LOW-COST CAST CREEP-RESISTANT AUSTENITIC STAINLESS STEELS THAT FORM ALUMINA FOR HIGH TEMPERATURE OXIDATION RESISTANCE

1 . An air castable Fe-based stainless steel alloy comprising in weight % based on the total weight of the alloy:

18-22% Cr

15-22% Ni

3-6% Al

0.5-5% Mn

0-3.5% W

0-5% Cu

0-2% Si

1-2.5% Nb

0.3-0.5% C

balance Fe wherein, Cu+W+Si=0.5-10.5, and the alloy provides an oxidation resistance oxidation resistance of −0.5<mass change <+2 mg/cm 2 after 400 one hour cycles at 900° C. in 10% water vapor.

2 . The alloy of claim 1 , further comprising 0-2% Ta.

3 . The alloy of claim 2 , wherein Ta+Nb<4.0.

4 . The alloy of claim 2 , wherein Ta/Nb=0-0.75.

5 . The alloy of claim 1 , further comprising 0.1-5.0% Co.

6 . The alloy of claim 1 , wherein the alloy is non-magnetic and free of alpha or delta ferrite phases, and does not form a thermal or strain induced martensite phase.

7 . The alloy of claim 1 , wherein the Cu/W ratio is 0.75-1.67.

8 . The alloy of claim 1 , wherein Nb/C is from 2-5.

9 . The alloy of claim 1 , wherein N is less than 0.1.

10 . The alloy of claim 1 , wherein Cr/Al 4.7-8.

11 . The alloy of claim 1 wherein the Cr/(Al+Si) ratio can be 2.25 to 6.15.

12 . The alloy of claim 1 , wherein the alloy provides anof −2<mass change <+2 mg/cm 2 after 300 one hour cycles at 950° C. in 10% water vapor.

13 . The alloy of claim 1 , wherein the alloy provides creep rupture resistance of 863 hrs at 950° C., 35 MPa and 469 hours at 1050° C., 10 MPa.

14 . The alloy of claim 1 , wherein the alloy provides a yield strength of 41.6 Ksi and tensile strength of 84.1 Ksi at room temperature.

15 . The alloy of claim 1 , wherein the alloy provides an elongation of 11.1 at room temperature and 39% at 1000° C.