US3151981A - Nickel-chromium-cobalt alloy - Google Patents

Nickel-chromium-cobalt alloy Download PDF

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Publication number
US3151981A
US3151981A US175555A US17555562A US3151981A US 3151981 A US3151981 A US 3151981A US 175555 A US175555 A US 175555A US 17555562 A US17555562 A US 17555562A US 3151981 A US3151981 A US 3151981A
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alloy
iron
alloys
content
niobium
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US175555A
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English (en)
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Ronald A Smith
Heslop John
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Huntington Alloys Corp
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International Nickel Co Inc
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/055—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 20% but less than 30%

Definitions

  • This invention relates to heatand creep-resistant alloys and, more particularly, to nickel-chromium-cobalt alloys suitable for use in rotor discs for gas turbines.
  • a common type of rotor consists of a disc mounted on a shaft and carrying a number of blades fastened to its rim by means of the well known fir-tree type of joint. Advances in the field of alloy evelopment during the last two decades have resulted in improved blading materials which have enabled operating temperatures, and hence turbine efliciency, to be greatly increased. The materials used for the disc components have not been correspondingly improved, partly owing to improvements in design, including the development of disc cooling techniques.
  • the diiferent properties required of a rotor disc material are manifold and complex and, to a large extent, conflicting. Of particular significance is the large variation of temperature occurring radially between the center or hub and the periphery or rim of the disc. This temperature gradient is accompanied by a stress gradient in the opposite sense so that the highest stress occurs in the low temperature region near the hub and vice versa.
  • a rotor disc material must, therefore, have a high creep strength, i.e., a low creep rate at high stresses, up to relatively high temperatures, e.g., 600 C., to ensure freedom from distortion by creep in service, particularly at the rim, and a high proof stress and ultimate tensile strength at more moderate temperatures to ensure that the high hub stresses do not lead to distortion or fracture on loading.
  • the disc material should have a high value of Youngs modulus and a low coefiicient of thermal expansion to minimize the overall expansion of the disc. It must have adequate ductility and must not be notch sensitive at temperatures corresponding to that at which the rim, with its fir-tree recesses, operates. Furthermore, the need to produce a relatively complex shape of appreciable size requires that the alloy shall be hot workable.
  • Another object of the invention is to provide a novel alloy especially suited for use as gas turbine structures, especially power rotor discs.
  • the invention also contemplates providing gas turbine power rotor discs made of an alloy having an advantageous combination of tensile characteristics, creep characteristics and other characteristics, properties, etc., necessary to provide enhanced qualities of utility in a turbine power rotor.
  • the alloy contains, in percent by weight, about 0.03% to 0.09% carbon, about 14% to about 22% chromium, about 10% to 20% cobalt, from 3% to about 8% molybdenum, from 2% to about 3.5% titanium, from 0% to about 0.8% aluminum, the sum of the titanium and aluminum contents being greater than 2.5% (i.e., at least 2.6%), about 2% to about 5.25% niobium (i.e., columbium), from 0% to about 25% iron, the contents of niobium and iron being so correlated that they are within the area ABCDEA in the accompanying drawing, about 0.001% to 0.01% boron and about 0.01% to about 0.1% zirconium, the balance, apart from impurities and residual deoxidants, being nickel.
  • the molybdenum content of the alloy can be up to about 10% (i.e., from 3% to 10%).
  • the usual major impurities in alloys of this kind are silicon and manganese and not more than 1% of each of these may be present, and the total amount of impurities and residual deoxidants should not exceed 2%.
  • the impurity content should be kept as low as is practicable and, in particular, it is advantageous to keep the silicon content below 0.3%.
  • chromium contents less than 14% the resistance of the alloy to oxidation and to attack by the products of combustion of turbine fuel falls off.
  • increasing the chromium content tends to reduce the hot workability of the alloy.
  • the chromium content must, therefore, not be greater than 22%.
  • Cobalt has some beneficial effect on creep resistance and also improves hot workability, and may usefully be present in amounts from 10% up to 20%.
  • Molybdenum has a beneficial effect on both tensile and creep ductility and is very desirable in order to avoid notch sensitivity.
