Cobalt-chromium-iron-nickel alloys amenable to nitride strengthening
AssigneeHaynes International, Inc.
InventorS. Krishna Srivastava
Life of this patent
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Abstract
A wroughtable, cobalt alloy capable of through thickness nitridation and strengthening using practical treatments and practical sheet thicknesses contains in weight percent about 23 to about 30% chromium, about 15 to about 25% iron, up to about 27.3% nickel, about 0.75 to about 1.7% titanium, about 0.85 to about 1.9% niobium or zirconium, up to 0.2% carbon, up to 0.015% boron, up to 0.015% rare earth elements, up to 0.5% aluminum, up to 1% manganese, up to 1% silicon, up to 1% tungsten, up to 1% molybdenum, and the balance cobalt plus impurities and the total weight percent of titanium plus niobium or equivalents is from about 1.6 to about 3.6.
Claims11
A wroughtable, cobalt alloy capable of through thickness nitridation and strengthening consisting essentially of in weight percent:
- about 23 to about 30% chromium
- about 15 to about 25% iron
- up to about 27.3% nickel
- about 0.75 to about 1.7% titanium
- about 0.85 to about 1.9% niobium, zirconium or a combination thereof
- up to 0.2% carbon
- up to 0.015% boron
- up to 0.015% rare earth elements
- up to 0.5% aluminum
- up to 1% manganese
- up to 1% silicon
- up to 1% tungsten
- up to 1% molybdenum, and
- balance cobalt plus impurities
- wherein titanium +niobium is from about 1.6 to about 3.6%.
A wroughtable, cobalt alloy consisting essentially of in weight percent:
- 23.6 to 29.5% chromium
- 16.7 to 24.8% iron
- 0.56 to 27.3% nickel
- 0.75 to 1.7% titanium
- 0.85 to 1.92% niobium
- up to 0.2% carbon
- up to 0.012% boron
- up to 0.015% rare earth elements
- up to 0.5% aluminum
- up to 0.92% manganese
- up to 0.97% silicon
- up to 1% tungsten
- up to 1% molybdenum;
- and
- balance cobalt plus impurities
- wherein titanium +niobium is from about 1.6 to about 3.6%.
A wroughtable, cobalt alloy capable of through thickness nitridation and strengthening consisting essentially of in weight percent:
- about 23 to about 30% chromium
- about 15 to about 25% iron
- up to about 27.3% nickel
- at least one element selected from the group consisting of titanium, zirconium and hafnium such that:
- 0.75≦Ti+Zr/1.91+Hf/3.73≦1.7
- at least one element selected from the group consisting of vanadium, niobium, zirconium and tantalum such that:
- 0.87≦Nb+Zr+V/1.98+Ta/1.98≦1.92
- up to 0.2% carbon
- up to 0.015% boron
- up to 0.015% rare earth elements
- up to 0.5% aluminum
- up to 1% manganese
- up to 1% silicon
- up to 1% tungsten
- up to 1% molybdenum, and
- balance cobalt plus impurities
- wherein the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
- 1.6≦Ti+1.52Zr+Hf/3.73+Nb+V/1.98+Ta/1.98≦3.6.
Dependencies are inferred from the claim text.