Non-grain-oriented metal electrical strip or sheet, method for producing a non-grain-oriented electrical strip, and use

Abstract

The invention relates to a non-grain-oriented metal electrical strip or sheet which is characterized, in addition to its alloy composition, by a thickness of < 0.270 mm and a 0.2% proof stress Rp0.2 > 420 MPa. Another aspect of the invention relates to a method for producing a non-grain-oriented electrical strip and to a use.

Description

[0001] Non-grain-oriented metallic electrical steel strip or sheet, process for producing a non-grain-oriented electrical steel strip and use

[0002] The invention relates to non-grain-oriented metallic electrical steel strip or sheet. The invention also relates to a process for producing a non-grain-oriented electrical steel strip and to a use thereof.

[0003] Non-grain-oriented flat products, in particular non-grain-oriented electrical steel strip or sheet, are required in many electrical engineering applications and are known from practice.

[0004] Non-grain oriented electrical steel or sheet, often referred to as "NO electrical steel" or "NO electrical sheet", or in English as "NGO electrical steel" ("NGO" = Non Grain Oriented), is used, for example, as a starting material for the manufacture of components for a rotating electrical machine. The non-grain oriented electrical steel or sheet is used to guide and amplify electromagnetic fields. Typical applications for such steel strips and sheets are rotors and stators in electric motors and electric generators.

[0005] For many electric motors, operation at high speeds per unit of time is desired. For example, for motors that are being developed for applications in the field of electromobility, which is therefore becoming increasingly important. The operation of an electric motor at high speeds goes hand in hand with the high frequencies of the required alternating electromagnetic field, which ultimately forms the basis for driving the motor. Therefore, materials that are designed for use in alternating electromagnetic fields with comparatively high frequencies are increasingly required. When developing electric motors for operation in high-frequency alternating fields, materials developers are faced with the challenge of making a contribution to increasing the efficiency of the electric motor.Against this background, such non-grain-oriented metallic flat products, in particular non-grain-oriented electrical steel strip and non-grain-oriented electrical sheet, are required, which combine comparatively low core losses at comparatively high frequencies with a comparatively high magnetic polarization and induction as well as a comparatively high permeability, in particular in the relevant ranges of the magnetic field strength, i.e. at comparatively low magnetic field strengths.A further challenge that arises in the search for suitable materials lies in the planned application in high-frequency alternating electromagnetic fields, which are often accompanied by rotational movements at high rotational frequencies. In order to withstand the resulting mechanical stresses for a sufficiently long time, the materials require sufficiently high strength, in particular a sufficiently high 0.2% yield strength. This presents a particular difficulty, particularly with regard to finding the right alloy composition, since measures to improve high-frequency suitability often result in a reduction in strength.

[0006] Good combinations of these properties are achieved in proven electrical steel strip and electrical sheets by a comparatively high weight proportion of the alloying components silicon and / or aluminum in the starting alloy of the electrical steel strip or electrical sheet. However, high contents of these elements are generally associated with the disadvantageous effect that corresponding previously known NO electrical steel strip or NO electrical sheets, due to their high silicon and / or aluminum content, exhibit comparatively high brittleness with the associated disadvantages in processability, e.g. in cold rolling. For example, cold rolling of NO electrical steel strip can lead to increased strip breaks. The permissible degree of brittleness, in turn, depends on the sheet thickness of the electrical steel strip or sheet, so that optimization of the material properties is necessary, taking opposing physical effects into account.

[0007] In light of the above, the object of the invention is to provide alternatives to the known electrical steel strips and sheets that meet the requirements regarding their magnetic properties on the one hand and their mechanical properties on the other to the same or greater extent, while allowing for production in thin thicknesses. The developers' primary goal is to achieve good handling, particularly with a view to avoiding impairments to cold rolling properties as far as possible.

[0008] The invention is achieved with a non-grain-oriented metallic electrical strip or sheet having the features of claim 1 and with a method for producing a non-grain-oriented electrical strip having the features of claim 10. The invention is also achieved with an electrical strip having the features of claim 20 and with a use according to claim 21.

[0009] A non-grain-oriented metallic electrical steel strip or sheet is provided. The non-grain-oriented metallic electrical steel strip or sheet consists of a composition with the following components, each in percent by weight, in short: wt.%:

[0010] C: 0.0005 up to 0.0040, preferably 0.0005 up to 0.0035;

[0011] Si: 2.8 up to 3.2, preferably 2.9 up to 3.1; Al: 1.3 up to 1.7, preferably 1.40 up to 1.60;

[0012] Mn: 0.5 to 0.7, preferably 0.55 to 0.65;

[0013] P: up to 0.040, preferably up to 0.020;

[0014] S: up to 0.0030, preferably up to 0.0010;

[0015] N : up to 0.0030;

[0016] Ti: up to 0.0070, preferably up to 0.0040;

[0017] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : for all of these with the proviso: the sum of all the elements mentioned is less than 0.1 wt.%;

[0018] Remainder to 100 wt.%: Fe and unavoidable impurities. Furthermore, the electrical strip or sheet according to the invention is characterized in that it has a thickness < 0.270 mm, preferably < 0.260 mm, and a 0.2% yield strength Rp0.2 > 420 MPa.

