Methods for processing alloys
First Claim
Patent Images
1. A method of processing a workpiece to inhibit precipitation of intermetallic compounds, the method comprising:
- at least one of thermomechanically working and cooling a workpiece including an austenitic alloy, wherein during the at least one of thermomechanically working and cooling the workpiece, the austenitic alloy is at temperatures in a temperature range spanning a temperature just less than a calculated sigma solvus temperature of the austenitic alloy down to a cooling temperature for a time no greater than a critical cooling time;
wherein the austenitic alloy comprises, in weight percentages based on total alloy weight, up to 0.2 carbon, up to 20 manganese, 0.1 to 1.0 silicon, 14.0 to 28.0 chromium, 15.0 to 25.43 nickel, 2.0 to 9.0 molybdenum, 0.1 to 3.0 copper, 0.08 to 0.9 nitrogen, 0.1 to 5.0 tungsten, 0.5 to 5.0 cobalt, up to 1.0 titanium, up to 0.05 boron, up to 0.05 phosphorus, up to 0.05 sulfur, 0.01 to 1.0 vanadium, 20 to 60 iron, and incidental impurities;
wherein the calculated sigma solvus temperature is a function of the composition of the austenitic alloy in weight percentages and, in Fahrenheit degrees, is equal to 1155.8−
(760.4)·
(nickel/iron)+(1409)·
(chromium/iron)+(2391.6)·
(molybdenum/iron)−
(288.9)·
(manganese/iron)−
(634.8)·
(cobalt/iron)+(107.8)·
(tungsten/iron);
wherein the cooling temperature is a function of the composition of the austenitic alloy in weight percentages and, in Fahrenheit degrees, is equal to 1290.7−
(604.2)·
(nickel/iron)+(829.6)·
(chromium/iron)+(1899.6)·
(molybdenum/iron)−
(635.5)·
(cobalt/iron)+(1251.3)·
(tungsten/iron); and
wherein the critical cooling time is a function of the composition of the austenitic alloy in weight percentages and, in minutes, is equal to, in log10, 2.948+(3.631)·
(nickel/iron)−
(4.846)·
(chromium/iron)−
(11.157)·
(molybdenum/iron)+(3.457)·
(cobalt/iron)−
(6.74)·
(tungsten/iron), and wherein the critical cooling time is in a range of 10 minutes to 30 minutes.
2 Assignments
0 Petitions
Accused Products
Abstract
A method of processing a workpiece to inhibit precipitation of intermetallic compounds includes at least one of thermomechanically processing and cooling a workpiece including an austenitic alloy. During the at least one of thermomechanically working and cooling the workpiece, the austenitic alloy is at temperatures in a temperature range spanning a temperature just less than a calculated sigma solvus temperature of the austenitic alloy down to a cooling temperature for a time no greater than a critical cooling time.
-
Citations
38 Claims
-
1. A method of processing a workpiece to inhibit precipitation of intermetallic compounds, the method comprising:
-
at least one of thermomechanically working and cooling a workpiece including an austenitic alloy, wherein during the at least one of thermomechanically working and cooling the workpiece, the austenitic alloy is at temperatures in a temperature range spanning a temperature just less than a calculated sigma solvus temperature of the austenitic alloy down to a cooling temperature for a time no greater than a critical cooling time; wherein the austenitic alloy comprises, in weight percentages based on total alloy weight, up to 0.2 carbon, up to 20 manganese, 0.1 to 1.0 silicon, 14.0 to 28.0 chromium, 15.0 to 25.43 nickel, 2.0 to 9.0 molybdenum, 0.1 to 3.0 copper, 0.08 to 0.9 nitrogen, 0.1 to 5.0 tungsten, 0.5 to 5.0 cobalt, up to 1.0 titanium, up to 0.05 boron, up to 0.05 phosphorus, up to 0.05 sulfur, 0.01 to 1.0 vanadium, 20 to 60 iron, and incidental impurities; wherein the calculated sigma solvus temperature is a function of the composition of the austenitic alloy in weight percentages and, in Fahrenheit degrees, is equal to 1155.8−
(760.4)·
(nickel/iron)+(1409)·
(chromium/iron)+(2391.6)·
(molybdenum/iron)−
(288.9)·
(manganese/iron)−
(634.8)·
(cobalt/iron)+(107.8)·
(tungsten/iron);wherein the cooling temperature is a function of the composition of the austenitic alloy in weight percentages and, in Fahrenheit degrees, is equal to 1290.7−
(604.2)·
(nickel/iron)+(829.6)·
(chromium/iron)+(1899.6)·
(molybdenum/iron)−
(635.5)·
(cobalt/iron)+(1251.3)·
(tungsten/iron); andwherein the critical cooling time is a function of the composition of the austenitic alloy in weight percentages and, in minutes, is equal to, in log10, 2.948+(3.631)·
(nickel/iron)−
(4.846)·
(chromium/iron)−
(11.157)·
(molybdenum/iron)+(3.457)·
(cobalt/iron)−
(6.74)·
(tungsten/iron), and wherein the critical cooling time is in a range of 10 minutes to 30 minutes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. A method of processing an austenitic alloy workpiece to inhibit precipitation of intermetallic compounds, the method comprising:
-
forging the workpiece; cooling the forged workpiece; and optionally, annealing the cooled workpiece; wherein the austenitic alloy comprises, in weight percentages based on total alloy weight, up to 0.2 carbon, up to 20 manganese, 0.1 to 1.0 silicon, 14.0 to 28.0 chromium, 15.0 to 25.43 nickel, 2.0 to 9.0 molybdenum, 0.1 to 3.0 copper, 0.08 to 0.9 nitrogen, 0.1 to 5.0 tungsten, 0.5 to 5.0 cobalt, up to 1.0 titanium, up to 0.05 boron, up to 0.05 phosphorus, up to 0.05 sulfur, 0.01 to 1.0 vanadium, 20 to 60 iron, and incidental impurities; wherein during forging the workpiece and cooling the forged workpiece the austenitic alloy cools through a temperature range spanning a temperature just less than a calculated sigma solvus temperature of the austenitic alloy down to a cooling temperature for a time no greater than a critical cooling time; wherein the calculated sigma solvus temperature is a function of the composition of the austenitic alloy in weight percentages and, in Fahrenheit degrees, is equal to 1155.8−
(760.4)·
(nickel/iron)+(1409)·
(chromium/iron)+(2391.6)·
(molybdenum/iron)−
(288.9)·
(manganese/iron)−
(634.8)·
(cobalt/iron)+(107.8)·
(tungsten/iron);wherein the cooling temperature is a function of the composition of the austenitic alloy in weight percentages and, in Fahrenheit degrees, is equal to 1290.7−
(604.2)·
(nickel/iron)+(829.6)·
(chromium/iron)+(1899.6)·
(molybdenum/iron)−
(635.5)·
(cobalt/iron)+(1251.3)·
(tungsten/iron);wherein the critical cooling time is a function of the composition of the austenitic alloy in weight percentages and, in minutes, is equal to, in log10, 2.948+(3.631)·
(nickel/iron)−
(4.846)·
(chromium/iron)−
(11.157)·
(molybdenum/iron)+(3.457)·
(cobalt/iron)−
(6.74)·
(tungsten/iron), and wherein the critical cooling time is in a range of 10 minutes to 30 minutes. - View Dependent Claims (36, 37, 38)
-
Specification