US2162596A - Furnace heating element - Google Patents

Furnace heating element Download PDF

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Publication number
US2162596A
US2162596A US139938A US13993837A US2162596A US 2162596 A US2162596 A US 2162596A US 139938 A US139938 A US 139938A US 13993837 A US13993837 A US 13993837A US 2162596 A US2162596 A US 2162596A
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United States
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alloy
furnace
molybdenum
nickel
group
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US139938A
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Le Roy L Wyman
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General Electric Co
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General Electric Co
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Priority to US139938A priority Critical patent/US2162596A/en
Priority to FR837359D priority patent/FR837359A/en
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C19/00Alloys based on nickel or cobalt
    • C22C19/03Alloys based on nickel or cobalt based on nickel
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C19/00Alloys based on nickel or cobalt
    • C22C19/03Alloys based on nickel or cobalt based on nickel
    • C22C19/05Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/057Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being less 10%

Definitions

  • alloy furnace heater wires or ribbons containing about 80% nickel and 20% chromium Prior to the present invention it has been customary to employ alloy furnace heater wires or ribbons containing about 80% nickel and 20% chromium. Alloys of this composition have a cold resistance of about 105 microhms per cubic centimeter and at operating temperatures the resistance increase is about 5%. However, when operating in furnace atmosphere containing carbon monoxide and at temperatures in the neighborhood of about 1000 C. this alloy or any alloy containing chromium or aluminum-gradually disintegrates and ultimately fails completely due to corrosion of the chromium or aluminum. The corrosion is quite rapid at a furnace temperature of about 1000 C. and more slowly at lower temperatures.
  • I employ an alloy consisting of one or more of the metals of the iron group and one or more of the elements of the group consisting of molybdenum and tungsten.
  • I employ an alloy consisting principally of nickel.
  • the alloy which I prefer to employ as a heater element contains -l0 about 80% nickel and 20% molybdenum.
  • An alloy of this composition has substantially the same strength at operating furnace temperatures as the 80% nickel, 20% chromium alloy. It also has a cold resistance of about 105 microhms per cubed centimeter and the resistance increase at operating furnace temperatures in the neighborhood of 1150 C. is about 10%.
  • the nickel-molybdenum alloy is substantially unaffected by reducing furnace atmospheres, and
  • the nickel-molybdenum alloy may contain from about 5 to 40% molybdenum. Those alloys While pure nickel resists which contain the lower quantities of molybdenum change considerably in resistance in going from the cold state to the operating furnacetemperature. Also, those alloys containing the higher percentages of molybdenum have a tendency toward brittleness. I prefer therefore to employ nickel-molybdenum alloys containing more than 12% but not more than 40% molybdenum.
  • tungsten may be substituted for the molybdenum in whole or in part. If an alloy consisting of nickel and tungsten is employed, the
  • tungsten content of the alloy may vary from about 2 to 45% of the total content of the alloy and preferably is somewhat higher than the quantity of molybdenum which may be employed with nickel.
  • Alloys consisting for. example of about nickel, 20% molybdenum and 15% iron; and 65% nickel, 12% molybdenum and 23% iron or corresponding nickel-iron-tungsten alloys give satisfactory results as to strength, electrical characteristics, and resistance to oxidation in atmospheres containing carbon monoxide gas.
  • forging is facilitated if a small quantity of manganese, i. e. about .5%, is added to the alloy and if the forging is carried out at a temperature of about 1250 C.
  • alloys are particularly adapted for use as heater elements in furnaces employing reducing atmospheres containing carbon monoxide gas their use is not limited to such furnace atmospheres or to heater elements.
  • the alloys if desired, may be employed to advantage in the construction of furnace equipment such as rolls, brackets, or other supporting means, hearths, tracks, conveyor links and the like.
  • An alloy heater element consisting of metal a of the iron group and metal from the group consisting of tungsten and molybdenum, the metal from said group consisting of tungsten and molybdenum comprising about 2% to 45% by weight of said alloy.
  • An alloy heater element consisting substantially of nickel and metal from the group consisting of molybdenum and tungsten, said metal from said group comprising about 12 to 40% of said alloy.
  • An alloy furnace heater element consisting principally of nickel, the remainder of the alloy consisting of about 5% to 40% molybdenum.
  • An alloy furnace heater element containing about 80% nickel and 20% molybdenum.
  • An alloy furnace heater element subject to furnace temperatures and to a reducing furnace g atmosphere containing carbon monoxide, said alloy containing about 65% nickel the remainder of the alloy consisting of about 13% to 23% iron and about 12% to 20% molybdenum.
  • An alloy comprising a portion of the equiplo ment of a furnace, said alloy being subject to the temperature and atmosphere of said furnace, said alloy consisting of metal of the iron group and metal from the group consisting of tungsten and molybdenum, said metal from the group consisting of tungsten and molybdenum comprising about 2% to 45% by weight of said alloy.
  • an alloy subject to elevated furnace temperatures and to a furnace atmosphere containing carbon mongo oxide said alloy consisting principally of nickel but containing about 12 to 40% of metal from the group consisting of tungsten and molybdenum.
  • An alloy comprising a portion of the equipg5 ment of a furnace and subject to elevated temperatures and to a furnace atmosphere containing carbon monoxide, said alloy containing about 80% nickel and 20% molybdenum.
  • a furnace employing a reducing atmosphere containing carbon monoxide 5 gas and an alloy heater element therein, said alloy consisting of metal of the iron group and metal from the group consisting of tungsten and molybdenum, the metal from said latter group comprising 2% to 45% by weight of said alloy.
  • An alloy furnace attachment or structure subject to elevated furnace temperatures and to a furnace atmosphere containing carbon monoxide said alloy consisting of about 65% nickel, 12% to 20% molybdenum, and to 23% iron. 15
  • An alloy furnace attachment or structure subject to elevated furnace temperatures and to a furnace atmosphere containing carbon monoxide, said alloy consisting of metal from the iron group and metal from the group consisting of tungsten and molybdenum, the metal from the latter group comprising more than 12% but not more than of said alloy.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Resistance Heating (AREA)
  • Furnace Details (AREA)

