-- Cu-Zn-Ce La Nd Pr alloys for EDMEnergy Discharge Machine wire and its manufacturing method

摘要

PURPOSE: To obtain an alloy for EDM(Energy Discharge Machine) wire that has improved cutability with no discolor on cutting surface when compared with conventional 65Cu-35Zn alloy for EDM, trace amounts of Ce, La, Nd and Pr is diffused in a brass alloy incorporating Zn 35-45%. Trace rare earth metals abovementioned improve hot/cold workability because these metals inoculated as nucleus in solidification accelerate the growth of uniformly fine dendrite structure. CONSTITUTION: Cu-Zn-Ce, La, Nd, Pr alloys for EDM(Energy Discharge Machine) wire is produced by (i) preparation and weighing of raw materials where each weight percent of raw materials is as follow: Zn 35-45%, 0.05-2.0% of at least two elements selected from Ce, La, Nd and Pr, the balance Cu; (ii) after melting Cu completely, Zn ingots are deeply pushed into molten metal with a plunger to prevent Zn-oxidation, and then rare earth metals selected from Ce, La, Nd and Pr are poured into the molten metal in such a manner that Cu is pushed into molten metal; (iii) raising the temperature of the molten metal up to 1050-1200deg.C followed by casting into a mould to prepare alloy slab; (iv) performing annealing and cold drawing operations repeatedly to prepare wire after hot extrusion of the alloy slab; (v) annealing the wire in low temperature range of 180 to 200deg.C to give elasticity and straightness to the wire while removing residual stress in the wire.