[0019] The material characteristic value yield strength Rp0.2 is to be understood as determined according to DIN EN ISO 6892-1:2020-06.

[0020] By combining an alloy specification with narrowly defined content proportions, particularly specific for Si, Al, and Mn, as well as the permitted total contents of optional components, with a comparatively low thickness of the electrical steel strip or sheet combined with a sufficiently high yield strength, it was surprisingly possible to provide an electrical steel strip or sheet with a novel combination of desired magnetic and advantageous mechanical properties. In particular, the comparatively high proportion of Si, Al, and Mn prevented the extent of eddy current losses. Despite the high proportion of Si, Al, and Mn as alloy components, it was found that the magnetic polarization of the samples according to the invention and its further developments is also comparatively high.By deliberately providing a combination of Si, Al, and Mn as alloy components of the electrical steel strip or sheet, a combination of magnetic and mechanical advantages was achieved: The surprisingly high magnetic polarization mentioned above, combined with magnetic properties in alternating fields that are otherwise very useful for the application, and comparatively excellent handling with regard to mechanical properties were combined in a particularly advantageous manner. In particular, it was possible to achieve sufficiently high strength with cold rollability, which is very important in practice, as evidenced by the comparatively low number of strip breaks observed during test runs.The previous assumption that in order to improve magnetic properties in an alternating field, elements that promote the brittleness of the material must necessarily be used, and that this in turn has a negative effect on cold rollability, could thus be largely rejected or overcome.

[0021] The electrical steel strip or sheet showed particularly good properties when the composition of the alloy was as follows:

[0022] C: 0.0005 up to 0.0035;

[0023] Si : 2.9 up to 3.1;

[0024] Al: 1.40 up to 1.60;

[0025] Mn: 0.55 to 0.65;

[0026] P : up to 0.040;

[0027] S : up to 0.0030;

[0028] N : up to 0.0030;

[0029] Ti: up to 0.0070, preferably up to 0.0040;

[0030] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1; the remainder is Fe and unavoidable impurities. The electrical steel strip or sheet exhibited particularly good properties according to a preferred refinement, which complies with the following alloying specification:

[0031] C: 0.0005 up to 0.0035; Si: 2.9 up to 3.1;

[0032] Al: 1.40 up to 1.60;

[0033] Mn: 0.55 to 0.65;

[0034] P: up to 0.040, preferably up to 0.020;

[0035] S: up to 0.0030, preferably up to 0.0010;

[0036] N : up to 0.0030;

[0037] Ti: up to 0.0070, preferably up to 0.0040;

[0038] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1;

[0039] Rest Fe and unavoidable impurities.

[0040] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0041] C: 0.0005 up to 0.0035;

[0042] Si : 2.9 up to 3.0;

[0043] Al: 1.40 up to 1.60;

[0044] Mn: 0.55 to 0.65;

[0045] P: up to 0.040, preferably up to 0.020;

[0046] S: up to 0.0030, preferably up to 0.0010;

[0047] N : up to 0.0030;

[0048] Ti: up to 0.0070, preferably up to 0.0040;

[0049] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0050] Rest Fe and unavoidable impurities.

[0051] The electrical steel strip or sheet showed particularly good properties when the composition of the alloy was as follows:

[0052] C: 0.0025 up to 0.0035;

[0053] Si : 2.9 up to 3.1;

[0054] Al: 1.40 up to 1.60;

[0055] Mn: 0.55 to 0.65;

[0056] P : up to 0.040;

[0057] S : up to 0.0030;

[0058] N : up to 0.0030;

[0059] Ti: up to 0.0040; Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0060] Rest Fe and unavoidable impurities.

[0061] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0062] C: 0.0027 up to 0.0033;

[0063] Si : 2.9 up to 3.1;

[0064] Al: 1.40 up to 1.60;

[0065] Mn: 0.55 to 0.65;

[0066] P: up to 0.040, preferably up to 0.020;

[0067] S: up to 0.0030, preferably up to 0.0010;

[0068] N : up to 0.0030;

[0069] Ti: up to 0.0040;

[0070] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0071] Rest Fe and unavoidable impurities.

[0072] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0073] C: 0.0027 up to 0.0033;

[0074] Si : 2.9 up to 3.0;

[0075] Al: 1.40 up to 1.60;

[0076] Mn: 0.55 to 0.65;

[0077] P: up to 0.040, preferably up to 0.020;

[0078] S: up to 0.0030, preferably up to 0.0010;

[0079] N : up to 0.0030;

[0080] Ti: up to 0.0040;

[0081] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0082] Rest Fe and unavoidable impurities.

