Process for improving the bend formability of copper alloys

• US 5,486,244 A
• Filed: 04/25/1994
• Issued: 01/23/1996
• Est. Priority Date: 11/04/1992
• Status: Expired due to Term

• Current Assignee: GBC Metals LLC
• Original Assignee: OLIN Corporation
• Inventors: Caron, Ronald N., Breedis, John F.
• Primary Examiner(s): Yee, Deborah
• Application Number:
  US08/233,147
• Time in Patent Office: 638 Days
• Field of Search: 148/554, 148/432
• US Class Current: 148/554
• CPC Class Codes: C22C 9/00 Alloys based on copper
• CPC Class Codes: C22F 1/08 of copper or alloys based thereon

Abstract

There are disclosed processing methods to improve the properties of copper base alloys containing chromium and zirconium. One method of processing results in a copper alloy having high strength and high electrical conductivity. A second method of processing results in a copper alloy with even higher strength and a minimal reduction in electrical conductivity. While a third method of processing results in a copper alloy having improved bend formability.

Claims

1. A method for the manufacture of a copper alloy, comprising the steps of:

a) casting a precipitation hardenable copper alloy containing from about 0.001% to about 2.0% by weight chromium and from about 0.001% to about 2.0% by weight zirconium;

b) heating said copper alloy for at least partial homogenization;

c) hot rolling said copper alloy to an area reduction in excess of about 50%;

d) cold rolling said copper alloy to an area reduction in excess of about 25%;

e) recrystallizing said copper alloy for a first time;

f) cold rolling said copper alloy to a cross sectional area reduction of from about 40% to about 90%;

g) recrystallizing said copper alloy for a second time at a temperature effective to produce the desired aging response during precipitation aging;

h) cold rolling said copper alloy to final gauge; and

i) precipitation aging said copper alloy.

2. The method of claim 1 wherein in step g, said copper alloy is recrystallized a second time at a temperature in excess of 925°

C.

3. The method of claim 2 wherein the temperature for recrystallization in step e and in step g is independently between about 500°

C. and the solidus temperature of said copper alloy.

4. The method of claim 3 wherein the temperature for recrystallization in step e and in step g is independently between about 800°

C. and 950°

C.

5. The method of claim 3 wherein the dwell time for recrystallization in step e and step g is independently between about 5 seconds and 16 hours.

6. The method of claim 5 wherein the dwell time for recrystallization in step e and step g is independently between about 30 seconds and 5 minutes.

7. The method of claim 6 wherein the precipitation aging temperature of step i is from about 350°

C. to about 600°

C. and the dwell time is from about 15 minutes to about 16 hours.

8. The method of claim 4 wherein said alloy is selected to consist essentially of 0.4%-1.2% by weight chromium, 0.08%-0.2% zirconium, 0.03%-0.06% magnesium and the balance copper.

9. The method of claim 4 wherein said alloy is selected to consist essentially of from an effective amount to increase strength up to about 1.0% by weight chromium, from about 0.05% to about 0.40% by weight zirconium, from about 0.1 to about 1.0% by weight of "M" where "M" is selected from the group consisting of cobalt, iron, nickel and mixtures thereof with a maximum nickel content of about 0.25% by weight, and from about 0.05% to about 0.7% by weight titanium where the atomic ratio of "M" to titanium, M:

Ti, is from about 1.2;

1 to about 7.0;

1.