TIN PACKAGE AND METHOD FOR PRODUCING A HIGHLY PERMEABLE SOFT MAGNETIC ALLOY

Description

[0001] The present invention relates to a method for producing a soft magnetic precursor from a highly permeable soft magnetic alloy.

[0002] Non-grain-oriented electrical steel with approximately 3 wt% silicon (SiFe) is the most widely used crystalline soft magnetic material in the laminated cores of electric machines. With the advancing field of electromobility, more efficient materials are needed that offer better performance than SiFe. This means that, in addition to sufficiently high electrical resistance, a higher inductance level is particularly desirable to achieve high torques and / or a small form factor.

[0003] For use in certain technologies, such as the automotive industry and electromobility, even more efficient materials are desirable to further increase power density. Soft magnetic cobalt-iron alloys (CoFe) are also used in electric machines due to their exceptionally high saturation induction. Commercially available CoFe alloys typically have a composition of 49 wt% Fe, 49 wt% Co, and 2 wt% V. With such a composition, a saturation induction of approximately 2.35 T is achieved, along with a high electrical resistance of 0.4 µΩm. However, it is desirable to reduce the material and manufacturing costs for CoFe alloys, which arise, for example, from the high Co content, the additional manufacturing steps, and the scrap content.

[0004] WO 2013 / 125790 A1 discloses a method for producing a plate from a CoFe alloy with 10 to 35 wt% Co, wherein {100} planes of grains are parallel to the surface of the plate.

[0005] The task to be solved is therefore to provide a pre-product made from an FeCo alloy that has lower material costs and is also easy to process in order to reduce the manufacturing costs of the alloy up to the sheet stack, while at the same time enabling a high power density.

[0006] This is resolved through the subject matter of the independent claims. Further advantageous developments are the subject matter of the respective dependent claims.

[0007] According to the invention, a method for producing a precursor from a soft magnetic alloy, in particular a high-permeability soft magnetic FeCo alloy, is provided. First, a precursor is provided which has a composition consisting of 5 wt.% ≤ Co ≤ 25 wt.% 0.3 wt.% ≤ V ≤ 5.0 wt.% 0 wt.% ≤ Cr ≤ 3.0 wt.% 0 wt.% ≤ Si ≤ 3.0 wt.% 0 wt.% ≤ Mn ≤ 3.0 wt.% 0 wt.% ≤ Al ≤ 3.0 wt.% 0 wt.% ≤ Ta ≤ 0.5 wt.% 0 wt.% ≤ Ni ≤ 0.5 wt.% 0 wt.% ≤ Mo ≤ 0.5 wt.% 0 wt.% ≤ Cu ≤ 0.2 wt.% 0 wt.% ≤ Nb ≤ 0.25 wt.% 0 wt.% ≤ Ti ≤ 0.05 wt.% 0 wt.% ≤ Ce ≤ 0.05 wt.% 0 wt.% ≤ Ca ≤ 0.05 wt.% 0 wt.% ≤ Mg ≤ 0.05 wt.% 0 wt.% ≤ C ≤ 0.02 wt.% 0 wt.% ≤ Zr ≤ 0.1 wt.% 0 wt.% ≤ O ≤ 0.025 wt.% 0 wt.% ≤ S ≤ 0.015 wt.%

[0008] The remainder consists of iron, with Cr+Si+Al+Mn ≤ 3.0 wt%, and up to 0.2 wt% of other melt-related impurities. Other impurities include, for example, B, P, N, W, Hf, Y, Re, Sc, Be, and other lanthanides except Ce.

[0009] The precursor exhibits a phase transition from a BCC phase region to a BCC / FCC mixed region to an FCC phase region, wherein, with increasing temperature, the phase transition between the BCC phase region and the BCC / FCC mixed region takes place at a first transition temperature TÜ1 and, with further increasing temperature, the transition between the BCC / FCC mixed region and the FCC phase region takes place at a second transition temperature TÜ2, wherein TÜ2 > TÜ1 and the difference TÜ2 - TÜ1 is less than 45K, preferably less than 25K.

