Ferritic stainless steel

Abstract

The invention relates to a Ferritic stainless steel having excellent corrosion and sheet forming properties consisting of weight percentages 0.003-0.035% carbon, 0.05-1.0% silicon, 0.10-0.8% manganese, 18-24% chromium, 0.05-0.8% nickel, 0.003-2.5% molybdenum, 0.2-0.8% copper, 0.003-0.05% nitrogen, 0.05-1.0% titanium, 0.05-1.0% niobium, 0.03-0.5% vanadium, 0.0IO-0.04% aluminium, and the sum C+N less than 0.06%, the remainder being iron and inevitable impurities, wherein the ratio (Ti+Nb)/(C+N) is higher or equal to 8, and less than 40, and the ratio Tieq/Ceq=(Ti+0.515*Nb+0.940*V)/(C+0.858*N) is higher or equal to 6, and less than 40, and Leq=5.8*Nb+5*Ti*Si is higher or equal to 3.3, and the steel is produced using AOD (Argon-Oxygen-Decarburization) technology.

1 . Ferritic stainless steel having corrosion and sheet forming properties, wherein the steel consists of in weight percentages 0.003-0.035% carbon, 0.05-1.0% silicon, 0.10-0.8% manganese, 18-24% chromium, 0.05-0.8% nickel, 0.003-2.5% molybdenum, 0.2-0.8% copper, 0.003-0.05% nitrogen, 0.05-1.0% titanium, 0.05-1.0% niobium, 0.03-0.5% vanadium, 0.010-0.04% aluminium, and the sum C+N less than 0.06%, the remainder being iron and inevitable impurities, wherein the ratio (Ti+Nb)/(C+N) is higher or equal to 8, and less than 40, and the ratio Tieq/Ceq=(Ti+0.515*Nb+0.940*V)/(C+0.858*N) is higher or equal to 6, and less than 40, and Leq=5.8*Nb+5*Ti*Si is higher or equal to 3.3, and the steel is produced using AOD (Argon-Oxygen-Decarburization) technology. 
     
     
         2 . Ferritic stainless according to the  claim 1 , wherein the carbon content is less than 0.03 weight %, but at least 0.003%. 
     
     
         3 . Ferritic stainless steel, according to  claim 1 , wherein the manganese content is 0.10-0.65%. 
     
     
         4 . Ferritic stainless steel, according to  claim 1 , wherein the chromium content is less than 22.0 weight %, but at least 20.0%. 
     
     
         5 . Ferritic stainless steel, according to  claim 1 , wherein the nickel content is less than 0.5 weight %, but at least 0.05%. 
     
     
         6 . Ferritic stainless steel, according to  claim 1 , wherein the molybdenum content is 0.003-0.5 weight % in corrosive environments with neutral or high pH-values >4. 
     
     
         7 . Ferritic stainless steel, according to  claim 1 , wherein the molybdenum content is 0.5-2.5 weight % in highly corrosive environments with low acidic pH-values ≤4. 
     
     
         8 . Ferritic stainless steel, according to  claim 1 , wherein the copper content is less than 0.5 weight %, but at least 0.2%. 
     
     
         9 . Ferritic stainless steel, according to  claim 1 , wherein the nitrogen content is less than 0.03 weight %, but at least 0.003%. 
     
     
         10 . Ferritic stainless steel, according to  claim 1 , wherein the titanium content is 0.07-0.40 weight %. 
     
     
         11 . Ferritic stainless steel, according to  claim 1 , wherein the vanadium content is 0.03-0.20 weight %. 
     
     
         12 . Ferritic stainless steel, according to  claim 1 , wherein the ratio (Ti+Nb)/(C+N) is higher or equal to 20, and less than 30. 
     
     
         13 . Ferritic stainless steel, according to  claim 1 , wherein the ratio Tieq/Ceq=(Ti+0.515*Nb+0.940*V)/(C+0.858*N) is higher or equal to 15, and less than 30. 
     
     
         14 . Ferritic stainless steel, according to  claim 1 , wherein the Leq=5.8*Nb+5*Ti*Si is higher or equal to 4.5.