Evaluation of Corrosion Resistance of Weld Metal in x۹۰ API-۵L Micro Alloy Steel Joints with GTAW Process

In this research, the corrosion resistance of weld metal in API-۵L X۹۰ micro-alloy steel joints was investigated. Welding was performed using filler metals ER۱۲۰S-G, ER۱۰۰S-G and ER۹۰S-B۳ by GTAW process. Microstructural studies were performed using light microscope and SEM scanning electron microscope. Microstructural studies showed that the base metal microstructure consists of ferrite and granular bentite. It was found that different weld metals all contain different amounts of accular Ferrite, polygonal ferrites and martensite / austenite (MA) islands. The highest amount of accular Ferrite was observed in ER ۱۲۰ SG welding metal. The results of corrosion test showed that ER۱۲۰SG welding metal and base metal had the lowest flow density and corrosion rate. And the highest corrosion rate was obtained for ER۱۰۰SG welding metal.