[0083] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0084] C: 0.0027 up to 0.0033;

[0085] Si: 2.9 up to 3.0; Al: 1.40 up to 1.60;

[0086] Mn: 0.55 to 0.65;

[0087] P : up to 0.040;

[0088] S : up to 0.0030;

[0089] N : up to 0.0030;

[0090] Ti: up to 0.0040;

[0091] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1;

[0092] Rest Fe and unavoidable impurities.

[0093] This embodiment has the particular advantage that the Si content is even more limited upwards, with the advantage that disadvantages associated with Si addition, such as effects of brittleness, can be further reduced.

[0094] In order to ensure in an optimized manner that the proportion of Al in the total of Si and Al is optimum, in an advantageous further development the relationship should apply according to which Al / (Si + Al) has a value between 0.30 and 0.40, preferably between 0.30 and 0.35. This means that the quotient of the weight proportion of Al and the sum of the weight proportions of Si and Al has a value between 0.30 and 0.40, preferably between 0.30 and 0.35. Within this range, the upper limit ensures, on the one hand, that the Si proportion is sufficiently high to ensure a reduction in magnetization losses due to the increase in electrical resistance by Si, and on the other hand, the lower limit ensures that the Si proportion within the total of Si and Al does not exceed an acceptable level of impairment of the processability of the electrical strip or sheet.

[0095] The approach presented provides that, compared to previously known alloys with Si contents of, for example, 3.2 wt.% or more and Al contents of, for example, 1.0 wt.% or less, the relative proportion of Al to the total proportion of Al and Si is increased, and in doing so, in particular, the ranges mentioned above are achieved. It was found that by increasing the Al proportion to the total proportion of Al and Si in the manner described, it was possible to influence the electrical and magnetic properties in the desired way. The influence of Si, in particular on the specific electrical resistance of the electrical strip or sheet and thus also on other electromagnetic properties, could therefore be fully or partially compensated for by the influence of Al.Surprisingly, it has been shown that, in addition, the electrical strips or sheets according to the invention show an unexpectedly low tendency to embrittlement, which was, for example, qualitatively noticeable in a smaller proportion of observed strip cracks.

[0096] A further contribution to the electromagnetic properties was achieved by Mn contents of previously unusual magnitude. It was found that Mn contents of up to 0.7 wt.%, in combination with the other elemental components provided for in the invention, did not result in any qualitatively detectable tendency to embrittlement.

[0097] The electrical strip or sheet preferably has an average grain size of between 60 and 100 micrometers, particularly preferably between 70 and 95 micrometers, which advantageously promotes low magnetization losses. In an advantageous development, the thickness of the electrical strip or sheet is between 0.180 mm and 0.270 mm, preferably between 0.230 mm and 0.270 mm, particularly preferably between 0.235 mm and 0.250 mm, these thicknesses being advantageous for current applications in electromobility and therefore expected to be in demand from industry.With the precise matching of the strip thickness or sheet thickness and the alloying specification to each other, a major hurdle was overcome, since with the stated values ​​for the thickness and when observing the alloying specifications specified in the invention, it has been shown that samples with, on the one hand, very good magnetic properties and, on the other hand, sufficiently good mechanical properties, in particular the values ​​for the 0.2% proof stress provided for in the invention, are obtained.

[0098] It is particularly preferred that the electrical steel strip or sheet has a 0.2% yield strength Rp0.2 with 430 MPa < Rp0.2 < 470 MPa. Samples with sufficiently good strength are available in this range, as demonstrated by the experiments conducted.

[0099] Alternatively or additionally, the electrical steel strip or sheet has an A8 O elongation at break of more than 14%, preferably more than 15%, which has been demonstrated on manufactured samples.

[0100] The material characteristic value yield strength Rp0.2 and the elongation at break A80 are to be taken as determined according to DIN EN ISO 6892-1:2020-06, for samples taken from the longitudinal direction of the strip.

[0101] In a preferred further development, the electrical strip or sheet has values ​​of the core loss values ​​P (1, 0T; 400Hz) < 13.00 W / kg, preferably P (1, 0T; 400Hz) < 12.40 W / kg, particularly preferably P (1, 0T; 400Hz) < 12.30 W / kg.

[0102] Alternatively or additionally, it has core loss values ​​P ( 1 , 0T ; 2000Hz ) < 150.00 W / kg, preferably P(l,0T; 2000Hz) < 145.00 W / kg, particularly preferably P(l,0T; 2000Hz) < 143.00 W / kg .

