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
• • 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
  • C21D8/1205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular fabrication or treatment of ingot or slab
• • 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
  • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
  • C21D8/1233—Cold rolling
• • 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
  • C21D2201/00—Treatment for obtaining particular effects
  • C21D2201/04—Single or very large crystals
• • 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
  • C21D2201/00—Treatment for obtaining particular effects
  • C21D2201/05—Grain orientation
• • 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
  • C21D2281/00—Making use of special physico-chemical means
  • C21D2281/01—Seed crystals being used
• • 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
  • C21D2281/00—Making use of special physico-chemical means
  • C21D2281/02—Making use of special physico-chemical means temperature gradient
• • 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
  • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
  • C21D8/1222—Hot rolling
• • 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

• a strong preferred grain orientation is desirable in sheet and strip material formed by rolling or forging, particularly in the case of silicon steel sheet or strip.
• This preferred grain orientation has been previously produced in silicon steel, for example, by hot and cold rolling silicon steel ingots into sheets or strips combined with appropriate heat treatment, as is well known in the art.
• the finished product is, of course, a polycrystalline material which has the body-centered cubic lattice form, and in which a majority of the grains have substantially the same orientation with respect to the plane ofthe sheetor strip and the direction of rolling.
• This orientation may be described as one in which the unit cube lattices of the oriented grains have a plane containing diagonally opposite cube edges substantially parallel to the plane of. the.
• this preferred orientation improves the useful magnetic properties of these materials in the plane of the sheet and in the rolling direction, but these magnetic properties in the plane of the sheet and transverse to the rolling. direction are comparativelyp'oor.
• orientation may be described as one in which a majority of the grains have their body-centered cubic lattices oriented: so that four (4) of the cube faces are substantially parallel to the rolling direction, two of these faces being also substantially parallel with the plane of the sheet and the other two being substantially perpendicular .to the plane of the sheet, and the remaining .two cube faces substantially perpendicular to both the rolling direction and the plane of. the sheet.
• This orientation may be conveniently termed cube texture or defined in terms of Miller Indices, (100) [001].
• These sheet and strip materials having, this orientation have been found to have magnetic properties which are equivalent to those of previously known (1'10) [001] materials ofv the same composition in the rolling direction and in the plane of the sheet, and much more desirable magnetic properties in the plane of the sheet transverse to the rolling direction than the previously known. materials.
• this preferred orientation i.e., cube texture
• this preferred orientation may be produced by particularly preparingcast ingots having an entirely or substantially entirely columnar as-cast grain structure. These castings are produced so that substan. tially all the metal therein is comprised of elongated columnar grains, the longitudinal axis of each of whichis: substantially parallel to each other longitudinal grain axis and all of which. axes are substantially parallel to a single direction in the ingot. It was found that byape limbately hot, warm and cold rolling as-cast slabs; of up to about 1 inch in thickness or slabs of that thickness cut from larger ingots, with particular reference to the?
• this reduction procedure involved heating such slabs to a temperature range of from. about 700 C. to about 1100" C., reducing the thickness of the so-heated slabs about to 97% in a plurality of rolling passes without reheating, annealing, cold reducing the annealing material at least 40% in thicknessby cold rolling and annealing to effect recrystallization of the cold rolled grain structure to produce the cube textured sheet or strip material.
• An additional object of my invention is the provision sheet or strip material may be producedrfrom ingots com- 7 sectioned grain oriented castings of these posed of columnar as-cast grains without regard to the initial thicknessof the start ng flight t n av to perform a slabbing operation'upon' such ingots.
• molybdenum-iron, and aluminum-iron which may be proucked in wrought recrystallized sheet or strip-like bodies of these materials, unexpectedly may be retained through a successive working and recrystallization treatments so that there is no limitation save practical or economical considerations on the initial size of the ingot'which may be so processed.
• polycrystalline iron and body-centered cubic iron alloys such as, for example, commercial silicon-iron electrical grade alloys containing 2 to 5% silicon, less than about 0.005% carbon, balance substantially all iron, including minor amounts of impurities customarily present in such materials, tend to invariably assume certain well known preferred orientations? or texture when subjected to substantial amounts of cold plastic deformation by unidirectional rolling.
• the cold rolled texture of these materials is chiefly one in which [110] directions of substantially all the grains lie along the direction of rolling, with adeviation of a few degrees, and (001) planes liein the plane of the rolled sheet, with a deviation from this position chiefly about the rolling direction as an axis.
• the preferred orientation or texture of the annealed sheet will change to an orientation which jis different'from" the cold rolled texture.
• the 'annealed'preferred orientation of such materials has previously been found to consist of a majority of the grains havinga (110) [001] orientation, which has been previouslydescribed, It would, therefore, reasonably be expectedthat when polycrystalline bodies of iron and the body-centered alloys of iron were severely cold rolled in one direction into sheet material the grains comprising such bodies would assume the (100) [011] stable texture or one of the previouslymentioned variations thereof, and when recrystallized by annealing, that the annealed texture would be predominantly the (110) [001] orientation usually obtained. I have discovered, however, that contrary to that which would be expected, the plastically deformed structure resulting from unidirectionally cold rolling cube texture polycrystalline iron base alloys of this type recrystallizes into cube texture instead of a predominantly (110) [001] orientation.
• a grain oriented casting composed of about 3% by weight silicon, balance substantially all iron was prepared by pouring the molten alloy into a tubular mold of fused alumina, the sidewalls of which were heated 7 tea temperature of about 1400? 0, just prior to pouring.
• the bottom of the mold consisted of a substantially planar water-cooled-copper body whose temperature was maintained at about 20 C. whereby substantially all the superheat and latent heat of the molten metal was extracted through said cooled copper bottom durin'gsolidification' to provide an ingot having an as-cast grain structuresubstantially consisting of a plurality of elongated columnarg'rains extending upwardly from'the copper bottom, sub--. stantially as shown and disclosed'injthe previously referenced co-pending application.
• the 'ingot was cut into a 'plurality of slabs, each slab having a pair of parallel faces, said faces extending in a direction'parallel to the mean direction of the longitudinal axes of the columnar grains, i.e., sub- I stantially parallel to the direction of flow of the majority of the heat extracted duringsolidification of the casting or, in other words, substantially perpendicular to the copper bottom of the mold.
• f i i These slabs were reduced by'a plurality of rolling passes during which passes the longitudinal axes of the columnar grains were maintained in a direction substantially parallel to the rolling plane and to the rolling direction.
• ingots having an as-cast grain orientation consisting of columnar grains as previously disclosed may be reduced from quite heavy as-cast sections to sheet or strip-like material having a recrystallized cube texture without any substantial restriction as to the initial thickness of the ingot. From this, it may be seen that large ingots may be so-cast, rolled and heat treated to form cube texture or strip without having to first reduce said ingots into relatively thin slabs prior to rolling.
• nominal 0.012 inch thick cube texture sheet material of 3% silicon-iron from, for example, a 24" x 24" square, cross section ingot of any appropriate length having substantially all of its as-cast grains in the form of elongated columnar grains Whose longitudinal axes extend substantially lengthwise of said ingot.
• the ingot is heated to a temperature of about 1100 C. and rolled without reheating in a plurality of passes to elfect about a 90% reduction in thickness to an intermediate slab of about 1.4" thick.
• the ingot is preferably rolled with its length parallel to the rolling plane and the rolling direction.
• This intermediate slab is annealed by heating to about 1000 C. and holding at that temperature for about four hours.
• the 1.4" thick slab is then cold reduced about 70% by rolling to about 0.42" thick, annealed to a temperature of about 1150 C. and permitted to furnace cool to produce a strong cube texture.
• This cube texture material is then further reduced in a plurality of cold rolling steps with interspersed anneals.
• the annealing steps are accomplished after a substantial amount of cold reduction, for example, about 50 to 70% has been accomplished.
• the 0.42" thick sheet material having cube texture is then cold reduced about 70% to about 0.126" thickness, annealed, for example, for about 8 hours at about 1000" C., cold reduced about 70% to about 0.38" thickness, annealed for about 8 hours at about 1000 C., cold reduced about 70% to about 0.012 thick sheet material and annealed for about 8 hours at about 1000 C. to eifect recrystallization of the cold worked crystal structure to cube texture.
• the recrystallization of the cold worked structure of these materials may be efiected over annealing temperature range of from about 800 C. to over 1200" C. for intervals of time ranging from a few minutes to several, i.e., 8 or more hours, depending primarily upon the particular temperature employed.
• the specific amounts of rolling reduction and annealing times and temperatures may be varied. For example, it would appear desirable that the amount of cold reduction of thickness before annealing be at least 40% in every case and for commercial considerations may be as large as is convenient. Further, the annealing times and temperatures required after each cold reduction would appear to be quite flexible, ranging from about ,6 hour at about 1200 C. to as much as 8 hours or more at about 800 C., so long as the cold worked structure is recrystallized.
• a method for producing polycrystalline sheet-like metal having the body-centered cubic crystal lattice form by rolling and heat treating in which a majority of the grains thereof have the cube texture preferred orientation with respect to the rolling direction and rolling plane of said sheet comprising the steps of rolling a grain oriented ingot composed of a binary alloy selected from the group consisting essentially of up to about 5% silicon, balance substantially all iron, up to about 8% aluminum, balance substantially all iron, and up to about 5% molybdenum, balance substantially all iron to effect a reduction in thickness of at least 40% and form an elongated slab-like body, said ingot being characterized in its as-cast state by being substantially entirely composed of a plurality of elongated columnar grains, the longitudinal axes of which are substantially parallel, said longitudinal grain axes being maintained substantially parallel to the rolling direction and the rolling plane during the rolling operations, annealing said slab at a temperature of from about 800 C.

