US3203791A - Nickel-chromium-iron alloys - Google Patents

Nickel-chromium-iron alloys Download PDF

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Publication number
US3203791A
US3203791A US216125A US21612562A US3203791A US 3203791 A US3203791 A US 3203791A US 216125 A US216125 A US 216125A US 21612562 A US21612562 A US 21612562A US 3203791 A US3203791 A US 3203791A
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Prior art keywords
alloys
nickel
chromium
titanium
content
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Expired - Lifetime
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US216125A
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English (en)
Inventor
Franklin Arthur William
Smith Ronald Alfred
Richards Edward Gordon
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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
    • C22C19/056—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 10% but less than 20%

Definitions

  • the present invention relates to nickel-chromium alloys and, more particularly, to weldable nickel-chromium alloys including nickel-chromium-iron alloys.
  • Nickel-chromium and nickel-chromium-i-ron base heatand creep-resistant alloys containing titanium and aluminum to provide a precipitable phase of Ni (Ti, Al) type and also containing molybdenum are now well known. In most alloys of this type, however, it is found that the ductility decreases with increasing temperature and is generally at a minimum in the temperature range 700 C.- 850 C. While these alloys in the form of thin sheet not more than about /s inch thick can be welded under mild conditions and without restraint, the ductility of the Welded joints decreases to an even greater extent in this temperature range so that the elongation of the welded joints in high temperature tensile tests may fall below the commercially desirable minimum of 5% or 7%.
  • Another object of the invention is to provide a novel welding process.
  • the invention also contemplates providing novel welded structures.
  • the figure is a graph illustrating the relationship be-- tween titanium and aluminum contents which are characteristic of alloys in accordance with the present invention.
  • the present invention contemplates providing heatand creep-resistant alloys that largely retain their strength and ductility after welding with a simple or no post-weld heat treatment.
  • This object is achieved by adding critical amounts of the elements carbon, titanium, aluminum, molybdenum, boron and zirconium to nickel-chromium or nickel-chromium-iron base alloys containing about and especially about 16% to about 17% chromium.
  • Patented Aug. 31, 1965 ice Alloys according to the invention contain, in percent by weight, chromium about 15% to 25% and preferably about 16% to about 17%, iron 0% to 45%, carbon about 0.04% to 0.15%, titanium about 0.7% to 2.5%, aluminum about 0.7% to 1.5%, molybdenum about 3% to 6% and preferably 3.5% to 4.5%, boron 0.001% to 0.009%, zirconium 0.01% to 0.1%, silicon 0% to about 0.5% manganese 0 to about 0.5%, cobalt 0% to about 1%, the balance (apart from impurities in an amount not exceeding 0.5%) being nickel in an amount not less than 35%.
  • the total titanium and aluminum content is 2% to 3.5%
  • the ratio titanium/aluminum is 0.5 to 4
  • the Ti+Al content is so correlated with the Ti/Al ratio that the alloy lies within the area ABCDA in the figure of the accompanying drawing.
  • the carbon content should be at least 0.04% in order to obtain an acceptable level of ductility.
  • free carbides are formed in the alloy during working that reduce the creep resistance at elevated temperatures and also make it difiicult to form the alloy into sheet or shape the sheet into components. Prolonged exposure to temperatures above 600 C. leads to precipitation of carbides at carbon contents of less than 0.16% and at carbon contents of above 0.08%, these carbides tend to be deposited at the grain boundaries in a form that may ultimately lead to embrittlement of the alloys, after say 500 hours or more. This efiect is particularly pronounced at temperatures of less than 700 C.
  • alloys for use under conditions of stress at high temperatures should not only be resistant to creep but also should not become embrittled on prolonged exposure to high temperatures.
  • carbon contents up to 0.12% may advantageously be used.
  • Both the total content of titanium and aluminum and the Ti/Al ratio are important.
  • the effect of increasing the Ti+Al content is to increase the strength of the alloy and at the same time decrease its tensile ductility, both at room temperature and at elevated temperatures.
  • At Ti+Al contents below 2% the strength is inadequate, while above a Ti+Al content depending on the Ti/Al ratio and defined by the line A-B in the figure of the drawing, the alloys have very low ductilities at elevated temperatures, particularly after welding.
  • Alloys having Ti+Al contents corresponding to points substantially above the line A-B but less than 3.5 have undesirably low ductility at high temperatures after welding and at Ti+Al content-s greater than 3.5%, their room temperature ductility also rapidly falls off to such an extent that fabrication of the alloy in the form of sheets becomes impractical.
