Reduced aging time of 7xxx series alloy

Patent metadata

Field	Value
Publication number	US-2016160332-A1
Application number	US-201514963318-A
Country	US
Kind code	A1
Filing date	Dec 9, 2015
Priority date	Dec 9, 2014
Publication date	Jun 9, 2016
Grant date	—

Abstract

The present invention relates to the reduction of artificial aging time of 7xxx series alloys. Currently, the artificial aging times for typical 7xxx series alloy can be as long as 24 hrs. The current invention allows for a significant reduction of aging times, thereby saving time, energy, money and storage space hence increasing the productivity.

First claim

1 . A method for achieving desired yield strength and elongation in an 7xxx aluminum alloy sheet comprising:
a) rapidly heating the sheet to a temperature of 450° C. to 510° C.; b) maintaining the sheet at the temperature of 450° C. to 510° C. for up to 20 minutes; c) rapidly cooling the sheet to room temperature at more than 50° C. per second; d) heating the sheet to a temperature between about 50° C. and 150° C.; e) maintaining the sheet at the temperature between about 50° C. and 150° C. for a duration of about 0.5 hrs to 6 hrs.

2 . The method of claim 1 , further comprising
f) heating the sheet at a temperature between about 150° C. and 200° C.; and, g) maintaining the sheet at the temperature between about 150° C. and 200° C. for a duration of about 0.5 to 6 hrs.

3 . The method of claim 2 , further comprising cooling the sheet to room temperature after step g.

4 . The method of claim 3 , further comprising measuring the yield strength and elongation of the sheet to determine if the sheet attains the desired yield strength and elongation.

5 . The method of claim 4 , wherein the yield strength is at least 400 MPa.

6 . The method of claim 4 , wherein the elongation is at least 5%.

7 . The method of claim 1 , wherein the 7xxx alloy is 7075, 7010, 7040, 7050, 7055, 7150, 7085, 7016, 7020, 7021, 7022, 7029, or 7039.

8 . The method of claim 2 , wherein heating the sheet to a temperature between about 50° C. and 150° C. comprises heating the sheet to a temperature between about 70° C. and about 120° C., and wherein maintaining the sheet at the temperature between about 50° C. and 150° C. for a duration of about 0.5 hrs to 6 hrs comprises maintaining the sheet at the temperature between about 70° C. and about 120° C. for about 1 to 6 hrs.

9 . The method of claim 8 , wherein heating the sheet at a temperature between about 150° C. and 200° C. comprises heating the sheet to a temperature between about 150° C. and 175° C., and wherein maintaining the sheet at the temperature between about 150° C. and 200° C. for a duration of about 0.5 to 6 hrs comprises maintaining the sheet at the temperature between about 150° C. and 175° C. for a duration of 1 to 6 hours.

10 . The method of claim 8 , wherein heating the sheet at a temperature between about 150° C. and 200° C. comprises heating the sheet to a temperature of about 180° C., and wherein maintaining the sheet at the temperature between about 150° C. and 200° C. for a duration of about 0.5 to 6 hrs comprises maintaining the sheet at the temperature of about 180° C. for a duration of about 0.5 hrs.

11 . The method of claim 2 , wherein heating the sheet to a temperature between about 50° C. and 150° C. comprises heating the sheet to a temperature between about 100° C. and 120° C., and wherein maintaining the sheet at a temperature between about 50° C. and 150° C. comprises maintaining the sheet at the temperature between about 100° C. and 120° C. for a duration of about 1 hour.

12 . The method of claim 11 , wherein heating the sheet at a temperature between about 150° C. and 200° C. comprises heating the sheet to a temperature of about 150° C., and wherein maintaining the sheet at the temperature between about 150° C. and 200° C. for a duration of about 0.5 to 6 hrs comprises maintaining the sheet at a temperature of about 150° C. for a duration of about 1 hour.

13 . The method of claim 12 , further comprising heating the sheet to a temperature of about 180° C. and maintaining the sheet at the temperature of about 180° C. for a duration of about 0.5 hr.

14 . A method for achieving desired yield strength and elongation in an 7xxx aluminum alloy sheet comprising:
a) rapidly heating the sheet to a temperature of 450° C. to 510° C.; b) maintaining the sheet at the temperature of 450° C. to 510° C. for up to 20 minutes; c) rapidly cooling the sheet to room temperature at more than 50° C. per second; d) heating the sheet to a temperature of from about 130° C. to about 150° C.; e) maintaining the sheet at the temperature of from about 130° C. to about 150° C. for a duration of about 1 to 5 hrs.

15 . The method of claim 14 , further comprising measuring the yield strength and elongation of the sheet to determine if the sheet attains the desired yield strength and elongation.

16 . The method of claim 15 , wherein the yield strength is at least 400 MPa.

17 . The method of claim 15 , wherein the elongation is at least 5%.

18 . The method of claim 14 , wherein the 7xxx alloy is 7075, 7010, 7040, 7050, 7055, 7150, 7085, 7016, 7020, 7021, 7022, 7029, or 7039.

19 . An aluminum alloy sheet produced by the method of claim 1 , wherein the sheet is in the T6 or T7 temper.

20 . The method of claim 1 , further comprising forming the alloy into a finished product, semi-finished products, formed part, plate or sheet.

Assignees

• Novelis Inc

Inventors

• Kamat Rajeev G
• Mousavi-Anijdan Hashem
• Kulkarni Rahul
• Salgado-Ordorica Mario A

Classifications

• C21D9/46

  for sheet metals · CPC title

• C21D9/0068

  for particular articles not mentioned below · CPC title

• C22F1/053 Primary

  of alloys with zinc as the next major constituent · CPC title

• C22F1/04 Primary

  of aluminium or alloys based thereon · CPC title

• C22F1/002

  by rapid cooling or quenching; cooling agents used therefor · CPC title