STEEL PLATE

摘要

A steel plate comprises a base metal, scales that correspond to a thickness of 10.0 μm or less from the surface of the base metal, and subscales positioned between the base metal and the scales. In the subscales, the average Cr concentration is 1.50 to 5.00% by mass, and there is at least one area in which the ratio of the Cr concentration in one of adjacent two measurement areas that are located 1 μm apart from each other to the Cr concentration in the other is 0.90 to 1.11 inclusive in a zone having a length of 50 μm as observed in the rolling direction. The ratio of the amount of Ti contained in a carbide or a carbonitride having a particle diameter of 100 nm to 1 μm inclusive to a parameter Tieff that is expressed by the formula "Tieff = [Ti] - 48/14[N]" is 30% or less, wherein [Ti] represents the amount (% by mass) of Ti and [N] represents the amount (% by mass) of N.