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
  • 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
• • 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
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/008—Heat treatment of ferrous alloys containing Si
• • 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
  • 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
  • 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
  • C21D8/1272—Final recrystallisation annealing

Definitions

• the invention relates to a method for producing non-grain-oriented electrical sheet, in which a hot strip is produced from a material produced from a steel, such as cast slabs, strips, pre-strips or thin slabs, the electrical sheet having a low loss of toxicity and a high polarization and has good mechanical properties.
• a hot strip is produced from a material produced from a steel, such as cast slabs, strips, pre-strips or thin slabs
• the electrical sheet having a low loss of toxicity and a high polarization and has good mechanical properties.
• Such non-grain-oriented electrical sheets are mainly used as core material in electrical machines, such as motors and generators, with a rotating magnetic flow direction.
• non-annealed electrical sheet here means electrical sheets falling under DIN EN 10106 (“final annealed electrical sheet”) and DIN EN 10165 (“non-final annealed electrical sheet”).
• final annealed electrical sheet means electrical sheets falling under DIN EN 10106 (“final annealed electrical sheet”) and DIN EN 10165 (“non-final annealed electrical sheet”).
• stronger anisotropic grades are included as long as they are not considered grain-oriented electrical sheets.
• One way of producing a highly permeable electrical sheet based on medium or weakly silicated alloys is to subject the hot strip to a hot strip annealing during the course of production.
• a hot strip annealing during the course of production.
• an annealing of the coil is provided directly from the rolling heat. In this way an end product with good magnetic properties is obtained.
• increased costs have to be accepted.
• an increased reel temperature in combination with an additional hot strip annealing is desirable in order to obtain useful magnetic properties even with low alloy contents. This too can only be accomplished by accepting additional costs.
• the object of the invention is to provide an inexpensive way of producing electrical sheets with improved properties.
• This object is achieved by a method for producing non-grain-oriented electrical sheet metal, in which a starting material, such as cast slabs, strips or thin slabs, is made from a steel with (in% by weight)
• a hot strip is produced by the prematerial directly from the casting heat or after a previous reheating to a reheating temperature of at least 1000 ° C and at most 1180 ° C several forming passes are hot-rolled and then coiled, with at least the first forming pass in the austenite area and at least one further forming pass in the two-phase mixing area austenite / ferrite being carried out during the hot rolling, and one during the rolling in the two-phase mixing area
• the magnetic properties of an electrical sheet are deliberately influenced by a deformation during the individual forming passes that are carried out in the course of hot rolling, depending on the particular structural condition. Rolling in the two-phase mixing area plays a decisive role, whereas the amount of deformation in the ferrite area should be as low as possible.
• the method according to the invention is therefore particularly suitable for the processing of such Fe-Si alloys which have a pronounced two-phase mixing region between the austenite and ferrite regions.
• the coordination of the alloy additives to ferrite- and austenite-forming elements is based on a, taking into account the content ranges of the individual elements provided according to the invention
• cast slabs are used as pre-material, they are reheated to a temperature> 1000 ° C., so that the material is completely in the austenitic state. For the same reason cast thin slabs or cast strips using the casting heat directly and, if necessary, heated to the initial rolling temperature of more than 1000 ° C.
• the required reheating temperature grows with increasing Si content, an upper limit of 1180 ° C. not being exceeded.
• the hot rolling according to the invention is generally carried out in a finishing rolling mill formed from a plurality of rolling stands.
• the purpose of rolling in one or more passes in the austenite area is, on the one hand, to be able to carry out the transition from the austenite ms two-phase mixing area and from the two-phase mixing area ms ferrite area in a controlled manner within the finishing mill.
• the forming passages passed through in the austenite area serve to adjust the thickness of the hot strip before the beginning of rolling in the two-phase mixing area in such a way that the desired overall shape change is reliably achieved during the rolling ("mixing rolls") taking place in the two-phase mixing area.
• the mixing rolling also comprises at least one forming pass. However, preferably a plurality of forming passages are run through in the austenite / ferrite mixing area in order to reliably achieve the overall shape change of at least 35% required for this mixing roll and thus to obtain the desired setting of the hot strip structure.
