Effects of Si and Al Addition on Welding Structure of Spheroidal Cast Iron and Mild Steel

摘要

In this study, spheroidal graphite cast iron (FCD45O) and mild steel (SS400) were welded by tungsten inert gas (TIG) welding method using cast iron or mild steel welding rods. After welding, microstructure, Vickers hardness and quantitative analysis of welding zone were investigated. The results proved that chill formations in the weld metal decreased easily using hypereutectic cast iron welding rods. Furthermore Ca-Si-Ba inoculant and an aluminum foil were placed in a single V groove of the base metals and they were welded together using hypereutectic cast iron welding rods. In the case where only Ca-Si-Ba inoculant was added, no chill was formed in the weld metal but in the bonded zone of FCD base metal. However, by the addition of 0.6 percent aluminum, no chill was formed and the weld metal formed into a ferritic spheroidal graphite structure. Consequently Vickers hardness in the weld metal and in the bonded zone was 239-355HV and 300HV respectively.