Investigations on weld metal chemistry and mechanical behaviour of bimetallic welds using CaO–CaF2–SiO2–Ni based electrode coatings

TLDR: In this paper, an attempt has been made to design and develop an intermediate electrode based on CaO-CaF2-SiO2 ternary phase diagram system and nickel as an additional electrode coating ingred...

Abstract: The bimetallic welds between ferritic low alloy steels and austenitic stainless steels are widely used in the heat piping transport systems of nuclear power plants for connecting the heavy section low alloy steel components with those of high temperature stainless steel pipes. The operating experience of major nuclear power plant components has recently shown that bimetallic joints can jeopardize the plant availability and safety because of increased incidences of failure. In shielded metal arc welding process, the occurrence and severity of weld defects mainly depend upon the type of electrode filler wire and the electrode coating ingredients used. The use of nickel based filler metals is no longer considered as the final solution for unexpected failures of bimetallic welds due to incidences of hot cracking. In the present paper, an attempt has been made to design and develop an intermediate electrode based on CaO–CaF2–SiO2 ternary phase diagram system and nickel as an additional electrode coating ingred...