Aluminum base alloy plate

Claim 1

THE METHOD OF PRODUCING IMPROVED ALUMINUM BASE ALLOY PLATE COMPRISING: (1) PROVIDING AN ELONGATED BODY COMPOSED OF AN ALLOY CONSISTING ESSENTIALLY OF ALUMINUM, 3 TO 6% COPPER, 0.8 TO 3% MAGNESIUM AND 0.3 TO 1% MANGANESE, THE MINIMUM MAGNESIUM CONTENT BEING GOVERNED BY THE RELATION: MG MIN.=0.32 CU WHERE MN IS NOT GREATER THAN 0.5%, MG MIN.=0.2+0.32 CU-0.4 MN WHERE MN IS GREATER THAN 0.5%, THE BODY HAVING A LENGTH TO BASE RATIO OF AT LEAST 2 TO 1. (2) HEATING SAID BODY TO A TEMPERATURE OF AT LEAST 800*F. FOR A PERIOD OF TIME SUFFICIENT TO HOMOGENIZE THE INTERNAL STRUCTURE OF SAID BODY, (3) INITIALLY UPSETTING BY FORGING, AT A TEMPERATURE OF ABOUT 600* TO 900*F., SAID BODY IN AN AXIAL DIRECTION TO EFFECT AN "A" REDUCTION TO FORM A BISCUIT HAVING A HEIGHT OF NOT MORE THAN 400*F., OF THE ORIGINAL BODY LENGTH, (4) FURTHER REDUCING THE BISCUIT AT A TEMPERATURE OF ABOUT 600* TO 900*F. IN THE "A" DIRECTION TO FORM AN ELONGATED SLAB HAVING A THICKNESS OF NOT MORE THAN 3/4 OF THE BISCUIT HEIGHT, (5) HOT ROLLING AT A TEMPERATURE OF ABOUT 600* TO 900* F. SAID ELONGATED SLAB TO A FINAL PLATE THICKNESS OF FROM 1 TO 8 INCHES, (6) SOLUTION HEAT TREATING THE PLATE AT A TEMPERATURE OF ABOUT 800* TO 950*F. FOR A PERIOD OF TIME SUFFICIENT TO EFFECT SUBSTANTIAL SOLUTION OF THE SOLUBLE ALLOY CONSTITUENTS AND QUENCHING THE PLATE, AND (7) ARTIFICIALLY AGING THE PLATE AT A TEMPERATURE OF ABOUT 300* TO 400*F. FOR ABOUT SIX TO TWENTY-FOUR HOURS, THE RESULTING PLATE EXHIBITING IMPROVED SHORT TRANSVERSE ELONGATION, RANGING FROM 3% TO 6%, IMPROVED SHORT TRANSVERSE TEAR RESISTANCE CHARACTERIZED BY A UNIT PROPAGATION ENERGY OF AT LEAST 100, AND SUBSTANTIAL IMMUNITY TO STRESS CORROSION IN THE SHORT TRANSVERSE DIRECTION AT A STRESS OF 50% OF THE YIELD STRENGTH IN THE SHORT TRANSVERSE DIRECTION.

Claim 2

THE METHOD OF PRODUCING IMPROVED ALUMINUM BASE ALLOY PLATE COMPRISING: (1) PROVIDING AN ELONGATED BODY COMPOSED OF AN ALLOY CONSISTING ESSENTIALLY OF ALUMINUM, 3 TO 6% COPPER, 0.8 TO 3% MAGNESIUM AND 0.3 TO 1% MANGANESE, THE MINIMUM MAGNESIUM CONTENT BEING GOVERNED BY THE RELATION: MG MIN.=0.32 CU WHERE MN IS NOT GREATER THAN 0.5%, MG MIN.=0.2+0.32 CU-0.4 MN WHERE MN IS GREATER THAN 0.5%, THE BODY HAVING A LENGTH TO BASE RATIO OF AT LEAST 2 TO 1. (2) HEATING SAID BODY TO A TEMPERATURE OF AT LEAST 800*F. FOR A PERIOD OF TIME SUFFICIENT TO HOMOGENIZE THE INTERNAL STRUCTURE OF SAID BODY, (3) INITIALLY UPSETTING BY FORGING, AT A TEMPERATURE OF ABOUT 600* TO 900*F., SAID BODY IN AN AXIAL DIRECTION TO EFFECT AN "A" REDUCTION TO FORM A BISCUIT HAVING A HEIGHT OF NOT MORE THAN 400*F., OF THE ORIGINAL BODY LENGTH, (4) FURTHER REDUCING THE BISCUIT AT A TEMPERATURE OF ABOUT 600* TO 900*F. IN THE "A" DIRECTION TO FORM AN ELONGATED SLAB HAVING A THICKNESS OF NOT MORE THAN 3/4 OF THE BISCUIT HEIGHT, (5) HOT ROLLING AT A TEMPERATURE OF ABOUT 600* TO 900* F. SAID ELONGATED SLAB TO A FINAL PLATE THICKNESS OF FROM 1 TO 8 INCHES, (6) SOLUTION HEAT TREATING THE PLATE AT A TEMPERATURE OF ABOUT 800* TO 950*F. FOR A PERIOD OF TIME SUFFICIENT TO EFFECT SUBSTANTIAL SOLUTION OF THE SOLUBLE ALLOY CONSTITUENTS AND QUENCHING THE PLATE, AND (7) ARTIFICIALLY AGING THE PLATE AT A TEMPERATURE OF ABOUT 300* TO 400*F. FOR ABOUT SIX TO TWENTY-FOUR HOURS, THE RESULTING PLATE EXHIBITING IMPROVED SHORT TRANSVERSE ELONGATION, RANGING FROM 3% TO 6%, IMPROVED SHORT TRANSVERSE TEAR RESISTANCE CHARACTERIZED BY A UNIT PROPAGATION ENERGY OF AT LEAST 100, AND SUBSTANTIAL IMMUNITY TO STRESS CORROSION IN THE SHORT TRANSVERSE DIRECTION AT A STRESS OF 50% OF THE YIELD STRENGTH IN THE SHORT TRANSVERSE DIRECTION.