[0103] The symbol P ( 1 , 0T ; 400Hz ) symbolizes

[0104] Core reversal losses in watts per kilogram, or W / kg for short, in an alternating electromagnetic field with a core reversal frequency of 400 Hz and a magnetic flux density of 1.0 T in the material. The same applies analogously to other numerical values ​​given in parentheses. Since P is a thickness-dependent parameter, it applies to the measured sample as presented according to the invention, with the sample thickness advantageously being between 0.230 mm and 0.270 mm, preferably between 0.235 mm and 0.250 mm. The given parameters were chosen as representative because they are frequently encountered in the performance requirements placed on manufacturers. Core reversal losses are to be understood in the sense of DIN EN 60404-2:2019-05: Magnetic materials - Part 2: Method for the determination of the magnetic properties of electrical steel strip and sheet using an Epstein frame.

[0105] In an advantageous further development, the electrical strip or sheet alternatively or additionally has a magnetic polarization

[0106] J100;50Hz > 0.910 T, preferably J100;50Hz > 0.930 T, and / or a magnetic polarization J2500;50Hz >= 1.510 T, preferably J2500;50Hz >= 1.520 T. The symbol J100;50Hz denotes the magnetic polarization at a magnetic field strength of 100 A / m in an alternating electromagnetic field at 50 Hz. The parameters given were chosen as representative because they are frequently encountered parameters in the performance requirements placed on manufacturers. Methods for determining polarization and field strength are known to those skilled in the art, for example using an Epstein frame to determine polarization, in particular according to "DIN EN 60404-2:2019-05: Magnetic materials - Part 2: Methods for determining magnetic

[0107] Properties of electrical steel strip and sheet using an Epstein frame". The polarization applies in particular to the measured sample as it is presented according to the invention, wherein the thickness of the sample is advantageously between 0.180 mm and 0.270 mm, preferably between 0.230 mm and 0.270 mm, particularly preferably between 0.235 mm and 0.250 mm. The parameters for polarization are to be understood in this sense.

[0108] Particularly preferably, the electrical strip or sheet has a specific electrical resistance between 0.59 pΩm and 0.70 pΩm at a temperature of 25 degrees Celsius. In particular, these values ​​are obtained at a thickness, preferably at any thickness, between 0.180 mm and 0.270 mm, preferably between 0.230 mm and 0.270 mm, particularly preferably between 0.235 mm and 0.250 mm. A specific electrical resistance with this measure correlates with the good magnetic properties obtained.

[0109] A further aspect of the invention relates to a method for producing a non-grain-oriented electrical steel strip. Using one of the methods explained below, materials can be produced that have advantages of the type described above. For example, the method according to the invention explained below produces an electrical steel strip that has a particularly advantageous combination of properties. The following steps are carried out:

[0110] (A) Providing a hot-rolled and hot-strip annealed, non-grain-oriented electrical steel strip having a thickness between 1.6 mm and 2.2 mm, preferably between 1.8 mm and 2.1 mm;

[0111] (B) cold rolling the electrical steel strip provided in step (A) to a thickness between 0.180 mm and 0.270 mm; (C) final annealing and cooling the cold steel strip obtained in step (B) to obtain the non-grain-oriented electrical steel strip.

[0112] The provision of the non-grain-oriented electrical steel strip of greater thickness, as mentioned in step (A), will not be explained in detail here, as it is a process well known to those skilled in the art. For example, the non-grain-oriented electrical steel strip of greater thickness can be produced via a conventional production route using a continuous casting plant or via thin slab production. In both methods, a steel melt with a suitable specification, for example of the type mentioned at the beginning, is melted into a starting material and cast into a starting material, which in conventional production can be a slab or a thin slab.

[0113] The resulting pre-material can then be heated to a pre-material temperature, for example, between 1100 and 1300 degrees Celsius. For this purpose, the pre-material is reheated if necessary or maintained at the respective target temperature using the casting heat.

[0114] The precursor material heated in this way can then be hot-rolled into a hot strip with a thickness of, for example, between 1.6 mm and 2.2 mm, preferably between 1.8 mm and 2.1 mm.

[0115] For example, hot rolling begins in a manner known per se at an initial hot rolling temperature in the finishing stage of 900 to 1150 degrees Celsius and ends, for example, with a final hot rolling temperature of 700 to 920 degrees Celsius, in particular 780 to 850 degrees Celsius.

[0116] The resulting hot strip can then be cooled to a coiling temperature and coiled into a coil. The coiling temperature is ideally selected to avoid problems during the subsequent cold rolling. In practice, the coiling temperature is, for example, a maximum of 700 degrees Celsius, preferably between 550 and 700 degrees Celsius. Hot strip annealing, preferably performed after coiling, is preferably carried out at a temperature of 700 to 1000 degrees Celsius.

[0117] According to the invention, the final annealing is carried out in a continuous furnace.

