ELECTRIC STRIP CAPABLE OF FURTHER ANNEALING BUT NOT SUBJECT TO FURTHER ANNEALING

Abstract

The invention relates to an electrical strip or sheet of non-oriented grain, particularly for electrotechnical uses, to an electrotechnical component manufactured from such an electrical strip or sheet, to a process for producing an electrical strip or sheet, and to the use of such an electrical strip or sheet in components for electrotechnical uses.

Description

[0001] Electrical tape capable of glow-in-the-dark but not required to glow-in-the-dark

[0002] Technical field

[0003] The invention relates to a non-grain-oriented electrical steel strip or sheet, in particular for electrotechnical applications, an electrotechnical component made from such an electrical steel strip or sheet, a method for producing an electrical steel strip or sheet and the use of such an electrical steel strip or sheet in components for electrotechnical applications.

[0004] Non-grain oriented electrical steel strips or sheets, also known in technical terminology as "NO electrical steel strips or sheets" or in English as "NGO electrical steel" ("NGO" = Non Grain Oriented), are used to increase the magnetic flux of rotating electrical machines. Typical applications of such sheets are electric motors and generators, particularly in the stator or rotor.

[0005] The non-grain-oriented electrical steel strips used in the stator and rotor of a high-frequency electrical machine, particularly a motor or generator, preferably exhibit different mechanical and magnetic properties. The rotor assembly of an electrical machine is preferably made of a material with significantly enhanced mechanical properties, while the stator should have enhanced magnetic properties. Improving the magnetic properties of a material generally has a negative impact on its mechanical properties, and vice versa. Therefore, in the manufacture of electrical machines, either a material representing a compromise between mechanical and magnetic properties is chosen for both the rotor and stator, or two different types of electrical steel strip must be used for the rotor and stator.

[0006] Technical background

[0007] EP 2 612 942 discloses a non-grain-oriented electrical steel strip or sheet made of a steel which, in addition to iron and unavoidable impurities, contains 1.0 to 4.5 wt.% Si, up to 2.0 wt.% Al, up to 1.0 wt.% Mn, up to 0.01 wt.% C, up to 0.01 wt.% N, up to 0.012 wt.% S, 0.1 to 0.5 wt.% Ti, and 0.1 to 0.3 wt.% P, where the ratio of Ti content to P content, in wt.%, is 1.0 < Ti content to P content < 2.0. The non-grain-oriented electrical steel strip or sheet, and components made from such a strip or sheet for electrotechnical applications, are characterized by good magnetic properties. The NO electrical steel strip or sheet is produced in accordance with EP 2 612 942 by cold-rolling a hot-rolled strip made of steel with the aforementioned composition to a cold-rolled strip and then subjecting this cold-rolled strip to a final annealing.EP 2 840 157 discloses a non-grain-oriented electrical steel strip or sheet, particularly for electrotechnical applications, made from a steel which, in addition to iron and unavoidable impurities, contains 2.0 to 4.5 wt.% Si, 0.03 to 0.3 wt.% Si, up to 2.0 wt.% Al, up to 1.0 wt.% Mn, up to 0.01 wt.% C, up to 0.01 wt.% N, up to 0.001 wt.% S and up to 0.015 wt.% P, wherein the microstructure of the electrical steel strip or sheet contains ternary Fe-Si-Zr precipitates. EP 2 840 157 also discloses a process for producing such electrical steel strips and sheets, which includes final annealing.

[0008] WO 00 / 65103 A2 discloses a process for the production of non-grain-oriented electrical steel, in which a steel pre-material containing less than 0.06 wt.% C, 0.03 to 2.5 wt.% Si, less than 0.4 wt.% Al, 0.05 to 1 wt.% Mn and less than 0.02 wt.% S is hot-rolled to a hot strip with a thickness of less than 3.5 mm, then pickled and after pickling is cold-rolled to a strip with a thickness of 0.2 to 1 mm.