Description

Patented i 13, 1939 UNITED" STATES PATENT OFFICE FURNACE HEATING ELEMENT Le Roy L. Wyman, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York No Drawing. Application April 30, 1937. Serial No. 139,938
11 Claims. (Cl. 75-123) tric furnaces which employ reducing atmospheres :1 containing carbon monoxide gas.
Prior to the present invention it has been customary to employ alloy furnace heater wires or ribbons containing about 80% nickel and 20% chromium. Alloys of this composition have a cold resistance of about 105 microhms per cubic centimeter and at operating temperatures the resistance increase is about 5%. However, when operating in furnace atmosphere containing carbon monoxide and at temperatures in the neighborhood of about 1000 C. this alloy or any alloy containing chromium or aluminum-gradually disintegrates and ultimately fails completely due to corrosion of the chromium or aluminum. The corrosion is quite rapid at a furnace temperature of about 1000 C. and more slowly at lower temperatures.
It is an object of the present invention to pro vide an alloy suitable for use in a furnace as a heater element or other device which resists corrosion in furnace atmospheres containing carbon monoxide and which has desirable electrical and physical characteristics. Other objects will appear herinafter.
In carrying out my invention I employ an alloy consisting of one or more of the metals of the iron group and one or more of the elements of the group consisting of molybdenum and tungsten. Preferably I employ an alloy consisting principally of nickel.
oxidation at high temperatures in an atmosphere containing carbon monoxide, it does not have the requisite strength or electrical characteristics for use as a furnace heater-element. The alloy which I prefer to employ as a heater element contains -l0 about 80% nickel and 20% molybdenum. An alloy of this composition has substantially the same strength at operating furnace temperatures as the 80% nickel, 20% chromium alloy. It also has a cold resistance of about 105 microhms per cubed centimeter and the resistance increase at operating furnace temperatures in the neighborhood of 1150 C. is about 10%. However, the nickel-molybdenum alloy is substantially unaffected by reducing furnace atmospheres, and
particularly those containing carbon monoxide, at any temperature. It is also easy to work and has a very long life as compared to heater elements containing chromium.
The nickel-molybdenum alloy may contain from about 5 to 40% molybdenum. Those alloys While pure nickel resists which contain the lower quantities of molybdenum change considerably in resistance in going from the cold state to the operating furnacetemperature. Also, those alloys containing the higher percentages of molybdenum have a tendency toward brittleness. I prefer therefore to employ nickel-molybdenum alloys containing more than 12% but not more than 40% molybdenum.
If desired, tungsten may be substituted for the molybdenum in whole or in part. If an alloy consisting of nickel and tungsten is employed, the
tungsten content of the alloy may vary from about 2 to 45% of the total content of the alloy and preferably is somewhat higher than the quantity of molybdenum which may be employed with nickel.
If desired I may add molybdenum or tungsten, or both, to one or more of the elements iron, nickel and cobalt. Alloys consisting for. example of about nickel, 20% molybdenum and 15% iron; and 65% nickel, 12% molybdenum and 23% iron or corresponding nickel-iron-tungsten alloys give satisfactory results as to strength, electrical characteristics, and resistance to oxidation in atmospheres containing carbon monoxide gas. In fabricating the alloys containing iron and molybdenum, forging is facilitated if a small quantity of manganese, i. e. about .5%, is added to the alloy and if the forging is carried out at a temperature of about 1250 C.
While the above alloys are particularly adapted for use as heater elements in furnaces employing reducing atmospheres containing carbon monoxide gas their use is not limited to such furnace atmospheres or to heater elements. The alloys, if desired, may be employed to advantage in the construction of furnace equipment such as rolls, brackets, or other supporting means, hearths, tracks, conveyor links and the like.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. An alloy heater element consisting of metal a of the iron group and metal from the group consisting of tungsten and molybdenum, the metal from said group consisting of tungsten and molybdenum comprising about 2% to 45% by weight of said alloy. I
2. An alloy heater element consisting substantially of nickel and metal from the group consisting of molybdenum and tungsten, said metal from said group comprising about 12 to 40% of said alloy.
3. An alloy furnace heater element consisting principally of nickel, the remainder of the alloy consisting of about 5% to 40% molybdenum.
2 areasaa 4. An alloy furnace heater element containing about 80% nickel and 20% molybdenum.
5. An alloy furnace heater element subject to furnace temperatures and to a reducing furnace g atmosphere containing carbon monoxide, said alloy containing about 65% nickel the remainder of the alloy consisting of about 13% to 23% iron and about 12% to 20% molybdenum.
6. An alloy comprising a portion of the equiplo ment of a furnace, said alloy being subject to the temperature and atmosphere of said furnace, said alloy consisting of metal of the iron group and metal from the group consisting of tungsten and molybdenum, said metal from the group consisting of tungsten and molybdenum comprising about 2% to 45% by weight of said alloy.
7. In a furnace attachment or structure, an alloy subject to elevated furnace temperatures and to a furnace atmosphere containing carbon mongo oxide said alloy consisting principally of nickel but containing about 12 to 40% of metal from the group consisting of tungsten and molybdenum.
8. An alloy comprising a portion of the equipg5 ment of a furnace and subject to elevated temperatures and to a furnace atmosphere containing carbon monoxide, said alloy containing about 80% nickel and 20% molybdenum.
9. In combination, a furnace employing a reducing atmosphere containing carbon monoxide 5 gas and an alloy heater element therein, said alloy consisting of metal of the iron group and metal from the group consisting of tungsten and molybdenum, the metal from said latter group comprising 2% to 45% by weight of said alloy.
10. An alloy furnace attachment or structure subject to elevated furnace temperatures and to a furnace atmosphere containing carbon monoxide, said alloy consisting of about 65% nickel, 12% to 20% molybdenum, and to 23% iron. 15
11. An alloy furnace attachment or structure subject to elevated furnace temperatures and to a furnace atmosphere containing carbon monoxide, said alloy consisting of metal from the iron group and metal from the group consisting of tungsten and molybdenum, the metal from the latter group comprising more than 12% but not more than of said alloy.
LE ROY L. WYMAN. g5
US139938A 1937-04-30 1937-04-30 Furnace heating element Expired - Lifetime US2162596A (en)

