JPS6453757A - Low pressure casting method for light alloy castings - Google Patents

Abstract

PURPOSE:To promote a directional solidification and to prevent casting defect by using the material having different thermal conductivity respectively on the dies of a cavity and cooling block and constituting so that the thermal conductivity becomes lower toward a sprue from the cavity end part. CONSTITUTION:The die 32 for structure is composed by using the metal member of the different materials so that the thermal conductivity becomes lower in order toward a lower die 34. The metal member is also cooled by varying the cooling conditions on each metal member to solidify the molten metal filled up in a cavity 42. In this case, since an upper die 36 is of the material having the highest thermal conductivity the water cooling action guided to the cooling hole 52a or 52d of a cooling block 54 is effectively transferred to the upper die 36 by the high thermal conductivity of the cooling block 54. And yet the cooling start time is set most quickly, hence the thickness part of the molten metal faced to the upper die 36 and sand core 30a is foremost solidified and the casting defect of a shrinkage cavity, etc., caused by the delay in solidification is avoided.