Methods of producing steel plate, hot-dip steel plate and alloyed hot-dip steel plate

A method of producing a cold rolled steel sheet having an excellent workability, wherein a steel comprising C:

• 0.0005-0.005 mass %, Si:
• not more than 1.5 mass %, Mn:
• not more than 2.5 mass %, Al:
• not more than 0.1 mass %, P:
• not more than 0.10 mass %, Si:
• not more than 0.02 mass %, N:
• not more than 0.005 mass % and one or more of Ti:
• 0.010-0.100 mass % and the remainder being Fe and inevitable impurities is subjected to a rough hot rolling under a condition of finish rolling temperature:
• not lower than Ar3 transformation point but not higher than 950° C. and to a hot finish rolling through lubrication rolling under conditions of finish rolling temperature:
• not lower than 500° C. but not higher than Ar3 transformation point and rolling reduction:
• not less than 80%, and then a steel sheet after the hot finish rolling is subjected to a heat treatment at a temperature range of 650-950° C. in substantially non-reducing atmosphere while being adhered with a black skin scale to form an internal oxide layer in a surface layer portion of an iron matrix of the steel sheet, pickled to remove the black skin scale, and subjected to a cold rolling at a rolling reduction:
• 50-90% and further to a recrystallization annealing at a temperature of not lower than a recrystallization temperature but not higher than 950° C.