Classifications

• • 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
  • 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
  • C21D8/1266—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 between cold rolling steps
• • 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
  • C21D8/1261—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 following hot rolling

Definitions

• ABSTRACT A process for producing silicon steel having a cubeon-edge orientation and a permeability of at least 1850 (6/0,) at 10 oersteds, which includes the steps of: annealing silicon steel prior to a final cold roll at a temperature of from 1400 to 2150F; cooling the steel from a temperature below 1700F and above 750F to a temperature at least as low as 500F at a rate which is faster than a still air cool and from its maximum annealing temperature to the temperature below 1700F and above 750F at a rate which is no faster than a still air cool; and cold rolling the steel at a reduction of at least 80 percent.
• the present invention relates to a process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1850 (G/O,.) at 10 oersteds.
• Oriented silicon steels containing 2.60 to 4.0 percent silicon are generally produced by processes which involve hot rolling, av double cold reduction, an anneal before each cold roll and a high temperature texture anneal. Characterizing these steels are permeabilities at 10 oersteds of from about 1790 to 1840 (Ci/ In recent years a number of patents have disclosed silicon steels with permeabilities in excess of 1850 (6/0 at 10 oersteds. Of these, U.S. Pat. Nos.
• Described herein is another, and improved method for producing silicon steel having a cube-on-edge orientation and a permeability of at least 1850 (G/O at oersted from steel of a particular chemistry.
• the method includes the steps of: annealing silicon steel prior to a final cold roll at a temperature of from l400 to 2150F; cooling the steel from a temperature below 1700F and above 750F to a temperature at least as low as 500F at a rate which is faster than a still air cool and from its maximum annealing temperature to the temperature below 1700F and above 750F at a rate which is no faster than a still air cool; and cold rolling the steel at a reduction of at least 80 percent.
• the present invention provides a method for producing silicon steel having a cubeaon-edge orientation and a permeability of at least 1850 (6/0 and preferably at least 1900 (G/O at 10 oersteds.
• Involved therein are the steps of: preparing a melt of silicon steel having, by weight, up to 0.07% carbon, from 2.60 to 4.0% silicon, from-0.03% to 0.24% manganese, from 0.01 to 0.07% sulfur, from 0.015 to 0.04% aluminum, up to 0.02% nitrogen, and from 0.1 to 0.5% copper; casting the steel; hot rolling the steel into a hot rolled band; subjecting the steel to at least one cold rolling and generally two; subjecting the steel to a final annealing prior to the final cold rolling; decarburizing the steel; and
• Preferred conditions include annealing at a temperature of from l800 to 2125F, cooling at a rate faster than a still air cool from a temperature below 1600F and above 1200F, and cold rolling at a reduction of at least percent.
• Illustrative means are gaseous streams and liquid quenching mediums.
• still air. cools include those wherein the steel is cooled in a static atmosphere as well as those wherein there is relative motion between the atmosphere and the steel, as in a continuous processing line, so long as there is no deliberate intention to cause the motion for cooling purposes.
• all gaseous atmospheres are considered to have the same cooling effect as air.
• the steel melt must include silicon, aluminum, manganese, sulfur and copper. Silicon is necessary as it increases the steels resistivity, decreases its magnet0- striction, decreases its magnetocrystalline anisotropy and hence decreases its core less. Aluminum, manganese and sulfur are necessary as they form inhibitors which are essential to controlling the steels orientation and its properties which are dependent thereon.
• aluminum combines with nitrogen, in the steel or from the atmosphere to form aluminum nitride
• manganese combines with sulfur to form manganese sulfide and/or manganese copper sulfide; and these compounds act so as to inhibit normal grain growth during the final texture anneal, while at the same time, aiding in the development of secondary recrystallized grains having the desired cube-on-edge orientation.
• Copper in addition to possibly forming manganese copper sulfide, is believed to be beneficial in that it is hypothesized that copper can lower the annealing temperature, lower the temperature from which the rapid cool can occur, improve rollability, simplify melting and relax annealing atmosphere requirements. Alloys with more than 0.15 percent copper have been successfully annealed prior to the final cold rolling at temperatures of from l400 to l700F.
• a steel in which the process of the present invention is particularly adaptable to consist essentially of, by weight, from 0.02 to 0.07% carbon, from 2.60 to 3.5% silicon, a manganese equivalent of from 0.05 to 0.24% as expressed by an equivalency equation of %Mn (0.1 to 0.25) X %Cu, from 0.0l to 0.5% sulfur, from 0.0 l 5 to 0.04% aluminum, from 0.0030 to 0.0090% nitrogen, from 0.1 to 0.3% copper, balance iron and residuals; and wherein the ratio of manganese equivalent to sulfur is in the range of from 2.0 to 4.75.
• the steel has its chemistry balanced so as to produce a highly beneficial structure when processed according to the present invention.
• the anneal conditions the steel for cold rolling and provides an operation during which inhibitors can form; and that the slow cool to a temperature below 1700F and [or the use of annealing temperatures in the lower part of the annealing temperature range, increase the uniformity in which the inhibitors are distributed, as essentially only ferrite phase is present in the steel at temperatures below l700F, contrasted to the presence of austenite and ferrite phases and different solubilities for the inhibiting elements in each phase 'at somewhat higher temperatures.
• the primary inhibitors are aluminum nitride and manganese sulfide and/or manganese copper sulfide. No criticality is placed upon the particular annealing atmosphere. Illustrative atmospheres therefore include nitrogen; reducing gases such as hydrogen; inert gases such as argon; air; and mixtures thereof.
• EXAMPLE 1 Twelve samples (Samples l 12) of silicon steel were cast and processed into silicon steel having a cube-onedge orientation from two heats (l-leats A and B) of BOF silicon steel. The chemistry of the heats, that is Heats A and B, appears hereinbelow in Table I.
• Cooling Method I was applied to samples 1, 4, 7 and 10, and is one in which the samples are cooled in a welded box. it is a cool which is slower than an air cool. Samples 1, 4, 7 and 10 took approximately minutes to cool to 750F. Cooling Method [I was applied to samples 2, 5,
• Samples 1 12 were tested for permeability and core less. The results of the tests appear hereinbelow in Table II. Results have been broken up into four groups so that only samples from the same heat and'coil are directly compared. Samples l, 2 and 3 are from the same heat and coil and form one group, as do samples 4, 5 and 6, samples 7, Band 9, and samples 10, l l and 12.
• samples 3, 6, 9 15 and Sample 15 had a lower core loss than did and 12 had lower core losses than did samples 2, 5, 8 ple and 11, and samples 2, 5, 8 and 11 had lower core 10 losses than did samples 1, 4, 7 and 10.
• samples 3, 6, 9 15 and Sample 15 had a lower core loss than did and 12 had lower core losses than did samples 2, 5, 8 ple and 11, and samples 2, 5, 8 and 11 had lower core 10 losses than did samples 1, 4, 7 and 10.
• said melt consisting essentially of, by weight, up
• Example II or at least two cold rollings as in Example said steel is cooled from a temperature below l600F l.
• Sample 16 was annealed in nitrogen for 1 hour at and above 1200F to a temperature at least as low as 1475F and cooled therefrom to a temperature below 500F at a rate which is faster than a still air cool and 500F at a rate faster than a still air cool; and had a perfrom its maximum annealing temperature to said temmeability in excess of 1900 (6/0,) at 10 0,..
• sample 14 which was annealed as was samwhich is no faster than a still air cool.
• said steel consists essentially of, by weight, from 0.02 to 0.07% carbon, from 2.60 to 3.5% silicon, a manganese equivalent of from 0.05 to 0.24% as expressed by an equivalency equation of Mn (O.l to 0.25) X Cu, from 0.01 to 0.05% sulfur, from 0.015 to 0.04% aluminum, from 0.0030 to 0.0090% nitrogen, from O.l to 0.3% copper, balance iron and residuals; and wherein the ratio of manganese equivalent to sulfur is in the range of from 2.0 to 4.75.

