Method for making aluminum alloy product

Claim 3

PROVIDING A BODY COMPOSED OF AN ALLOY CONSISTING ESSENTIALLY OF 4.5 TO 8 PERCENT ZN, 1.7 TO 3.25 PERCENT CU, 1.4 TO 2.6 PERCENT MG, THE TOTAL OF ZN + CU + MG BEING FROM 8.75 PERCENT TO 12.25 PERCENT, CU + MG BEING 5.4 PERCENT MAXIMUN M WITH 0.2 CU + MG BEING 2 PERCENT MINIMUM, THE CU/MG RATIO BEING AT LEAST 0.85, AND 0.05 TO 0.25 PERCENT ZR, CHROMIUM NOT TO EXCEED 0.04 PERCENT, THE BALANCE BEING ALUMINUM AND IMPURITIES AND INCIDENTAL ELEMENTS,

Claim 4

PROVIDING A BODY COMPOSED OF AN ALLOY CONSISTING ESSENTIALLY OF 4.5 TO 8 PERCENT ZN, 1.7 TO 3.25 PERCENT CU, 1.4 TO 2.6 PERCENT MG, THE TOTAL OF ZN + CU + MG BEING FROM 8.75 PERCENT TO 12.25 PERCENT, CU + MG BEING 5.4 PERCENT MAXIMUN M WITH 0.2 CU + MG BEING 2 PERCENT MINIMUM, THE CU/MG RATIO BEING AT LEAST 0.85, AND 0.05 TO 0.25 PERCENT ZR, CHROMIUM NOT TO EXCEED 0.04 PERCENT, THE BALANCE BEING ALUMINUM AND IMPURITIES AND INCIDENTAL ELEMENTS,

Claim 5

WORKING SAID BODY TO PRODUCE SAID PRODUCT, 3.SOLUTION HEAT TREATING SAID PRODUCT,

Claim 6

WORKING SAID BODY TO PRODUCE SAID PRODUCT, 3.SOLUTION HEAT TREATING SAID PRODUCT,

Claim 7

working said body to produce said product,

Claim 8

working said body to produce said product,

Claim 9

The method according to claim 1 wherein the said alloy contains 0.05 to 0.2 percent Zr and, additionally, 0.15 to 0.5 percent Mn.

Claim 10

In the method of producing a solution heat treated, quenched and artificially aged aluminum alloy wrought product in an aluminum alloy of the type containing zinc, magnesium and copper as the major alloying additions wherein the alloy is worked to a wrought condition, solution heat treated, quenched and artificially aged, the improvement wherein said alloy is provided as a composition consisting essentially of 4.5 to 8 percent Zn, 1.7 to 3.25 percent Cu, 1.4 to 2.6 percent Mg, the total of Zn + Cu + Mg being from 8.75 percent to 12.25 percent, Cu + Mg being 5.4 percent maximum with 0.2 Cu + Mg being 2 percent minimum, the Cu/Mg ratio being at least 0.85, and 0.05 to 0.25 percent Zr, chromium not to exceed 0.04 percent, the balance being aluminum and impurities and incidental elements, said improvement imparting to the wrought product so produced the abiLity to achieve high resistance to stress corrosion cracking substantially in the condition of maximum strength and low sensitivity in strength to quench rate and good toughness.

Claim 11

In the method of producing a solution heat treated, quenched and artificially aged aluminum alloy wrought product in an aluminum alloy of the type containing zinc, magnesium and copper as the major alloying additions wherein the alloy is worked to a wrought condition, solution heat treated, quenched and artificially aged, the improvement wherein said alloy is provided as a composition consisting essentially of 4.5 to 8 percent Zn, 1.7 to 3.25 percent Cu, 1.4 to 2.6 percent Mg, the total of Zn + Cu + Mg being from 8.75 percent to 12.25 percent, Cu + Mg being 5.4 percent maximum with 0.2 Cu + Mg being 2 percent minimum, the Cu/Mg ratio being at least 0.85, and 0.05 to 0.25 percent Zr, chromium not to exceed 0.04 percent, the balance being aluminum and impurities and incidental elements, said improvement imparting to the wrought product so produced the abiLity to achieve high resistance to stress corrosion cracking substantially in the condition of maximum strength and low sensitivity in strength to quench rate and good toughness.

Claim 12

solution heat treating said product,

Claim 13

solution heat treating said product,

Claim 14

quenching said product,

Claim 15

quenching said product,

Claim 16

QUENCHING SAID PRODUCT,

Claim 17

QUENCHING SAID PRODUCT,

Claim 18

In the method according to claim 3, the further improvement wherein the artificial aging treatment includes exposing said alloy to a temperature of between 300* and 380*F for at least one hour, the minimum time being further determined by the following equation:

Claim 19

In the method according to claim 3 wherein the alloy composition is further controlled such that Fe does not exceed 0.35 percent, Si does not exceed 0.25 percent, V does not exceed 0.02 percent and Ti does not exceed 0.06 percent.

Claim 20

SUBJECTING SUCH PRODUCT TO AN ARTIFICIAL AGING TREATMENT WHICH INCLUDES AN EXPOSURE AT AN ELEVATED METAL TEMPERATURE TO DEVELOP RESISTANCE TO STRESS CORROSION CRACKING.

Claim 21

SUBJECTING SUCH PRODUCT TO AN ARTIFICIAL AGING TREATMENT WHICH INCLUDES AN EXPOSURE AT AN ELEVATED METAL TEMPERATURE TO DEVELOP RESISTANCE TO STRESS CORROSION CRACKING.

Claim 22

subjecting such product to an artificial aging treatment which includes an exposure at an elevated metal temperature to develop resistance to stress corrosion cracking.

Claim 23

subjecting such product to an artificial aging treatment which includes an exposure at an elevated metal temperature to develop resistance to stress corrosion cracking.

Claim 24

In the method according to claim 3 wherein the alloy composition is further controlled such that Zr range from 0.05 to 0.2 percent and Mn is included in amounts of 0.15 to 0.5 percent.

Claim 25

In the method according to claim 3 wherein the alloy composition is controlled such that the ratio Cu/Mg is equal to at least 1.

Claim 26

The method according to claim 1 wherein said artificial aging treatment exposure is at a metal temperature of between 300* and 380*F and for a time of at least one hour the minimum time being further determined by the following equation: