| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a cold rolled steel plate, which can extremely reduce a variation of tensile strength and is advantageous to a 440 MPa-class cold rolled steel plate. <P>SOLUTION: In the method for manufacturing the cold rolled steel plate by hot-rolling, cold-rolling and continuously annealing a steel raw material which preferably contains 0.08 to 0.20 mass% of C and 0.65 to 1.50 mass% of Mn, the method of manufacturing the cold rolled steel plate is characterized in that: a relational expression among contents of C and Mn of the steel raw material, a winding temperature after hot rolling and a soaking temperature and a soaking time at continuous annealing, and the tensile strength of the steel plate after the continuous annealing is obtained in advance; the contents of C and Mn of the steel raw material, an actual value of the winding temperature after the hot rolling, a scheduled soaking time at the continuous annealing, and target tensile strength are substituted in the relational expression; a set soaking temperature at the continuous annealing is calculated; and the continuous annealing for soaking and annealing the steel plate at the set soaking temperature and at a set soaking time is applied. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