• the "overall shape change ⁇ h" is understood here to mean the ratio of the decrease in thickness during rolling in the respective phase area to the thickness of the strip when it enters the relevant phase area.
• a Hot strip produced according to the invention for example after rolling in the austenite region, has a thickness h 0 .
• the thickness of the hot strip is reduced to h x .
• the total change in shape ⁇ h during rolling in the two-phase austenite / ferrite mixing area should reach at least 35% in order to set a condition of the hot-rolled strip which favors the desired magnetic and technological properties with regard to grain size, texture and precipitations or to prepare for the subsequent processing steps.
• Optimal processing results can be achieved if the total deformation in the two-phase mixing area austenite / ferrite is limited to a maximum of 60%.
• the hot rolling which mainly takes the form of mixed rolling, largely bypassing rolling in the ferrite region, allows a hot strip to be produced which can further be used for the production of an electrical sheet and for the production of components with excellent magnetic properties. Additional processing steps which cause costs or the maintenance of certain high temperatures during hot rolling are not necessary for this purpose. Instead, the method according to the invention enables a temperature control as well as rolling strategy optimized with regard to the staggering of the formations in conjunction with a suitably selected reel temperature, the cost-effective production of high-quality electrical sheet material.
• An advantageous embodiment of the invention is characterized in that after the forming in the austenite area, the hot strip is only finished rolled in the two-phase mixing area austenite / ferrite.
• the overall shape change ⁇ h achieved during rolling in the austenite / ferrite two-phase mixing area should be at least 50%.
• rolling in the ferrite state of the hot strip is completely avoided. Strips which are based on Fe-Si steels and have a pronounced two-phase mixing area austenite / ferrite during the transition from austenite to ferrite are particularly suitable for this sequence of rolling steps excluding rolling in the ferrite region.
• At least one forming pass is carried out in the ferrite area following the rolling in the austenite / ferrite two-phase mixing area.
• the total shape change ⁇ h achieved during rolling in the ferrite area should be at least 10% and at most 33%.
• the rolling in the ferrite area is limited to a minimum, so that the focus of the forming, despite the final rolling in the ferrite area, remains unchanged in the austenite / ferrite mixing area.
• a reel temperature of at least 700 ° C. is generally suitable for carrying out the method according to the invention. If this coiling temperature is maintained, hot strip annealing can be saved entirely or at least in part.
• the Hot strip is already softened in the coil, whereby the characteristics determining its properties, such as grain size, texture and excretions, are positively influenced.
• Such "m-line" annealing of the hot strip coiled at high temperature and not significantly cooled in the coil can completely replace a hot strip hood annealing which may otherwise be necessary. This way, annealed hot strips with particularly good magnetic and technological properties can be produced. The time and energy required for this is considerably less than with the hot strip annealing conventionally carried out to improve the properties of electrical sheet.
• the hot strip is rolled after rolling in the finishing season at a coiling temperature of less than 600 ° C., in particular less than 550 ° C, coiled. Coiling at these temperatures leads to a solidified hot strip state in the alloys concerned.
• At least one of the last forming passes in the ferrite area is hot-rolled with lubrication.
• 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 Lubrication reduces the rolling forces so that a greater decrease in thickness is possible over the respective roll pass. Therefore, depending on the desired properties of the electrical sheet to be produced, it can be advantageous if all the forming stitches taking place in the ferrite area are carried out with roll lubrication.
• a further improvement in the properties of the electrical steel strip produced can be achieved in that the hot strip is additionally annealed after coiling and cooling at an annealing temperature of at least 740 ° C.
• This annealing can be carried out in the hood furnace or in the continuous furnace.
• hot strips can be produced whose thickness is ⁇ 1.5 mm.
• the production of particularly high-quality strips can be accomplished in this context by the fact that the cast primary material has been produced in a casting and rolling mill and is fed from it directly into the rolling mill.
