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Publication numberUS1550508 A
Publication typeGrant
Publication dateAug 18, 1925
Filing dateJan 24, 1922
Priority dateJan 24, 1922
Publication numberUS 1550508 A, US 1550508A, US-A-1550508, US1550508 A, US1550508A
InventorsCooper Hugh S
Original AssigneeKemet Lab Company Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Alloy
US 1550508 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

I Patented Aug. 18 1925.

' HUGH S. COOPER,

PATENT OFFICE.

OF CLEVELAND, O HIO, ASSIGNOR TO KEMET LABORATORIES GOM- PANY, INC., A. CORPORATION OF NEW YORK.

ALLOY.

llo Drawing.

To all whom it may concern:

, Be it known that I, HUGH S. COOPER,

' a citizenofthe United States, residing at like. As. will appear hereinafter the .third' component imparts malleability to an otherwise unworkable binary. alloy, and it may therefore be conveniently designated a malleability component. Many of the compositions according tomy invention may be readily worked into wire, ribbon or the like suitable for use in electrical resistance elements and for like purposes.

It is known that certain iron-aluminum alloys, for example those containing about 9% of aluminum, exhibit high electrical resistance and good heat resistivity, but such binary alloys are of little practical value because their brittleness precludes the possi-- bility of their being used for most industrial purposes. Any increase in the aluminum content of such alloys accentuates their undesirable qualities. A decrease in aluminum content serves to improve the working properties; and if the aluminum content is -less than 5.6%, the alloy is malleable, ac-

cording to Hadfield. Such low-aluminum binary alloys are however deficient in the desired electrical resistance and heat resistivity.

I have discovered that a rather high aluminum content, for example 10 to 16%, may be maintained and surprising y good working qualities nevertheless imparted by suitable additions of manganese and chromium, or mixtures 'of these metals; and that, in addition, the electrical resistance is greatly increased over that exhibited by the corresponding binary alloys of aluminum and iron. The increase in workability and resistance is especially pronounced when chromium is the third metal of the alloy, and.

Application filed January 24, 1922. Serial No. 531,466.

chromium is accordinglymy preferred addition. However, iron-aluminum-manganese alloys within the range indicated have properties which render them valuable for many purposes. For example, an alloy of iron 70%, aluminum 20% and manganese 10% gives excellent heat resistant castings, showing a, fine silky fracture; while alloys of aluminum 12-15% and manganese 68%, with the balance iron, may even be rolled to some extent. i

For the preparation of attenuated members suitable for electrical resistance elements, I prefer iron-aluminum-chromium alloys, as intimated above. Compositions containing 12-16% aluminum with. additions of 5-10% ofchromium may be readily rolled, forged or swaged while hot, and may be formed into fine wire or ribbon, which,

after annealing, possesses suflicient flexibility and toughness for such purposes as are contemplated herein. In order to obtain maximum toughness, it is necessary to keep the carbon content low, and for this reason a carbon content of less than 0.20% is preferred when attenuated members are to be prepared.

Iron-aluminum-chromium alloys of certain composition have, as already indicated, a remarkably high electrical resistance, in fact a resistance which so far as I am aware is unprecedented in alloys heretofore investigated. The range of compositions for high resistance is somewhat broader than that indicated above for a high degree of workability, as the chromium may be in excess of the 10% there mentioned. However, the maximum electrical resistance falls within the range of compositions giving workable alloys, as demonstrated by the tabulation given below:

Composition Resistance (microhms per centimeter Chromium. Aluminum. cube) 6 1 150 a Z 14 Z 165 10 o 1 0 ms 1 1 D 176 10 a 14 a 172 1 c 12;, 14s 10 o 15 a 184 The highest resistances noted in the table are of the order of one hundred times that of copper.

With respect to both working and electrical qualities, my preferred composition is, chromium about 8%, aluminum about 14% with the balance predominantly iron, and carbon less than 0.20%. The presence of other elements in relatively small proportion is not excluded.

