Aluminum alloy sheet for can lids

Abstract

Provided is an aluminum alloy sheet for a can lid, the sheet achieving both high strength and high toughness while blending scrap materials derived from can materials. In one aspect of the present disclosure, the sheet comprises: a Si content of 0.10 mass % or more and 0.60 mass % or less; a Fe content of 0.20 mass % or more and 0.70 mass % or less; a Cu content of 0.10 mass % or more and 0.40 mass % or less; a Mn content of 0.5 mass % or more and 1.2 mass % or less, and a Mg content of 1.1 mass % or more and 4.0 mass % or less, wherein a 0.2% yield strength σ0.2, a tensile strength OB and an average value σfm of the 0.2% yield strength and the tensile strength satisfy a following formula (1):σfm/(σ0.2/σB)≥350 MPa  (1)

1 . A paint-baked aluminum alloy sheet for a can lid, the sheet comprising:
 a silicon (Si) content of 0.20 mass % or more and 0.40 mass % or less;   an iron (Fe) content of 0.29 mass % or more and 0.70 mass % or less;   a copper (Cu) content of 0.11 mass % or more and 0.40 mass % or less;   a manganese (Mn) content of 0.7 mass % or more and 1.2 mass % or less;   a magnesium (Mg) content of 1.1 mass % or more and 4.0 mass % or less; and   a balance consisting of or including aluminum and inevitable impurities,   wherein a 0.2% yield strength σ 0.2 , a tensile strength σ B  and an average value σ fm  of the 0.2% yield strength and the tensile strength satisfy a following formula (1), and   wherein in a cross section parallel to a sheet surface in a surface layer, a ratio of a total area of Mg 2 Si particles each having an area of 0.3 μm 2  or more is 1.0% or less.
   σ fm /(σ 0.2 /σ B )≥350 MPa  (1)
 
   
     
     
         2 . (canceled) 
     
     
         3 . The paint-baked aluminum alloy sheet for a can lid according to  claim 1 ,
 wherein in a circumferential direction of an Erichsen cup formed according to an Erichsen test,   an average value “h 0p ” obtained from a maximum side wall height in each of a region at approximately 0° and a region at approximately 180° with respect to a rolling direction,   an average value “h 45p ” obtained from a maximum side wall height in each of a region at approximately 45°, a region at approximately 135°, a region at approximately 225°, and a region at approximately 315° with respect to the rolling direction and   an average value “h v ” obtained from a minimum side wall height in each of a region at 0° to 45°, a region at 45° to 135°, a region at 135° to 180°, a region at 180° to 225°, a region at 225° to 315°, and a region at 315° to 360° with respect to the rolling direction   satisfy a following formula (2).
   ( h   0p   −h   45p )/ h   v ×100≥−7.0  (2)
 
   
     
     
         4 . The paint-baked aluminum alloy sheet for a can lid according to  claim 1 ,
 wherein the sheet comprises   the Si content of 0.20 mass % or more and 0.40 mass % or less,   the Fe content of 0.30 mass % or more and 0.70 mass % or less,   the Cu content of 0.11 mass % or more and 0.40 mass % or less,   the Mn content of 0.7 mass % or more and 1.2 mass % or less, and   the Mg content of 1.1 mass % or more and 3.0 mass % or less.