| 摘要 |
A steel plate having a plated layer on the upper and lower surfaces thereof to be processed into a battery can which is cylindrical and open in one end thereof by drawing and ironing processing. The plated steel plate has more than 1.2 as a Lankford value (r) which is a width deformation degree in a lengthwise direction thereof/a thickness deformation degree in the lengthwise direction thereof, a width deformation degree in a widthwise direction thereof/a thickness deformation degree in the widthwise direction thereof, a width deformation degree in an oblique direction thereof/a thickness deformation degree in the oblique direction thereof. In-plane anisotropy DELTA r which is the difference among the Lankford values (r) is set to be less than +/-0.15 so that the elongation coefficient of the plated steel plate in lengthwise, widthwise, and oblique directions is almost constant, i.e., so that the generation of earring can be prevented in drawing and ironing a sheet comprising the steel plate into the battery can. In order to make the elongation coefficient of the plated steel plate constant in the three directions, a very low carbon steel plate is used. The steel plate is cold-rolled at 80-90 %. The plated layer is allowed to have a granular structure by annealing it after it is plated.
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