| 摘要 |
PROBLEM TO BE SOLVED: To provide a cold rolled steel sheet superior in a stamping property, by controlling a micro structure so as to improve the stamping property of a Ti-IF steel (Interstitial Free Steel), and by defining a manufacturing condition for obtaining the structure. SOLUTION: The objective cold rolled steel sheet superior in the stamping property includes, by mass%, 0.003% or less C, 0.3% or less Si, 0.05-0.5% Mn, 0.03% or less P, 0.003-0.015% S, 0.03-0.06% sol.A1, 0.02-0.08% Ti, and 0.003% or less N, and has such average ferrite particle diameters ds and db that ds/db is 0.95 or less, where ds and db are the diameters respectively in the surface layer part within sheet thickness of 15% or less from the surface of the steel sheet, and in the central part of the sheet thickness except the sheet thickness of 15% or less from the surface of the steel sheet (hereafter, referred to as the sheet thickness central part).
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