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US 8,557,063 B2Granted
Method for heat treating serviced turbine part
AssigneeGeneral Electric Company
InventorsSamuel V. Thamboo, Ling Yang
Life of this patent
Estimating the term…
Abstract
A method for heat treating a serviced turbine part to improve a hold time fatigue cracking resistance of the serviced turbine part is provided. The method includes positioning the serviced turbine part in a vacuum furnace configured to limit surface oxidation. The serviced turbine part is controllably heated to prevent distortion. A surface damage layer is recrystallized into a fine grain structure to prevent fatigue crack initiation. The serviced turbine part is controllably cooled to prevent distortion.
Claims18
A method for heat treating a turbine part, said method comprising:
- positioning a serviced turbine part, prior to crack initiation, and including a surface damage layer, in a vacuum furnace configured to limit surface oxidation, wherein the surface damage layer includes the outermost surface of the turbine part, and wherein positioning the turbine part comprises positioning the turbine part in contact with a support configured to facilitate preventing distortion of the turbine part;
- controllably heating the turbine part to a peak heat treatment temperature of between about 1750° F. to about 1900° F. to prevent distortion, wherein controllably heating the turbine part comprises:
- heating the turbine part to a first holding temperature of between about 1000° F. to about 1100° F.;
- and
- stabilizing the turbine part at the first holding temperature for a predetermined amount of time to facilitate substantially equalizing a temperature of an outer surface and a temperature of an interior region of the turbine part;
- recrystallizing the surface damage layer at the peak heat treatment temperature into a fine grain structure to prevent fatigue crack initiation;
- and
- controllably cooling the turbine part to prevent distortion.
5 more elements
A method for heat treating a serviced turbine rotor disk, said method comprising:
- positioning a serviced turbine rotor disk, prior to crack initiation, and including a surface damage layer, in a vacuum furnace configured to prevent surface oxidation, wherein the surface damage layer includes the outermost surface of the serviced turbine rotor disk, and wherein positioning the serviced turbine rotor disk comprises positioning the serviced turbine rotor disk in contact with a support configured to facilitate preventing distortion of the turbine rotor disk;
- controlling a heating rate to a peak heat treatment temperature of between about 1750° F. to about 1900° F. to minimize a temperature difference between an outer surface of the serviced turbine rotor disk and an interior region of the serviced turbine rotor disk, wherein controlling a heating rate further comprises stabilizing the serviced turbine rotor disk at a series of intermediate holding temperatures for a time period of about 1 hour to about 3 hours;
- and
- recrystallizing the surface damage layer of the serviced turbine rotor disk at the peak heat treatment temperature.
1 more element
A method for heat treating a serviced turbine rotor disk, said method comprising:
- positioning a serviced turbine rotor disk, prior to crack initiation, and including a surface damage layer, in a vacuum furnace configured to prevent surface oxidation, wherein the surface damage layer includes the outermost surface of the serviced turbine rotor disk, and wherein positioning the serviced turbine rotor disk comprises positioning the serviced turbine rotor disk in contact with a support configured to facilitate preventing distortion of the turbine rotor disk;
- heating the serviced turbine rotor disk at a rate of about 2° F./min. to about 4° F./min. to a first holding temperature of about 1100° F.;
- stabilizing the serviced turbine rotor disk at the first holding temperature for a period of about 1 hour to about 3 hours;
- heating the serviced turbine rotor disk at a rate of about 2° F./min. to about 4° F./min. to a second holding temperature of about 1500° F.;
- stabilizing the serviced turbine rotor disk at the second holding temperature for a period of about 1 hour to about 3 hours;
- and
- heating the serviced turbine rotor disk at a rate of about 2° F./min. to about 4° F./min. to a peak heat treatment temperature of about 1750° F. to about 1900° F. to recrystallize the surface damage layer of the serviced turbine rotor disk.
4 more elements
Dependencies are inferred from the claim text.