Claims
- 1. A method for preventing the formation of segregated carbide precipitates in an alloy susceptible to the reprecipitation of segregated metal carbides, said alloy comprising by weight 13-15% Mo, 6-8% Cr, 0-2% Fe, 0-2% Mn, 1.8-2.2% Ti, 0.05-0.08% C and the balance Ni, said method comprising the steps of:
- (a) first annealing said alloy having a segregated carbide phase at a temperature above the minimum single phase temperature for a time sufficient to dissolve said metal carbides and provide a single phase alloy; and
- (b) further annealing said single phase alloy at a temperature above the minimum single phase temperature for a time, at least three-quarters hour, to prevent the precipitation of segregated metal carbides upon subsequent aging or thermomechanical treatment, said minimum single phase temperature being above 1205.degree. C.
- 2. The method of claim 1 in which said alloy has a composition by weight comprising about 15% Mo, 7% Cr, 0.5% Mn, 1.8-2.2% Ti, 0.05-0.08% C and the balance Ni.
- 3. The alloy prepared by the method of claim 1 and having a precipitated metal carbide phase uniformly dispersed throughout the alloy.
- 4. The method of claim 1 in which said annealing steps (a) and (b) are performed at a temperature above 1280.degree. C.
- 5. A method for preventing the formation of segregated carbide precipitates in an alloy susceptible to the reprecipitation of segregated metal carbides, said alloy comprising by weight 12-16% Mo, 5-9% Cr, 0-3% Fe, 0-3% Mn, 1-2% Ti, 0.02-0.08% C and the balance Ni, said method comprising the steps of:
- (a) first annealing said alloy having a segregated carbide phase at a temperature above the minimum single phase temperature for a time sufficient to dissolve said metal carbides and provide a single phase alloy; and
- (b) further annealing said single phase alloy at a temperature above the minimum single phase temperature for a time, at least three-quarters hour, to prevent the precipitation of segregated metal carbides upon subsequent aging or thermomechanical treatment, said minimum single phase temperature being above 1177.degree. C.
- 6. The alloy prepared by the method of claim 5 and having a precipitated metal carbide phase uniformly dispersed throughout the alloy.
BACKGROUND OF THE INVENTION
This invention was made in the course of, or under, a contract with the United States Department of Energy. This invention relates to the homogenization of alloys and more specifically to the homogenization of alloys prone to the formation of precipitate stringers.
US Referenced Citations (7)
Non-Patent Literature Citations (1)
Entry |
Braski, D. N., Lietnaker, J. M., "Production of Homogeneous Titanium-Hastelloy N Alloys", ORNL/TM-5697, 2/1977. |