Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest

Definitions

• This invention relates to a method of heat treating high aluminum-iron alloys to develop outstanding mag netic properties in .the resulting products.
• Aluminum-iron alloys have heretofore been annealed in dry hydrogen at temperatures of 900 to 1050 C., and the investigators have reported that the magnetic properties of the alloy were independent of the temperature of treatment. In contrast to those reported results we have found that, surprisingly, the-magnetic properties of high aluminum-iron alloys annealed in hydrogen-are significantly affected when the annealing. temperature used is onthe order of about 12.00". C. Indeed, :the esulting products thereby obtained. have outstanding magnetic properties. That discovery forms the subject matter of our United States application Serial No. 678,- 539, filed August 16,-1.957.
• Our invention generally is practiced by annealing a magnetic aluminum-iron alloy in air at an elevated temperature.
• the air anneal is carried out at a temperature 'of about 800 to 1000 C. and generally extends for at least 30 minutes and preferably for about 1 10 5 hours.-
• the product After annealing, the product is cooled to a temperature of about 600 to 700 C.f Furnace cooling, or
• Thesample is cooled to a temperature approaching the ordering [transformation a temperature, i.e.. that temperature at which the structure of the alloy changes from FeAl to Fe A1, which' normally is about 550 C. for alloys that are used in this invention.
• a temperature i.e.. that temperature at which the structure of the alloy changes from FeAl to Fe A1
• the specimen is quenched to room temperature.
• Quenching can be carried out in any manner now known that will suppress ordering transformation whereby FeAl would transform to Fe Al.
• the specimen may .be waterquenched .or .oil quenched.
• the materials to which our invention relates are mag.- netic aluminum iron alloys containing about 14 to 17.5 weight percent of aluminum.
• Aluminum-iron alloys are non-magnetic at an aluminum content that is greater than construed to include the magnetic compositions and is not an absolute value.
• Other alloying constituents and incidental impurities maybe present in varying amounts provided they do not deleteriously interfere with obtaining the described improved properties in the resulting We have discovered that these alloys in general can be air annealed successfully to produce products with good magnetic properties.
• the alloys for use in the invention can be prepared by any procedure desired. A method that we have used does not depend on hydrogen atmosphere; and that requires no special equipment for its successful utilization.
• the melt is cast either in avacuum of under 'a protective atmosphere to avoid loss of the aluminum and the uncontrolled introduction of impurities.
• the resulting ingot maybe hot or cold rolled to thedesired thickness.
• we roll the material to a thickness on the order of 1 to -30 mils because most commercial-applications require'that size; it should be'unde'rpracticed allow with an aluminum content of 14.7 Weight percent and others with greater amounts of aluminum were pre- 3 induction-heated, magnesium oxide crucible in a vacuum furnace at a pressure of 0.1 micron. Helium was then admitted to the furnace, and commercial aluminum bar was added to. the melt.
• the resulting melts were'cast andwhen theingots had'solidified, they were hot rolled at 1000 C. to 0.007 inch sheets.
• Two sets of standard ring laminations were stamped from the 14.7 percent aluminum-iron (see table, below) while three sets of laminations were stamped from each sheet with an aluminum content of 15 or more percent.
• One set, or sample, of each composition was annealed at 900 C. for 2 hours in air; a second sample of each composition was annealed at 900 C. in dry hydrogen.
• the third sample of the higher compositions was annealed at 1200 C. in air for 2 hours.
• the annealed laminations were then furnace cooled to 600 C. Each sample was maintained at 600 C.
• a method for providing improved magnetic properties of coercive force, remanence, and maximum permeability in an aluminum-iron alloy sheet which comprises heating in the presence of air for at least one half hour a magnetic alloy sheet consisting essentially of 14 to 17.5 weight percent of aluminum and the remainder iron at a temperature of from 800 C. to 1200 C., and then quenching the resultant annealed sheet from a temperature that is above that at which an ordering transformation occurs, wherein the structure normally changes to Fe Al, to-about room temperatures, the quenching suppressing the ordering transformation.
• a method for providing improved magnetic properties of coercive force, remanence, and'maximum permeability in an aluminum-iron alloy sheet which comprises heating a magnetic alloy sheet consisting essentially of 15 to 17 weight percent of aluminum and the remainder iron, in air ata temperature of about 800 to 1000 C. for about 1 to 5 hours, cooling the resultant annealed sheet to about 600 and then quenching the sheet to about room temperature, the quenching suppressing the ordering transformation.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Electromagnetism (AREA)
• Dispersion Chemistry (AREA)
• Power Engineering (AREA)
• Hard Magnetic Materials (AREA)
• Soft Magnetic Materials (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=24723159

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (1)

• 0
  • BE BE570383D patent/BE570383A/xx unknown
• 1957
  • 1957-08-16 US US678524A patent/US2937115A/en not_active Expired - Lifetime
• 1958
  • 1958-08-01 CH CH6250358A patent/CH388631A/de unknown

Patent Citations (1)

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