METHOD FOR CONTROLLING DIRECTIONAL SOLIDIFICATION BY EXOTHERMIC CORE

摘要

PURPOSE:To control efficiently directional solidification and to obtain a defectless casting by holding an exothermic core having a projecting part in the lower part in the riser part of a casting mold prior to casting. CONSTITUTION:The exothermic core 3 is formed by solidifying a powdery exothermic agent and the shape thereof is provided with a projecting part 4 in a circular conical shape into the lower part of the core body. The core is made into the shape having at least the projecting part 4 extending downward. Such core 3 is held in the riser part 1 of the casting mold by a holding body 5. Then the exothermic effect is generated from the point of the time when the riser surface arrives at the projecting part 4 of the core 3 in casting. The exothermic effect is kept generated continuously according to the shape of the core 3 as the riser surface rises and therefore the replenishing effect of the riser is continuously maintained and the directional solidification is attained. Shrinkage 6 is generated in the lower part of the core 3 and the generation of a defect such as secondary shrinkage in a casting 2 is obviated.