Method for manufacturing plated steel sheet having excellent clarity of image after coating, and plated steel sheet manufactured thereby

Abstract

Provided is a method of manufacturing a plated steel sheet having excellent image clarity after coating. The method includes: providing a cold rolled steel sheet by cold rolling; plating the cold rolled steel sheet to manufacture a plated steel sheet; and temper rolling the plated steel sheet by inserting the plated steel sheet into a temper rolling mill. A long-wavelength waviness (Wsa1-5) of a final stand rolling roll is 0.4 μm or less (not including 0) during the cold rolling.

1 . A method of manufacturing a plated steel sheet having excellent image clarity after coating, comprising:
 providing a cold rolled steel sheet by cold rolling;   plating the cold rolled steel sheet to manufacture a plated steel sheet; and   temper rolling the plated steel sheet by inserting the plated steel sheet into a temper rolling mill,   wherein a long-wavelength waviness (Wsa1-5) of a final stand rolling roll is 0.4 μm or less (not including 0) during the cold rolling.   
     
     
         2 . The method of  claim 1 , wherein the cold rolled steel sheet has a long-wavelength waviness (Wsa1-5) of 0.2 μm or less (not including 0). 
     
     
         3 . The method of  claim 1 , wherein the plating the cold rolled steel sheet is performed to allow a plating amount on a single surface to be 45 g/m 2  or greater. 
     
     
         4 . The method of  claim 1 , wherein, in the temper rolling the plated steel sheet, a roll having a long-wavelength waviness (Wsa1-5) of 0.4 μm or less (not including 0) is used. 
     
     
         5 . The method of  claim 1 , wherein the plated steel sheet is provided as one of a hot-dip galvanized steel sheet, a hot-dip aluminized steel sheet, an aluminum alloy plated steel sheet, an electro-galvanized steel sheet, an alloy electro-galvanized steel sheet, and a hot-dip galvannealed steel sheet. 
     
     
         6 . A plated steel sheet having excellent image clarity after coating, comprising:
 a cold rolled steel sheet and a plating layer formed on the cold rolled steel sheet,   wherein the cold rolled steel sheet has a long-wavelength waviness (Wsa1-5) of 0.2 μm or less (not including 0).   
     
     
         7 . The plated steel sheet having excellent image clarity after coating of  claim 6 , wherein the plated steel sheet has a long-wavelength waviness (Wsa1-5) of 0.28 μm or less (not including 0). 
     
     
         8 . The plated steel sheet having excellent image clarity after coating of  claim 6 , wherein the plated steel sheet has a surface long-wavelength waviness (Wsa1-5) of less than 0.35 μm (not including 0) after processing at a strain rate of 5%.