Integrated quiescent processing of melts
A quiescent melt handling system includes a melting furnace and a holding furnace communicating with the melting furnace for holding a molten metal melt. The holding furnace has a relatively large surface area and a relatively shallow depth, having a width to depth ratio in the range of 4-100 to 1. Also provided is structure in the holding furnace for separating inclusions from the melt in the holding furnace. A mold communicates with the holding furnace. A counter gravity casting system, which might comprise a vacuum assisted casting system, draws the melt into the mold.
1. A quiescent melt handling system comprising:
a melting furnace;
a holding furnace communicating with said melting furnace, said holding furnace containing a molten metal, wherein said holding furnace comprises a relatively large surface area and a relatively shallow depth having a width to depth ratio in the range of 4-100 to 1 such that the dimensions of said holding furnace are selected to retard a convection flow of the molten metal in said holding furnace;
a means for separating inclusions from the melt in said holding furnace;
a mold communicating with said holding furnace;
a means for replenishing a dry atmosphere in said holding furnace, wherein said holding furnace allows hydrogen in the melt to equilibrate with the dry atmosphere being replenished into said holding furnace wherein the means for replenishing comprises a gas inlet located adjacent an outlet of said holding furnace so that a counter current flow of the dry atmosphere takes place; and,
a vacuum assist system for said mold to draw the melt from said holding furnace into said mold.
2. The system of claim 1 further comprising:
a conduit communicating said holding furnace with said mold; and
a heating element disposed adjacent said conduit for transferring heat thereto.
3. The system of claim 1 wherein said melting furnace comprises a dry hearth furnace, including a sloping hearth.
4. The system of claim 3 wherein said holding furnace further comprises a dry heating means.
5. The system of claim 3 wherein said holding furnace has a length in the range of 1 to 200 meters and wherein a length to width ratio is in the range of 1-100 to 1.
6. The system of claim 1 wherein said means for separating inclusions comprises at least one of a filter and a flow obstructing device.
7. A quiescent melt handling system comprising:
a dry hearth melting furnace including a sloping hearth;
a holding furnace communicating with said melting furnace, said holding furnace containing a molten metal, wherein said holding furnace has a length, width and depth with the length being in the range of 1 to 200 meters and wherein a length to width ratio is in the range of 1-100 to 1 such that said holding surface comprises a relatively large surface area, said holding furnace depth being relatively shallow such that said holding furnace has a width to depth ratio in the range of 4-100 to 1 such that the dimensions of said holding furnace retard convection of the molten metal in the holding furnace;
a structure for separating inclusions from the melt in said holding furnace;
a mold communicating with said holding furnace;
a supply system for replenishing a dry atmosphere in said holding furnace, wherein said holding furnace allows hydrogen in the melt to equilibrate with the dry atmosphere being replenished into said holding furnace, wherein the supply system comprises a gas inlet located adjacent an outlet of said holding furnace so that a counter current flow of the dry atmosphere takes place; and,
a counter gravity mold filling device located in a path between said mold and said holding furnace to enable said mold to draw the melt from said holding furnace into said mold.
8. The system of claim 7 further comprising:
a conduit communicating said holding furnace with said mold; and
a heating element disposed adjacent said conduit for transferring heat thereto.
9. The system of claim 7 wherein said holding furnace further comprises a dry heating system.
10. The system of claim 7 wherein said structure for separating inclusions comprises at least one of a filter and a flow obstructing device.
11. A quiescent melt handling system comprising:
a melting furnace;
a holding furnace communicating with said melting furnace, said holding furnace containing a molten metal, wherein said holding furnace comprises a relatively large surface area and a relatively shallow depth having a width to depth ratio in the range of 4-100 to 1;
a structure for separating inclusions from the melt in said holding furnace;
a mold communicating with said holding furnace;
a vacuum assist system connected to said mold to draw the melt from said holding furnace into said mold; and
a gas inlet located adjacent an outlet of said holding furnace and a gas outlet located adjacent an inlet of said holding furnace for replenishing a dry atmosphere in said holding furnace so that a counter current flow of the dry atmosphere takes place, wherein said holding furnace allows hydrogen in the melt to equilibrate with the dry atmosphere being replenished into said holding furnace.