Microstructure & mechanical properties of dissimilar material joints between T91 martensitic & S304H austenitic steels using different filler wires

The power generating sector uses combination of both ferritic steels, employed at temperatures below 635 degrees C and stainless steels at steam temperatures above 635 degrees C in a boiler. Considerable savings on cost is made by dissimilar metal welding of the economical steels replacing the expensive high alloy steels. The austenitic steels have the better stability of microstructures at high temperature and creep strength along with good corrosion resistance whereas ferritic steels have good thermal conductivity and mechanical properties. The austenitic steels are expensive as the contents of alloying element is high. Consequently, different steels are chosen from both service and economical point of view in a boiler as per the requirements, satisfying both performance parameters and savings. Until now, many previous studies have focused mainly on the individual properties of austenitic stainless steel (S304H/Super304H/ SA213 S30432) and martensitic steel (T91), however, there is almost no report about T91 and Super304H dissimilar materials joints with Semi-Automatic Gas Tungsten Arc Welding (SGTAW) process using three different filler wire. Therefore, in the present study, the Super304H and T91 was welded together using SGTAW process by using ERNiCrCoMo-1, ER90S-B9 and YT304H filler material. The dissimilar material welding was studied for mechanical properties and microstructure in this paper. (c) 2019 Elsevier Ltd. Selection and Peer-review under responsibility of the scientific committee of the International Mechanical Engineering Congress 2019: Materials Science.