| 摘要 |
PURPOSE: A low carbon cold rolled steel plate having a low plastic strain ratio anisotropy coefficient, and a method for manufacturing the same are provided to manufacture a low carbon steel plate having superior processability in the continuous annealing method by increasing a plastic strain ratio of low carbon steel and decreasing a plastic strain ratio anisotropy coefficient thereof. CONSTITUTION: In a low carbon cold rolled steel plate having a plastic strain ratio anisotropy coefficient and superior processability, the cold rolled steel plate consists 0.015 to 0.050 wt.% of C, 0.010 wt.% or less of Mn, 0.002 to 0.030 wt.% of Ti, 0.020 wt.% or less of P, 0.015 wt.% or less of S, 0.015 wt.% or less of Si, 0.04 wt.% or less of Al, 0.004 wt.% or less of N, and a balance of Fe. A method for manufacturing the cold rolled steel plate comprises the steps of reheating the cold rolled steel plate at a temperature of 1050 to 1300 deg.C, hot rolling the reheated steel plate at a finishing temperature of 890 to 950 deg.C and a winding temperature of 660 to 750 deg.C, cold rolling the hot rolled steel plate at a temperature of 65 to 90 deg.C, continuously annealing the cold rolled steel plate at a crack temperature of 840 to 870 deg.C, a jet cooling section cooling rate of 20 to 100 deg.C/sec and an overageing section temperature of 350 to 500 deg.C, and temper milling the continuously annealed steel plate to 0.5 to 2.0.
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