A Non-Magnesium process to produce Compacted Graphite Iron (CGI)

摘要

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 die 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.