| 摘要 |
A cooled mold assembly for the continuous, high-speed casting of metallic strands, especially upcasting strands of copper alloys such as brass, has a hollow die in fluid communication with a melt typically held in a casting furnace. A coolerbody surrounds the die in a tight-fitting relationship to form a solidification front in the melt as it advances through the casting zone of the die. The die is preferably slip fit in the coolerbody. A shoulder on the die engages a lower face of the coolerbody and together with a small irregularity on the upper coolerbody wall prevents an axial movement of the die before it thermally expands against the coolerbody. An insulating member located between the die and the coolerbody and below the solidification front fixes the location of that front within a dimensionally uniform area of the die. The insulating member is preferably a ring of a material such as cast silica that has a low coefficient of thermal expansion, a low porosity, and is highly resistant to thermal shock. The insulating member also preferably creates a steep longitudinal temperature gradient at its upper end to promote a high cooling rate over a relatively short casting zone. An insulating hat substantially encloses the coolerbody allowing it to be immersed in the melt and preferably deeply immersed to a level above the casting zone. This mold assembly is preferably used in conjuction with apparatus for drawing the casting through the die in a cycled pattern of forward and reverse strokes characterized by a low frequency, long forward strokes, a high forward velocity and high forward and reverse accelerations. |
