Steel compositions having improved anti-coking properties

Abstract

Special usage steels, particularly those intended to be in contact with combustion fumes, are described. Tubular components produced based on such steels are also described. The steel both is resistant to the coking phenomenon and has improved mechanical performances. The steel contains no more than 0.15% carbon, from 0.3 to 1% manganese, from 1.4 to 3% silicon, from 0.5 to 3% copper, from 8 to 10% chrome, from 0.5 to 3% nickel, from 0.01 to 0.07% nitrogen, from 0.8 to 1.1% molybdenum, with the remainder being iron and impurities.

1 . A steel composition, comprising in percentage by weight:
 no more than 0.15% carbon,   from 0.3 to 1% manganese,   from 1.4 to 3% silicon,   from 0.5 to 3% copper,   from 8 to 10% chrome,   from 0.5 to 3% nickel,   from 0.01 to 0.07% nitrogen,   from 0.8 to 1.1% molybdenum, and   iron.   
     
     
         2 . The steel composition according to  claim 1 , further comprising:
 no more than 0.04% aluminum,   no more than 0.025% phosphorus,   no more than 0.02% sulfur,   no more than 0.02% titanium,   no more than 0.05% niobium,   no more than 0.05% vanadium,   no more than 0.1% tungsten, and   no more than 0.05% cobalt.   
     
     
         3 . The steel composition according to  claim 2 , wherein the content by weight of each of aluminum, phosphorus, sulfur, titanium, niobium, vanadium, tungsten, and cobalt does not exceed 0.01%. 
     
     
         4 . The steel composition according to  claim 1 , comprising: from 0.08% to 0.15% of carbon. 
     
     
         5 . The steel composition according to  claim 1 , comprising: from 0.09% to 0.11% of carbon. 
     
     
         6 . The steel composition according to  claim 1 , comprising: from 1.5% to 2.5% of silicon. 
     
     
         7 . The steel composition according to  claim 1 , comprising: from 0.5% to 2% of copper. 
     
     
         8 . The steel composition according to  claim 1 , comprising: from 0.5% to 2.7% of nickel. 
     
     
         9 . The steel composition according to  claim 1 , comprising: from 0.4% to 0.8% of manganese. 
     
     
         10 . The steel composition according to  claim 1 , comprising: from 0.02% to 0.05% of nitrogen. 
     
     
         11 . The steel composition according to  claim 2 , comprising: from 0.005% to 0.03% of aluminum. 
     
     
         12 . The steel composition according to  claim 1 , further comprising:
 no more than 0.025% phosphorus,   no more than 0.02% sulfur,   no more than 0.02% titanium,   no more than 0.05% niobium,   no more than 0.05% vanadium,   no more than 0.1% tungsten, and   no more than 0.05% cobalt.   
     
     
         13 . The steel composition according to  claim 1 , further comprising: phosphorus and sulfur as impurities. 
     
     
         14 . The steel composition according to  claim 1 , wherein the percentages by weight of silicon [Si], copper [Cu], and nickel [Ni] satisfy the following inequalities:
   [Si]<1.5*(0.3[Cu]+[Ni]) for [Si]<2.5%;     2*[Si]<1.5*(0.3[Cu]+[Ni]) for [Si]≥2.5%;
     and     [Cu]<[Ni].   
     
     
         15 . A tubular component, at least one part of which comprises:
 the steel composition according to  claim 1 .   
     
     
         16 . The tubular component according to  claim 15 , wherein the at least one part is designed to be placed in contact with atmosphere containing coke.