Abstract: A casting mold is disclosed for preventing growth of parasitic grains in the casting of a workpiece from a liquid metal by a single crystal solidification technique. The mold has a mold portion which defines a casting cavity in the shape of the desired workpiece as well as a feeder portion which defines a separate feeder cavity not in communication with the casting cavity. The feeder portion is in heat exchange contact with the mold and is located adjacent to the areas of the workpiece in which a parasitic grain may be nucleated during the controlled solidification. The feeder portion is filled with a thermal mass which emits heat to slow the liquid metal solidification in these zones in order to prevent a growth of the parasitic grain. The thermal mass in the feeder cavity may consist of a liquid metal which undergoes a phase change at the same temperature, or a slightly higher temperature than that of the liquid metal located in the casting cavity from which the workpiece is cast.

Abstract: A heat shield for a casting furnace consists of at least two elements slidably mounted in the furnace. The elements are generally planar in shape and extend between heating and cooling zones to provide the requisite heat insulation characteristics. The heat shield elements are movable in a direction generally parallel to their plane which extends generally perpendicularly to the path of movement of the mold from the heating zone into the cooling zone. Each of the heat shield elements consists of a generally planar, substantially rigid portion slidably mounted in the furnace and a generally planar second portion formed of a flexible refractory material. Distal edges of the second portions may overlap each other and may define an opening, the contour of which closely approximates that of the cross sectional contour of the mold.