[0009] The invention is therefore based on the objective of providing a non-grain-oriented electrical steel strip or sheet which can be used in electrical machines, in particular electric motors or generators, both as a rotor with improved mechanical properties and as a stator with improved magnetic properties, whereby these different, inherently opposing properties should be easily convertible into one another.

[0010] This problem is solved by a non-grain-oriented electrical steel strip or sheet containing, in addition to iron and unavoidable impurities (values ​​given in wt.%), up to 0.0040 C, 0.1500 to 0.3000 Mn, 2.300 to 2.700 Si, 0.3000 to 0.8000 Al, up to 0.0400 P, up to 0.0035 S, up to 0.0070 N and up to 0.0070 Ti, where the ratio of remagnetization loss Pi ,0 / 50 in the fully annealed state to remagnetization loss Pi 0 / 50 in the reference annealed condition, it is at least 1.50.

[0011] Within the scope of the present invention, "reference annealing" of the non-grain-oriented electrical steel strip according to the invention is understood to mean the annealing of the non-grain-oriented electrical steel strip or sheet according to the invention at the end of the manufacturing process, corresponding to the optional step (D) of the process described below, at a temperature of 600 to 1000 °C. The "reference-annealed condition" is thus the condition of the non-grain-oriented electrical steel strip or sheet according to the invention after annealing at a temperature of 600 to 1000 °C. Correspondingly, the "final-annealed condition" is the condition of the non-grain-oriented electrical steel strip according to the invention before annealing at a temperature of 600 to 1000 °C, corresponding to the optional step (D) of the process according to the invention.The problems are further solved by a method for producing the non-grain-oriented electrical steel strip or sheet according to the invention, by a component for electrotechnical applications made from such an electrical steel strip, and by using the electrical steel strip in components for electrotechnical applications.

[0012] The non-grain-oriented electrical steel according to the invention is made from a steel which, in addition to iron and unavoidable impurities (values ​​in wt.%), contains up to 0.0040 C,

[0013] 0.1500 to 0.3000 Mn,

[0014] 2,300 to 2,700 Si,

[0015] 0.3000 to 0.8000 AI,

[0016] up to 0.0400 P,

[0017] up to 0.0035 S,

[0018] up to 0.0070 N and

[0019] up to 0.0070 Ti. Preferably, the non-grain-oriented electrical steel according to the invention is produced from a steel which, in addition to iron and unavoidable impurities (values ​​in wt.%),

[0020] 0.001 to 0.0035 C,

[0021] 0.15 to 0.25 Mn,

[0022] 2.35 to 2.7 Si,

[0023] 0.33 to 0.75 AI,

[0024] up to 0.030 P, more preferably at least 0.005 wt% P,

[0025] 0.0005 to 0.0015 S,

[0026] 0.002 to 0.004 N and

[0027] Contains 0.001 to 0.004 Ti.

[0028] The quantities of the individual elements contained in the steel preferably used according to the invention are determined by methods known to those skilled in the art, for example by chemical analysis according to DIN EN 10351:2011-05 "Chemical analysis of ferrous materials - Analysis of unalloyed and low-alloy steels by inductively coupled optical emission spectrometry". The inventors of the present invention have found that a non-grain-oriented electrical steel can be provided which can be used in electrical machines, in particular electric motors and generators, both as a stator with good magnetic properties and as a rotor with good mechanical properties, the change in properties being achieved by reference annealing of the material obtained after final annealing.According to the invention, reference annealing can yield a non-grain-oriented electrical steel which, compared to the final annealed material, exhibits improved magnetic properties; in particular, the remagnetization losses P are significantly reduced at various polarizations and / or frequencies. This property of the material according to the invention is expressed by the fact that the ratio of remagnetization loss Pi... 0 / 50 in the annealed state to remagnetization loss Pi 0 / 50 in the reference annealed condition is at least 1.30, i.e., that the remagnetization loss Pi 0 / 50 The grain-oriented electrical steel according to the invention is significantly reduced in the reference annealed condition. On the other hand, the grain-oriented electrical steel according to the invention exhibits improved mechanical properties in the final annealed condition compared to the reference annealed condition.