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Citations (4)

• 0
  • BE BE560975D patent/BE560975A/xx unknown
  • BE BE560974D patent/BE560974A/xx unknown
  • LU LU35460D patent/LU35460A1/xx unknown
  • NL NL220951D patent/NL220951A/xx unknown
  • LU LU35456D patent/LU35456A1/xx unknown
  • BE BE560972D patent/BE560972A/xx unknown
  • LU LU35457D patent/LU35457A1/xx unknown
  • BE BE560938D patent/BE560938A/xx unknown
  • BE BE560976D patent/BE560976A/xx unknown
  • NL NL220953D patent/NL220953A/xx unknown
  • NL NL112430D patent/NL112430C/xx active
  • BE BE560973D patent/BE560973A/xx unknown
• 1956
  • 1956-09-20 US US610904A patent/US2940881A/en not_active Expired - Lifetime
• 1957
  • 1957-09-17 GB GB29228/57A patent/GB870209A/en not_active Expired
  • 1957-09-17 GB GB19866/59A patent/GB870214A/en not_active Expired
  • 1957-09-17 GB GB29230/57A patent/GB870211A/en not_active Expired
  • 1957-09-17 GB GB29229/57A patent/GB870210A/en not_active Expired
  • 1957-09-19 FR FR1183119D patent/FR1183119A/fr not_active Expired
  • 1957-09-19 FR FR1183118D patent/FR1183118A/fr not_active Expired
  • 1957-09-20 FR FR72331D patent/FR72331E/fr not_active Expired
  • 1957-09-20 FR FR72332D patent/FR72332E/fr not_active Expired

Patent Citations (4)

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