  • alloys in accordance with the present invention which have a carbon content about 0.04% to about 0.08%, a chromium content about 16% to about 17%, a molybdenum content about 3% to about 3.5%, and a nickel content about 37% to about 50%, the re- 5 It is important that the nickel content should not be mainder of the composition being within the ranges set reduced below 35%, other-wise severe embrittlement ocforth hereinbefore.
  • the titanium concurs after long exposure to temperatures in the range 650 tent is about 1.0% to about 2.5% and the aluminum con- C.-850 C. tent is about 0.7% to about 1.5%.
  • High temperature strength of the alloys is complementary These alloys were cast into ingots that were forged to to that of Ti-l-Al. At a given Ti+Al content, increasing bar, which was then heat treated by solution heating at the molybdenum content increases the high temperature 1080 C. for 8 hours, air cooling, aging at 700 C. for strength and the fall in strength that occurs on reducing the 16 hours, and again air cooling. Stress-rupture properties Ti-i-Al content from a given level can be partly or wholly determined on specimens of alloy No. 1 machined from compensated by increasing the molybdenum content by the bar are shown in Table II: 0.5% for every 0.1% that the Ti+Al content decreases.
  • suitable content is 0.003%.
  • Zirconium contributes to the creep resistance of the alloys and for this purpose it should be present in the range 0.01% to 0.1%, preferably 0.05%. Greater amounts of A particularly zirconium than 0.1% again may lead to cracking on welding.
  • the preferred alloys are particularly suitable as materials for components of steam plant, for example superheater tubes, steam pipes and parts of steam turbines, and for other articles subjected to stress for long .periods of elevated temperatures.
  • the alloys may be melted in any convenient manner. It is common practice in air melting nickel-chromium alloys to deoxidize them by an addition of calcium or magnesium. When this technique is used for the present alloys, particlarly those containing less than 5% iron, care should be taken that the residual calcium or magnesium content is a low as possible, preferably not exceeding 0.005%, as otherwise cracking may occur on welding thick sections or under restrained conditions and the high temperature ductility of the welded joints may be impaired. To develop the optimum properties in the alloys, it is essential that they should be given an age hardening heat treatment consisting of solution heating followed by aging at a lower temperature.
  • this treatment consists of heating at 1020 C.-1150 C., followed by cooling in air and aging at 650 C.850 C.
  • the first treatment should be for 2 30 minutes and the second treatment for 2-16 hours.
  • the first treatment should be for a longer time, say 2-8 hours.
  • welding refers to a process wherein elements, structures and the like are joined by means of a fusion process during which a liquid metallic content is established while at least the adjacent surfaces of the structures, elements, etc., to be joined are at a temperature in excess of the incipient fusion temperature of the alloy or metal from which the structures or elements are made. Subsequent cooling during which contact is maintained establishes the weld bond by freezing of the liquid contacting metal.
  • the molybdenum in the alloys can be wholly or partly replaced by an equal atomic percentage of tungsten.
  • the alloys are suitable for use both in the sheet and wrought forms and can be used in the manufacture of welded structures, including composite welded structures comprising sheet components with wrought stiffening members welded to them.
  • welded structures including composite welded structures comprising sheet components with wrought stiffening members welded to them.
  • Examples of such structures are parts of aircraft gas turbines such as jet pipes, flame tubes and jet silencers and steam pipe assemblies for use in contact with superheated steam.
  • An alloy characterized by highly enhanced resistance to impact after a long-time exposure of 1000 hours to elevated temperatures up to about 750 C. and consisting essentially of, by weight, about 16% to about 17% chromium, about 0.04% to about 0.08% carbon, about 3% to about 3.5% molybdenum, about 0.7% to about 2.5% titanium, about 0.7% to about 1.5% aluminum, about 0.001% to about 0.009% boron, about 0.01% to about 0.1% zirconium, up to about 0.5% silicon, about 37% to about 50% nickel, up to about 0.5% manganese, up to about 1% :cobalt with the balance being essentially iron, the sum of the said titanium percentage and said aluminum percentage being 2% to about 3.5% and the ratio of said titanium percentage to said aluminum percentage being about 0.5 to about 4 and said sum being correlated with said ratio so that when the values of said sum and said ratio are plotted, the resultant point lies within the area ABCDA set forth in the figure on the accompanying drawing.

