US2015174647A1PendingUtilityA1

Method of Manufacturing Ti-Containing Austenitic Stainless Steel Sheet by Twin Roll Strip Caster

Assignee: POSCOPriority: Dec 20, 2013Filed: Dec 15, 2014Published: Jun 25, 2015
Est. expiryDec 20, 2033(~7.4 yrs left)· nominal 20-yr term from priority
B22D 11/0622B22D 11/001C22C 38/50B22D 11/002B22D 11/16B22D 11/11
51
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Claims

Abstract

There is provided a method of manufacturing a titanium (Ti)-containing austenitic stainless steel sheet having a high degree of surface quality by using a twin roll strip caster. The method includes controlling a composition of molten steel such that a TiN precipitation temperature may be higher than a temperature of the molten steel in a tundish (T/D) by at least 50° C. (ΔT≧50° C.), the TiN precipitation temperature being defined by the following formula 2: Log(N%)=−19,755/(T+273)+7.78+0.07[% Ti]−log [% Ti]+ 0.045[% Cr] T(° C.)=−19,755/log(N%)−7.78−0.07(%Ti)+log(%ti)−0.045(%Cr)−273  [Formula 2]

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A method of manufacturing a titanium (Ti)-containing austenitic stainless steel sheet having a high degree of surface quality by using a twin roll strip casting process, the method comprising controlling a composition of molten steel such that a TiN precipitation temperature is higher than a temperature of the molten steel in a tundish (T/D) by at least 50° C. (ΔT≧50° C.), the TiN precipitation temperature being defined by the following formula 2: 
       
         
           
             
               
                 
                   
                     
                       
                         Log 
                          
                         
                           ( 
                           
                             N 
                              
                             
                                 
                             
                              
                             % 
                           
                           ) 
                         
                       
                       = 
                       
                         
                           
                             - 
                             19 
                           
                           , 
                           
                             755 
                             / 
                             
                               ( 
                               
                                 T 
                                 + 
                                 273 
                               
                               ) 
                             
                           
                         
                         + 
                         7.78 
                         + 
                         
                           0.07 
                            
                           
                             [ 
                             
                               % 
                                
                               
                                   
                               
                                
                               Ti 
                             
                             ] 
                           
                         
                         - 
                         
                           log 
                            
                           
                             [ 
                             
                               % 
                                
                               
                                   
                               
                                
                               Ti 
                             
                             ] 
                           
                         
                         + 
                         
                           0.045 
                            
                           
                             [ 
                             
                               % 
                                
                               
                                   
                               
                                
                               Cr 
                             
                             ] 
                           
                         
                       
                     
                      
                     
                       
 
                     
                      
                     
                       
                         T 
                          
                         
                           ( 
                           
                             ° 
                              
                             
                                 
                             
                              
                             
                               C 
                               . 
                             
                           
                           ) 
                         
                       
                       = 
                       
                         
                           
                             
                               - 
                               19 
                             
                             , 
                             755 
                           
                           
                             
                               
                                 
                                   
                                     log 
                                      
                                     
                                       ( 
                                       
                                         N 
                                          
                                         
                                             
                                         
                                          
                                         % 
                                       
                                       ) 
                                     
                                   
                                   - 
                                   7.78 
                                   - 
                                   
                                     0.07 
                                      
                                     
                                       ( 
                                       
                                         % 
                                          
                                         
                                             
                                         
                                          
                                         Ti 
                                       
                                       ) 
                                     
                                   
                                   + 
                                 
                               
                             
                             
                               
                                 
                                   
                                     log 
                                      
                                     
                                       ( 
                                       
                                         % 
                                          
                                         
                                             
                                         
                                          
                                         Ti 
                                       
                                       ) 
                                     
                                   
                                   - 
                                   
                                     0.045 
                                      
                                     
                                       ( 
                                       
                                         % 
                                          
                                         
                                             
                                         
                                          
                                         Cr 
                                       
                                       ) 
                                     
                                   
                                 
                               
                             
                           
                         
                         - 
                         273 
                       
                     
                   
                 
                 
                   
                     [ 
                     
                       Formula 
                        
                       
                           
                       
                        
                       2 
                     
                     ] 
                   
                 
               
             
           
         
       
     
     
         2 . The method of  claim 1 , wherein the molten steel comprises, by weight %, carbon (C): 0.025% to 0.055%, silicon (Si): 0.25% to 0.55%, manganese (Mn): 1.5% to 1.8%, chromium (Cr): 17.1% to 17.7%, nickel (Ni): 9.25% to 9.65%, titanium (Ti): 0.2% to 0.5%, nitrogen (N): 0.025% or less, and the balance of iron (Fe) and inevitable impurities. 
     
     
         3 . The method of  claim 1 , wherein the molten steel has a Ti/C ratio of 8 or greater.

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