Abstract: A preheating and melting apparatus for scrap, for preheating and melting the scrap highly efficiently, includes a scrap melting furnace having a top blowing lance and an electric arc heater and a preheater for introducing an exhaust gas generated from the melting furnace and preheating the scrap. The scrap preheater is a shaft furnace and a rotary furnace is disposed at the bottom portion of the shaft furnace to continue the shaft furnace. The scrap discharged from the shaft furnace is transferred into the rotary furnace and it is then charged into the scrap melting furnace.

Abstract: In a plastic-surrounded bearing in which a pulley made of plastic wider than the width of the outer race of the bearing and provided with extended portions on the opposite sides of the outer race is integrally coupled to the outer race of the bearing by insert injection molding, the pulley has gates for pouring plastic therethrough in one end surface thereof, recesses are provided at a plurality of circumferential locations between the inner peripheral edge and the outer peripheral edge of the end surface of the extended portion of the pulley, and the plastic portions lying between the recesses are reinforcing ribs, the thickness of the ribs between the adjacent recesses in at least one end surface is made greater in the circumferential direction away from the gates.