[0029] According to the invention, the non-grain-oriented electrical steel strip or sheet exhibits good mechanical properties in the final annealed condition and good magnetic properties in the reference annealed condition. This allows for a significant increase in the efficiency of electrical machines compared to a uniform material for both rotor and stator, since a material with either improved mechanical or improved magnetic properties can be provided for the rotor and stator respectively.

[0030] In a preferred embodiment, the present invention relates to the non-grain-oriented electrical steel strip or sheet according to the invention, wherein it has very low specific grain sizes in the final annealed condition, for example, a grain size of 50 to 130 pm, preferably 70 to 100 pm. The present invention therefore preferably relates to the non-grain-oriented electrical steel strip according to the invention, wherein it has a grain size of 50 to 130 pm, preferably 70 to 100 pm, in the final annealed condition. The grain size can be determined by any method known to those skilled in the art, for example, by microstructure analysis using light microscopy according to ASTM E12 "Standard Test Methods for Determining Average Grain Size".

[0031] The non-grain-oriented electrical steel strip or sheet according to the invention exhibits an advantageous ratio of remagnetization losses P in the final annealed condition to remagnetization losses P in the reference annealed condition. According to the invention, the term "final annealed" includes a "semi-finished" condition, including a finishing pass (rolling step). Within the scope of this invention, the designation Pi means 0 / 50The remagnetization loss P at a polarization of 1.0 T and a frequency of 50 Hz. According to the invention, the remagnetization losses P can be determined, for example, using an Epstein frame, in particular according to DIN EN 60404-2:2009-01: Magnetic materials - Part 2: Method for determining the magnetic properties of electrical steel strip and sheet using an Epstein frame. In this process, corresponding electrical steel sheets are measured in longitudinal (L), transverse (Q), or a combination of both (mixed orientation (M)). Within the scope of this invention, the values ​​for the mixed orientation (M) are specified.

[0032] In the non-grain-oriented electrical steel strip or sheet according to the invention, the ratio of remagnetization loss is Pi. 0 / 50 in the annealed state to remagnetization loss Pi 0 / 50In the reference annealed condition, at least 1.30, preferably at least 1.32, particularly preferably at least 1.60. An upper limit for this ratio is, for example, 2.50.

[0033] Preferably, in the non-grain-oriented electrical steel strip or sheet according to the invention, the ratio of remagnetization loss to Pi is 5 / 50 in the annealed state to remagnetization loss Pi 5 / 50 In the reference annealed condition, at least 1.10, particularly preferably at least 1.20, most preferably at least 1.60. An upper limit for this ratio is, for example, 2.0.

[0034] Furthermore, preferably in the non-grain-oriented electrical steel strip or sheet according to the invention, the ratio of remagnetization loss RI is , OMOO in the annealed state to remagnetization loss Pi ,0 / 400 in the reference annealed condition at least 1.10, particularly preferably at least 1.15, most preferably at least 1.20. An upper limit for this ratio is, for example, 1.60.

[0035] These inventive ratios of remagnetization losses at different polarizations and / or frequencies clearly show that the magnetic properties of the non-grain-oriented electrical steel strip or sheet according to the invention are significantly improved by reference annealing.

[0036] Preferably, in the non-grain-oriented electrical steel strip or sheet according to the invention, the ratio yield strength Rp is 0 2 in the annealed state to yield strength Rp 0 2 In the reference annealed condition, at least 1.05, particularly preferably at least 1.10, most preferably at least 1.15. An upper limit for this ratio is, for example, 1.40.

[0037] Preferably, in the non-grain-oriented electrical steel strip or sheet according to the invention, the ratio tensile strength R is m in the annealed state to tensile strength R m In the reference annealed condition, at least 1.01, particularly preferably at least 1.05. An upper limit for this ratio is, for example, 1.30.

