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
  • 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
• • 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
  • C21D8/1216—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
  • 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

• non-grain-oriented electrical steel with cube texture (100) [001] or with cube surface texture (100) [0vw] and a final thickness of about 0.35 to 0.65 mm and a method for its production.
• non-grain-oriented electrical steel is understood here, regardless of its crystallographic texture, to be one according to DIN 46 400 Part 1 or 4, the loss anisotropy of which does not exceed the maximum values specified in DIN 46 400 Part 1.
• J 2500 denotes the magnetic polarization at a magnetic field strength of 2500 A / m and "P 1.5" the magnetic loss at a polarization of 1.5 T and a frequency of 50 Hz.
• the electrical steel or electrical sheet according to the invention is largely isotropic in its plane and has good properties in all directions, e.g. B. J 2500> 1.66 T and P 1.5 ⁇ 3.3 W / kg, and is therefore particularly suitable for electromagnetic circuits that are magnetized in all directions, for. B. for electric motors and generators.
• a recovery annealing is interposed in order to achieve a large reduction in thickness by cold rolling in order to reduce residual stresses without changing the magnetic properties of the finished strip.
• a hot strip with a thickness of 1.52 to 4.06 mm is cold rolled to an intermediate thickness of 0.51 to 1.01 mm and then cold rolled to 0.152 to 0.457 mm.
• a non-grain-oriented electrical steel with high proportions of cube or cube surface texture and with a polarization J 2500> 1.7 T and low magnetic loss which consists of a steel that
• the Si content is preferably in the range from 0.5 to 4.0%, in particular in the range from 0.5 to 2.0%. While with the choice of the steel composition provided according to the invention with (% Si) + 2 (% Al)> 1.6% a substantial ⁇ - ⁇ conversion freedom of the steel is determined, it is advantageous that the steel slab Si and Al in one contains such an amount that the relationship (% Si) + 2 (% Al)> 2% is satisfied.
• the aluminum content is preferably in the range from 0.3 to 2.0%.
• the carbon content should expediently be limited to a maximum of 0.015% and should preferably be between 0.001 and 0.015%.
• This low initial carbon content is advantageous, inter alia, with regard to the duration of the decarburization annealing in order to achieve an aging-free electrical steel strip or sheet a C content of less than 0.002%.
• surface-active elements such as, for example, antimony and / or tin, leads to a considerable delay in the decarburization reaction.
• the limitation of the carbon content to a maximum of 0.015%, in particular in connection with the setting of the Si and Al content in accordance with (% Si) + 2 (% Al)> 2% ensures complete freedom from transformation of the steel, which with regard to the desired properties of the electrical steel or sheet is particularly advantageous.
• the freedom from transformation of the steel is important for the final annealing, since the set texture is lost when the alpha-gamma phase boundary is exceeded, and for the hot forming, since the ferritic single-phase area is necessary for the targeted formation of cubic texture components during hot rolling.
• surface-active elements such as antimony and / or tin
• a total amount of 0.005 to 0.15%, preferably 0.02 to 0.06% leads to the suppression of the growth of grains with unfavorable (111) Texture components. This is particularly advantageous for long-term annealing in the hood furnace or in the stamping furnace when processing electrical steel that has not been finally annealed.
• the method according to the invention for producing a non-grain-oriented electrical steel with high proportions of cube or cube surface texture and with a polarization J 2500> 1.7 T and low magnetic loss, consisting of a steel with is characterized in that the steel slab is hot rolled to a thickness of not less than 3.5 mm, whereupon the hot strip thus obtained is cold rolled without recrystallizing intermediate annealing with a degree of deformation of at least 86% and the cold strip is annealed.
• phase transformation largely does not occur as a result of the steel composition according to the invention, which is important because the texture generated would be lost if the alpha-gamma phase boundary were exceeded, and this is also important for hot forming because of the targeted formation cubic texture components during hot rolling the ferritic single phase area is necessary.
• the cold forming provided according to the invention with a total degree of deformation of at least 86% while avoiding recrystallizing intermediate annealing also contributes significantly to the formation of cubic texture components.