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US139938A US2162596A (en) 1937-04-30 1937-04-30 Furnace heating element
FR837359D FR837359A (en) 1937-04-30 1938-04-29 Alloys for heating elements

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428042A (en) * 1940-06-05 1947-09-30 Hartford Nat Bank & Trust Co Cathode for electric discharge tubes
US2469715A (en) * 1945-06-12 1949-05-10 Hugh S Cooper Cobalt base alloy composition
US2720458A (en) * 1952-04-29 1955-10-11 Sylvania Electric Prod Nickel-tungsten-aluminum alloy for cathode structure
US3350294A (en) * 1962-11-21 1967-10-31 Ici Australia Ltd Electrodes
US3778254A (en) * 1971-11-18 1973-12-11 Atomic Energy Commission Brazing filler metal for molybdenum
US4079164A (en) * 1975-11-07 1978-03-14 Hitachi, Ltd. Base metal plate for directly heated oxide cathode

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB812113A (en) * 1956-10-08 1959-04-15 Union Carbide Corp Corrosion-resistant cobalt and/or nickel-base alloy

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428042A (en) * 1940-06-05 1947-09-30 Hartford Nat Bank & Trust Co Cathode for electric discharge tubes
US2469715A (en) * 1945-06-12 1949-05-10 Hugh S Cooper Cobalt base alloy composition
US2720458A (en) * 1952-04-29 1955-10-11 Sylvania Electric Prod Nickel-tungsten-aluminum alloy for cathode structure
US3350294A (en) * 1962-11-21 1967-10-31 Ici Australia Ltd Electrodes
US3778254A (en) * 1971-11-18 1973-12-11 Atomic Energy Commission Brazing filler metal for molybdenum
US4079164A (en) * 1975-11-07 1978-03-14 Hitachi, Ltd. Base metal plate for directly heated oxide cathode

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Publication number Publication date
FR837359A (en) 1939-02-08

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