HIGH CONDUCTIVITY COPPER ALLOYS FOR SEMI-SOLID FORMING AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A copper alloy in which solid-liquid coexistence zone is wide enough to minimize forming difficult according to temperature variation during operation, and electrical conductivity is maintained to 70% IACS or more to manufacture rotor for medium and small sized electric motors in semi-solid forming methods, and a manufacturing method thereof are provided. CONSTITUTION: The method comprises the steps of maintaining Cu-Ca based copper alloy comprising 0.1 to 1.5 wt.% of Ca and a balance of Cu as melt having a temperature of 1,100 to 1,150 deg.C for 1 to 5 minutes; casting the melt into a copper alloy ingot by injecting the melt into a mold preheated to a temperature of 100 to 150 deg.C after the melt maintenance step; and performing heat treatment process in which the copper alloy ingot is heated to the semi-solid section of 910 to 1,085 deg.C, the heated copper alloy ingot is maintained for 5 to 10 minutes, and the resulting copper alloy ingot is cooled so as to remove internal segregation and stress generated during the casting step and spheroidize primary phase produced in dendrite at the same time, thereby manufacturing spherical copper primary phase appropriate for semi-solid forming structure.