JPS6157881B

PURPOSE:To reduce members having plural-layered structure in a diametral direction through composite powder molding with good production efficiency by premolding a part of plural kinds of powder materials, installing the same in dies, supplying the remaining powder materials and compacting these. CONSTITUTION:A binder is mixed with inexpensive powder of Fe-C systems and is packed in preheated sectional dies 11, whereby it is lightly compressed and a premolding 13 provided with four recesses, etc., is obtained. This premolding 13 is inserted into a die 15 in such a way as to be fitted to a core 14, and high- grade powder 18 of Fe-C-Ni-Cu type or the like is supplied into the space enclosed by the inside circumferential surface of the die 15, the outside circumferential surface of the premolding 13 and the inside surface of a lower punch 16. Thence, an upper punch 19 is lowered to compress the premolding 13 and the supplied powder 18 simultaneously. According to this method, the need for partition cylinders is eliminated, set-up of tooling is simplified, and the joint strength between dissimilar metallic materials is improved. This molding method is adapted to production of gears, etc., of plural-layered structure.