Alloy selection for in mould inoculation to control chill width in ductile iron

Abstract

The relative performance of six FeSi based inoculants was tested for of ductile iron chill width control using in the mould inoculation after FeSiCaMgRE treatment. In the prevailing solidification conditions (W3 chill wedge, ASTM A367-85, resin sand mould), Sr–FeSi alloys did not perform well, but had a 15–30% benefit from preconditioning with Al,Zr,Ca–FeSi. Ba,Ca–FeSi alloy had the lowest efficiency, without any benefit from preconditioning. The best inoculant performance is achieved using a complex inoculant chemistry (Ca,RE,S,O–FeSi), while the Ca,Zr–FeSi alloy was the second rated inoculant, with important benefits from preconditioning in both cases. Al,Zr,Ca–FeSi preconditioning of the base iron before Ca–FeSi inoculation showed better performance than an inoculation only treatment using the same active elements (Ca,Zr,Al–FeSi alloy).