Continuous annealing line, continuous hot-dip galvanizing line, and steel sheet production method

A steel sheet production method comprising, in the following order:

• a step (A) of uncoiling a cold-rolled coil to feed a cold-rolled steel sheet by a payoff reel;
• a step (B) of passing the cold-rolled steel sheet through an annealing furnace in which a heating zone, a soaking zone, and a cooling zone are arranged from an upstream side in a sheet passing direction, to continuously anneal the cold-rolled steel sheet by a step (B-1) of annealing the cold-rolled steel sheet in a reducing atmosphere containing hydrogen in the heating zone and the soaking zone and a step (B-2) of cooling the cold-rolled steel sheet in the cooling zone;
• a step (C) of continuously passing the cold-rolled steel sheet discharged from the annealing furnace;
• and
• a step (D) of coiling the cold-rolled steel sheet by a tension reel to obtain a product coil,
• wherein the steel sheet production method comprises
• a vibration application step of applying vibration to the cold-rolled steel sheet being passed in or after the step (B-2) and before the step (D) so that the cold-rolled steel sheet is caused to vibrate at a frequency of 100 Hz or more and 100,000 Hz or less and a maximum amplitude of 10 nm or more and 500 μm or less.