[0038] In the non-grain-oriented electrical steel strip or sheet according to the invention, the polarization ratio is J200. / 0 in the final annealed state to polarization J 25 oo / 50In the reference annealed condition, a ratio of at least 1.01 is preferred. An upper limit for this ratio is, for example, 1.10. Within the scope of this invention, the designation J2500 / 50 denotes the polarization at a field strength of 2500 A / m and a frequency of 50 Hz. Methods for determining polarization and field strength are known to those skilled in the art, for example, by means of an Epstein frame for determining the polarization, in particular according to DIN EN 60404-2:2009-01: "Magnetic materials - Part 2: Method for determining the magnetic properties of electrical steel strip and sheet using an Epstein frame".

[0039] The non-grain-oriented electrical steel strip or sheet according to the invention exhibits an advantageously higher specific electrical resistance compared to grain-oriented electrical steel strips according to the prior art. Methods for determining the specific electrical resistance are known to those skilled in the art, for example by means of a four-point measurement according to DIN EN 60404-13:2008-05 "Magnetic materials - Part 13: Test for the measurement of density, specific resistance and stacking factor of electrical steel strip and sheet".

[0040] In general, the non-grain-oriented electrical steel strip or sheet according to the invention can be available in all thicknesses suitable for electrotechnical applications. Preferably, the electrical steel strip or sheet is available in particularly low thicknesses, since the magnetization losses are lower at these low thicknesses than at greater thicknesses. The electrical steel strip or sheet according to the invention is available in a thickness of preferably 0.26 to 0.38 mm, with a deviation of up to 8%.

[0041] The non-grain-oriented electrical steel strip or sheet according to the invention preferably has a tensile strength Rm of 400 to 600 N / mm². 2 on, wherein the non-grain-oriented electrical steel strip or sheet according to the invention preferably has a tensile strength R in the final annealed condition m from 480 to 600 N / mm 2 and preferably a tensile strength Rm of 400 to 520 N / mm² in the reference annealed condition 2The test is performed in the longitudinal direction of the material, i.e., in the rolling direction of the electrical steel strip. This is generally the less favorable direction for tensile strength due to any anisotropy that may be present in the material. According to the invention, the tensile strength is determined using a method known to those skilled in the art, for example, a tensile test according to DIN EN ISO 6892-1:2017-02 "Metallic materials - Tensile tests - Part 1: Test methods at room temperature".

[0042] The non-grain-oriented electrical steel strip or sheet according to the invention preferably has a yield strength Rp 0 2 from 300 to 440 N / mm 2 on, wherein the non-grain-oriented electrical steel strip or sheet according to the invention preferably has a yield strength Rp in the final annealed state 0 2 from 400 to 440 N / mm 2 and in the reference annealed condition a yield strength Rp 0 2 from 300 to 400 N / mm 2The yield strength is determined according to the invention using a method known to those skilled in the art, for example a tensile test according to DIN EN ISO 6892-1 : 2017-02 “Metallic materials - Tensile tests - Part 1 : Test methods at room temperature”.

[0043] The non-grain-oriented electrical steel according to the invention is characterized by the fact that, in the annealed state, it exhibits particularly advantageous mechanical properties and can be transformed by reference annealing into a material that possesses particularly advantageous magnetic properties. Thus, this material can be used in electrical machines, especially electric motors or generators, both as a stator and as a rotor, which in turn yields the aforementioned advantages.

[0044] The present invention also relates to a method for producing a non-grain-oriented electrical steel strip or sheet according to the invention, comprising at least the following process steps:

[0045] (A) Providing a hot-rolled strip containing, besides iron and unavoidable impurities (in each case in wt.%), up to 0.0040 C,

[0046] 0.1500 to 0.3000 Mn,

[0047] 2,300 to 2,700 Si,

[0048] 0.3000 to 0.8000 AI,

[0049] up to 0.0400 P,

[0050] up to 0.0035 S,

[0051] up to 0.0070 N and

[0052] up to 0.0070 Ti,

[0053] (B) Cold rolling of the hot strip to a cold strip, and

[0054] (C) Heat treat the cold strip from step (B) to obtain a non-grain-oriented electrical steel strip.