[0118] It has been shown that the targeted adjustment of the infeed and / or outfeed belt tension during the final annealing is beneficial for preferred further developments. During development, it has been shown to be particularly preferable for the specific infeed belt tension to be no more than 5 N / mm 2 , preferably not more than 2.5 N / mm 2, particularly preferably not more than 2.3 N / mm 2 and / or the specific discharge belt tension is not more than 4 N / mm 2 , preferably not more than 3.5 N / mm 2 , particularly preferably not more than 2.5 N / mm 2 Preferably, both conditions are met cumulatively. The specific strip tension is the quotient of the strip tension, which is a force with the unit Newton, symbol: N, and the cross-section of the strip. Strip tension is a quantity known to those skilled in the art when transporting steel strip, and its measurement and monitoring is a standard professional practice in the operation of strip lines. The measurement can be performed, for example, using a commercially available force transducer, also known as a strain gauge, with a measuring amplifier.

[0119] Particularly preferably, the electrical steel strip is transported with an infeed roller stand positioned in front of the passage of the strip, as seen in the strip transport direction, with the infeed belt train, and with an outfeed roller stand positioned after the passage of the strip, as seen in the strip transport direction, with the outfeed belt train.

[0120] During the final annealing of step (C), a high annealing temperature, i.e. maximum temperature, is preferably set which is a value between 1010 degrees Celsius and 1090 degrees Celsius, preferably between 1020 degrees Celsius and 1080 degrees Celsius, particularly preferably between 1030 degrees Celsius and 1070 degrees Celsius. Surprisingly, during the development of the electrical strips and sheets according to the invention and their further developments, it was found that the temperature at which the final annealing took place had a significant influence on the successful establishment of the desired combination of properties: comparatively low magnetization losses and comparatively high saturation polarization on the one hand, and high strength with good cold rollability on the other. The best results were obtained when the temperature set during the final annealing was in the range between 1030 degrees Celsius and 1070 degrees Celsius.The developers assume that the average grain size of about 80 micrometers achieved with the temperature control mentioned above promotes the advantageous low magnetization losses.

[0121] Particularly preferably, the final annealing carried out in step (C) is carried out with the following parameters:

[0122] ( CI ) First , the material is heated at a heating rate of at least 40 K / s to a temperature between 850 degrees Celsius and 950 degrees Celsius , preferably to a temperature between 880 degrees Celsius and 920 degrees Celsius .

[0123] (C2) Once the temperature specified in step (CI) has been reached, the material is heated above this temperature at a heating rate between 5 and 150 K / s to the annealing temperature. The annealing temperature is the previously introduced and defined temperature.

[0124] Particularly preferred is the process being set up such that the high annealing temperature is maintained for a period of between 10 and 90 seconds. In operational practice, the maintenance of the high annealing temperature is adjusted in specific furnace zones, among other things, by the furnace length and the appropriate adjustment of the belt transport speed.

[0125] After the final annealing, the cold-rolled strip cools to room temperature. Cooling is preferably carried out at a maximum cooling rate of 25 K / s, meaning that a cooling rate of 25 K / s is not exceeded during the entire cooling process. Controlled cooling serves, among other things, to prevent the formation of undesirable residual stresses in the electrical steel strip, which have adverse effects on its magnetic properties.

[0126] The annealing of step (C) preferably takes place in an annealing atmosphere which

[0127] - consists of at least 60 vol. percent H2, preferably more than 70 vol. percent H2, and / or

[0128] - is carried out at a dew point of Tp < 5 degrees Celsius, preferably a dew point of Tp < 0 degrees Celsius. Preferably, both conditions are met cumulatively.

[0129] It is particularly preferred that the electrical steel provided in step (A) is made from a material with the alloy specification mentioned below, wherein the details are given in weight percent, in short: wt.%:

[0130] C: 0.0005 up to 0.0035;

[0131] Si : 2.9 up to 3.1;

[0132] Al: 1.40 to 1.60; Mn: 0.55 to 0.65;

[0133] P : up to 0.040;

[0134] S : up to 0.0030;

[0135] N : up to 0.0030;

[0136] Ti: up to 0.0070, preferably up to 0.0040;

[0137] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1;

[0138] Rest Fe and unavoidable impurities.

[0139] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0140] C: 0.0005 up to 0.0035;

[0141] Si : 2.9 up to 3.1;

[0142] Al: 1.40 up to 1.60;

[0143] Mn: 0.55 to 0.65;

[0144] P: up to 0.040, preferably up to 0.020;

[0145] S: up to 0.0030, preferably up to 0.0010;

[0146] N : up to 0.0030;

[0147] Ti: up to 0.0070, preferably up to 0.0040;

[0148] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0149] Rest Fe and unavoidable impurities.

