Classifications

• • 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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
• • 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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
• • 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
  • 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
  • C21D8/1277—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment

Definitions

• the invention is applicable to a wide variety of ferro-magnetic materials.
• ferrous magnetic materials While the permeabilities and other magnetic properties of ferrous magnetic materials will of course vary with composition and other gross characteristics of the material including grain size, the kind and degree of grain orientation (it any) and the like, the present invention is based upon the discovery of hitherto unknown effects of the surface condition of magnetic sheet stocks, which effects are essentially independent of the said gross characteristics,
• the factor of cost enters into the availability and use of ferro-magnetic stocks, so that a very large proportion of the sheet stocks used is made up of magnetic ingot irons, low alloy sheets and even materials classifiable as silicon-irons which can be produced cheaply and which are essentially devoid of preferential grain orientation.
• the present invention is applicable to such materials as well as to silicon-irons in the cube-on-edge orientation, nickel irons containing approximately 20% to 80% nickel, and others.
• a stock which has been hot rolled to gauge will have a rough surface within the meaning of this application whether or not the hot mill scale has been removed from the surfaces of the stock, as by pickling.
• ferromagnetic sheet stocks of any kind, have been produced in the practical art with very smooth surfaces.
• the first of these classes is that of exceedingly thin materials which be cause of their thinness must be produced on precision mills having very small working rolls. The working rolls of such mills are generally made with highly polished surfaces.
• the second of these classes is that of siliconiron sheet stocks which are made to have a cubic texture, i.e. a [001] grain orientation by Millers Indices, by processes involving the production in the stock of a number of grains having the cubic texture, and then subjecting the stock to a secondary recrystallization which proceeds basically by the phenomenon of surface energy.
• the annealing atmosphere used for the secondary recrystallization contains a minute quantity of a polar compound which shifts the order of the energy levels of grains having different orientations; and the Kohler US. Patent No. 3,090,711 teaches that the cubic texture cannot be attained in high degree unless the sheet stock being treated has a smooth surface, which apparently affects the surface energy of the grains. But if any other or different magnetic effects are attained in products of the two classes just mentioned (as to which there is no evidence), such effects could not be observed or detected. Since the products can be made only in the Ways indicated, there is no basis of comparison.
• the secondary recrystallization proceeds by grain boundary phenomena, and is not controlled by the obtaining of the desired orientation and the roughness or smoothness of the surfaces of the sheet stock.
• a smooth surface on the magnetic sheet stock is meant a smoothness which will measure not more than about. 5 microinches on the profilometer.
• the sheet or strip stock of this invention will give a profilometer reading range from less than one to about 5 microinches.
• the magnetic benefits which are derived from the practice of the invention are most apparent at the higher inductions, by which is meant conditions of operation of a core at inductions from about the knee of the magnetization curve up to saturation.
• high induction operation would be generally in the range of '14 to 19 kilogausses; while the knee of the curve for non-oriented silicon steel is at about 11 kilogausses.
• Magnetic ingot iron, low alloy steel, and non-oriented nickel-iron of the 48% nickel type have knees at about 6 kilogausses.
• Grain-oriented nickel-iron has a knee at about 14 kilogausses.
• the improvement in magnetic qualities obtained through the practice of the invention include an improvement in permeability and a reduction in core loss at high inductions as above defined. These phenomena were hitherto unknown.
• ferrous magnetic materials of the types herein taught are provided withvvery smooth surfaces. This may be done at any stage in their manufacture providing treatments at a subsequent stage do not produce or recreate a rough condition, as later explained. For. reasons which will also be given later the formation of the smooth surfaces-upon the ferrous magnetic sheet stock is ordinarily accomplished prior to the treatment which develops the ultimate magnetic characteristics in the products.
• Sensitivity of the magnetic properties to stressproduced changes in lattice or grain structure dictates to a considerable extent the stage at which the smoothing operation may be applied.
• the necessary surface smoothness can be attained in the laboratory for the extremely sensitive cube-on-edge oriented material even after development of the grain orientation.
• the amount of reduction required with the smooth surfaced rolls may be of the orderof the reductions taken in temper rolling or skin passing steps which form a part of some routings. Also it is generally somewhat less than the cold rolling made for critical straining procedures, sometimes employed for the purpose of growing large grains.
• the invention is applicable to and may be practiced upon, or in the course of the manufacture of, ferrous magnetic sheet stocks greater than about mils in thickness, and of the following classes or grades which are well recognized in the art:
• composition of the ferrous metal or alloy does not constitute a limitation on the invention, inasmuch as the benfits derived from the practices herein taught do not depend upon any specific composition.
• Non-oriented silicon steel is a non-oriented silicon steel
• Nickel-irons containing both lesser and greater amounts of nickel and other alloying elements are also improved by the practice of this invention.
• silicon-irons is generally applied to ferrous materials containing about /2% to about 5% silicon.
• the materials of the present invention may contain silicon up to the practical limit of workability, which for stocks hot rolled to substantially final gauge may be as high as 5%.
• Stocks intended for substantial reduction in gauge by cold rolling may contain silicon up to the practical limit of cold workability, which is currently in the neighborhood of 3.5%.
• the ferrous magnetic stocks of this invention may be unoriented (random), or the silicon-irons may have the cube-on-edge orientation or variations thereof in which the cube faces, while still lying at a significant angle to the plane of the surface of the sheet stock, depart more or less from a 45 angle to that surface, or cubic texture in the case of nickel-iron, which tends to assume that texture even Without secondary recrystallization.
• Orientations of the described char- 'acter for the designated materials, or the lack of any preferred orientation, do not affect the obtaining of the benefits of the invention as such.
• the magnetic benefits are affected in degree only by the gross factors mentioned above and by others. By and large, greater magnetic benefits will be attained in the case of oriented stocks than in the cases of non-oriented stocks because, inter alia, oriented stocks have higher general permeabilities.
• the thickness or gauge of the ferrous magnetic stocks is another factor, since it will be obvious that for a given degree of roughness, the volume of material affected by the smoothing operation will be greater as the number of laminations present in a given core thickness is increased.
• the obtaining of the benefits of this invention is likewise not dependent upon the routing by which the ferrous magnetic sheet stock is made, excepting for the attainment of the described surface condition in the ultimate product.
• the sheet stock may be hot rolled to substantially final gauge, or it may be hot rolled to an intermediate gauge and then cold rolled to final gauge in one or more stages, with or without intermediate annealing. Normally a ferrous magnetic sheet stock will be given a final heat treatment.
• the present invention is applicable to all of the procedures current in the art for making ferrous magnetic sheet stocks of the classes indicated, and the practice of the teachings of this application does not preclude the use of any of those steps hitherto known for improving the characteristics of such magnetic sheet stocks, including but without limitation the nature and temperature of the stages of hot rolling and coiling, the number and extent of cold rolling treatments, and the nature, atmospheres and temperatures of all heat treatments, whether for softening, decarburization, primary or secondary recrystallization, or for any other purpose.
• Examples I and II relates respectively to non-oriented iron stocks and to silicon-iron stocks having a high degree of cube-on-edge orientation.
• the fer- Sulfa Rollghnessi Difference in Micromches Magnetizmg Force rous magnetic material was substantially devoid of silicon Due to Surface (containing no more than about 0.1% thereof) and had 55 5 a carbon content not greater thanabout 0.005%.
• the samples were from the same heat and were treated idengggg g BT Space Factor, Percent tically including cold rolling to gauge with Pangborn rolls. A portion of the samples were then machined to 97A 994 produce a smooth surface.
• Profilometer measurements r showed roughness values of about 55 microinches for-the Type Surface Omteds Percent first mentioned group of samples, and values of about 5 microinches for the second group of samples.
• the samples Pangbom Ground were nominally mils in thickness.
• P10z60 signifies a test induction of 10 kilogausses at a test frequency of 60 cycles per second.
• the rough surfaced samples showed a core loss .065 watts per pound (9.4%) greater than the smooth surfaced samples.
• the rough surfaced samples showed a core loss .026 watts per pound (5.3%) higher than the smooth surfaced samples.
• the differences in the surface characteristics of the samples were measured by the profilometer.
• the rough samples showed a value of about 50 microinches while the smooth surfaced samples showed a value of about 5 microinches.
• a process of cold rolling ferrous magnetic sheet stock selected from the group consisting of magnetic ingot iron, low alloy steel, non-oriented silicon-iron, silicon-iron having a cube-on-edge type of orientation, nickel-iron magnetic alloys, and oriented aluminum-iron alloys containing up to about 20% aluminum, to a final thickness of about 10 mils or greater, and a smoothness of no more than about 5 microinches, and then heat treating the stock to produce therein an improved core loss and permeability at high inductions from about the knee of the magnetization curve up to saturation.

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

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Cited By (21)

Citations (2)

• 1964
  • 1964-01-20 US US338572A patent/US3347718A/en not_active Expired - Lifetime
• 1965
  • 1965-01-12 GB GB1360/65A patent/GB1089892A/en not_active Expired
  • 1965-01-15 BE BE658357D patent/BE658357A/xx unknown
  • 1965-01-19 DE DE1489620A patent/DE1489620C3/de not_active Expired
  • 1965-01-19 SE SE00668/65A patent/SE325286B/xx unknown

Patent Citations (2)

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