Patent ID: 6264717
Filing Date: 2001-07-24
Classification: B22D,B22F,C22B

Abstract:
An article comprising a fine-grain, homogeneous microstructure that is essentially oxide- and sulfide-free and segregation defect free, the article produced by a process that comprises:forming a source of clean refined metal that has oxides and sulfides refined out by electroslag refining; andforming the article by nucleated casting, wherein the step of forming the article comprises:disrupting a stream of clean metal from the source of clean metal to form molten metal droplets;partially solidifying the molten metal droplets such that, on average, from about 5% to about 40% by volume of each droplet is solid and the remainder of each droplet is molten; andcollecting and solidifying the partially solidified droplets in a mold that forms the article, wherein a turbulent zone is generated by the droplets at an upper surface and wherein the step of collecting and solidifying the partially solidified droplets comprises collecting the droplets in the turbulent zone, and solidifying on average less than about 50% by volume of the droplet.