Austenitic fe-cr-ni alloy for high temperature use

Abstract

An austenitic alloy for high temperature use, particularly for use in resistance heating elements. The alloy includes primarily the elements Fe, Ni, and Cr, and it has the following main composition, given in weight %, Ni 38-48, Cr 18-24, Si 1.0-1.9, C<0.1, and the balance Fe. The alloy provides good hot form stability, good oxidation resistance, and a relatively high electrical resistance coupled with a low change in resistance as a function of temperature.

1 . An alloy for high temperature use, and including Fe, Ni, and Cr, said alloy comprising the following, in weight %: 
 Ni 38-48,    Cr 18-24,    Si 1.0- 1.9,    C<0.1,    and wherein the balance is Fe.    
   
   
       2 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Mn less than 2,    Al, C, Ca, N, Ti, Zr, Hf, Ta, Nb, V, Mg, Ta, W, Ce, and rare earth elements together less than approximately 7, and    wherein the balance is Fe.    
   
   
       3 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Cr between −0.1 Ni+23 and −0.2667 Ni+36; and    Si between 0.8 and −0,0133 Ni+2.2.    and wherein the balance is Fe.    
   
   
       4 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Ni 39-41,    Cr 20-22,    Si 1-1.5,    N<0.15,    Ce 0.01-0.04,    C<0.1,    impurities up to 2%, and    wherein the balance is Fe.    
   
   
       5 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Ni 44-46,    Cr 20-22,    Si 1-1.5,    N<0.15,    Ce 0.01-0.04,    C<0.1,    impurities up to 2%, and    wherein the balance is Fe.    
   
   
       6 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Cr between −0.1 Ni+24 and −0.1667 Ni+30,    Si between 1.0 and −0.01 Ni+1.9,    and wherein the alloy includes up to 5 wt % Co as a substitute for a corresponding amount of Ni, and wherein the alloy includes Mn up to 2,    Al up to 0.6,    rare earth elements, Y, and Ca up to 0.2% total,    N<0.15,    Ti, Zr, Hf, Ta, Nb, and V up to 0.4 total,    S<50 wt ppm,    other elements <2 total,    and wherein the balance is Fe.    
   
   
       7 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Cr 18-22,    Si 1.0-1.5,    Al<0.6,    N<0.15,    Mn<1,    S<50 wt ppm,    wherein the alloy further includes elements selected from the group consisting of Ti, Zr, Hf, Y, Rare Earth Elements (Lantanoid group), Ca, Mg, and Ta at less than 0.5 total, and elements belonging to the group Mo, Co, Ta, W with less than 5, and elements to selected from the group consisting of Ti, Zr, Hf, Nb, and V at less than 0.4 total,    wherein other elements are <2 total    and wherein the balance is Fe.    
   
   
       8 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Ni 39-41,    Cr 20-22,    Si 1-1.5,    C 0.02,    N<0.15,    Ce 0.01-0.04,    impurities up to 2%,    and wherein the balance is Fe.    
   
   
       9 . An alloy in accordance with  claim 1 , wherein the alloy further comprises in weight %: 
 Ni 44-46,    Cr 20-22,    Si 1-1.5,    C 0.02,    N<0.15,    Ce 0.01-0.04,    impurities up to 2%,    and wherein the balance is Fe.