High strength copper alloy and manufacturing method therefor

Abstract

A high strength copper alloy is made of a prescribed material composed of Cu and inevitable impurities as well as titanium (Ti) at 0.1 to 4 weight percent, wherein it is possible to further include at least one of Ag, Ni, Fe, Si, Sn, Mg, Zn, Cr, and P at a prescribed weight percent ranging from 0.01 to 2 in total. In a manufacturing method, the material is subjected to cold rolling, precipitation treatment, and additional cold rolling sequentially, wherein the reduction rate of the additional cold rolling is set to 3% or more, and the total reduction rate of the cold rolling and the additional cold rolling ranges from 15% to 50%, so that a ratio of yield strength versus tensile strength is set to 0.9 or more. In addition, it is possible to perform stress relaxation annealing after the additional cold rolling upon heating of the material for a prescribed time.

What is claimed is:  
     
         1 . A high strength copper alloy composed of Cu and inevitable impurities as well as titanium (Ti) at 0.1 to 4 weight percent, which is produced by subjecting a material to cold rolling, precipitation treatment, and additional cold rolling sequentially, wherein a reduction rate of the additional cold rolling is set to 3% or more, and a total reduction rate of the cold rolling and the additional cold rolling ranges from 15% to 50%, so that a ratio of yield strength versus tensile strength is set to 0.9 or more.  
     
     
         2 . A manufacturing method for a high strength copper alloy, comprising the steps of: 
 performing cold rolling on a copper alloy material composed of Cu and irreversible impurities as well as titanium at 0.4 to 4 weight percent;    performing precipitation treatment on the copper alloy material; and    performing additional cold rolling on the copper alloy material,    wherein reduction rate of the additional cold rolling is set to 3% or more, and total reduction rate of the cold rolling and the additional cold rolling ranges from 15% to 50%.    
     
     
         3 . The manufacturing method of a high strength copper alloy according to  claim 2 , further comprising the step of: 
 performing stress relaxation annealing after the additional cold rolling, wherein the copper alloy material is heated to a temperature ranging from 200° C. to 700° C. for a prescribed time ranging from 0.5 hour to 15 hours.    
     
     
         4 . The manufacturing method for a high strength copper alloy according to  claim 2 , further comprising the step of: 
 performing stress relaxation annealing after the additional cold rolling, wherein the copper alloy material is heated to a temperature ranging from 300° C. to 950° C. for a prescribed time ranging from 10 seconds to 1000 seconds.    
     
     
         5 . The manufacturing method for a high strength copper alloy according to any one of  claims 2  to  4 , wherein the copper alloy material includes at least one of Ag, Ni, Fe, Si, Sn, Mg, Zn, Cr, and P at a weight percent ranging from 0.01 to 2 in total, and wherein Ni at a weight percent ranging from 0.01 to 0.04, and Si at a weight percent ranging from 0.01 to 0.1.  
     
     
         6 . A high strength copper alloy according to  claim 1 , wherein the reduction rate of the additional cold rolling exceeds one third of the reduction rate of the cold rolling.