[0055] For this purpose, a hot-rolled strip, composed in the manner described above for the non-grain-oriented electrical steel strip or sheet according to the invention, is first provided. This strip is then cold-rolled and, as a cold-rolled strip, subjected to a heat treatment (step (C), also called final annealing). After step (C) of the process according to the invention, a non-grain-oriented electrical steel strip is obtained, which is ready for use in electrical machines and is characterized by a stress-free state combined with above-average mechanical properties compared to non-grain-oriented electrical steel grades of the prior art. Due to the fine grain structure also achieved, potential damage from a separation process such as cutting, punching, or laser cutting is less than with non-grain-oriented electrical steel grades of the prior art.

[0056] According to the invention, the non-grain-oriented electrical steel obtained after step (C) of the inventive method can be subjected to a further heat treatment step (D), the so-called "reference annealing". This repairs any damage that may have occurred at the cut edges during the separation process and stimulates grain growth in the core of the material. As a result, the treated material has excellent magnetic properties.

[0057] The present invention therefore preferably relates to the method according to the invention, wherein after step

[0058] (C) the following step (D) is performed:

[0059] (D) Reference annealing of the non-grain-oriented electrical steel strip from step (C) at a temperature of 600 to 1000 °C.

[0060] The individual steps of the method according to the invention are described in detail below.

[0061] Step (A) of the process according to the invention comprises providing a hot-rolled strip containing, in addition to iron and unavoidable impurities (each expressed in wt.%), up to 0.0040 C, 0.1500 to 0.3000 Mn, 2.300 to 2.700 Si, 0.3000 to 0.8000 Al, up to 0.0400 P, up to 0.0035 S, up to 0.0070 N and up to 0.0070 Ti. Preferred amounts are given above.

[0062] The production of the hot-rolled strip provided according to the invention can be carried out largely conventionally. For this purpose, a molten steel with a composition corresponding to the specifications of the invention can first be melted and cast into a pre-material, which in conventional production can be a slab or thin slab.

[0063] The resulting pre-material can then be heated to a temperature of 1020 to 1300 °C. If necessary, the pre-material is reheated or held at the target temperature using the heat generated during casting.

[0064] The heated pre-material can then be hot-rolled to produce a strip with a thickness typically of 1.5 to 4 mm, particularly 1.5 to 3 mm. The hot rolling process begins, in a manner known per se, at a starting temperature in the finishing stage of higher than 900 °C, for example 1000 to 1150 °C, and ends with a final hot rolling temperature of below 900 °C, for example 700 to 920 °C, particularly 780 to 850 °C.

[0065] The resulting hot-rolled strip can then be cooled to a coiling temperature and wound into a coil. Ideally, the coiling temperature is chosen to avoid problems during the subsequent cold rolling process. In practice, the coiling temperature for this purpose is typically no more than 700 °C.

[0066] Optionally, annealing can be carried out in the coiled state after hot rolling or before cold rolling. This annealing step is performed, for example, at a temperature of 600 to 900 °C.

[0067] Prior to cold rolling in step (B) of the process according to the invention, a cleaning step by pickling can optionally be carried out. Such processes are known to those skilled in the art.

[0068] Step (B) of the method according to the invention comprises cold rolling the hot strip to a cold strip.

[0069] The supplied hot-rolled strip is cold-rolled to a thickness that typically corresponds to the thickness of the electrical steel strip or sheet according to the invention, i.e., preferably 0.26 to 0.38 mm, with a deviation of up to 8%. The cold-rolling process and procedure are known to those skilled in the art. According to the invention, preferably the reduction in material thickness in the first pass is no more than 35%. More preferably, the reduction in material thickness in the last pass is no more than 20%.

[0070] Step (C) of the inventive method comprises heat-treating the cold-rolled strip from step (B) to obtain a non-grain-oriented electrical steel strip.

[0071] Preferably, step (C) of the process according to the invention is carried out as a continuous process. Suitable devices, i.e., furnaces in which the cold-rolled strip from step (B) of the process according to the invention can be continuously heat-treated, are known to those skilled in the art. The heat treatment in step (C) of the process according to the invention preferably takes place at a temperature of 750 to 1000 °C, particularly preferably at 750 to 950 °C. The process speed at the aforementioned temperature is preferably 60 to 100 m / min.