[0150] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0151] C: 0.0005 up to 0.0035;

[0152] Si : 2.9 up to 3.0;

[0153] Al: 1.40 up to 1.60;

[0154] Mn: 0.55 to 0.65;

[0155] P: up to 0.040, preferably up to 0.020;

[0156] S: up to 0.0030, preferably up to 0.0010;

[0157] N : up to 0.0030;

[0158] Ti: up to 0.0070, preferably up to 0.0040;

[0159] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0160] The remainder is Fe and unavoidable impurities. The electrical steel strip or sheet exhibited particularly good properties when the alloy composition was as follows:

[0161] C: 0.0025 up to 0.0035;

[0162] Si : 2.9 up to 3.1;

[0163] Al: 1.40 up to 1.60;

[0164] Mn: 0.55 to 0.65;

[0165] P : up to 0.040;

[0166] S : up to 0.0030;

[0167] N : up to 0.0030;

[0168] Ti: up to 0.0040;

[0169] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1;

[0170] Rest Fe and unavoidable impurities.

[0171] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0172] C: 0.0027 up to 0.0033;

[0173] Si : 2.9 up to 3.1;

[0174] Al: 1.40 up to 1.60;

[0175] Mn: 0.55 to 0.65;

[0176] P: up to 0.040, preferably up to 0.020;

[0177] S: up to 0.0030, preferably up to 0.0010;

[0178] N : up to 0.0030;

[0179] Ti: up to 0.0040;

[0180] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0181] Rest Fe and unavoidable impurities.

[0182] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0183] C: 0.0027 up to 0.0033;

[0184] Si : 2.9 up to 3.0;

[0185] Al: 1.40 up to 1.60;

[0186] Mn: 0.55 to 0.65; P: up to 0.040, preferably up to 0.020;

[0187] S: up to 0.0030, preferably up to 0.0010;

[0188] N : up to 0.0030;

[0189] Ti: up to 0.0040;

[0190] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1;

[0191] Rest Fe and unavoidable impurities.

[0192] The electrical steel strip or sheet showed particularly good properties according to a preferred further development, which satisfies the following alloy specification:

[0193] C: 0.0027 up to 0.0033;

[0194] Si : 2.9 up to 3.0;

[0195] Al: 1.40 up to 1.60;

[0196] Mn: 0.55 to 0.65;

[0197] P : up to 0.040;

[0198] S : up to 0.0030;

[0199] N : up to 0.0030;

[0200] Ti: up to 0.0040;

[0201] Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1;

[0202] Rest Fe and unavoidable impurities.

[0203] In a further development, the cold rolling in step (B) is carried out to a thickness of the cold strip between 0.180 mm and 0.270 mm, preferably to a thickness of the cold strip between 0.230 mm and 0.270 mm, particularly preferably to a thickness between 0.235 mm and 0.250 mm.

[0204] A further aspect of the invention relates to an electrical steel strip that can be obtained using a method of the aforementioned type, but is manufactured using any other method. This includes, in particular, but not exclusively, the electrical steel strips of the type mentioned above and their further developments, as well as the advantageous material properties associated with them.

[0205] An electrical strip or an electrical sheet of the type mentioned at the beginning or a further development thereof is particularly suitable for use in electrical machines. One concept of the invention therefore comprises a cutout punched out of an electrical strip or an electrical sheet, which is used as a lamination of a component of an electrical machine, in particular as a component of a stator or a rotor of an electrical machine. For example, a number of laminations can be punched out of an electrical strip or an electrical sheet of the type mentioned at the beginning or a further development thereof and joined to one another, for example by gluing with a suitable adhesive, so that the laminations joined to one another form a stator or a rotor.

[0206] The invention is illustrated in more detail below using exemplary embodiments.

[0207] Strips were produced from alloys with different analyses, namely analyses A, B and C. The analyses are listed in Table 2.

[0208] Non-grain-oriented electrical steel was produced from the corresponding analyses.

[0209] A cold rolled strip with the specified thickness was finally annealed and then cooled.

[0210] During the final annealing, final annealing was carried out at a final annealing temperature as specified in column "SG" of Table 1, for a annealing period of between 10 and 90 seconds (see column t of Table 1, where the annealing period is specified in seconds). During the final annealing, different inlet and outlet belt tensions were used, which are also specified in the corresponding columns of Table 1.

[0211] The obtained samples were characterized in their magnetic and mechanical properties , which were determined in the

[0212] Table 1 lists: The core losses P were determined using an Epstein frame, in accordance with DIN EN 60404-2:2019-05: "Magnetic materials - Part 2: Methods for the determination of the magnetic properties of electrical steel strip and sheet using an Epstein frame". Electrical steel sheets were cut into longitudinal and transverse strips and measured as a mixed sample in the Epstein frame. The magnetic values ​​P, core losses, were determined at 1.0 T for 400 Hz and 2000 Hz respectively. The magnetic values ​​J, polarization, were determined at 50 Hz and 100 A / m and 2500 A / m using an Epstein frame, in particular in accordance with DIN EN 60404-2:2019-05: "Magnetic materials - Part 2: Methods for the determination of the magnetic properties of electrical steel strip and sheet using an Epstein frame". The corresponding electrical sheets were cut into longitudinal and transverse strips and measured as a mixed sample in the Epstein frame.

