| 摘要 |
<p>PURPOSE:To obtain an Al alloy sheet for a negative pressure can for noncarbonated drinks in which the can bottom part deforms preferentially to the can side part at the time when the pressure of the inside of the can turns into negative one by using the sheet material of an Al alloy contg. specified amounts of Mn and Mg or other alloy elements as the material for a DI can. CONSTITUTION:As the material for a DI can for noncarbonated drinks such as fruit juice and coffee, and Al alloy contg., by weight, 0.5 to 1.5% Mn and 0.5 to 2.0% Mg, or furthermore contg. one or >= two kinds among 0.2 to 0.7% Fe, 0.1 to 0.5% Si, 0.05 to 0.5% Cu and 0.1 to 1.0% Zn and the balance Al is used. The cast slab of this Al alloy is subjected to homoge nizing heat treatment at >=550 deg.C and is thereafter subjected to ordinary hot rolling, cold rolling and process annealing into a thin sheet material having 18 to 25kg/mm<2> tensile strength to manufacture a DI can. The strength of side part of the DI can is >=1.2 times that of the can bottom part and at the time the pressure in the can reduces into the negative one of <1kg/cm<2> after the can is filled with coffee or the like at a high temp. and is thereafter cooled, the can bottom part is concaved and deforms inwardly in the ratio of 8 to 15ml preferentially to the can side part and the pressure in the can therefore reduces into positive one and free from the need of using an N2 gas can be obtd.</p> |
