Method for producing two-phase Ni—Cr—Mo alloys
In a method for making a wrought nickel-chromium-molybdenum alloy having homogeneous, two-phase microstructures the alloy in ingot form is subjected to a homogenization treatment at a temperature between 2025° F. and 2100° F., and then hot worked at start temperature between 2025° F. and 2100° F. The alloy preferably contains 18.47 to 20.78 wt. % chromium, 19.24 to 20.87 wt. % molybdenum, 0.08 to 0.62 wt. % aluminum, less than 0.76 wt. % manganese, less than 2.10 wt. % iron, less than 0.56 wt. % copper, less than 0.14 wt. % silicon, up to 0.17 wt. % titanium, less than 0.013 wt. % carbon, and the balance nickel.
1. A method for making a wrought nickel-chromium-molybdenum alloy having homogeneous, two-phase microstructures comprising:
a. obtaining a nickel-chromium-molybdenum alloy ingot that contains 18.47 to 20.78 wt. % chromium, 19.24 to 20.87 wt. % molybdenum, 0.08 to 0.62 wt. % aluminum, less than 0.76 wt. % manganese, less than 2.10 wt. % iron, less than 0.56 wt. % copper, less than 0.14 wt. % silicon, up to 0.17 wt. % titanium, less than 0.013 wt. % carbon, and the balance nickel,
b. subjecting the ingot to a homogenization treatment at a temperature between 2025° F. and 2100° F., and,
c. hot working the ingot at a start temperature between 2025° F. and 2100° F.
2. The method of claim 1 wherein the hot working comprises at least one of hot forging and hot rolling.
3. The method of claim 1 wherein the nickel-chromium-molybdenum alloy ingot contains tungsten.
4. The method of claim 1 wherein the nickel-chromium-molybdenum alloy ingot has a combined content of chromium and molybdenum which is greater than 37.87 wt.
5. The method of claim 1 wherein the nickel-chromium-molybdenum alloy ingot contains up to 4 wt. % tungsten.
6. The method of claim 1 wherein the temperature of the homogenization treatment is between 2025° F. and 2075° F.
7. The method of claim 1 wherein the temperature of the homogenization treatment is 2050° F.
8. The method of claim 1 wherein the homogenization treatment is performed for 24 hours.