• Hot strips produced in accordance with the invention have such good properties that they can be used directly as electrical sheets for a large number of applications without the need for repeated cold rolling, in which a cold deformation that goes beyond smoothing or skin-passaging is carried out. Therefore, a preferred embodiment of the invention is that the hot strip is assembled and delivered as electrical sheet. It should be noted that particularly good magnetic properties are achieved in such cases in which directly used primary material is processed into hot strip in the manner according to the invention when hot rolling in the austenite / ferrite mixing area is ended. It has been shown that hot rolled hot strips, in particular avoiding the ferrite area, are suitable for being delivered to the end user without further deformation in the course of cold rolling.
• a hot strip, if necessary pickled, produced in accordance with the invention can be used for certain applications without any final cold forming.
• this can be achieved in that the pickled hot strip is smooth-rolled with a degree of deformation of ⁇ 3%.
• unevenness of the strip surface is smoothed out without having any appreciable influence on the microstructure created in the course of hot rolling.
• the magnetic properties of the hot-rolled strip produced according to the invention can also be improved in that the pickled hot strip is skin-pass rolled with a degree of deformation of more than 3 to at most 15%.
• This re-rolling also does not lead to a typical reduction in thickness which was comparable to that achieved with typical cold rolling because of the high degrees of deformation achieved in the process Change in tape thickness. Rather, additional deformation energy is introduced into the strip, which has a positive influence on the later processability of the skin-rolled strip.
• the electrical sheet which is delivered as a hot strip according to the invention, can be finally annealed in the usual way before its assembly and delivery at an annealing temperature> 740 ° C. If, on the other hand, the final annealing is carried out by the processor, a non-final annealed electrical hot strip can be made available by recrystallizing the hot strip to a non-final annealed electrical steel prior to its assembly and delivery at annealing temperatures> 650 ° C.
• the hot strip produced in accordance with the invention is also particularly suitable for being cold-rolled to a final thickness in a conventional manner in one or more stages. If the cold rolling is carried out in several stages, intermediate annealing should take place after at least one of the cold rolling stages in order to maintain the good mechanical properties of the strip.
• the cold rolling is followed by a final glow at an annealing temperature which is preferably> 740 ° C.
• a "semi-finished" electrical strip is to be produced, then the cold rolling, which may be carried out in several stages, is followed by a re-installing annealing in the hood or Continuous furnace at temperatures of at least 650 ° C. The cold-rolled and annealed electrical steel is then straightened and re-rolled.
• Cold-rolled electrical steel produced in accordance with the invention is excellently cut and punchable and, as such, is particularly suitable for processing into components, such as lamellae or round blanks.
• components such as lamellae or round blanks.
• the components made from this electrical sheet are expediently annealed by the user.
• the final annealing of the cold-rolled electrical sheet is preferably carried out in a decarburizing atmosphere.
• J2500 denotes the magnetic polarization at magnetic field strengths of 2500 A / m, 5000 A / m and 10000 A / m.
• Reverse magnetization loss understood with a polarization of 1.0 T or 1.5 T and a frequency of 50 Hz.
• Table 1 shows the contents of the essential alloy constituents in% by weight for three steels used for the production of electrical sheet according to the invention.
• the slabs cast from steels A, B and C are re-heated as raw materials to a temperature of more than 1000 ° C and fed into a finishing mill comprising several rolling stands. In the finishing mill, at least the first forming pass was carried out exclusively in the austenite area.
• Table 2 shows the magnetic properties Jsoo, J5000, J10000, P ⁇ , o and P ⁇ , 5 for two electrical sheets B1, B2 produced from steels A and B, respectively.
• the respective hot strips intended for the production of the electrical sheets B1, B2 are after the rolling in
• Austenite area with a total forming degree ⁇ h of 66% in the two-phase mixing area austenite / ferrite was finished rolled.
• the rolled hot strips were then coiled at a reel temperature of 750 ° C. Immediately afterwards, the coiled hot strips were cooled and sent for further processing.
• Table 2 Table 3 shows the magnetic properties J2500, J5000, Jioooo, P ⁇ , o and P ⁇ _ 5 for electrical sheets B3, B4, B5.
• the sheet B3 was produced using the steel A, the sheet B4 using the steel B and the sheet B5 using the steel C.
• the hot strips intended for the production of the electrical sheets B3, B4, B5 were also formed after the shaping in the austenite area exclusively in the two-phase mixing area austenite / ferrite. The total deformation ⁇ h achieved during rolling in the mixing area was 66%.