[0213] The material properties yield strength Rp0.2, tensile strength Rm and elongation at break A80 were determined according to DIN EN ISO 6892-1:2020-06 using samples in the longitudinal direction of the strip.

[0214] The results can be found in Table 1.

[0215] According to the requirement that samples with a combination of favorable magnetic properties and favorable mechanical properties should be obtained, the samples can be classified.

[0216] The following results are obtained:

[0217] 1. Only with alloys of analysis A was it possible to produce samples with P ( 1, 0T ; 400Hz ) < 12.40 W / kg and with P(l,0T; 2000Hz) < 145.00 W / kg. Samples from analyses B and C were therefore designated as "V",

[0218] Abbreviation for comparative test, marked.

[0219] 2. At a high annealing temperature of 1000 degrees Celsius during the final annealing, the polarization

[0220] J100;50Hz with a value of 0.886 T lower than the value 0.910 T always exceeded by the samples according to the invention. Sample 1 was therefore considered

[0221] marked "V".

[0222] 3. At a final annealing temperature of 1100 degrees Celsius, the polarization J100;2500Hz was 1.518 T, lower than the value of 1.520 T consistently achieved by samples according to the invention. Sample 2 was therefore designated as "V".

[0223] The result is a picture according to which samples with small thicknesses and sufficient yield strength Rp0.2 can be obtained by classifying systematic property profiles depending on the composition of the starting alloy.

[0224] Furthermore, internal counts showed that the selected analysis A produced tapes whose tape breakage frequency was 34 percent lower than analyses B and C.

[0225] Therefore, samples 3, 4, 5 and 6 remain as samples according to the invention.

[0226] It also follows that the samples classified according to the invention can be produced using the method according to the invention, while a method not according to the invention produces samples not according to the invention.

[0227]

[0228] Table 1

[0229]

[0230] Table 2

Claims

Patent claims 1. Non-grain-oriented metallic electrical steel strip or sheet, consisting of the following components, each in percent by weight, in short: % by weight: C: 0.0005 up to 0.0040, preferably 0.0005 up to 0.0035; Si: 2.8 up to 3.2, preferably 2.9 up to 3.1; Al: 1.3 up to 1.7, preferably 1.40 up to 1.60; Mn: 0.5 to 0.7, preferably 0.55 to 0.65; P: up to 0.040, preferably up to 0.020; S: up to 0.0030, preferably up to 0.0010; N : up to 0.0030; Ti: up to 0.0070, preferably up to 0.0040; Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1; Remainder Fe and unavoidable impurities, characterized in that the electrical strip or sheet has a thickness < 0.270 mm, preferably < 0.260 mm, and a 0.2% yield strength Rp0.2 > 420 MPa.

2. Electrical strip or sheet according to claim 1, wherein C: 0.0005 up to 0.0035; Si: 2.9 up to 3.1, preferably 2.9 up to 3.0; Al: 1.40 up to 1.60; Mn: 0.55 to 0.65; P: up to 0.040, preferably up to 0.020; S: up to 0.0030, preferably up to 0.0010; N : up to 0.0030; Ti: up to 0.0070, preferably up to 0.0040; Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1; Rest Fe and unavoidable impurities.

3. Electrical steel strip or sheet according to claim 1 or Claim 2, wherein C: 0.0025 up to 0.0035, preferably 0.0027 up to 0.0033; Si: 2.9 up to 3.1, preferably 2.9 up to 3.0; Al: 1.40 up to 1.60; Mn: 0.55 to 0.65; P: up to 0.040, preferably up to 0.020; S: up to 0.0030, preferably up to 0.0010; N : up to 0.0030; Ti: up to 0.0040; Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1; Rest Fe and unavoidable impurities.

4. Electrical strip or sheet according to one of the preceding claims, wherein Al / (Si + Al) has a value between 0.30 and 0.40, preferably between 0.30 and 0.

35.

5. Electrical strip or sheet according to one of the preceding claims, wherein the thickness of the electrical strip or sheet is between 0.180 mm and 0.270 mm, preferably between 0.230 mm and 0.270 mm, particularly preferably between 0.235 mm and 0.250 mm.

6. Electrical strip or sheet according to one of the preceding claims, wherein the electrical strip or sheet has a 0.2% proof stress Rp0.2 with 430 MPa < Rp0.2 < 470 MPa and / or an A8 O elongation at break of more than 14%, preferably more than 15%.

7. Electrical strip or sheet according to one of the preceding claims, wherein it has core loss values P (1, 0T; 400Hz) < 13.00 W / kg, preferably P (1, 0T; 400Hz) < 12.40 W / kg, particularly preferably P (1, 0T; 400Hz) < 12.30 W / kg, and / or it has core loss values P (1, 0T; 2000Hz) < 150.00 W / kg, preferably P (1, 0T; 2000Hz) < 145.00 W / kg, particularly preferably P (1, 0T; 2000Hz) < 143.00 W / kg.

