| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of a crack at a degreasing time by using an organic binder having the same component as an organic binder of a compound to form a formed body for an core for insert forming to roughly equalizing the thermal expansion coefficients of the formed body and the core. SOLUTION: For example, by kneading about 90 wt.% stainless steel powder having an average particle size of about 10μm and an organic binder contg. about 3 wt.% polystyrene, about 3% acryl, about 3 wt.% wax and about 1 wt.% stearic acid and granulating them to a pellet state, a compound for a forming body is produced. On the other hand, by blending the organic binder having the same component and formulation ratio as that of the compound for the forming body and alumina powder having an average particle size of about 8μm in the same way as they case of the formed body, a compound for a core for insert forming is produced. When the core obtained by this method is inserted into a die and the forming body is injection-molded, degreased and sintered, the degreasing of the core is performed in a short time and a sintered body having good dimension is obtained. |
