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
• • 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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• • 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
  • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
• • 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
  • 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
  • C21D2211/00—Microstructure comprising significant phases
  • C21D2211/005—Ferrite
• • 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

Definitions

• the invention relates to a hot-rolled steel strip intended for the production of electrical sheet and a method for the production thereof.
• non-grain-oriented electrical sheet means a steel sheet or a steel strip which, regardless of its texture, falls under the sheets mentioned in DIN 46 400 Part 1 or 4 and whose loss anisotropy does not exceed the maximum values specified in DIN 46 400 Part 1 ,
• sheet metal and “strip” are used synonymously here.
• non-grain-oriented electrical sheet comprises the following steps:
• the invention was based on the object of realizing a cost-effective hot strip with a partially softened microstructure with a thickness of at most 1.8 mm, which is particularly suitable for the production of high-quality electrical sheets due to these properties.
• Orientation distribution functions in the range up to 60 °.
• the invention is based on the knowledge that a hot strip can be made available if a suitable production path is selected, which, even in the hot-rolled state, has a structure which can only be produced in conventional production methods by cold rolling at high degrees of deformation.
• hot strip assembled and procured according to the invention has a partially softened structure with a strip thickness of at most 1.8 mm.
• This microstructure is characterized by high intensities of the ⁇ -fiber in the range of angles up to 60 ° for specific layers, that is to say in an angular range in which no noticeable intensities for these layers can usually be found in conventional hot strips of comparable composition.
• the high intensities of the specific layers (112) ⁇ 110> and (111) ⁇ 110> are characteristic, the ratios of the intensities I n2 of the layer (112) ⁇ 110> to the intensity I 0 o ⁇ of the layer (001) ⁇ 110> a value> 0.4 or the intensity Imder layer (111) ⁇ 110> to intensity I 0 o ⁇ layer (001) ⁇ 110> gives a value> 0.2. Because of this nature, hot strip according to the invention can be excellently Process to cold-rolled NO electrical steel, the final thickness of which is typically 0.35 mm to 0.75 mm, in particular 0.2 mm, 0.35 mm, 0.50 mm or 0.65 mm.
• Conventional hot strips differ from the invention in that noticeable intensities only occur in the range of up to 25 ° (-30 °), while no higher intensities can be determined for components (112) ⁇ 110> and (111) ⁇ 110> are.
• conventional hot strips typically an intensity maximum of the ⁇ -fiber structure at 0 °, from which the intensity decreases with increasing angle. This intensity distribution of the ⁇ fiber corresponds to a solidified structure. It is only through the cold rolling process in such steel strips that the structure is softened by a
• hot strip according to the invention is such that the intensities of component (112) ⁇ 110> and the intensities of layer (111) ⁇ 110> are high.
• hot strip according to the invention has a particularly low final thickness.
• the war band according to the invention creates far more favorable conditions for the subsequent processing than conventional hot strips can afford.
• hot strip according to the invention can be cold-formed, starting from its small thickness of at most 1.8 mm, with minimized total forming into a non-grain-oriented electrical sheet, the properties of which are at least equal to the properties of conventionally produced NO electrical sheets.
• orientation distribution function describes the relative position of the crystal coordinate system and the sample coordinate system.
• Orientation distribution function assigns an orientation density or intensity to each point in space. Since a representation of the orientation distribution function is very complicated and not very descriptive, a simplified description with the help of fibers is chosen.
• the fibers relevant for steels are:
• the ⁇ 110> direction is parallel to the rolling direction; it runs between the layers (001) ⁇ 110> and (110) ⁇ 110>.
• a hot strip according to the invention has a particularly favorable softening state for further processing if its strip thickness is at most 1.2 mm.
• the ⁇ -fiber-formed ratio In 2 / loo ⁇ > 0.75 and that from the intensity In 2 of the layer (112) ⁇ 110> to the intensity I 0 o ⁇ of the layer (001) ⁇ 110> is regular the intensity I m of the layer (111) ⁇ 110> to the intensity I 0 o ⁇ of the layer (001) ⁇ 110> of the ⁇ -fiber formed ratio Im / I OOI > 0.4.
• Hot-rolled strip softened in this way can be processed into NO electrical steel sheet with particularly low degrees of deformation.
• Hot strips according to the invention with hot strip thicknesses of ⁇ 1.8 mm can be produced in various ways; conventional hot strip mills with the possibility of realizing the above thicknesses, casting and rolling systems (casting of Thin slabs with subsequent in-line hot rolling), thin strip casting systems with subsequent single or multi-stage hot rolling of the thin strip.
• At least one pass of the hot rolling is carried out at temperatures at which the hot strip has an austenitic structure, and a plurality of subsequent passes of the hot rolling are carried out at temperatures at which the hot strip has a ferritic structure.
• lubrication is carried out on at least one of the last forming passes.
• Hot rolling with lubrication results in less shear deformation on the one hand, so that the rolled strip as a result obtains a more homogeneous structure across the cross section.
• the rolling forces are reduced by the lubrication, so that the respective Roll pass a higher thickness reduction is possible. Therefore, depending on the desired properties of the electrical sheet to be produced, it can be advantageous if all the forming passes in the ferrite area are carried out with roller lubrication.
• Hot strips according to the invention can be produced in particular with reliably reproducible work results by first melting a steel composed according to the invention and then casting this steel into thin slabs, which are then hot-rolled ("in-line") continuously to form hot strips.
• the total degree of forming achieved during hot rolling is preferably at least 90%, hot rolling usually being carried out in several passes.
• the continuous succession of casting of the steel into thin slabs and hot rolling of the thin slabs into hot strip which is known from the known casting and rolling, also makes it possible to save work steps, such as reheating the slabs and pre-rolling, in the production of hot strips according to the invention.
• the saving of the relevant work steps affects the material condition in the various manufacturing phases. In some cases, this differs considerably from that achieved with conventional hot strip production, in which reheating of the cooled slab is started. In particular, it is the macro segregations and the state of dissolution and excretion that distinguish hot strips produced according to the invention from conventionally produced ones.
• the forming process takes place with in-line casting and rolling during hot rolling under favorable thermal conditions. The rolling passes can be applied with higher degrees of forming and the forming conditions can be used specifically to control the development of the structure.
• the phosphorus content is preferably limited to less than 0.08% by weight in order to achieve sufficient casting properties.
• Orientation distribution function (orientation density) plotted over the angle ⁇ .
• " ⁇ " is one of the Euler angles that describe the relative position of the crystal coordination and sample coordination system.
• special locations are entered: (001) ⁇ 110>, (112) ⁇ 110>, (111) ⁇ 110> and others.
• a steel with (in% by weight or ppm by weight) ⁇ 30 ppm C, 0.2 % Mn, 0.050% " P, 1.3% Si, 0.12% Al, 0.01% Si and the remainder Fe and impurities have been melted.
• the molten steel was cast into a slab, which was then cooled, reheated, pre-rolled in a conventional manner and to a final thickness of
• the high density in the area of small angles and the low density in the area of large angles prove that the hot strip Wb V ⁇ was in a solidified state in which it first has to be subjected to expensive cold rolling and aftertreatment in order to be used as NO electrical steel to be able to.
• the same steel was first cast in a casting and rolling plant to form a thin slab, which was then hot-rolled "in-line” in several passes to a final hot strip thickness of 3 mm.
• the hot strip Wb V2 obtained in this way just like the hot strip Wb V ⁇ , had an orientation density of the ⁇ -fiber of at least 4 for an orientation angle Band of 0 ° to 20 °, while the Orientation density for angles ⁇ of more than 20 ° was regularly significantly less than 3.
• the value of the ratio In 2 / Ioo ⁇ of the intensity I 112 of the layer (112) ⁇ 110> to the intensity I 110 of the layer (001) ⁇ 110> of the ⁇ fiber was 0.2, while the value of the ratio Im / I OOI of intensity I of position (111) ⁇ 110> to intensity In 0 of position (001) ⁇ 110> only reached 0.06.
• the hot strip Wb V2 the high density in the area of small angles and the low density in the area of large angles prove that the hot strip Wb V2 was in a solidified state in which it first has to be subjected to extensive cold rolling and aftertreatment, to be able to use it as NO electrical sheet.
• the hot strip Wb E according to the invention is also made from the same steel as the hot strip Wb V ⁇ produced for comparison.
• the steel in question was also cast in a casting and rolling plant to form a thin slab, which was then hot-rolled "in-line" in several passes.
• the final thickness of the hot strip was only 1.04 mm.
• the hot strip Wb E obtained in this way had an orientation density of the ⁇ -fiber determined in the center of the strip for all orientation angles ⁇ in the range from 0 ° to 60 ° from at least 4 to. Only in the angular range of more than 60 ° did the orientation density drop below 3.
• the value of the ratio I112 / I001 of the intensity in 2 in the position (112) ⁇ 110> to the intensity I ⁇ 10 of the component (001) ⁇ 110> of the ⁇ -fiber was at a high level, namely at 0.81.
• the value of the ratio I / Ioox of the intensity Im in position (111) ⁇ 110> to the intensity I no of position (001) ⁇ 110> reached a high level, namely 0.54.
• the high orientation densities up to an angle of 60 ° and the high intensities of components (112) ⁇ 110> and (111) ⁇ 110> show that the hot strip according to the invention is in a largely partially softened state.

