Steel sheet annealing device, device for producing plated steel sheet comprising the same, and production method for plated steel sheet using the same

Abstract

Provided is an annealing device which comprises at least one section and in which the at least one section is filled with a gas constituting a non-reducing atmosphere or a weakly reducing atmosphere, as well as a device for producing plated steel sheet comprising the annealing device, and a method for producing plated steel sheet by means of such a device to substantially improve the quality of plating onto hot-dipped steel sheet, including the plating properties, alloying properties, anti-pickup properties, plating adhesion properties, anti-flaking properties, anti-cratering properties and anti-ash properties, by using prior-art annealing equipment and heat-treatment cycle without any additional oxidation-reduction heat treatment process or large quantities of high-cost alloying elements.

1 . An annealing device for a steel sheet including at least one section, the device characterized in that the at least one section is filled with a gas constituting anon-reducing atmosphere or a weakly reducing atmosphere. 
     
     
         2 . The device of  claim 1 , wherein the steel sheet comprises at least one of Si, Mn, Al and B. 
     
     
         3 . The device of  claim 1 , wherein the steel sheet is one of a hot rolled steel sheet, a full hard steel sheet and a cold rolled steel sheet. 
     
     
         4 . The device of  claim 1 , wherein the gas contains hydrogen (H 2 ) of 3 vol % or less and nitrogen (N 2 ) of 97 vol % or more. 
     
     
         5 . The device of  claim 1 , wherein the annealing device includes at least one or two among a pre heating section, a heating section, a soaking section, a slow cooling section, a rapid cooling section, and a final cooling section. 
     
     
         6 . The device of  claim 1 , wherein the annealing device further includes at least one of an overaging section and a re-heating section. 
     
     
         7 . The device of  claim 5 , wherein the pre heating section or the heating section is an induction heater, an infrared heater, a radiant tube burner, an ultrasonic wave burner, or a device having a combination thereof. 
     
     
         8 . The device of  claim 6 , wherein the re-heating section is the induction heater, the infrared heater, the radiant tube burner, the ultrasonic wave burner, or a device having a combination thereof. 
     
     
         9 . A plated steel sheet manufacturing apparatus comprising the annealing device for a steel sheet according to  claim 1 . 
     
     
         10 . A plated steel sheet manufacturing method including:
 performing a series of processes for manufacturing a plated steel sheet by performing an annealing process on a steel sheet in an annealing device,   the annealing device including at least one section, and the annealing process being performed in the at least one section containing a gas constituting a non-reducing atmosphere or a weakly reducing atmosphere.   
     
     
         11 . The method of  claim 10 , wherein the annealing process includes at least one or two among pre heating, heating, soaking, slow cooling, rapid cooling, and final cooling operations. 
     
     
         12 . The method of  claim 11 , wherein the annealing process further includes at least one of overaging and re-heating operations. 
     
     
         13 . The method of  claim 11 , wherein the pre heating operation or the heating operation is an induction heating scheme, an infrared heating scheme, a radiant tube burning scheme, an ultrasonic wave burning scheme, or a scheme having a combination thereof. 
     
     
         14 . The method of  claim 12 , wherein the re-heating operation is the induction heating scheme, the infrared heating scheme, the radiant tube burning scheme, the ultrasonic wave burning scheme, or a scheme having a combination thereof. 
     
     
         15 . The method of  claim 11 , wherein at least one or two cooling operations among the slow cooling operation, the rapid cooling operation, and the final cooling operation are a cooling scheme using at least one of nitrogen, liquid nitrogen, and nitrogen containing hydrogen. 
     
     
         16 . The method of  claim 10 , wherein the gas contains hydrogen (H 2 ) of 3 vol % or less and nitrogen (N 2 ) of 97 vol % or more. 
     
     
         17 . The method of  claim 10 , wherein the plated steel sheet is one of a hot-dip galvanized steel sheet, a galvannealed steel sheet, a galvanium plated steel sheet, an aluminum plated steel sheet and a zinc-magnesium-based plated steel sheet.