Processing of Fe3Al based intermetallic alloys through electroslag remelting

Abstract

A process comprising air induction melting (AIM) and electroslag remelting (ESR) for production of iron aluminides based on Fe3Al is reported. Extensive hydrogen gas porosity is observed in air induction melted electrodes. Electroslag remelting of AIM electrode results in ingots free from gas porosity. Possible mechanisms for elimination of gas porosity during electroslag remelting are discussed. The cast ESR ingots exhibit a marked susceptibility to cracking at high power inputs due to high thermal gradients prevailing in the ingot. This may be attributed to the relatively low thermal conductivity and high coefficient of thermal expansion of Fe3Al. At very low power levels the ESR ingots exhibited poor surface quality. Proper selection of process parameters during electroslag remelting of air induction melted electrodes results in sound ingots free from thermal cracks and exhibiting good surface quality.