Ferro Silicon Zirconium is the alloy of Iron Silicon and Zirconium produced by direct reduction of zircon sands in electric arc furnaces at high temperature.
This alloy is used as Zirconium additive in steel melt, which reacts with Nitrogen, Oxygen and Sulphur.
Zirconium has been used in steel making additive for over more than forty years. But this alloy (FeSiZr) is still today the lowest cost source of Zr available as steel additive.
Al 1.5% max
Cr 0.5% max
Mn 0.5% max
FeSiZr is used to scavenge impurities (Oxygen, Nitrogen, Sulphur) or modify inclusion through the formation of complex sulphides and oxysulphides. ZrS is significantly more stable than MnS in steel. Therefore, if enough free zirconium is available during the early stages of solidification of a steel ingot, ZrS will form and prevent the formation of MnS.
ZrS is much more refractory than MnS and practically non â deformable during hot rolling while, in aluminum killed steels, MnS produces long flat stringer inclusions in hot rolled plate and strip.
The efficacy of Zirconium additions will therefore be measured not by the amount of residual "acid soluble" metal which remains, but by the extent to which inclusions are beneficially modified. It also raises the yield/tensile ratio and improves weldability through the reduction of under bead cracking and the elimination of porosity. In high alloys steels, Zirconium increases hardness but decreases ductility.