Patent ID: 7871478
Filing Date: 2011-01-18
Classification: B22D,C22F,Y10T

Abstract:
1. A method of heating a cast metal ingot made of an aluminum alloy selected from the group consisting of AA3003 and AA3104 to prepare said ingot for hot-working at a predetermined temperature, which method comprises: (a) pre-heating said ingot to a nucleating temperature, at which precipitate nucleation occurs in the metal to cause nucleation to take place, within a range of 380-450° C. and below said predetermined hot-working temperature; (b) holding said ingot at said nucleating temperature, or gradually raising the temperature of said ingot from said nucleating temperature at a rate of 25° C./hr or less to a higher temperature within said range of 380-450° C., for a period of 2 to 4 hours; (c) heating said ingot further to a precipitate growth temperature at which precipitate growth occurs to cause precipitate growth in the metal; and (d) if said ingot is not already at said predetermined hot-working temperature after step (c), heating said ingot further to said predetermined hot-working temperature ready for hot-working.