US3871928A — Heat treatment of nickel alloys

Claim 1

Independent Claim 354 words

A PROCESS OF HEAT TREATING AN AGE-HARDENABLE HEATRESISTANT NICKEL ALLOY CONSISTING ESSENTIALLY OF AT LEAST ABOUT 25% NICKEL AND UP TO 60% IRON, WITH A TOTAL OF AT LEAST 50% NICKEL-PLUS-IRON, AND PRECIPITABLE AMOUNTS OF GAMMA-PRIME FORMING METAL SELECTED FROM THE GROUP CONSISTING OF UP TO 6.5% COLUMBIUM, UP TO 5% TITANIUM AND UP TO 6% TANTALUM AND MIXTURES THEREOF WITH A TOTAL OF AT LEAST 2% COLUMNIUMPLUS-TITANIUM-PLUS-1/2 TANTALUM UP TO 6.5% ALUMINUM, THE TOTAL OF THE COLUMBIUM CONTENT PLUS THE TITANIUM CONTENT PLUS THE ALUMINUM CONTENT PLUS ONE-HALF THE TANTALUM CONTENT DOES NOT EXCEED 10%, UP TO 2% VANDIUM, UP TO 25% CHROMIUM, UP TO 30% COBALT, UP TO 10% MOLYBDENUM, TUNGSTEN OR MIXTURES THEREOF, UP TO 0.2% BORON, UP TO 0.2% ZIRCONIUM AND UP TO 0.2% CARBON AND CHARACTERIZED BY A SOLIDUS TEMPERATURE OF AT LEAST ABOUT 2,300*F., A GAMMA-PRIME SOLVUS TEMPERATURE OF AT LEAST 1600*F. AND A GAMMA-PRIME PRECIPITATION TEMPERATURE OF AT LEAST 1100*F. COMPRISING: A.HEATING THE ALLOY AT A TEMPERATURE OF ABOUT 1,600 TO 1,950*F AND GAMMA-PRIME SOLID SOLUTION RANGE OF THE ALLOY AND OBTAINING THE ALLOY IN THE SOLID SOLUTION CONDITION HAVING PRECIPITABLE AMOUNTS OF THE GAMMA-PRIME FORMING METAL IN SOLID SOLUTION, B. COOLING THE ALLOY FROM THE SOLID SOLUTION TEMPERATURE DOWN TO THE GAMMA-PRIME SOLVUS TEMPERATURE; THEN SLOWLY COOLING THE ALLOY UNIFORMLY AT A CONTROLLED COOLING RATE OF AT LEAST ABOUT 20*F. PER HOUR AND NOT GREATER THAN 500*F. PER HOUR FROM THE GAMMA-PRIME SOLVUS TEMPERATURE DOWN TO ABOUT 1,100*F OR LOWER, D.HEAT TREATING THE SLOW-COOLED ALLOY AT AN UPPER TEMPERATURE IN THE PRECIPITATION RANGE TO PRECIPITATE COARSE PATCHES OF GAMMA-PRIME IN THE VINCINITY OF THE GRAIN BOUNDERIES OF THE ALLOY AND DISPERSED UNIFORMLY WITHIN THE GRAINS WHILE RETAINING A PORTION OF THE GAMMA-PRIME FORMING METAL IN SOLUTION; E.THEREAFTER HEAT TREATING THE ALLOY AT A LOWER TEMPERATURE IN THE PRECIPITATION HARDENING RANGE TO PRECIPITATE FINE PARTICLES OF GAMMA-PRIME DISPERSED UNIFORMLY WITHIN THE GRAINS, AND F. THEN COOLING THE ALLOY TO ROOM TEMPERATURE, TO THEREBY PROVIDE THE ALLOY IN THE HEAT TREATED CONDITION CHARACTERIZED BY HAVING COARSE GAMMA-PRIME PARTICLES AT LEAST TWICE THE SIZE OF THE FINE GAMMA-PRIME PARTICLES.