  • excessive additions of molybdenum carry the penalties of increased creep rate and decreased machineability and the content should, therefore, not exceed 10% and, advantageously, is not more than 8%.
  • Aluminum has a particularly harmful effect on ductility, and not more than 0.8% may be present. Other things being equal, lower levels of ductility are obtained in the presence of much iron than in its absence, and if the iron content exceeds 10%, the aluminum content preferably does not exceed 0.5% Increasing the titanium content also leads to a decrease in the room temperature impact strength of the alloys, and the titanium content must not exceed 3.5%.
  • Niobium available from commercial sources is usually contaminated by tantalum, which element is substantially equivalent to niobiurn in its efiect, and niobium may be partly or wholly replaced by an equal weight of tantalum up to a maximum tantalum content of 3%.
  • the alloys can be air melted, but advantageously, they are melted and cast under vacuum conditions. If they are melted in air they are advantageously deoxidized by means of magnesium. If too much deoxidant is added the workability of the alloys is seriously reduced and, advantageously, the residual magnesium content does not exceed 0.01%.
  • Air melted alloys are advantageously refined by holding under vacuum in the molten state for some time before casting.
  • the pressure during this treatment should not be more than 0.1 mm. Hg and advantageously is lower, e.g., 5 microns or less.
  • the temperature is suitably 1400" C.-1600 C., and the holding timeshould be at least 5 minutes and, advantageously, is at least 10 minutes.
  • the cast ingots can be processed to rotor disc form by conventional extrusion, forging, or pressing techniques.
  • the discs require suitable heat treatment in order to develop the critical combination of properties required.
  • the alloys are of the age-hardenable type and require both solution and aging treatments. The former is most important in that for a given alloy it largely decides the relative levels of creep strength and proof strength that can be achieved. Very high solution treatment temperatures give the highest possible creep resistance, while on the other hand lower solution treatment temperatures favor increased proof strength.
  • the solution heating temperature should, of course, not be higher than the solidus temperature of the alloy, but high enough to ensure that all constituents of the alloy are taken into solution.
  • a suitable heat treatment for discs made from the alloys comprises solution treatment for /2-8 hours at 900 C.-1200 0., followed by air cooling or oil quenching and then aging at temperatures in the range 600 C.-850 C.
  • the solution temperature is advantageously at least 1000 C. and a high level of proof strength together with reasonable creep strength is obtained after a heat treatment comprising solution heating for one hour at 1050 C., followed by air cooling and aging for 16-40 hours at 700 C.
  • a further increase in proof stress is achieved by following the solution heating by a double aging treatment comprising heating for 2-4 hours at 750 C.-800 C., air cooling and heating for 16-40 hours at 680 C.-720 C., e.g., 700 C.
  • the solution heating temperature is advantageously at least 1100 C.
  • two alloys Nos. 1 and 3 were made by vacuum melting at a pressure of less than 1 micron Hg and cast under vacuum to ingots which were extruded to bar.
  • the extruded bar was heat treated by solution heating for one hour at 1000 C. followed by air cooling and aging at 700 C. for 16 hours and tensile and creep test pieces were machined from it.
  • Two further alloys Nos. 1a and 3a of similar composition to Nos. 1 and 3 respectively, were air-melted and cast into 2 /2 inch diameter ingots which were forged to /2 inch diameter bar.
  • the forging was completed at a temperature of about 800 C. to about 900 C.
  • the forged bar was heat treated by solution heating for 1 hour at 1050 C., followed by air cooling and aging at 700 C. for 16 hours, and tensile and creep test pieces were machined from it.
  • the present invention provides alloys which for a given iron content exhibit in the age- I 8 hardened condition after solution treatment, an optimum combination of engineering characteristics when the given iron content is correlated to the columbium content in accordance with the accompanying drawing. More particularly it provides such alloys which exhibit, after a heat-treatment suitable for forged gas turbine rotor discs, the high proof and tensile stress values together with high resistance to deformation by creep under high stresses at elevated temperatures, as evidenced by a low creep rate,
  • alloys having increased temperature capability under creep conditions together with a high combined level of other engineering characteristics such as low and high temperature proof stress, ductility, tenacity, elasticity, expansivity, etc.
  • alloys con-' taining less than 10% iron, for example, less than 5% iron, together with correlated amounts of columbium within the range of about 3% to about 5.25% can advantageously be employed.
