Durable iron-chromium-aluminum alloy showing minor changes in heat resistance
An iron-chromium-aluminum alloy having a long service life and exhibiting little change in heat resistance, comprising (as percentages by weight) 4.5 to 6.5% Al, 16 to 24% Cr, 1.0 to 4.0% W, 0.05 to 0.7% Si, 0.001 to 0.5% Mn, 0.02 to 0.1% Y, 0.02 to 0.1% Zr, 0.02 to 0.1% Hf, 0.003 to 0.030% C, 0.002 to 0.03% N, a maximum of 0.01% S, and a maximum of 0.5% Cu, the remainder being iron and the usual steel production-related impurities.
1. An iron-chromium-aluminum alloy having a long service life and exhibiting little change in heat resistance, comprising in % by weight:
4.9 to 5.8% Al;
16 to 24% Cr;
1.0 to 4.0% W;
0.05 to 0.7% Si;
0.001 to 0.5% Mn;
Y and/or at least one of Sc, La and Ce, the total amount of Y and/or at least one of Sc, La and Ce being 0.02 to 0.1%;
a Zr-containing portion consisting of Zr or Zr and at least one of Sc, La and Ce, the total amount of the Zr-containing portion being 0.02 to 0.1%;
a Hf-containing portion consisting of Hf or Hf and at least one of Sc, La and Ce, the total amount of the Hf-containing portion being 0.02 to 0.1%;
wherein Ti replaces a portion of at least one of Zr and Hf in the Zr-containing and Hf-containing portions in a total amount not exceeding 0.1%;
0.003 to 0.030% C;
0.002 to 0.03% N;
a maximum of 0.01% S;
a maximum of 0.5% Cu;
the remainder being iron and usual steel production-related impurities,
wherein Y, Hf, Zr, Ti and C satisfy the formula:
I=−0.015+0.065*Y+0.030*Hf+0.095*Zr+0.090*Ti −0.065*C<0, where I is the inner oxidation, and the numbers preceding Y, Hf, Zr, Ti, C denote the concentration of those elements in % by weight.
2. The alloy according to claim 1 , comprising 4.9 to 5.5% Al by weight.
3. The alloy according to claim 1 , comprising 18 to 23% Cr by weight.
4. The alloy according to claim 1 , comprising 19 to 22% Cr by weight.
5. The alloy according to claim 1 , comprising 0.05 to 0.5% Si by weight.
6. The alloy according to claim 1 , comprising 0.005 to 0.5% Mn by weight.
7. The alloy according to claim 1 , comprising 0.03 to 0.09% Y by weight.
8. The alloy according to claim 1 , comprising 0.02 to 0.08% Zr by weight.
9. The alloy according to claim 1 , comprising 0.02 to 0.08% Hf by weight.
10. The alloy according to claim 1 , comprising 0.003 to 0.020% C by weight.
11. The alloy according to claim 1 , further comprising 0.0001 to 0.03% Mg by weight.
12. The alloy according to claim 1 , further comprising 0.0001 to 0.02% Mg by weight.
13. The alloy according to claim 1 , further comprising 0.0002 to 0.01% Mg by weight.
14. The alloy according to claim 1 , further comprising 0.0001 to 0.02% Ca by weight.
15. The alloy according to claim 1 , further comprising 0.0002 to 0.01% Ca by weight.
16. The alloy according to claim 1 , further comprising 0.003 to 0.025% P by weight.
17. The alloy according to claim 1 , further comprising 0.003 to 0.022% P by weight.
18. The alloy according to claim 1 , which is free of Y and includes at least one of the elements Sc, La and Ce.
19. The alloy according to claim 1 , comprising Y and at least one of the elements Sc and/or La and/or Ce.
20. The alloy according to claim 1 , wherein at least one of Sc, La and Ce are present in the alloy and the sum of Hf, Zr and at least one of Sc, La and Ce being 0.02 to 0.1% by weight of the alloy, and the sum of at least one of Sc, La and Ce being at least 0.01% by weight of the alloy.
21. The alloy according to claim 1 , comprising a maximum of 0.02% N by weight and a maximum of 0.005% S by weight.
22. The alloy according to claim 1 , comprising a maximum of 0.01% N by weight and a maximum of 0.003% S by weight.
23. The alloy according to claim 1 , further comprising a maximum of 0.002% by weight boron.
24. A heating element, comprising a foil of the alloy according to claim 1 .
25. An electrically heatable heating element, comprising a foil of the alloy according to claim 1 .
26. An electrically heatable heating element according to claim 25 , wherein thickness of the foil is 0.020 to 0.30 mm.
27. An electrically heatable heating element according to claim 25 , wherein thickness of the foil is 20 to 200 μm.
28. An electrically heatable heating element according to claim 25 , wherein thickness of the foil is 20 to 100 μm.
29. A glass ceramic cook top, comprising the foil according to claim 25 as a heat conductor foil.
30. A heatable metallic exhaust gas catalyst on a carrier foil, comprising the foil of claim 24 as the carrier foil.
31. A fuel cell, comprising the foil according to claim 24 .
32. The alloy according to claim 1 , further comprising 0.0001 to 0.05% Mg by weight.
33. The alloy according to claim 1 , further comprising 0.0001 to 0.03% Ca by weight.
34. The alloy according to claim 1 , further comprising 0.0002 to 0.03% P by weight.
35. The alloy according to claim 1 , further comprising a maximum of 0.1% Nb by weight.
36. The alloy according to claim 1 , further comprising a maximum of 0.1% V by weight.
37. The alloy according to claim 1 , further comprising a maximum of 0.1% Ta by weight.
38. The alloy according to claim 1 , further comprising a maximum of 0.01% O by weight.
39. The alloy according to claim 1 , further comprising a maximum of 0.5% Ni by weight.
40. The alloy according to claim 1 , further comprising a maximum of 0.003% B by weight.