Manufacturing method and manufacturing equipment of cold-rolled steel sheet

Manufacturing equipment of a cold-rolled steel sheet, the equipment comprising:

• a full-width heating device that heats a steel sheet over an entire area in a width direction of the steel sheet;
• an edge heating device that heats end portions in the width direction of the steel sheet;
• and
• a cold rolling mill that rolls the steel sheet and that is arranged on a downstream side in a rolling direction with respect to the full-width heating device and the edge heating device, wherein
• the full-width heating device and the edge heating device heat the steel sheet in such a manner that temperatures of the end portions in the width direction becomes higher than a temperature of a central portion in the width direction of the steel sheet on an entry side of the cold rolling mill,
• wherein the full-width heating device and the edge heating device heat the temperatures of the central portion in the width direction and the end portions in the width direction of the steel sheet on the entry side of the cold rolling mill to temperatures that are calculated from following expressions (1) and (2), the temperatures calculated from the expressions (1) and (2) being configured to change depending on an Si content α:
• TC≥0.1α4.5+15 (1)
• TE≥0.1α4.8+15 (2)
• TC:
• Steel sheet temperature of a central portion in a width direction of a steel sheet on entry side of a rolling mill [° C.] TC≤200° C.
• TE:
• Steel sheet temperatures of end portions in a width direction of a steel sheet on entry side of a rolling mill [° C.] TE≤200° C.
• α:Si content [%] 0<α≤4.5.