• the hot strips were then coiled at a temperature of 750 ° C.
• the hot strips intended for the production of the sheets B3, B4, B5 were then kept at the reel temperature for at least 15 minutes before they were passed on for further processing to cold strip.
• Table 4 shows the magnetic properties J2500, J 5 000 Jioooo, P ⁇ , o and P ⁇ _ 5 are given for electrical sheets B6, B7, B8, has which is generated in the order given, likewise based on the steels A, B and C are.
• the hot strips intended for the production of the electrical sheets B6, B7, B8 are after the forming in the austenite area in the two-phase mixing area austenite / Ferrite has been formed.
• the total deformation ⁇ h achieved in the two-phase mixing area was 50%.
• the hot strip then went through several forming passes in the ferrite area. The achieved thereby
• Total deformation ⁇ h in the ferrite area was less than 30%.
• the hot-rolled strip thus finished has been coiled at a temperature of 750 ° C. Immediately afterwards, the hot strip was cooled in the coil.
• Table 5 shows the magnetic properties J 2 soo, J5000, Jioooo, P ⁇ , o and P ⁇ _ 5 for electrical sheets B9, BIO, B1.
• the sheet B9 was produced using steel A, the sheet BIO using steel B and the sheet B1 using steel C.
• the hot strips intended for the production of the electrical sheets B9, BIO, B1 have been subjected to the same transformations in the finishing rolling mill as the strips intended for the production of the sheets B6, B7, B8.
• the hot-rolled strip thus finished has been coiled at a temperature of 750 ° C.
• the hot strips intended for the production of the sheets B9, BIO, B1 were then kept at the reel temperature for at least 15 minutes before they were sent to cold strip for further processing.
• Table 6 shows the magnetic properties J2500, J5000, Jioooo, P ⁇ , o and P1.5 for an electrical sheet B12, which was generated based on the steel C.
• Table 7 shows the percentages by weight of the alloy constituents that are essential for the properties of two other steels used to produce a hot strip produced in accordance with the invention and then assembled without pronounced cold rolling and delivered as electrical steel.
• melts formed in accordance with the compositions given in Table 7 were continuously cast to a preliminary strip, which was also continuously fed into a hot rolling mill comprising several rolling stands.
• a hot rolling mill comprising several rolling stands.
• the focus of the deformation was in each case placed in the area in which the respective strip is in the austenitic state.
• the last pass of hot rolling was carried out according to the invention in the austenite / ferrite mixing area.
• the total deformation ⁇ H achieved was 40%.
• the hot strips were then coiled at a temperature of 750 ° C.
• Tables 8a - 8c show the magnetic properties J 25 oo, J5000, Jioooo, P ⁇ , o and P 1 # 5 for the three electrical sheets Cl - C3 and Dl - D3 produced from steel C and D, respectively.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Electromagnetism (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)
• Soft Magnetic Materials (AREA)
• Metal Rolling (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)

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• 1999
  • 1999-07-05 DE DE19930519A patent/DE19930519C1/de not_active Expired - Fee Related
• 2000
  • 2000-04-07 KR KR1020027000106A patent/KR100707503B1/ko active IP Right Grant
  • 2000-04-07 AT AT00918861T patent/ATE230803T1/de active
  • 2000-04-07 US US10/030,259 patent/US6773514B1/en not_active Expired - Lifetime
  • 2000-04-07 DE DE50001064T patent/DE50001064D1/de not_active Expired - Lifetime
  • 2000-04-07 AU AU39655/00A patent/AU3965500A/en not_active Abandoned
  • 2000-04-07 BR BR0012227-0A patent/BR0012227A/pt not_active Application Discontinuation
  • 2000-04-07 WO PCT/EP2000/003125 patent/WO2001002610A1/fr active IP Right Grant
  • 2000-04-07 JP JP2001508381A patent/JP2003504508A/ja active Pending
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  • 2000-04-07 PL PL353181A patent/PL194908B1/pl unknown
  • 2000-04-07 ES ES00918861T patent/ES2189751T3/es not_active Expired - Lifetime
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• 2009
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