Controlled fluid flow mold and molten metal casting method for improved surface

A mold for casting of molten metal alloys comprising:

• a cooled tubular body having a top surface having an orifice, a bottom surface having an orifice, and a cooled inner wall, defining a central cavity;
• an annular ring attached to said top surface of said cooled tubular body, said annular ring having a lip adjacent to said cooled inner wall of said cooled tubular body;
• a sealing means located between said annular ring and said top surface of said cooled tubular body;
• a cooling means comprising liquid inlet channels, liquid reservoirs, and liquid outlet channels, said liquid inlet channels connected to the sides of said cooled tubular body, said liquid reservoirs and outlet channels within said cooled tubular body;
• a lubricant means comprising lubricant feed lines, lubricant reservoirs, and lubricant channels, said lubricant feed lines and reservoirs located within said cooled tubular body, said lubricant channels located on said top surface of said cooled tubular body;
• a thermally insulated insert having a top portion and a bottom portion, said top portion being wider than said bottom portion, said bottom portion having a beveled sidewall overlapping said lip of said annular ring and said cooled inner wall of said cooled tubular body, said beveled sidewall of said bottom portion angled inwardly toward the center of the mold cavity of said mold, said bottom portion attached to said annular ring and said top surface of said cooled tubular body.

A method of casting molten metal alloys with improved surface quality, comprising:

• providing a direct chill casting mold having a thermally insulated insert and an annular ring over a cooled tubular body, said cooled tubular body having a top surface having an orifice, a bottom surface having an orifice, and a cooled inner wall, said cooled tubular body having a sealing means between said top surface of said cooled tubular body and said annular ring, said cooled tubular body containing a lubrication means comprising lubricant feed lines, lubricant reservoirs, lubricant channels, and a lubricant contained therein, said lubricant feed lines and reservoirs located within said cooled tubular body, said lubricant channels located on said top surface of said cooled tubular body, said thermally insulated insert having a top portion and a bottom portion whereby said bottom portion includes a beveled sidewall of said bottom portion angled toward the center of the mold cavity of said mold;
• cooling said cooled inner wall surface of said cooled tubular body;
• directing said lubricant to flow to said lubricant channels, across said top surface of said cooled tubular body, between said cooled inner wall and a lip of said annular ring and thereafter through a gap between said cooled inner wall and said molten metal to be cast, said annular ring and said sealing means providing continuous lubrication from said lubricant channels to said gap;
• introducing said molten metal to be cast adjacent to said bottom sidewall portion of said thermally insulated insert;
• continuing to pass said molten metal through said mold until said molten metal reaches said beveled sidewall of said bottom portion of said thermally insulated insert where said molten metal forms a horizontal melt surface layer, said beveled sidewall of said bottom portion forming an angle with said horizontal melt surface layer of said molten metal, said angle being below said horizontal melt surface layer and producing an eddy near said beveled sidewall during casting, said eddy creating a (1) recirculation zone that causes direction of the casting flow to be opposite the main casting flow on said horizontal melt surface thereby causing oxides formed during the casting process to remain in the beveled sidewall portion of said thermally insulated insert and (2) a break-up of said oxides into smaller pieces as said oxides flow toward said cooled tubular body thereby having limited surface area for nucleation and growth of oxide folds;
• solidification of said molten metal as said molten metal comes into contact with said cooled inner wall of said cooled tubular body;
• lowering of the starting block and removal of the solidified metal.