Austenitic stainless steels including molybdenum

Abstract

An austenitic stainless steel comprises, by weight, 9 to 23% chromium, 30 to 35% nickel, 1 to 6% molybdenum, 0 to 0.03% titanium, 0.15% to 0.6% aluminum, up to 0.1% carbon, 1 to 1.5% manganese, 0 to less than 0.8% silicon, 0.25 to 0.6% niobium and iron. Embodiments of austenitic stainless steels according to the present invention exhibit enhanced resistance to corrosion. Thus, the stainless steels of the present invention may find broad application as, for example, automotive components and, more particularly, as automotive exhaust system flexible connectors and other components, as well as in other applications in which corrosion resistance is desired.

I claim:  
     
         1 . An austenitic stainless steel comprising, by weight: 
 19% to 23% chromium;    30% to 35% nickel;    1% to 6% molybdenum;    0 to 0.03% titanium;    0.15% to 0.6% aluminum;    up to 0.1% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium; and    iron.    
     
     
         2 . The austenitic stainless steel of  claim 1 , comprising 19% to 21.5% chromium.  
     
     
         3 . The austenitic stainless steel of  claim 1 , comprising 2% to 4% molybdenum.  
     
     
         4 . The austenitic stainless steel of  claim 1 , comprising 1% to 2.7% molybdenum.  
     
     
         5 . The austenitic stainless steel of  claim 1 , comprising 0 to 0.01% titanium.  
     
     
         6 . The austenitic stainless steel of  claim 1 , comprising 0 to 0.005% titanium.  
     
     
         7 . The austenitic stainless steel of  claim 1 , comprising 0.15% to 0.4% aluminum.  
     
     
         8 . The austenitic stainless steel of  claim 1 , comprising up to 0.025% carbon.  
     
     
         9 . The austenitic stainless steel of  claim 1 , comprising 0 to 0.4% silicon.  
     
     
         10 . The austenitic stainless steel of  claim 1 , comprising 0.3% to 0.5% niobium.  
     
     
         11 . The austenitic stainless steel of  claim 1 , further comprising 0 to 0.75% copper.  
     
     
         12 . The austenitic stainless steel of  claim 1 , further comprising 0 to 0.4% copper.  
     
     
         13 . The austenitic stainless steel of  claim 1 , further comprising: 
 no greater than 0.05% phosphorus;    no greater than 0.02% sulfur; and    no greater than 0.1% nitrogen.    
     
     
         14 . The austenitic stainless steel of  claim 1  comprising, by weight: 
 19% to 21.5% chromium;  
 30% to 35% nickel;  
 1% to 2.7% molybdenum;  
 0 to 0.03% titanium;  
 0.15% to 0.4% aluminum;  
 up to 0.025% carbon  
 1% to 1.5% manganese;  
 0 to less than 0.8% silicon;  
 0.25% to 0.6% niobium; and  
 iron.  
 
     
     
         15 . The austenitic stainless steel of  claim 1 , consisting essentially of, by weight: 
 19% to 23% chromium;    30% to 35% nickel;    1% to 6% molybdenum;    0 to 0.03% titanium;    0.15% to 0.6% aluminum;    up to 0.1% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium;    0 to 0.75% copper;    up to 0.05% phosphorus;    no up to 0.02% sulfur;    up to 0.1% nitrogen;    iron; and    incidental impurities.    
     
     
         16 . An article of manufacture including an austenitic stainless steel comprising, by weight: 
 19% to 23% chromium;    30% to 35% nickel;    1% to 6% molybdenum;    0 to 0.03% titanium;    0.15% to 0.6% aluminum;    up to 0.1% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium; and    iron.    
     
     
         17 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 19% to 21.5% chromium.  
     
     
         18 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 2% to 4% molybdenum.  
     
     
         19 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 1% to 2.7% molybdenum.  
     
     
         20 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 0 to 0.01% titanium.  
     
     
         21 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 0 to 0.005% titanium  
     
     
         22 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 0.15% to 0.4% aluminum.  
     
     
         23 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises up to 0.025% carbon.  
     
     
         24 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 0 to 0.4% silicon.  
     
     
         25 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises 0.3% to 0.5% niobium.  
     
     
         26 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel further comprises 0 to 0.75% copper.  
     
     
         27 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel further comprises 0 to 0.4% copper.  
     
     
         28 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel further comprises: 
 no greater than 0.05% phosphorus;    no greater than 0.02% sulfur; and    no greater than 0.1% nitrogen.    
     
     
         29 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel comprises, by weight: 
 19% to 21.5% chromium;    30% to 35% nickel;    1% to 2.7% molybdenum;    0 to 0.03% titanium;    0.15% to 0.4% aluminum;    up to 0.025% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium; and    iron.    
     
     
         30 . The article of manufacture of  claim 16 , wherein the austenitic stainless steel consists essentially of, by weight: 
 19% to 23% chromium;    30% to 35% nickel;    1% to 6% molybdenum;    0 to 0.03% titanium;    0.15% to 0.6% aluminum;    up to 0.1% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium;    0 to 0.75% copper;    up to 0.05% phosphorus;    up to 0.02% sulfur;    up to 0.1% nitrogen; and    iron; and    incidental impurities.    
     
     
         31 . The article of manufacture of any of claims  16 ,  29  and  30 , wherein the article of manufacture is selected from the group consisting of an automobile, an automotive exhaust system component, an automotive exhaust system flexible connector, a heating element sheath, and a gasket.  
     
     
         32 . An automotive exhaust system flexible connector including an austenitic stainless steel comprising, in weight percent: 
 19% to 21.5% chromium;    30% to 35% nickel;    1% to 6% molybdenum;    0 to 0.03% titanium;    0.15% to 0.6% aluminum;    up to 0.1% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium; and    iron.    
     
     
         33 . A method of making an article of manufacture, the method comprising: 
 forming at least a portion of the article of manufacture from an austenitic stainless steel comprising, by weight:    19% to 23% chromium;    30% to 35% nickel;    1% to 6% molybdenum;    0 to 0.03% titanium;    0.15% to 0.6% aluminum;    up to 0.1% carbon    1% to 1.5% manganese;    0 to less than 0.8% silicon;    0.25% to 0.6% niobium;    0 to 0.75% copper; and    iron.    
     
     
         34 . The method of  claim 33 , wherein the article of manufacture is selected from the group consisting of an automobile, an automotive exhaust system component, an automotive exhaust system flexible connector, a heating element sheath, and a gasket.