[0072] After the heat treatment carried out in step (C) of the process according to the invention, the resulting non-grain-oriented electrical steel is preferably cooled to ambient temperature and, if desired, can be coated on the surface with a lacquer. Corresponding processes and lacquers are known to those skilled in the art. The non-grain-oriented electrical steel or sheet obtained after step (C) can advantageously be used in electrical machines.

[0073] Preferably the present invention relates to the method according to the invention, wherein after step (C) the following step (D) is carried out:

[0074] (D) Reference annealing of the non-grain-oriented electrical steel strip from step (C) at a temperature of 600 to 1000 °C.

[0075] Step (D) of the inventive process (“reference annealing”) is carried out when an electrical steel strip or sheet is to be obtained which has particularly advantageous magnetic properties and which can preferably be used as a stator in an electric machine. Step (D) of the inventive process is preferably carried out on components that have been cut from the non-grain-oriented electrical steel strip obtained in step (C). Preferably, parts are cut from the non-grain-oriented electrical steel strip obtained in step (C) by punching or cutting, which are to be used as stators in electric machines. Methods for this are known to those skilled in the art, for example, punching, laser cutting, waterjet cutting, and wire EDM.The optional step (D) of the process according to the invention can be carried out on the components themselves according to the invention; it is also possible according to the invention that the individual components are assembled into packages and then treated in step (D).

[0076] The optional step (D) of the process according to the invention comprises annealing at a temperature of 600 to 1000 °C, preferably 700 to 900 °C, particularly preferably 750 to 850 °C. According to the invention, the aforementioned temperatures can vary by up to 20 °C upwards and up to 15 °C downwards during step (C).

[0077] In the optional step (D) of the method according to the invention, the heating rate is preferably at least 100 °C / h. The holding time at the final temperature in this step is preferably at least 20 min according to the invention.

[0078] In general, the optional step (D) can be carried out in any manner known to those skilled in the art. Preferably, according to the invention, step (D) is carried out in a stationary furnace system. It is also possible to carry out step (D) in a continuous annealing process, which is known to those skilled in the art. The present invention also relates to a component for electrotechnical applications, manufactured from an electrical steel strip or sheet according to the invention, preferably with a theoretical density of 7.55 to 7.67 kg / cm³. 3 Examples of components for electrotechnical applications are electric motors, generators or transformers, in particular rotors or stators, which preferably represent basic components of an electrical machine with which one can perform an energy conversion, in particular electrical energy into mechanical energy or mechanical energy into electrical energy.

[0079] The present invention further relates to the use of an Elektra band or sheet according to the invention in components for electrotechnical applications, in particular in electric motors, generators or transformers, especially rotors or stators, which preferably represent basic components of an electrical machine with which an energy conversion, in particular electrical energy into mechanical energy or mechanical energy into electrical energy, can be carried out.

[0080] Examples

[0081] The invention will now be explained in more detail using exemplary embodiments.

[0082] Silicon steels with the compositions according to Table 1 are used as the base material.

[0083] Table 1:

[0084]

[0085] All values ​​in wt.%, remainder to 100 wt.% Fe and unavoidable impurities

[0086] Hot-rolled strip is produced from these steels. The hot-rolling temperature is 830 °C. After coiling the hot strip at 620 °C, it is cold-rolled to a thickness of 2.4 mm. The values ​​for Ri are then determined. i0 / 50 , Rp0.2 and Rm were determined. The values ​​are shown in Table 2. Table 2:

[0087]

[0088] A Ratio of the corresponding values ​​final annealed / reference annealed

[0089] n H

[0090] W

[0091] oo

[0092] The measured values ​​shown were determined using the following methods:

[0093] Rp0.2:

[0094] The value Rp0.2 describes the yield strength of the material and is determined according to DIN EN ISO 6892-1 : 2017-02 “Metallic materials - Tensile tests - Part 1 : Test methods at room temperature”.

