PRODUCTION OF UNIDIRECTIONALLY SOLIDIFIED CASTING

PURPOSE:To produce unidirectionally solidified castings of less disturbance in crystal bearings at a high production speed by suppressing the convection in the molten metal in a mold by means of magnetic fields or the like thereby making the crystal growth directions more uniform than heretofore. CONSTITUTION:Molten metal 4 is charged into a mold 3 disposed in a furnace body 2 heated with heating bodies 1, and a chiller 5 in the bottom part is cooled to cool the molten metal, thereby allowing the crystal to grow upward on the chiller 5. On the other hand, the mold is heated from the upper and lateral sides of the mold 3, and therefore the molten metal is allowed to solidify perpendicularly and unidirectionally from below to above. The front surface 7 of the solid phase is located always near the bottom end of a furnace body 2 by lowering the chiller 5 gradually downward with a vertically moving table 6. As a result, the upper part is heated and the lower part is cooled with the surface 7 as a boundary, whereby a large temp. gradient is created and directional solidification is accelerated. The conduction of a conductor, that is, the convection of the molten metal 4 is suppressed by generating static magnetic fields in the inside and outside parts of the body 2 by means of electromagnetic coils 8 with iron cores disposed around the body 1, whereby the intended unidirectionally solidified casting is produced.