Non-magnesium process to produce compacted graphite iron (cgi)

Abstract

The present invention pertains to a non-magnesium process to produce Compacted Graphite Iron (CGI) by placing a treatment alloy into a treatment ladle, and then placing an inoculant over the treatment alloy in the treatment ladle and pouring a molten base metal there over. The treatment alloy comprises iron, silicon and lanthanum, wherein lanthanum is 3-30% by weight of the treatment alloy, silicon is 40-50% by weight of the treatment alloy, and the remaining is Iron. Lanthanum in the treatment alloy makes the graphite precipitate as vermiculite (compacted form) instead of flake or spheroids. With extended process window offered by this new process (0.03-0.1% residual lanthanum in the metal) required to make CGI, this new process removes the stringent process control (0.01-0.02% residual magnesium in the metal) dictated by the magnesium process of making CGI.

We claim: 
     
         13 . A treatment alloy for treating a base metal to produce compacted graphite iron, the treatment alloy comprises iron, silicon and lanthanum, wherein the lanthanum is 3-30% by weight of the treatment alloy, and silicon is 40-50% by weight of the treatment alloy and the rest is Iron. 
     
     
         14 . The treatment alloy according to  claim 13 , wherein said lanthanum is in range of 3-10% by weight of the treatment alloy. 
     
     
         15 . The treatment alloy according to  claim 13 , wherein the treatment alloy further comprises at least one of calcium and aluminum or in combination thereof, wherein calcium and aluminum is in range of 0.5-3% by weight of the treatment alloy.