Landscapes

• 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)
• Manufacturing Of Steel Electrode Plates (AREA)
• Soft Magnetic Materials (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Metal Rolling (AREA)

Priority Applications (14)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23407796

Family Applications (1)

Country Status (14)

Cited By (11)

Families Citing this family (7)

Citations (10)

• 1973
  • 1973-05-07 US US00357974A patent/US3855020A/en not_active Expired - Lifetime
• 1974
  • 1974-03-28 AU AU67250/74A patent/AU474407B2/en not_active Expired
  • 1974-04-18 CA CA198,056A patent/CA1018440A/en not_active Expired
  • 1974-04-19 FR FR7413793A patent/FR2228855B1/fr not_active Expired
  • 1974-04-22 BE BE143468A patent/BE814021A/xx not_active IP Right Cessation
  • 1974-05-03 IT IT50771/74A patent/IT1011367B/it active
  • 1974-05-06 BR BR3628/74A patent/BR7403628D0/pt unknown
  • 1974-05-06 GB GB1980374A patent/GB1428901A/en not_active Expired
  • 1974-05-07 RO RO7478692A patent/RO68035A/ro unknown
  • 1974-05-07 PL PL1974170882A patent/PL90317B1/pl unknown
  • 1974-05-07 DE DE2422075A patent/DE2422075B2/de not_active Ceased
  • 1974-05-07 ES ES426046A patent/ES426046A1/es not_active Expired
  • 1974-05-07 JP JP49049840A patent/JPS5745292B2/ja not_active Expired
  • 1974-05-07 SE SE7406095A patent/SE415197B/xx unknown

Patent Citations (10)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events