Method of producing beryllium copper alloy member

A beryllium copper alloy member is provided having both a high electrical conductivity of not less than 70% IACS and a high strength of not less than 70 kgf/mm.sup.2 by an extensively simplified production method which widely decreases the production cost of the alloy member. The method includes, shaping a cast ingot alloy consisting in weight basis of 0.15-0.6% of Be, 0.6-3.0% of Ni, and the test of Cu and unavoidable impurities to a desired shape by working it to destroy the cast organization structure of the alloy, heat annealing the shaped alloy at a condition of 400.degree.-650.degree. C..times.1-100 hrs, and cold working the heat annealed alloy to a final shape by a working rate of at least 80%.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method of producing beryllium copper 
alloy members, such as, electrode members, lead frame members, and the 
like members which are required to have high electrical conductivity and 
high strength. 
2. Related Art Statement 
Heretofore, in order to produce beryllium copper alloy members of this type 
having high electrical conductivity and high strength, a production method 
has been used wherein a cold worked alloy is stabilized and then cold 
worked, or a production method wherein the solubilized alloy is cold 
worked and then further age-hardened. Such prior methods perform 
complicated process steps of heat annealing, cold working, solubilizing, 
cold working, and age-hardening, so that it is different to maintain the 
production cost of the alloy at a low level. 
As to the characteristic properties of the alloys, a prior representative 
42 alloy has a strength of 70 kgf/mm.sup.2 and an electrical conductivity 
of 5% IACS, and another prior representative CCZ (Cr-Cu-Zr series) alloy 
has a strength of 50 kgf/mm.sup.2 and an electrical conductivity of 80% 
IACS. Therefore, a beryllium copper alloy member having an electrical 
conductivity of not less than 70% IACS, while simultaneously having a 
strength of not less than 70 kgf/mm.sup.2, has been eagerly desired. 
SUMMARY OF THE INVENTION 
An object of the present invention is to obviate the problems of the prior 
methods. 
Another object of the present invention is to provide a method of producing 
beryllium copper alloy members having an electrical conductivity of not 
less than 70% IACS and a strength of not less than 70 kgf/mm.sup.2 which 
has such simplified process steps that the production cost of the alloy 
members can be decreased substantially. 
In the first aspect of the present invention, the present invention is a 
method of producing beryllium copper alloy member, wherein a cast ingot of 
a beryllium copper alloy consisting in weight basis of 0.15-0.6% of Be, 
0.6-3.0% of Ni, and the rest of Cu and unavoidable impurities is shaped to 
a desired form by working it to destroy the cast organization structure 
thereof, the shaped alloy is heat annealed at a condition of 
400.degree.-650.degree. C..times.1-100 hr, and the heat annealed alloy is 
further processed to a final shape by a cold working of a working rate of 
not less than 80%. 
In the second aspect of the present invention, the Ni component of 0.6-3.0 
wt % in the first aspect of the present invention is replaced by Co 
component of 0.6-5.0 wt %. Hereinafter, amounts expressed by % are weight 
basis, unless otherwise specified. 
In the third aspect of the present invention, the Ni component of 0.6-3.0% 
in the first aspect is replaced by 0.6-5.0% of Ni+Co (wherein 
Ni.ltoreq.3.0%). 
In this way, the present invention has remarkable features that the 
heretofore effected solubilizing treatment step and age-hardening 
treatment step are dispensed with, and that the heat annealing temperature 
is widely decreased from the conventional temperature of at least 
800.degree. C. to a temperature of 400.degree.-650.degree. C. 
In the present invention, the heat annealing is effected in a hyper 
age-hardening region of a relatively low temperature so as to precipitate 
intermetallic compounds, such as nickel berylite (Ni-Be), etc., and the 
purity of the remaining organization structure of the beryllium copper 
alloy is improved so as to increase the electrical conductivity of the 
alloy up to at least 70% IACS. In addition thereto, a cold working is 
effected at a working rate of at least 80% to obtain a beryllium copper 
alloy member of a strength of at least 70 kgf/mm.sup.2. 
In the first aspect of the present invention, a beryllium copper alloy of a 
composition consisting of 0.15-0.6% of Be, 0.6-3.0% of Ni, and the rest of 
Cu, is used. If Be is less than 0.15% or Ni is less than 0.6%, a 
sufficient amount of nickel berylite is not precipitated, so that the 
purposed strength of the alloy member can not be obtained. While, if Be 
exceeds 0.6% or Ni exceeds 3.0%, the purposed electrical conductivity of 
the alloy member can not be obtained. 
In the second aspect of the present invention, a beryllium copper alloy of 
a composition consisting of 0.15-0.6% of Be, 0.6-5.0% of Co, and the rest 
of Cu, is used. In this case, too, if the amount of Co is below the above 
range, the amount of precipitation of the intermetallic compounds becomes 
insufficient, so that the strength of the alloy member is decreased, and 
if the amount of Co is excessively large, the electrical conductivity of 
the alloy member is decreased. 
In the third aspect of the present invention, a beryllium copper alloy of a 
composition consisting of 0.15-0.6% of Be, 0.6-5.0% of Ni+Co, and the rest 
of Cu, is used. In this case, too, if the amount of Ni+Co is insufficient, 
the strength of the alloy member is decreased, and if the amount of Ni+Co 
is excessively large, the electrical conductivity of the alloy member is 
decreased, similarly as in the other aspects of the present invention. 
In the first through the third aspects of the present invention, a heat 
annealing condition of 400.degree.-650.degree. C..times.1-100 hr is used. 
If the heat annealing temperature is less than 400.degree. C., a 
sufficient amount of the intermetallic compounds is not precipitated, 
while, if the temperature exceeds 650.degree. C., once precipitated 
intermetallic compounds are again solubilized into the organization 
structure of the alloy, so that in either case the purposed high 
electrical conductivity of the alloy member can not be obtained. The heat 
annealing time is varied naturally depending on the heat annealing 
temperature. However, if the heat annealing time is less than 1 hr, an 
insufficient amount of the intermetallic compounds is precipitated, even 
when the heat annealing is effected at 650.degree. C., so that the 
purposed strength and electrical conductivity can not be obtained. While, 
if the heat annealing time exceeds 100 hrs, both the strength and the 
electrical conductivity of the alloy member are decreased, even when the 
heat annealing is effected at 400.degree. C., and the production cost of 
the alloy member is increased, so that the purposed merit in the 
production of the alloy member can not be obtained. 
In the present invention, a cold working of a working rate of at least 80% 
is effected, because if the working rate expressed by an equation of (size 
after working-original size).times.100/original size is less than 80%, the 
purposed strength of the alloy member can not be obtained.