Nickel-base alloys

Claim 2

A nickel base alloy having unusual corrosion resistance to both oxidizing and reducing environments in all of the annealed, welded and thermally aged conditions and consisting essentially by weight of about 12% to 18% chromium, about 10% to 18% molybdenum, about 0 to 3% iron, about 0 to 7% tungsten, less than 0.5% aluminum, 0.02 max. carbon, 0.08 max. silicon, less than 2% cobalt, up to 0.75% of a member from the group consisting of titanium, zirconium, and hafnium, up to 0.75% of a member from the group consisting of vanadium and tantalum and the balance nickel with usual impurities in ordinary amounts, said composition being adjusted so that the atomically averaged electron vacancy concentration number, Nv, is in the range about 2.1 to about 2.4, as calculated from the equation Nv = 0.61 (a.sub.Ni) + 1.71 (a.sub.Co) + 2.66 (a.sub.Fe) + 3.66 (a.sub.Mn) + 4.66 (a.sub.Cr) + 5.66 (a.sub.Ta+Nb+V) + 6.66 (a.sub.Zr+Ti+Si+Hf) + 7.66 (a.sub.Al) + 8.66 (a.sub.Mg) + 9.66 (a.sub.W+MO) where each "a" indicates the actual atomic fraction of the alloying elements indicated by the subscripts.

Claim 3

A nickel base alloy as claimed in claim 1 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resistance factor (mpy) in the range 200 to 300 in hydrochloric acid and in the range 75 to 150 in the ferric sulfate test.

Claim 4

A nickel base alloy as claimed in claim 1 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resistance factor (mpy) in the range 200 to 300 in hydrochloric acid.

Claim 5

A nickel base alloy as claimed in claim 1 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resistance factor (mpy) in the range 75 to 150 in the ferric sulfate test.

Claim 6

A nickel base alloy as claimed in claim 1 having the composite consisting essentially of: ______________________________________ Chromium about 14% to about 17% Molybdenum about 14% to about 16% Iron <2% Tungsten 0.5% max. Aluminum <0.5% Carbon 0.01% max. Silicon 0.03% max. Cobalt <1% Manganese <0.5% Titanium up to 0.5% Nickel and Balance incidental im- purities. ______________________________________

Claim 7

A nickel base alloy as claimed in claim 5 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resistance factor (mpy) in the range 200 to 300 in hydrochloric acid and in the range 75 to 150 in the ferric sulfate test.

Claim 8

A nickel base alloy as claimed in claim 5 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resitance factor (mpy) in the range 200 to 300 in hydrochloric acid.

Claim 9

A nickel base alloy as claimed in claim 5 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resistance factor (mpy) in the range 75 to 150 in the ferric sulfate test.

Claim 10

A nickel base alloy as claimed in claim 1 having a composition consisting essentially of: ______________________________________ Chromium about 16% Molybdenum about 15% Iron <2% Tungsten 0.5% max. Aluminum <0.5% Carbon 0.01% max. Silicon 0.03% max. Cobalt <1% Manganese <0.5% Titanium up to 0.5% Nickel with usual Balance properties. ______________________________________

Claim 11

A fabricated welded article characterized by unusual corrosion resistance to both oxidizing and reducing environments and made from a nickel base alloy consisting essentially of: ______________________________________ Chromium about 14% to about 17% Molybdenum about 14% to about 16% Iron <2% Tungsten 0.5% max. Aluminum <0.5% Carbon 0.01% max. Silicon 0.03% max. Cobalt <1% Manganese <0.5% Titanium up to 0.5% Nickel and Balance incidental impurities ______________________________________ said composition being adjusted so that the atomically averaged electron vacancy concentration number, Nv, is in the range about 2.1 to 2.4, as calculated from the equation Nv = 0.61 (a.sub.Ni) + 1.71 (a.sub.Co) + 2.66 (a.sub.Fe) + 3.66 (a.sub.Mn) + 4.66 (a.sub.Cr) + 5.66 (.sub.Ta+Nb+V) + 6.66 (a.sub.Zr+Ti+Si+Hf) + 7.66 (a.sub.Al) + 8.66 (a.sub.Mg) + 9.66 (a.sub.W+Mo) where each "a" indicates the actual atomic fraction of the alloying elements indicated by the subscripts.

Claim 12

A fabricated welded article characterized by unusual corrosion resistance to both oxidizing and reducing environments and made from a nickel base alloy consisting essentially of: ______________________________________ Chromium about 14% to about 17% Molybdenum about 14% to about 16% Iron <2% Tungsten 0.5% max. Aluminum <0.5% Carbon 0.01% max. Silicon 0.03% max. Cobalt <1% Manganese <0.5% Titanium up to 0.5% Nickel and Balance incidental impurities ______________________________________ said composition being adjusted so that the atomically averaged electron vacancy concentration number, Nv, is in the range about 2.1 to 2.4, as calculated from the equation Nv = 0.61 (a.sub.Ni) + 1.71 (a.sub.Co) + 2.66 (a.sub.Fe) + 3.66 (a.sub.Mn) + 4.66 (a.sub.Cr) + 5.66 (.sub.Ta+Nb+V) + 6.66 (a.sub.Zr+Ti+Si+Hf) + 7.66 (a.sub.Al) + 8.66 (a.sub.Mg) + 9.66 (a.sub.W+Mo) where each "a" indicates the actual atomic fraction of the alloying elements indicated by the subscripts.

Claim 13

A nickel base alloy as claimed in claim 10 having a balanced relationship of the elements Cr, Mo, Fe and W to provide in the annealed condition a corrosion resistance factor (mpy) in the range 200 to 300 in hydrochloric acid and in the range 75 to 150 in the ferric sulfate test.

Claim 14

A fabricated welded article as claimed in claim 10 made from an alloy consisting essentially of: ______________________________________ Chromium about 16% Molybdenum about 15% Iron <2% Tungsten 0.5% max. Aluminum < 0.5% Carbon 0.01% max. Silicon 0.03% max. Cobalt <1% Manganese <0.5% Titanium up to 0.5% Nickel and Balance incidental impurities ______________________________________ and wherein the atomically averaged electron vacancy concentration number, Nv, is in the range about 2.1 to 2.4, as calculated from the equation Nv = 0.61 (a.sub.Ni) + 1.71 (a.sub.co) + 2.66 (a.sub.Fe) + 3.66 (a.sub.Mn) + 4.66 (a.sub.Cr) + 5.66 (a.sub.Ta+Nb+V) + 6.66 (a.sub.Zr+Ti+Si+Hf) + 7.66 (a.sub.Al) + 8.66 (a.sub.Mg) + 9.66 (a.sub.W+Mo) where each "a" indicates the actual atomic fraction of the alloying elements indicated by the subscripts.