Investigation of fracture toughness of weld metal in X۹۰ API-۵L micro alloy steel joints produced by GTAW process

In this study, the fracture toughness of weld metal in API-۵L X۹۰ micro-alloy steel joints was investigated. Welding was performed using filler metals ER۱۲۰ S-G, ER۱۰۰ S-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 includes ferrite and granular bentite. While different welding metals all contain different amounts of needle, polygonal ferrites and islets of martensite / austenite (MA). The highest amount of needle ferrite was observed in ER۱۲۰ S-G welding metal. The toughness of base metal and weld metals was determined by Sharpe impact test. The test results showed that the weld metal ER۱۲۰ S-G at ambient temperature and -۲۰ ° C, has the highest fracture toughness compared to other weld metals.Keywords:Component

کلیدواژه ها:

Component ، API-۵L X۹۰ ، GTAW ، weld metal ، heat input ، microstructure ، fracture toughness.