Patent ID: 8709550

Claim:
A process for manufacturing a coated steel sheet, comprising: a coating step of applying a water-based coating liquid containing a resin and a passivator onto an annealed steel sheet comprising an electromagnetic steel sheet at a line speed of 150 m/min or more; a drying step of drying the applied coating liquid to form a substantially even coating layer in such a manner that the applied liquid is heated on the side close to the steel sheet; a preventing step of preventing coating fine unevenness as a surface property of the coating caused by vibration, impact and paint dripping while the steel sheet is conveyed on a transfer line from the coating step to the drying step at said line speed, by controlling time elapsed between the application of the coating liquid and substantial completion of drying, the substantial completion of drying being defined as the temperature of the steel sheet reaching 100° C., to 10 seconds or less; and a baking step of heating the dry coating layer to a predetermined temperature to bake the coating layer to form a coating film, wherein the steps are conducted with a vertical arrangement of a coating and a heating apparatus.