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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
  • 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
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
• • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1272—Final recrystallisation annealing
• • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1277—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment

Definitions

• a silicon-iron sheet stock having a high degree of cubic texture would be a useful material in the electrical arts. It would be a material in which the cube faces of the crystals lie parallel to or within a few degrees of parallelism to the surface planes of the sheet stock, while the cube edges are generally aligned with the rolling direction. As a consequence, such a material could be expected to have, and does in fact have, as high a permeability (or higher) in the straight grain or rolling direction as characterizes silicon-iron having the so-called cube-on-edge orientation, but also a high permeability in the transverse direction. Hence it would be especially useful in the manufacture of transformers using core stampings, and in rotating electrical machinery.
• the [001] orientation which has been mentioned above implies not only an alignment of the cube faces in parallelism or substantial parallelism with the surfaces of the sheet stock, but also a general alignment of the cube edges in the direction of rolling.
• Other stocks can be made in which the cube faces are parallel or substantially parallel to the sheet stock surfaces, but in which the cube edges are not so aligned, but instead are variously directed and may even be random in their relationship to the rolling direction.
• a stock of this general character is described in the copending application of John M. Jackson, Serial No. 706,091, filed December 30, 1957, and entitled Non-Directional Oriented Silicon-Iron.
• Such stocks may be made in any suitable way as by the process of the said copending application, by processes involving the starting of columnar grains at the surfaces as when a phase change takes place in the sheet stock at a substantially constant temperature and the like.
• a product of this character, in which the cube edges have a random orientation will not be characterized by permeabilities which are as high in the straight grain and cross grain directions as a material having the cubic texture which has been described. But, the product will have a substantially equal permeability in all directions including those intermediate the straight grain and cross grain directions.
• the teachings of this application are applicable to the manufacture by secondary recrystalhaving a silicon content of substantially 2.5 to 4.0%,
• silicon-iron may contain from 2.90 to 3.30 silicon, a carbon content of the melt of not more than about .030%, which will later be reduced to less than about 005%, about .03 to .15 manganese, the remainder being substantially all iron with a total oxide content which should not be more than about 015% at the start of the routing, and which will preferably be reduced to about .00 5 by the end of the routing.
• these polar compounds are absorbed or adsorbed on the surfaces of the crystals in the sheet stock so as to satisfy the unsatisfied positive bonds thereat, the net result of the procedure being a shifting of the energy levels of crystals having various orientations in the sheet stock in such a way that grains having the (100) plane parallel to the sheet surface become the lowest in energy level, so that during the high temperature heat treatment grains so oriented can grow vigorously as respects other grains having different orientations.
• the use of this annealing procedure is preferred for purposes of this invention; but the invention is not necessarily confined thereto. It is applicable to any high temperature annealing treatment capable of causing grains having the cubic texture to grow at the expense of other grains.
• the silicon-iron sheet stock itself should have high purity as above set forth and also that its surfaces should be clean, i.e. substantially free from foreign material other than suitable annealing separators, and in particular free from oxide inclusions of substantial or massive character (although a very thin film of iron oxide on the surfaces of the sheet stock may be tolerated).
• the surfaces of the sheet stock should be as free as possible from any oxide materials which are not reducible in a high temperature heat treatment in hydrogen.
• a rather high peak to valley variation as determined by a profilometer measurement can be tolerated if the transition from peaks to valleys is gradual and occupies a substantial dimension in the general plane of the sheet surface.
• variations in the sheet surfaces which are sharp or distinctly angular have been shown to be detrimental.
• a scratch deliberately formed on a surface of the sheet can be shown to impair drastically the grain growth action upon secondary recrystallization.
• the profilometer measurements given are those characteristic of the finishing treatments.
• the effect on grain growth in the secondary recrystallization is necessarily given in qualitative terms due to variations in specific samples, especially where the samples are relatively small; but this classification is the result of extended experience; and it is believed that the effect of the rolls on the siliconiron sheet stock is the factor producing the greatest irnprovement in the attainment of a high degree of cubic secondary growth, assuming that the secondary recrystallization is otherwise carried on under favorable conditions.
• the cold rolling reduction in stages prior to the final stage may be carried on with rolls having commercial finishes.
• the final stage of cold rolling if desired, may employ rolls with commercial finishes for the greater part of the reduction; but the purposes of this invention will be attained if the last part of the final cold rolling is carried on with polished rolls.
• An excellent efiect can be attained in a single final pass through polished rolls providing the reduction in that pass is great enough to produce the desired smooth surface i.e. a reduction of 2% or more.
• the cubic crystal orientation can be produced from a material which in a condition of final primary recrystallization is characterized by an alignment of at least about 70% of the cube edges to within 20 of the rolling direction and an angular relationship of the cube faces of a substantial number of the grains to within at most about 5 of parallelism with the sheet surfaces.
• primary recrystallization will occur at temperatures roughly between l400 and 1700 F., and that secondary recrystallization requires a temperature of substantially 1900 to 2300 F.
• a process of producing silicon-iron sheet stock having a high degree of cubic texture which comprises subjecting a silicon-iron material containing substantially 2.5 to 4.0% silicon, a carbon content not substantially greater than .005% and an oxide content not substantially greater than .005 to a cold rolling and primary recrystallization treatment in which the crystals thereof are caused to assume an orientation in which at least about of the cube edges are aligned within 20 of the rolling direction, and in which a substantial number of the grains have their cube faces tilted to within substantially 5 of parallelism With the sheet stock surfaces, and thereafter subjecting the stock to a secondary recrystallization, the improvement which consists in accomplishing at least the latter part of said cold rolling by means of polished rolls having a profilimeter reading of about .2 to 1 microinch.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Electromagnetism (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Metal Rolling (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)
• Heat Treatment Of Sheet Steel (AREA)

Priority Applications (6)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25242633

Family Applications (1)

Country Status (5)

Cited By (12)

Citations (3)

• 1959
  • 1959-07-06 US US824915A patent/US3090711A/en not_active Expired - Lifetime
• 1960
  • 1960-06-23 GB GB22074/60A patent/GB949187A/en not_active Expired
  • 1960-06-30 CH CH747760A patent/CH402031A/de unknown
  • 1960-06-30 BE BE592471A patent/BE592471A/fr unknown
  • 1960-07-01 DE DEA35032A patent/DE1273552B/de not_active Withdrawn

Patent Citations (3)

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