Steel Sheet And Plated Steel Sheet

Abstract: Provided are: a high-strength steel sheet having high plating properties, LME resistance, and hydrogen embrittlement resistance; and a plated steel sheet. The present invention provides a steel sheet containing 0.05-0.40% of C, 0.2-3.0% of Si, 0.1-5.0% of Mn, and 0.4-1.50% of sol. Al, wherein: the steel sheet has, at a surface layer thereof, an inner oxide layer containing fine granular oxides; the number density of the fine granular oxides in the inner oxide layer is 4.0 particles/µm2 or higher; and the steel sheet includes a surface depleted layer that has an oxide-free steel composition satisfying, in terms of mass%, Si = 0.6% and Al = 0.05%, at a depth of 1/2 the average depth of the inner oxide layer as calculated from a cross-sectional SEM image of the steel sheet. The present invention also provides a plated steel sheet using the aforementioned steel sheet.

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