| 摘要 |
815,889. Making magnesium-alloy foil. DOW CHEMICAL CO. Sept. 5, 1957 [Sept. 28, 1956], No. 28041/57. Classes 83 (2) and 83 (4). Rolling; working at specified temperatures.- A method of producing rolled strain hardenable magnesium base alloy sheet or foil in the recrystallized state comprises rolling a cast ingot at a temperature above its recrystallization temperature so as to reduce its thickness to between 118 to 143 per cent, preferably 125 per cent, of the desired final thickness, rolling the soreduced metal to the desired final thickness while lowering its temperature to below that at which it recrystallizes, and coiling the resulting rolled metal sheet or foil on a mandrel without reheating above its recrystallization temperature, the minimum radius of the coil so produced being not less than 50 times the thickness of the rolled metal sheet or foil. The ingot is subjected to a solution heat treatment by soaking in a furnace at 850 F. for about 10 to 20 hours the ingot being held at 850‹ F. for at least 4 to 6 hours. In the first rolling the number of hot passes varies according to the initial thickness of the ingot and the ultimate thickness desired and if coiling is necessary before the final pass the hot rolled metal is coiled while hot, uncoiled hot, and thereafter further rolled hot. The final cold rolling is carried out at a temperature of about 275‹ F. the hot rolled metal being about 25‹ F. to 200‹ F. above its minimum recrystallization temperature when about to enter the mill. Articles drawn or formed from the coiled metal foil exhibit a smooth surface free from twinning or sporadic grain growth. An initial ingot 12 inches thick, 40 inches wide and 76 inches long rolled according to the invention produced a sheet or foil 0.052 inch in thickness and about 1000 feet in length.
|
