STABILIZED ACID AND ALKALI RESISTANT Ni-Cr-Mo-Co ALLOYS
A nickel-chromium-molybdenum-copper alloy resistant to 70% sulfuric acid at 93° C. and 50% sodium hydroxide at 121° C. for acid and alkali neutralization in the field of waste management; the alloy contains, in weight percent, 27 to 33 chromium, 4.9 to 7.8 molybdenum, greater than 3.1 but no more than 6.0 copper, up to 3.0 iron, 0.3 to 1.0 manganese, 0.1 to 0.5 aluminum, 0.1 to 0.8 silicon, 0.01 to 0.11 carbon, up to 0.13 nitrogen, up to 0.05 magnesium, up to 0.05 rare earth elements, with a balance of nickel and impurities. Titanium or another MC carbide former can be added to enhance thermal stability of the alloy.
1 . A nickel-chromium-molybdenum-copper alloy resistant to 70% sulfuric acid at 93° C. and 50% sodium hydroxide at 121° C., consisting essentially of:
27 to 33 wt. % chromium
4.9 to 7.8 wt. % molybdenum
greater than 3.1 wt. % but no more than 6.0 wt. % copper
up to 3.0 wt. % iron
0.3 to 1.0 wt. % manganese
0.1 to 0.5 wt. % aluminum
0.1 to 0.8 wt. % silicon
0.01 to 0.11 wt. % carbon
up to 0.13 wt. % nitrogen
up to 0.05 wt. % magnesium
up to 0.05 wt. % rare earth elements
up to 0.56 wt. % titanium
up to 1.12 wt. % niobium
up to 2.24 wt. % tantalum
up to 2.24 wt. % hafnium
with a balance of nickel and impurities.
2 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the impurities comprise levels of at least one of cobalt, tungsten, sulfur, phosphorus, oxygen, and calcium.
3 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloys are in wrought forms selected from the group consisting of sheets, plates, bars, wires, tubes, pipes, and forgings.
4 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy is in cast form.
5 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy is in powder metallurgy form.
6 . The nickel-chromium-molybdenum-copper alloy of claim 1 , consisting essentially of:
30 to 33 wt. % chromium
5.0 to 6.2 wt. % molybdenum
3.5 to 4.0 wt. % copper
up to 1.5 wt. % iron
0.3 to 0.7 wt. % manganese
0.1 to 0.4 wt. % aluminum
0.1 to 0.6 wt. % silicon
0.02 to 0.10 wt. % carbon
7 . The nickel-chromium-molybdenum-copper alloy of claim 1 , consisting essentially of:
31 wt. % chromium
5.6 wt. % molybdenum
3.8 wt. % copper
1.0 wt. % iron
0.5 wt. % manganese
0.4 wt. % silicon
0.3 wt. % aluminum
0.03 to 0.07 wt. % carbon
with a balance of nickel, nitrogen, impurities, and trace amounts of magnesium.
8 . The nickel-chromium-molybdenum-copper alloy of claim 1 , consisting essentially of:
31 wt. % chromium
5.6 wt. % molybdenum
3.8 wt. % copper
1.0 wt. % iron
0.5 wt. % manganese
0.4 wt. % silicon
0.3 wt. % aluminum
0.03 to 0.07 wt. % carbon
with a balance of nickel, nitrogen, impurities, trace amounts of magnesium and trace amounts of the rare earth elements.
9 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy contains at least one MC carbide former.
10 . The nickel-chromium-molybdenum-copper alloy of claim 9 , wherein the MC carbide former is selected from the group consisting of titanium, niobium, tantalum and hafnium.
11 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy contains 0.20 to 0.56 wt. % titanium.
12 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy contains 0.30 to 1.12 wt. % niobium.
13 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy contains 0.60 to 2.24 wt. % tantalum.
14 . The nickel-chromium-molybdenum-copper alloy of claim 1 , wherein the alloy contains 0.60 to 2.24 wt. % hafnium.