抄録
Usually, risers used for casting are effective only at its center part to supply molten metal to prevent shrinkage cavity formation, because risers solidify from the surface toward the center. So most of the molten metal of the riser is wasted without being supplied into the casting. To realize effective use of risers, we attempted to heat a stick shaped thinner riser by high frequency heating to enable most of the molten metal of the riser to be supplied into the casting. We installed a heat resistance pipe in the mold at the location where the riser is usually located, and then we placed a coil surrounding the pipe, and heated molten metal in the pipe by high frequency heating to prevent solidification. Through many kinds of casting tests, we confirm that heating a riser by high frequency heating is very effective for reducing riser volume sharply. We also built a high frequency riser heating equipment, and proved the effectiveness of the equipment by practical use for ductile cast iron and copper alloy products.
