Effect of two kinds of refiners on the solidification structure and property of invar alloy

Abstract

The solidification structure of two 500 g cylindrical ingots of Fe-36Ni invar alloy, which were melted in a carbon tube furnace and cast adding Ce and Zr-Ti refiners respectively, were investigated. The results showed that the grain size became smaller. With the increase of refiner content, the ratio of equiaxed grains of ingot increased and the equiaxed grain size decreased. As for the 100 kg flat ingot, which was melted in a vacuum induction furnace and cast with Ce and Zr-Ti refiners respectively, the situation was different slightly. When adding Ce the dendritic grain diameter of the flat ingot became finer and the equiaxed grain ratio remained low; however, the mechanical property deteriorated. While adding Zr-Ti complex refiners, the solidification structure of the alloy was improved dramatically. Therefore, the mechanical properties at room temperature of as-cast flat ingots were improved. Furthermore, its high temperature ductility range expanded and the expansion coefficient of its hot-rolling plate remained almost the same.