To prevent generation of cracks in a formed body by using a composite die comprising a sand die (insulated die) to form a cavity and a die to reinforce the sand die as a die in performing the die-cast forming of cast iron to greatly reduce the thermal load of the die and suppress generation of the cementite structure in the die casting.
A die basically comprises a sand die 2 and a die 3. A cavity 4 is formed inside the sand die 2 to the shape of a formed body, and a runner 6 to be communicated with the cavity 4 is provided in a mating surface of the sand die 2. The outer contour of the sand die 2 is approximately of parallelepiped shape. The die 3 is made of the metal such as steel and copper, the sand die 2 is inserted therein, a recess 7 to reinforce the sand die 2 is provided, and a runner 9 to be communicated with the runner 6 formed in the mating surface 5 of the sand die is provided. A shell mold, ceramics die, etc., can be used in addition to the sand die, and for the practical application, the heat conductivity is preferably ≤10-2cal/cm.sec.deg.
ONOE TOSHIO
MORIMOTO HIROYUKI
TAKAHASHI YOICHI
ANDO YUICHI
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