Effect of filler metal on the microstructure of API ۵L X۶۵ welded steel joints coated with INCOLOY ۸۲۵ superalloy produced by SMAW process

In this study, the effect of filler metal on the microstructure of API ۵L X۶۵ welded steel joints coated with INCOLOY ۸۲۵ superalloy produced by SMAW process was investigated. Welding was performed using filler metals, ENiCrFe-۳, ENiCrMo-۳ in root passes and E۷۰۱۸ in surface passes by SMAW process. FESEM optical and scanning electron microscope equipped with EDS analysis was used to study the microstructure of weld metals and joints. The microstructural results showed that the structure of both Inconel ۶۲۵ and ۱۸۲ filler metals was completely austenitic and solidified with dendritic morphology. Also, the microstructure of weld metal ۷۰۱۸ mainly consists of polygonal ferrites and grain boundaries, among which some Widmann Statten and Acicular ferritesare also observed.

Keywords:

Incoloy ۸۲۵ , Electrode ۷۰۱۸ , Microstructure , SMAWprocess.