Inoculant enhancer to increase the potency of Ca-FeSi alloy in ductile iron produced from the low rare earth containing master alloy

Abstract

The world rare earth elements [REE] crisis will continue at least in the short and medium term. With less REE available, their future use in foundry alloys should be carefully thought out and other inoculation methods need to be investigated. The use of an inoculant enhancer [OS-IE] led to a substantial increase in the potency of a 75% Ca-bearing FeSi alloy in low REE produced ductile irons, as this [Ca-FeSi + OS-IE] inoculation variant led to the lowest chill tendency, the highest nodule count and graphite nodularity. This combination of inoculant was more effective than an equivalent addition of 1) a REE-bearing, Ca-FeSi alloy, or 2.) a Ca,Ba-FeSi alloy, or 3.) the standard Ca-FeSi alloy variant, but with 60% or 77% lower alloy consumption, respectively. The enhancement of the 75% Ca-bearing FeSi alloy by the contribution of an addition of sulphur, oxygen and oxide-forming elements, appears to be a better and more effective inoculation solution compared to using more expensive inoculating elements, such as the REE or Ba containing alloys.