  • a particular advantage of the present invention lies in the fact that a range of alloys is provided having an optimum combination of engineering characteristics for any particular design of structures subjected in use to conditions similar to those under which gas turbine power rotor discs are employed.
  • An alloy for use in turbine structures at temperatures up to about 600 C. and higher consisting essentially in percent by Weight of about 14% to about 22% chromium, about 10% to about 20% cobalt, about 3% to about 10% molybdenum, greater than 2.5% total aluminum and titanium, said aluminum being up to about 0.8% and said titanium being at least 2% to about 3.5%, about 0.03% to 0.09% carbon, about 0.001 to about 0.01% boron, about 0.01% to about 0.1% zirconium, about.2% to about 5.25 niobium correlated with up to about 25% iron with the balance being essentially nickel, said alloy after solution treatment and age hardening exhibiting an optimum combination of high and low tem-' perature tensile characteristics, creep characteristics, ductility characteristics and elastic characteristics for any particular iron content within said range of up to about 25 iron by virtue of the iron content being correlated to the niobium content so that the percentage of iron and the percentage of niobium are together representable by a point lying within the area
  • An alloy as in claim 1 which contains less than 0.01% magnesium and less than about 0.3% silicon.
  • An alloy as in claim 1 which contains less than about 0.5% aluminum when the iron content exceeds about 10%.
  • An alloy for use in turbine structures at temperatures up to about 600 C. and higher consisting essentially in percent by weight of about 14% to about 22% chromium, about 10% to about 20% cobalt, about 3% to about 10% molybdenum, greater than 2.5% total aluminum and titanium, said aluminum being up to about 0.8% and said titanium being at least 2% to about 3.5
  • tantalum in an amount up to 3% and nobium in an amount up to 5.25% with the total content of tantalum plus niobium being about 2% to about 5.25% and the balance essentially nickel, said tantalum plus niobium being correlated with the iron content such that the correlation is represented by a point lying within the area ABCDEA in the accompanying drawing, whereby said alloy after solution treatment and age hardening exhibits an optimum combination of high and low temperature tensile characteristics, creep characteristics, ductility characteristics and elastic characteristics at any particular iron content Within the said range of up to about 25% iron.
  • a gas turbine power rotor disc made of the alloy of claim 6.
  • An alloy for use in turbine structures at temperatures up to about 600 C. and higher consisting essentially in percent by weight of about 18% to about 22% chromium, about 13% to about 15% cobalt, about 4% to about 6.5 molybdenum, about 2.25% to about 2.75% titanium, about 0.3% to about 0.8% aluminum, about 0.04% to 0.09% carbon, about 0.001% to about 0.01% boron, about 0.01% to about 0.1% Zirconium, about 4.5% to about 5% niobium, up to about 1% iron with the balance being essentially nickel.
  • An alloy for use in turbine structures at temperatures up to about 600 C. and higher consisting essentially in percent by weight of about 14% to about 16% chromium, about 13% to about 15% cobalt, about 4% to about 6.5% molybdenum, about 2.75% to about 3.25% titanium, up to about 0.35% aluminum, about 0.04% to 10 0.09% carbon, about 0.001% to about 0.01% boron, about 0.01% to about 0.1% zirconium, about 2% to about 2.5% niobium, about 18% to about 22% iron and the balance being essentially nickel.
  • a gas turbine power rotor disc made of the alloy of claim 11.
  • An alloy for use in turbine structures at tempera tures up to about 600 C. and higher consisting essentially in percent by weight of about 14% to about 22% chromium, about 10% to about 20% cobalt, about 3% to about 10% molybdenum, gerater than 2.5 total aluminum and titanium, said aluminum being up to about 0.8% and said titanium being at least 2% to about 3.5 about 0.03% to 0.09% carbon, about 0.001% to about 0.01% boron, about 0.01% to about 0.1% zirconium, about 3.5% to about 5.25% niobium correlated with up to about 5% iron with the balance being essentially nickel, said alloy after solution treatment and age hardening exhibiting an optimum combination of high and low temperature tensile characteristics, creep characteristics, ductility characteristics and elastic characteristics for any particular iron content within said range of up to about 5% iron by virtue of the iron content being correlated to the niobium content so that the percentage of iron and the percentage of niobium are together representable by a point lying within the
  • a gas turbine power rotor disc made of the alloy of claim 13.
  • An alloy as in claim 13 which contains less than 0.01% magnesium and less than about 0.3% silicon.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Heat Treatment Of Nonferrous Metals Or Alloys (AREA)
  • Heat Treatment Of Articles (AREA)
US175555A 1961-02-28 1962-02-26 Nickel-chromium-cobalt alloy Expired - Lifetime US3151981A (en)

