Low expansion superalloy
AssigneeHuntington Alloys, Inc.
InventorsDarrell Franklin Smith, Jr., Edward Frederick Clatworthy, Donald Edward Wenschhof, Jr.
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Abstract
Nickel-iron and nickel-iron-cobalt alloys contain chromium and gamma-prime hardening elements in proportions balanced according to special compositional relationships providing desired thermal expansion, inflection temperature, strength and ductility characteristics, particularly including notch strength needed in machinery and structures subjected in use to varying temperatures and thermal gradients where operating temperatures become elevated above 500.degree. F.
Claims10
An alloy consisting essentially of 30% to 57% nickel, 1.7% to 8.3% chromium, 1 to 2% titanium, metal from the group columbium, tantalum and mixtures thereof in proportions providing the total percentage of columbium plus one-half the percentage of tantalum is 1.5 to 5%, up to 31% cobalt, up to 1.5% aluminum, up to 0.2% carbon, up to about 2% manganese, up to about 1% silicon, up to 0.03% boron and balance essentially iron in an amount of at least 34% of the alloy and having the composition proportioned in accordance with the following four relationships A, B, C' and D' whereby:
- A. %ni+0.88(%Co)-1.70(%Al)-2.01(%Ti)+ 0.26(%Mn+% Cr) equal up to 51.8
- B. %ni+1.13(%Co)-2.69(%Al)-1.47(%Ti)-1.93(%Mn)- 2.51(%Cr)+1.87(.sqroot.%Cr) at least 40.8
- C. %al+1.3(%Ti)+1.44(%Cb+1/2%Ta)-0.12(%Cb+1/2%Ta).sup.2 - 0.37(%Cr)+0.03(%Cr).sup.2 at least 3.81
- D. %al+1.3(%Ti)+0.25(%Cb+1/2% Ta)-0.125(%Cr) up to 3.18
Dependencies are inferred from the claim text.