• the deformation is a maximum of 30% per pass if the slab temperature is in the range between 1000 and 1060 ° C.
• the finish rolling temperature should preferably be between 900 and 960 ° C. This favors the aforementioned layer structure.
• a first section of the cold forming is to be carried out up to a strip thickness of 1.3 to 1.9 mm at an elevated temperature of 180 to 300 ° C.
• a blocking or anchoring of sliding dislocations and thus the activation of other sliding systems or a inhomogeneous deformation (shear bands) can be achieved, which particularly contributes to an increase in the magnetic polarization in the transverse direction.
• a better isotropy of the magnetic properties in the strip plane in the case of electrical steel with a cube-surface texture can be achieved in a further embodiment of the process according to the invention in that the cold-rolled strip is non-recrystallizing at a strip thickness which is still 1.12 to 1.2 times the final thickness Recuperation annealing, in particular between 400 and 500 ° C for 1 to 10 h, subjected and then cold rolled and annealed.
• the sheet produced in this way is particularly suitable for rotating machines.
• the strip rolled to its final thickness is preheated in a continuous furnace, optionally decarburizing in this furnace, and then finally annealed in the same furnace at temperatures between 900 and 1100 ° C.
• the final annealing temperature should not be below 900 ° C, because then the grain size of the material is not large enough to achieve a low loss of magnetization.
• the cold-rolled strip is placed in a hood furnace under a hydrogen atmosphere between 600 to 900 ° C or in a continuous furnace between 750 to 900 ° C for less than 5 min. annealed recrystallizing. in the In the case of bell annealing, the strip must then be straightened or re-rolled with a degree of deformation of less than 7%. Stamped parts are then produced in the usual manner from the strips which have not been finally annealed, and a stamped part annealing, e.g. B. according to DIN 46 400 Part 4. To achieve particularly good magnetic properties, however, the duration and temperature of the stamped part annealing should be reduced to e.g. B. 15 h and 950 ° C for steel compositions with surfactants.
• Bands B, C and D are comparative examples not belonging to the invention.
• the Si and Al portions of bands B and C do not satisfy the relationship (% Si) + 2 (% Al)> 1.6.
• Bands C and D have too high a Mn content.
• the strips were then decarburized and annealed for 1 minute at 1050 ° C (hot strip E, Table 3) or 1 h at 950 ° C (hot strip A, Table 4).
• variant b brings about a slight improvement in the polarization, which is even more clearly recognizable after long-term annealing (Table 4).
• the almost equally large values in the longitudinal direction (0 °) and transverse direction (90 °) indicate a particularly high proportion of grains with cube orientation.
• a pronounced isotropy of the polarization in the sheet metal plane can be achieved by variant c.
• Variant a) is required to produce a final annealed electrical sheet;
• Variants b) and c) represent the stamped annealing of a sheet that is not finally annealed.
• Table 5 shows the influence of the different annealing variants on the magnetic result.
• a melt was processed into hot strip (composition in Table 6).
• the hot strips were then cold rolled to a final thickness of 0.5 mm, decarburized and annealed at 950 ° C for 1 h. The result is shown in Table 7.
• the final rolling temperature of variant a is in the preferred range of 900 to 960 ° C and thus leads to a considerably higher polarization.

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

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• 1989
  • 1989-12-06 DD DD89335290A patent/DD299102A7/de not_active IP Right Cessation
• 1990
  • 1990-12-01 DE DE4038373A patent/DE4038373A1/de not_active Withdrawn
  • 1990-12-01 EP EP90123040A patent/EP0431502B1/fr not_active Expired - Lifetime
  • 1990-12-01 AT AT90123040T patent/ATE112326T1/de not_active IP Right Cessation
  • 1990-12-01 DE DE59007334T patent/DE59007334D1/de not_active Expired - Fee Related
  • 1990-12-04 ZA ZA909748A patent/ZA909748B/xx unknown
  • 1990-12-04 US US07/622,259 patent/US5258080A/en not_active Expired - Fee Related
  • 1990-12-05 CA CA002031579A patent/CA2031579C/fr not_active Expired - Fee Related
  • 1990-12-06 JP JP2413601A patent/JPH04218647A/ja active Pending
  • 1990-12-06 AU AU67841/90A patent/AU632876B2/en not_active Ceased
  • 1990-12-06 KR KR1019900020036A patent/KR0177801B1/ko not_active IP Right Cessation
  • 1990-12-06 BR BR909006197A patent/BR9006197A/pt not_active IP Right Cessation

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