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
  • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
• • 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
  • C21D1/76—Adjusting the composition of the atmosphere
• • 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
  • C21D8/1272—Final recrystallisation annealing
• • 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
  • C21D8/1277—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 structure of a wrought metal is capable of recrystallization. Such recrystallization effects a new grain formation with or without a change in texture.
• a secondary recrystallization follows the primary recrystallization, as is the case in the formation of the Goss texture and the pronounced cube texture, such new texture formation is especially apparent when the normal grain growth is hindered and only certain grains are permitted to grow. As a rule they possess a certain orientation.
• the normal grain growth for example, can be hindered by the presence of impurities at the grain boundaries. Use is made of this in the secondary recrystallization for the production of the Goss texture. On the other hand, care must be taken that the presence of too great a quantity of impurities does not hinder or prevent a secondary recrystallization.
• the present invention concerns a new way of producing the cube texture, namely, by carrying out the final anneal under certain controlled conditions.
• the atmosphere is changed during heating of the material to the temperature employed for the final anneal rather than. using the same atmosphere as previously has been customary.
• the gases or gas mixture employed during the initial heating period that is, before the change in atmosphere, are so selected that they have a carburizing, nitriding or oxidizing action thereon.
• Argon a vacuum of 0.1 to 0.005 mm.
• Hg an atmosphere of H CH and in some instances nitrogen have proved suitable as atmospheres before the change in atmosphere. It is advantageous if the change in atmosphere is effected before the actual annealing temperatures which, as is known, lie between 1000 and 1400 C. are reached.
• the change in atmosphere is effected at a temperature between 600 to 1200 C., preferably, between 700 and 1000 C.
• the selection of the temperature at which the change in atmosphere is effected depends upon the type of gas atmosphere employed and the material being treated and therefore also upon the quantity of impurities present. It is also important in carrying out such final anneal according to the invention to heat the material to be annealed rapidly before the atmosphere is changed, for example, to about 800 C. in 2 hours and to heat such material to the actual annealing temperature after the change in atmosphere more slowly.
• the rate of heating before the change in atmosphere should be about 500 to 1000" C. per hour, for example, 900 C. per hour.
• the slower heating after the change in atmosphere should be at a rate of about 10 to C. per hour, for example, 30 C. per hour.
• shock-like heating is carried out at a rate between 2000 and 20,000 C. per hour, for example, 3800 C. per hour.
• the material to be annealed can be heated inductively in a hot oven to 1250 C. in 25 minutes under high vacuum and annealed at such temperature for 12 hours.
• the final recrystallization anneal according to the invention can also be carried out in suitably designed pusher type furnaces and rotary furnaces containing one or more chambers and capable of providing a protective atmosphere for the material treated.
• a furnace for the slower procedure can be operated with argon under reduced pressure or another gas atmosphere of the described type in its first chamber, a medium vacuum of 10 to 1 mm. Hg in its second chamber, a fine vacuum of 1 to 10- mm. Hg in its third chamber and a high vacuum of 10" to l mm. Hg in its fourth chamber.
• the first cooling can also be effected in the last chamber.
• a protective gas such as helium or hydrogen is employed in the cooling zone, it is preferable to keep the gas in motion to obtain a better cooling action or to pump it out of the furnace and after cooling, for example, by heat exchange with the heating zone, recycling it to the cooling zone.
• the annealing of the band or sheet preferably is carried out in the bundle or coiled form.
• a further measure which is employed according to the invention during the final recrystallization anneal is to provide a sufficiently high aluminum and/or silicon partial pressure in the surrounding atmosphere that escape of silicon and/ or aluminum present at the grain boundaries cannot occur so that pitting along the grain boundaries is prevented.
• This can, for example, be achieved by surrounding the material being annealed with an iron silicon and/or aluminum alloy having a higher silicon and/or aluminum content so as to limit vaporization of such elements from the material being treated.