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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)
• Manufacturing & Machinery (AREA)
• Electromagnetism (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)
• Metal Rolling (AREA)
• Soft Magnetic Materials (AREA)
• Inorganic Fibers (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Electroplating Methods And Accessories (AREA)

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• 2001
  • 2001-10-31 DE DE10153234A patent/DE10153234A1/de not_active Withdrawn
• 2002
  • 2002-10-23 AT AT02779503T patent/ATE305983T1/de active
  • 2002-10-23 EP EP02779503A patent/EP1440173B1/fr not_active Expired - Lifetime
  • 2002-10-23 CN CNB028215958A patent/CN1302131C/zh not_active Expired - Fee Related
  • 2002-10-23 JP JP2003540399A patent/JP2005507458A/ja active Pending
  • 2002-10-23 WO PCT/EP2002/011822 patent/WO2003038135A1/fr active IP Right Grant
  • 2002-10-23 DE DE50204488T patent/DE50204488D1/de not_active Expired - Lifetime
  • 2002-10-23 KR KR1020047006653A patent/KR100951462B1/ko not_active IP Right Cessation
  • 2002-10-23 ES ES02779503T patent/ES2249622T3/es not_active Expired - Lifetime
  • 2002-10-23 PL PL369257A patent/PL205577B1/pl not_active IP Right Cessation
  • 2002-10-23 US US10/493,522 patent/US7658807B2/en not_active Expired - Fee Related

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