Investigation of High-Temperature Properties of Austenitic Stainless Steel Weld Metals

Abstract

Many cracks occurred at 308 austenitic stainless welds made by flux cored arc welding(FCAW) process in hot-wall type fluid catalytic cracking(FCC) units operated at a service temperature of more than 640℃ in oil refineries. During investigation the cause of cracking, it was cleared that the high temperature characteristics of these welds such as creep strength at over 640℃ are not fully understood due to little available data. Among many factors that may have caused cracks, a small amount of Bi contained in the weld metals was considered to be the most predominant factor that deteriorated creep ductility and increased reheat cracking susceptibility of the weld metals. This report shows also the results of the effect of welding process and weld metal type on creep rupture properties that contain Bi free and Bi free weld metal.