[0095] RM:

[0096] The value Rm describes the tensile strength of the material and is determined according to DIN EN ISO 6892-1 : 2017-02 “Metallic materials - Tensile tests - Part 1 : Test methods at room temperature”.

[0097] Polarization:

[0098] The polarization is determined according to DIN EN 60404-2 : 2009-01 “Magnetic materials - Part 2: Method for determining the magnetic properties of electrical steel strip and sheet using an Epstein frame”.

[0099] Losses P:

[0100] The loss P is determined according to DIN EN 60404-2 : 2009-01 “Magnetic materials - Part 2: Method for determining the magnetic properties of electrical steel strip and sheet using an Epstein frame”.

[0101] Commercial applicability

[0102] The non-grain-oriented electrical steel strip or sheet according to the invention can preferably be used in electric motors, especially for use in electric vehicles, or in generators.

Claims

Patent claims 1. Non-grain-oriented electrical steel strip or sheet, containing, besides iron and unavoidable impurities (each in wt.%), up to 0.0040 C, 0.1500 to 0.3000 Mn, 2,300 to 2,700 Si, 0.3000 to 0.8000 AI, up to 0.0400 P, up to 0.0035 S, up to 0.0070 N and up to 0.0070 Ti, characterized in that the ratio of remagnetization loss Pi 0 / 50 In the fully annealed state, the remagnetization loss Pi 0 / 50 in the reference annealed condition, it is at least 1.

30.

2. Non-grain-oriented electrical steel strip or sheet according to claim 1, characterized in that it has a thickness of 0.26 to 0.38 mm.

3. Non-grain-oriented electrical steel strip or sheet according to claim 1 or 2, characterized in that it has a grain size of 50 to 130 pm, preferably 70 to 100 pm, in the reference annealed condition.

4. Non-grain-oriented electrical steel or sheet according to one of claims 1 to 3, characterized in that the ratio of remagnetization loss Pi 5 / 50 in the fully annealed state to remagnetization loss Pi 5 / 50 in the reference annealed condition bears at least 1.10 be.

5. Non-grain-oriented electrical steel or sheet according to any one of claims 1 to 4, characterized in that the ratio of remagnetization loss RI , OMOO in the annealed state at remagnetization loss Pi , 0 / 400 in the reference annealed condition bears at least 1.10 be.

6. Non-grain-oriented electrical steel strip or sheet according to any one of claims 1 to 5, characterized in that the ratio of polarization J2500 / 50 in the final annealed condition to polarization J2500 / 50 in the reference annealed condition is at least 1.

01.

7. Non-grain-oriented electrical steel strip or sheet according to any one of claims 1 to 6, characterized in that the yield strength Rp 0 2 300 to 440 N / mm 2 amounts.

8. Non-grain-oriented electrical steel or sheet according to any one of claims 1 to 7, characterized in that the tensile strength R m 400 to 600 N / mm 2 amounts.

9. Method for producing the non-grain-oriented electrical steel strip or sheet according to any one of claims 1 to 8, comprising at least the following process steps: (A) Providing a hot-rolled strip containing, besides iron and unavoidable impurities (in wt.%), up to 0.0040 C, 0.1500 to 0.3000 Mn, 2,300 to 2,700 Si, 0.3000 to 0.8000 AI, up to 0.0400 P, up to 0.0035 S, up to 0.0070 N and up to 0.0070 Ti, (B) Cold rolling of the hot strip to a cold strip, and (C) Heat treat the cold strip from step (B) to obtain a non-grain-oriented electrical steel strip.

10. The method of claim 9, characterized in that after step (C) the following step (D) is carried out: (D) Reference annealing of the non-grain-oriented electrical steel from step (C) at a temperature of 600 to 1000 °C.11 .

11. Component for electrotechnical applications, manufactured from an electrical strip or sheet according to one of claims 1 to 8.

12. Use of an electrical tape or sheet according to any one of claims 1 to 8 in components for electrotechnical applications.