8. Electrical strip or sheet according to one of the preceding claims, wherein it has a magnetic polarization J100;50Hz > 0.910 T, preferably J100;50Hz > 0.930 T, and / or it has a magnetic polarization J2500;50Hz >= 1,510 T, preferably J2500;50Hz >= 1,520 T.

9. Electrical strip or sheet according to one of the preceding claims, having a specific electrical resistance between 0.59 pQm and 0.70 pQm at a temperature of 25 degrees Celsius.

10. Process for producing a non-grain oriented Electrical tapes, comprising at least the following Process steps: (A) Providing a hot-rolled and hot-strip annealed, non-grain-oriented electrical steel strip having a thickness between 1.6 mm and 2.2 mm, preferably between 1.8 mm and 2.1 mm; (B) cold rolling the electrical steel strip provided in step (A) to a thickness between 0.180 mm and 0.270 mm; (C) final annealing and cooling the cold strip obtained in step (B) to obtain the non-grain oriented electrical steel strip, wherein the final annealing is carried out in a single pass furnace.

11. A method according to claim 10, wherein during the final annealing the specific infeed strip tension is at most 5 N / mm 2 , preferably not more than 2.5 N / mm 2 , particularly preferably not more than 2.3 N / mm 2and / or the specific discharge belt tension is not more than 4 N / mm 2 , preferably not more than 3.5 N / mm 2 , particularly preferably not more than 2.5 N / mm 2 amounts.

12. The method according to claim 10 or claim 11, characterized in that during the final annealing during a high annealing period, a high annealing temperature is between 1010 degrees Celsius and 1090 degrees Celsius, preferably between 1020 degrees Celsius and 1080 degrees Celsius, particularly preferably between 1030 degrees Celsius and 1070 degrees Celsius.

13. A method according to claim 12, characterized in that the final annealing (CI) is heated at a heating rate of at least 40 K / s to a temperature between 850 degrees Celsius and 950 degrees Celsius, preferably between 880 degrees Celsius and 920 degrees Celsius, and thereafter (C2) is heated to the annealing temperature at a heating rate between 5 and 150 K / s.

14. A method according to claim 12 or claim 13, characterized in that the annealing period is a period of 10 seconds to 90 seconds.

15. The method according to any one of claims 10 to 14, characterized in that the cooling of the cold strip in step (C) to room temperature takes place at a cooling rate of maximum 25 K / s.

16. A method according to any one of claims 10 to 15, characterized in that the annealing of step (C) - in an annealing atmosphere with at least 60 vol. percent H2, preferably at least 70 vol. percent H2 and / or - is carried out at a dew point of Tp < 5 degrees Celsius, preferably a dew point of Tp < 0 degrees Celsius.

17. The method according to any one of claims 10 to 16, characterized in that the electrical steel provided in step (A) consists of: the following components, each in percent by weight, in short: % by weight: C: 0.0005 up to 0.0040, preferably 0.0005 up to 0.0035; Si: 2.8 up to 3.2, preferably 2.9 up to 3.1; Al: 1.3 up to 1.7, preferably 1.40 up to 1.60; Mn: 0.5 to 0.7, preferably 0.55 to 0.65; P: up to 0.040, preferably up to 0.020; S: up to 0.0030, preferably up to 0.0010; N : up to 0.0030; Ti: up to 0.0070, preferably up to 0.0040; Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni: up to 0.1; The balance is Fe and unavoidable impurities; preferably with a maximum content of 0.0100 wt% of the sum of C, S, N and Ti.

18. The method according to any one of claims 10 to 17, characterized in that the electrical steel provided in step (A) consists of: the following components, each in percent by weight, in short: % by weight: C: 0.0025 up to 0.0035, preferably 0.0027 up to 0.0033; Si: 2.9 up to 3.1, preferably 2.9 up to 3.0; Al: 1.40 up to 1.60; Mn: 0.55 to 0.65; P: up to 0.040, preferably up to 0.020; S: up to 0.0030, preferably up to 0.0010; N : up to 0.0030; Ti: up to 0.0040; Mo+Nb+V+Zr+Sb+Sn+Cu+Cr+Ni : up to 0.1; Rest Fe and unavoidable impurities.

19. The method according to any one of claims 10 to 18, characterized in that the cold rolling in step (B) is carried out to a thickness between 0.180 mm and 0.270 mm, preferably between 0.230 mm and 0.270 mm, particularly preferably between 0.235 mm and 0.250 mm.

20. Electrical steel obtainable by a process according to any one of claims 10 to 19. 21 . Use of a cutout punched out of the electrical strip or sheet according to one of claims 1 to 9 as a lamella which is used as a component of an electrical machine, in particular as a component of a stator or a rotor of an electrical machine.

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