| 摘要 |
PROBLEM TO BE SOLVED: To apply this steel sheet to the one for a high strength extra-thin can by allowing it to contain an insular tinning layer in which the total Sn coating weight is controlled to the value equal to or below a specified one, and the area ratio of the peak of the crest part in insular tin is controlled to the value equal to or above a specified one. SOLUTION: This steel sheet has an insular tinning layer in which the total Sn coating weight is controlled to <=2.8 g/m2, and the area ratio of the peak of the crest part in insular tin expressing the ratio of the area S1 of the peak of the crest part in insular tin to the total area in the case a reflected electron obtd. by scanning the surface of the steel sheet by an electron beam is transformed into a compositional signal, based on the signal, a histogram in which the axis of abscissas denotes the brightness value of the image information, and the axis of ordinates denotes brightness is prepared, the histogram is separated into the peak of the crest part in insular tin, the peak of the bottom part and the peak of the transition part, and the respective areas S1, S2 and S3 are found, is >=15%. Then, the steel sheet is preferably composed of an aging steel sheet having >=30 MPa aging index(AI).
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