• the vapor pressure of the aluminum and/ or silicon can be varied according to necessity by locally heating the aluminum and/ or silicon to a higher or lower temperature than that of the material being annealed or by employing alloys of silicon and/ or aluminum with a greater or lesser quantity of iron or another element. It is also possible to supply the silicon by introducing a silicon compound such as a silane, for example, Sit-I which decomposes at higher temperatures, into the annealing atmosphere.
• a silicon compound such as a silane, for example, Sit-I which decomposes at higher temperatures
• an electrolyte composed of 1 part by weight of chromic acid anhydride (CrO and 9 parts by weight of orthophosphoric acid was well suited as an electrolyte for the electrolytic polishing of silicon steels.
• the temperature of such electrolyte during the electrolytic polishing preferably is about C., the sheet or ribbon to be polished being made the anode and being subjected to a current density of 0.3 amp/emi
• a copper sheet can be used as the cathode.
• the time required for the electrolytic polishing lies between 1 and about 10 minutes, preferably about 5 minutes.
• the material given the final recrystallization anneals according to the invention was an alloy of iron with 2.5% of silicon (containing the usual impurities of the iron) which had been hot rolled to a rib bon, annealed and then cold rolled in two stages with an intermediate anneal to a thickness of 0.35 mm., the degree of deformation in the first cold rolling stage being 85% and in the second stage 65%.
• Example 1 The cold rolled ribbon was heated in about 1 hour to 900 C. in argon containing 0.015 vol. percent of oxygen and then heated to 1250 C. under a high vacuum (10* mm. Hg) in 10 hours. This temperature was maintained for 12 hours and the material was then cooled down under high vacuum. 80 vol. percent of the thus annealed ribbon was oriented in the cube texture.
• Example 2 The cold rolled ribbon was electropolished using the electrolyte and procedure described above and then immediately heated under vacuum to 1250 C. in 20 minutes. After such temperature was reached the pressure was adjusted to below 10- mm. Hg within 10 minutes. Such vacuum was maintained over the entire annealing period of 10 hours. The annealed ribbon was cooled under vacuum and 90 vol. percent of the thus annealed ribbon was oriented in the cube texture.
• Example 3 The cold rolled ribbon was polished chemically and given a skin pass between a pair of very smooth relatively large rollers and heated in about 1 hour to 700 C. under a vacuum of 5X10 mm. Hg and then in about 18 hours to 1250 C. under a high vacuum of 10 mm. Hg. Ferrosilicon of about the composition FeSi was placed alongside the ribbon being annealed and heated along therewith. The annealing period was 24 hours. The cooling was effected under hydrogen. vol. percent of the thus annealed ribbon was oriented in the cube texture.
• a process for producing [001] oriented cube texture in sheets of a magnetizable iron alloy selected from the group consisting of iron-silicon alloys containing 0.5 to 3.5% of silicon, iron-aluminum alloys containing 0.5 to 2.5% of aluminum and iron-silicon-l-aluminum alloys in which the silicon+aluminum content is 0.5 to 3.5% comprising hot rolling sheets of said alloy, cold rolling said hot rolled sheets, heating up the cold rolled sheets essentially consisting of said iron alloy in a final recrystallization anneal at a rate of about 500 to 1000 C. per hour to a temperature in the range of about 700 C. to 1000 C. in an atmosphere essentially consisting of argon and about 0.015 vol.
• a process for producing (100) [001] oriented cube texture in sheets of a magnetizable iron alloy selected from the group consisting of iron-silicon alloys containing 0.5 to 3.5% of silicon, iron-aluminum alloys containing 0.5 to 2.5% of aluminum and iron-silicon+aluminum alloys in which the silicon-i-aluminum content is 0.5 to 3.5% comprising hot rolling sheets of said alloy, cold rolling said hot rolled sheets, heating up the cold rolled sheets essentially consisting of said iron alloy in a final recrystallization anneal at a rate of about 500 to 1000 C. per hour to a temperature in the range of about 700 C. to 1000" C, under a vacuum of about 0.1 to 0.005 mm.
• Hg then increasing the vacuum to a high 6 vacuum of a pressure between 10- and 10- mm. Hg, then heating up said sheets further at a rate of about 10 C. to C. per hour to an annealing temperature between 1000 and 1400 C. under said high vacuum, the duration of the said heating up of the cold rolled sheets to the annealing temperature being a period of over an hour, and maintaining said sheets at said annealing temperature under said high vacuum until completion of the final recrystallization anneal.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Electromagnetism (AREA)
• Manufacturing & Machinery (AREA)
• Soft Magnetic Materials (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

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Citations (6)

• 1960
  • 1960-02-16 DE DE19601408973 patent/DE1408973A1/de active Pending
  • 1960-12-24 AT AT968260A patent/AT239826B/de active
• 1961
  • 1961-02-03 GB GB4223/61A patent/GB964707A/en not_active Expired
  • 1961-02-14 US US89105A patent/US3207639A/en not_active Expired - Lifetime

Patent Citations (6)

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