I am aware that it has been proposed to use for electric resistance elements, and for other purposes, alloys containing iron,

. aluminum and chromium, with'an addition of over 5% of titanium. It is my understanding that the function of the titanium, which may be present in quantities as high as 25%, is to harden the alloy; and I also understand that while these titanium-containing alloys are not too brittle to preclude their use as castings, they cannot be drawn and swaged as can the alloys of my invention. The appended claims are therefore not to be construed to cover alloys containing metals other than those described as suitable constituents for my alloys, in sufficient quantity materially to diminish the electrical resistance, resistance-to oxidation, or workability of the alloys.

The alloys of my invention are, for the most part, compositions in which the aluminum is present in excess of the manganese or chromium, or at least in substantially equal proportion therewith.

I claim:

1. An alloy consisting predominantly of iron, aluminum, and chromium, the aluminum content being within the range of 10% to 16%, and the chromium content being greater than 5% and less than the aluminum content.

2. An alloy consisting predominantly of iron, aluminum, and chromium, with aluminum and chromium contents of about 14% and 8% respectively.

3. .An alloy consisting predominantly of iron, aluminum, and chromium, with aluminum and chromium contents of about 141% and 8% respectively, and containing not more than about 0.2% carbon.

4. An alloy consisting predominantly of iron, aluminum, and manganese, the aluminum content being Within the range of 10% to 16%, and the manganese content being greater than 5% and less than the aluminum content.

In testimony whereof, I afiix my signature.

HUGH S. COOPER.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5238645 *Jun 26, 1992Aug 24, 1993Martin Marietta Energy Systems, Inc.Iron-aluminum alloys having high room-temperature and method for making same
US5595706 *Dec 29, 1994Jan 21, 1997Philip Morris IncorporatedAluminum containing iron-base alloys useful as electrical resistance heating elements
US5620651 *Apr 20, 1995Apr 15, 1997Philip Morris IncorporatedIron aluminide useful as electrical resistance heating elements
US5976458 *Jan 3, 1996Nov 2, 1999Philip Morris IncorporatedIron aluminide useful as electrical resistance heating elements
US6030472 *Dec 4, 1997Feb 29, 2000Philip Morris IncorporatedMethod of manufacturing aluminide sheet by thermomechanical processing of aluminide powders
US6033623 *Jul 11, 1996Mar 7, 2000Philip Morris IncorporatedMethod of manufacturing iron aluminide by thermomechanical processing of elemental powders
US6143241 *Feb 9, 1999Nov 7, 2000Chrysalis Technologies, IncorporatedMethod of manufacturing metallic products such as sheet by cold working and flash annealing
US6280682Sep 20, 1999Aug 28, 2001Chrysalis Technologies IncorporatedIron aluminide useful as electrical resistance heating elements
US6284191Sep 20, 1999Sep 4, 2001Chrysalis Technologies IncorporatedMethod of manufacturing iron aluminide by thermomechanical processing of elemental powers
US6293987Dec 7, 1999Sep 25, 2001Chrysalis Technologies IncorporatedPolymer quenched prealloyed metal powder
US6294130 *Mar 24, 2000Sep 25, 2001Chrysalis Technologies IncorporatedMethod of manufacturing metallic products such as sheet by cold working and flash anealing
US6332936Sep 20, 1999Dec 25, 2001Chrysalis Technologies IncorporatedThermomechanical processing of plasma sprayed intermetallic sheets
US6436163 *Dec 24, 1998Aug 20, 2002Pall CorporationMetal filter for high temperature applications
US6607576Oct 14, 1998Aug 19, 2003Chrysalis Technologies IncorporatedOxidation, carburization and/or sulfidation resistant iron aluminide alloy
US6660109Oct 31, 2001Dec 9, 2003Chrysalis Technologies IncorporatedMethod of manufacturing aluminide sheet by thermomechanical processing of aluminide powders
Classifications
U.S. Classification420/62, 420/79
International ClassificationC22C38/06
Cooperative ClassificationC22C38/06
European ClassificationC22C38/06