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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 Articles (AREA)
  • Arc Welding In General (AREA)
  • Furnace Charging Or Discharging (AREA)
US216125A 1961-08-11 1962-08-10 Nickel-chromium-iron alloys Expired - Lifetime US3203791A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB29092/61A GB949101A (en) 1961-08-11 1961-08-11 Improvements in nickel-chromium-iron alloys

Publications (1)

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US3203791A true US3203791A (en) 1965-08-31

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US (1) US3203791A (no)
BE (1) BE621346A (no)
DE (1) DE1458405C3 (no)
GB (1) GB949101A (no)
SE (1) SE317818B (no)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4780276A (en) * 1986-07-30 1988-10-25 The Unites States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Castable hot corrosion resistant alloy

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3039473A1 (de) * 1980-10-18 1982-06-09 GHT Gesellschaft für Hochtemperaturreaktor-Technik mbH, 5060 Bergisch Gladbach Aufkohlungs- und korrosionsgeschuetzte nickelbasislegierung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB728375A (en) * 1951-10-06 1955-04-20 Mond Nickel Co Ltd Improvements in heat-resistant alloys
CA548776A (en) * 1957-11-12 The International Nickel Company Of Canada Heat-resistant nickel-base alloy of low strategic alloying content
US2920956A (en) * 1956-10-08 1960-01-12 Universal Cyclops Steel Corp Method of preparing high temperature alloys
US2957239A (en) * 1958-12-10 1960-10-25 Orenda Engines Ltd Brazing of nickel base alloys
US2977222A (en) * 1955-08-22 1961-03-28 Int Nickel Co Heat-resisting nickel base alloys
US3051565A (en) * 1960-04-29 1962-08-28 Allegheny Ludlum Steel Austenitic alloys

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA548776A (en) * 1957-11-12 The International Nickel Company Of Canada Heat-resistant nickel-base alloy of low strategic alloying content
GB728375A (en) * 1951-10-06 1955-04-20 Mond Nickel Co Ltd Improvements in heat-resistant alloys
US2977222A (en) * 1955-08-22 1961-03-28 Int Nickel Co Heat-resisting nickel base alloys
US2920956A (en) * 1956-10-08 1960-01-12 Universal Cyclops Steel Corp Method of preparing high temperature alloys
US2957239A (en) * 1958-12-10 1960-10-25 Orenda Engines Ltd Brazing of nickel base alloys
US3051565A (en) * 1960-04-29 1962-08-28 Allegheny Ludlum Steel Austenitic alloys

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4780276A (en) * 1986-07-30 1988-10-25 The Unites States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Castable hot corrosion resistant alloy

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Publication number Publication date
DE1458405A1 (de) 1968-12-19
SE317818B (no) 1969-11-24
BE621346A (no)
DE1458405B2 (de) 1973-10-18
GB949101A (en) 1964-02-12
DE1458405C3 (de) 1974-05-16

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