Steel material having excellent alcohol-induced pitting corrosion resistance and alcohol-induced scc resistance

Abstract

A steel material excellent in alcohol-induced pitting corrosion resistance and alcohol-induced SCC resistance enables application in large structures without the need of alloy treatment or addition of inhibitors, by improving the pitting corrosion resistance and the SCC resistance of the steel material itself, by having a chemical composition containing, by mass % C: 0.03% to 0.3%, Si: 0.01% to 1.0%, Mn: 0.1% to 2.0%, P: 0.03% or less, S: 0.01% or less and Al: 0.1% or less, and one or both of Mo: 0.03% to 1.0% and W: 0.03% to 1.0%, and at least two of Sb: 0.005% to 0.5%, Sn: 0.01% to 0.3% and Nb: 0.005% to 0.1%, and the balance including Fe and incidental impurities.

1 .- 5 . (canceled) 
     
     
         6 . A steel material excellent in alcohol-induced pitting corrosion resistance and alcohol-induced SCC resistance containing, by mass % C: 0.03% to 0.3%, Si: 0.01% to 1.0%, Mn: 0.1% to 2.0%, P: 0.03% or less, S: 0.01% or less and Al: 0.1% or less, and one or both of Mo: 0.03% to 1.0% and W: 0.03% to 1.0%, and at least two of Sb: 0.005% to 0.5%, Sn: 0.01% to 0.3% and Nb: 0.005% to 0.1%, and the balance including Fe and incidental impurities. 
     
     
         7 . The steel material according to  claim 6 , wherein the total amount of Mo and W, and Sb, Sn and Nb satisfies, by mass % a range of 0.15%≦(Mo+W+Sb+Sn+Nb)≦1.0%, and the total amount of Mo and W satisfies, by mass % 0.08%≦(Mo+W). 
     
     
         8 . The steel material according to  claim 6 , wherein the steel material further contains, by mass % Ca in a range that satisfies Ca/S 0.5 and 0.01% or less. 
     
     
         9 . The steel material according to  claim 6 , wherein the steel material further contains, by mass % B: 0.0002% to 0.03%. 
     
     
         10 . The steel material according to  claim 6 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         11 . The steel material according to  claim 7 , wherein the steel material further contains, by mass % Ca in a range that satisfies Ca/S≧0.5 and 0.01% or less. 
     
     
         12 . The steel material according to  claim 7 , wherein the steel material further contains, by mass % B: 0.0002% to 0.03%. 
     
     
         13 . The steel material according to  claim 8 , wherein the steel material further contains, by mass % B: 0.0002% to 0.03%. 
     
     
         14 . The steel material according to  claim 11 , wherein the steel material further contains, by mass % B: 0.0002% to 0.03%. 
     
     
         15 . The steel material according to  claim 7 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         16 . The steel material according to  claim 8 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         17 . The steel material according to  claim 9 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         18 . The steel material according to  claim 11 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         19 . The steel material according to  claim 12 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         20 . The steel material according to  claim 13 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%. 
     
     
         21 . The steel material according to  claim 14 , wherein the steel material contains, by mass % one or more of Zr: 0.005% to 0.1%, V: 0.005% to 0.1% and Ti: 0.005% to 0.1%.