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GB7316/61A GB929687A (en) 1961-02-28 1961-02-28 Improvements relating to nickel-chromium-cobalt alloys

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CH (1) CH415063A (fr)
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GB (1) GB929687A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3343950A (en) * 1963-12-23 1967-09-26 Int Nickel Co Nickel-chromium alloys useful in the production of wrought articles for high temperature application
US3372068A (en) * 1965-10-20 1968-03-05 Int Nickel Co Heat treatment for improving proof stress of nickel-chromium-cobalt alloys
US3403059A (en) * 1965-06-24 1968-09-24 Gen Electric Nickel base alloy
US3411899A (en) * 1965-07-22 1968-11-19 Int Nickel Co Nickel-chromium alloys with delayed aging characteristics
US4685977A (en) * 1984-12-03 1987-08-11 General Electric Company Fatigue-resistant nickel-base superalloys and method
US5080734A (en) * 1989-10-04 1992-01-14 General Electric Company High strength fatigue crack-resistant alloy article
US5143563A (en) * 1989-10-04 1992-09-01 General Electric Company Creep, stress rupture and hold-time fatigue crack resistant alloys
US5527403A (en) * 1993-11-10 1996-06-18 United Technologies Corporation Method for producing crack-resistant high strength superalloy articles
US6258317B1 (en) 1998-06-19 2001-07-10 Inco Alloys International, Inc. Advanced ultra-supercritical boiler tubing alloy
US6761854B1 (en) 1998-09-04 2004-07-13 Huntington Alloys Corporation Advanced high temperature corrosion resistant alloy
US6974508B1 (en) 2002-10-29 2005-12-13 The United States Of America As Represented By The United States National Aeronautics And Space Administration Nickel base superalloy turbine disk

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1339811C (fr) * 1981-12-30 1998-04-14 David Noel Duhl Article en alliage monocristallin a base de nickel resistant a la corrosion et ayant une grande resistance
US5372662A (en) * 1992-01-16 1994-12-13 Inco Alloys International, Inc. Nickel-base alloy with superior stress rupture strength and grain size control
US9334547B2 (en) 2013-09-19 2016-05-10 L.E. Jones Company Iron-based alloys and methods of making and use thereof
DE102014202457A1 (de) 2014-02-11 2015-08-13 Siemens Aktiengesellschaft Verbesserte Verschleißbeständigkeit eines Hochtemperaturbauteils durch Kobaltbeschichtung

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB710413A (en) * 1951-03-15 1954-06-09 Mond Nickel Co Ltd Improvements relating to alloys
US2920956A (en) * 1956-10-08 1960-01-12 Universal Cyclops Steel Corp Method of preparing high temperature alloys
US2981621A (en) * 1957-07-29 1961-04-25 Sierra Metals Corp High temperature nickel-iron base alloy
US2994605A (en) * 1959-03-30 1961-08-01 Gen Electric High temperature alloys

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB715140A (en) * 1951-12-05 1954-09-08 Mond Nickel Co Ltd Improvements relating to heat-resisting alloys and articles and parts made therefrom

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB710413A (en) * 1951-03-15 1954-06-09 Mond Nickel Co Ltd Improvements relating to alloys
US2920956A (en) * 1956-10-08 1960-01-12 Universal Cyclops Steel Corp Method of preparing high temperature alloys
US2981621A (en) * 1957-07-29 1961-04-25 Sierra Metals Corp High temperature nickel-iron base alloy
US2994605A (en) * 1959-03-30 1961-08-01 Gen Electric High temperature alloys

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3343950A (en) * 1963-12-23 1967-09-26 Int Nickel Co Nickel-chromium alloys useful in the production of wrought articles for high temperature application
US3403059A (en) * 1965-06-24 1968-09-24 Gen Electric Nickel base alloy
US3411899A (en) * 1965-07-22 1968-11-19 Int Nickel Co Nickel-chromium alloys with delayed aging characteristics
US3372068A (en) * 1965-10-20 1968-03-05 Int Nickel Co Heat treatment for improving proof stress of nickel-chromium-cobalt alloys
US4685977A (en) * 1984-12-03 1987-08-11 General Electric Company Fatigue-resistant nickel-base superalloys and method
US5080734A (en) * 1989-10-04 1992-01-14 General Electric Company High strength fatigue crack-resistant alloy article
US5143563A (en) * 1989-10-04 1992-09-01 General Electric Company Creep, stress rupture and hold-time fatigue crack resistant alloys
US5527403A (en) * 1993-11-10 1996-06-18 United Technologies Corporation Method for producing crack-resistant high strength superalloy articles
US6258317B1 (en) 1998-06-19 2001-07-10 Inco Alloys International, Inc. Advanced ultra-supercritical boiler tubing alloy
US6761854B1 (en) 1998-09-04 2004-07-13 Huntington Alloys Corporation Advanced high temperature corrosion resistant alloy
US6974508B1 (en) 2002-10-29 2005-12-13 The United States Of America As Represented By The United States National Aeronautics And Space Administration Nickel base superalloy turbine disk

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Publication number Publication date
DE1232756B (de) 1967-01-19
CH415063A (fr) 1966-06-15
GB929687A (en) 1963-06-26

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