samples. In the corrosion plot, shifting the intensity of the corrosion current to the passive direction indicates the formation of Cr2O3 after the annealing of welded and forged samples. From the EBSD micrographs, it was observed that the appropriate annealing after welding and forging produces fewer pits as compared to the base metal. Results also indicates that both the mechanical characteristics and corrosion resistance deteriorate as a result of sensitization.