Claim 2

Dependent Claim 354 words

A PROCESS OF HEAT TREATING AN AGE-HARDENABLE HEATRESISTANT NICKEL ALLOY CONSISTING ESSENTIALLY OF AT LEAST ABOUT 25% NICKEL AND UP TO 60% IRON, WITH A TOTAL OF AT LEAST 50% NICKEL-PLUS-IRON, AND PRECIPITABLE AMOUNTS OF GAMMA-PRIME FORMING METAL SELECTED FROM THE GROUP CONSISTING OF UP TO 6.5% COLUMBIUM, UP TO 5% TITANIUM AND UP TO 6% TANTALUM AND MIXTURES THEREOF WITH A TOTAL OF AT LEAST 2% COLUMNIUMPLUS-TITANIUM-PLUS-1/2 TANTALUM UP TO 6.5% ALUMINUM, THE TOTAL OF THE COLUMBIUM CONTENT PLUS THE TITANIUM CONTENT PLUS THE ALUMINUM CONTENT PLUS ONE-HALF THE TANTALUM CONTENT DOES NOT EXCEED 10%, UP TO 2% VANDIUM, UP TO 25% CHROMIUM, UP TO 30% COBALT, UP TO 10% MOLYBDENUM, TUNGSTEN OR MIXTURES THEREOF, UP TO 0.2% BORON, UP TO 0.2% ZIRCONIUM AND UP TO 0.2% CARBON AND CHARACTERIZED BY A SOLIDUS TEMPERATURE OF AT LEAST ABOUT 2,300*F., A GAMMA-PRIME SOLVUS TEMPERATURE OF AT LEAST 1600*F. AND A GAMMA-PRIME PRECIPITATION TEMPERATURE OF AT LEAST 1100*F. COMPRISING: A.HEATING THE ALLOY AT A TEMPERATURE OF ABOUT 1,600 TO 1,950*F AND GAMMA-PRIME SOLID SOLUTION RANGE OF THE ALLOY AND OBTAINING THE ALLOY IN THE SOLID SOLUTION CONDITION HAVING PRECIPITABLE AMOUNTS OF THE GAMMA-PRIME FORMING METAL IN SOLID SOLUTION, B. COOLING THE ALLOY FROM THE SOLID SOLUTION TEMPERATURE DOWN TO THE GAMMA-PRIME SOLVUS TEMPERATURE; THEN SLOWLY COOLING THE ALLOY UNIFORMLY AT A CONTROLLED COOLING RATE OF AT LEAST ABOUT 20*F. PER HOUR AND NOT GREATER THAN 500*F. PER HOUR FROM THE GAMMA-PRIME SOLVUS TEMPERATURE DOWN TO ABOUT 1,100*F OR LOWER, D.HEAT TREATING THE SLOW-COOLED ALLOY AT AN UPPER TEMPERATURE IN THE PRECIPITATION RANGE TO PRECIPITATE COARSE PATCHES OF GAMMA-PRIME IN THE VINCINITY OF THE GRAIN BOUNDERIES OF THE ALLOY AND DISPERSED UNIFORMLY WITHIN THE GRAINS WHILE RETAINING A PORTION OF THE GAMMA-PRIME FORMING METAL IN SOLUTION; E.THEREAFTER HEAT TREATING THE ALLOY AT A LOWER TEMPERATURE IN THE PRECIPITATION HARDENING RANGE TO PRECIPITATE FINE PARTICLES OF GAMMA-PRIME DISPERSED UNIFORMLY WITHIN THE GRAINS, AND F. THEN COOLING THE ALLOY TO ROOM TEMPERATURE, TO THEREBY PROVIDE THE ALLOY IN THE HEAT TREATED CONDITION CHARACTERIZED BY HAVING COARSE GAMMA-PRIME PARTICLES AT LEAST TWICE THE SIZE OF THE FINE GAMMA-PRIME PARTICLES.

Claim 3

Dependent Claim 40 words

A process as set forth in claim 1 wherein the alloy is slowly cooled from the solid-solution temperature down through the precipitation hardening temperature range at a slow-cooling rate in the range of 50*F. per hour to 500*F. per hour.

Claim 4

Dependent Claim 24 words

A process as set forth in claim 2 wherein the slow-cooling rate is in the range of 100*F. per hour to 200*F. per hour.

Claim 5

Dependent Claim 24 words

A process as set forth in claim 2 wherein the slow-cooling rate is in the range of 250*F. per hour to 350*F. per hour.

Claim 6

Dependent Claim 100 words

A process as set forth in claim 1 wherein, after the alloy is slow-cooled to at least 100*F. below the gamma-prime solvus temperature, the reheating at an upper temperature is at about 1, 450*F. to about 1,625*F. for about 1 to 24 hours and the reheating at a lower temperature is accomplished by reheating at about 1,275*F. to 1,425*F. for about 1 to 24 hours, then cooling at a rate of about 20*F. per hour to 200*F. per hour to a range of about 1,100*F. to 1,200*F. and holding at about 1,100*F. to 1, 200*F. for at least 5 hours.

Claim 7

Dependent Claim 99 words

A process as set forth in claim 1 wherein, the solid solution temperature is at least about 1,675*F., the alloy is slow cooled from the solid solution temperature down through the precipitation hardening temperature at a rate in the range of 250*F. per hour to 350*F. per hour and is thereafter further heat treated by reheating at about 1,275*F. to 1,425*F. for about 1 to 24 hours, then cooling at a rate of about 20*F. per hour to 200*F. per hour to a range of about 1,100*F. to 1,200*F. and holding at about 1,100*F. for at least 5 hours.

Claim 8

Dependent Claim 52 words

A process as set forth in claim 1 wherein the alloy contains about 39% to 44% nickel, 14.5% to 17.5% chromium, 1.5% to 2% titanium, 2.5% to3.3% columbium, 0.05% to 0.4% aluminum, up to 0.06% carbon, up to 0.35% manganese, up to 0.35% silicon, up to 0.006% boron and balance essentially iron.

Claim 9

Dependent Claim 35 words

A process as set forth in claim 7 wherein the coarse particles are precipitated with sizes of 0.04 microns to 0.1 microns and the fine particles are precipitated with sizes of up to 0.02 microns.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-03-17	1978-09-16	1979-03-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-03-17	1982-09-16	1983-03-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-03-17	1986-09-16	1987-03-18	$7700.00	Window Closed / Lapsed

Heat treatment of nickel alloys

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