[0010] The pre-product undergoes the following heat treatment, whereby before the start of the heat treatment the pre-product has a cold-rolled texture or a fiber texture: Heating the precursor to a temperature T1, then heat-treating the precursor at temperature T1 for a duration t1, and then cooling from T1 to room temperature. or The pre-product undergoes the following heat treatment: Heating the precursor to a temperature T1, then heat-treating the precursor at temperature T1 for a time period t1, then cooling the precursor to a temperature T2, then heat-treating the precursor at temperature T2 for a time period t2, and then cooling the precursor from T2 to room temperature, where T1 > T2, T1 is above TÜ2 and T2 is below TÜ1, where 920°C ≤ T1 < Tm, 700°C ≤ T2 ≤ 1050°C, Tm is the solidus temperature, 15 minutes ≤ t1 ≤ 20 hours and 30 minutes ≤ t2 ≤ 20 hours.

[0011] For both methods, the heating rate over at least the temperature range from T Ü1 to T Ü2 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h, and the cooling rate over at least the temperature range from T Ü2 to T Ü1 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h.

[0012] The semi-finished product has the form of several stacked sheets or one or more sheet metal bundles and is weighted down with an additional weight, and the

[0013] The pre-product is subjected to heat treatment with added weight. The weight of the added weight can be at least 20%, preferably at least 50%, of the weight of the pre-product.

[0014] The precursor is conventionally heat-treated under a hydrogen-containing atmosphere or under an inert gas, preferably under a dry hydrogen-containing atmosphere. In the case of a hydrogen-containing atmosphere, the atmosphere can also contain an inert gas, such as argon, in addition to hydrogen.

[0015] According to the invention, the precursor is thus slowly heated and cooled through the transitions between the BCC phase region and the BCC / FCC mixing region and between the BCC / FCC mixing region and the FCC phase region. It has been found that the heating rate influences the shape of the precursor. In particular, the planarity of precursors in the form of sheets, including stacked sheets, is ensured after heat treatment when the heating rate is 1 K / h to 100 K / h, preferably 4 K / h to 100 K / h, preferably 10 K / h to 50 K / h, especially at least over the temperature range from TÜ1 to TÜ2. The same applies to the cooling rate between T Ü2 and T Ü1, so that the cooling rate is 1 K / h to 100 K / h, preferably 4 K / h to 100 K / h, preferably 10 K / h to 50 K / h, in particular at least over the temperature range from T Ü2 to T Ü1.

[0016] It has been found that excessively rapid heating or cooling leads to wavy sheets, which also exhibit a type of plastic deformation within the sheet. This observation can be attributed to the phase transformation of the alloy. During heating, as the alloy passes through the two-phase region, the body-centered α-phase (BCC) transforms into the more densely packed face-centered γ-phase (FCC). This results in a shortening of the sheets. During cooling, a reversion occurs, ideally restoring the original geometry. In the process according to the invention, the alloy undergoes two phase transformations. It is assumed that this observed deformation is due to the volume jump during the forward and reverse transformations. The slower heating and cooling rates according to the invention prevent the formation of this waviness and deformation.

[0017] Heating and cooling rates of 20 K / h and 10 K / h can be used. Suitable rates can be selected depending on the shape of the pre-product. For example, heating and cooling rates below 50 K / h can be used for a stack of 50 sheets and below 35 K / h for a stack of 100 sheets.

[0018] The cooling rate can also be 1 K / h to 100 K / h, preferably 4 K / h to 50 K / h, or preferably 10 K / h to 50 K / h over at least the temperature range from TÜ2 to TÜ1, in order to maintain the planarity of the sheets. A slower cooling rate can also be used to improve the soft magnetic properties, in particular to increase the induction B.

[0019] In one embodiment, the heating rate and / or the cooling rate is selectively controlled over a larger temperature range. In one embodiment, the heating rate over at least the temperature range from 900°C to T1 is 1 K / h to 100 K / h, preferably 4 K / h to 100 K / h, preferably 10 K / h to 50 K / h.

[0020] In one embodiment, the cooling rate over at least the temperature range from T 1 to 900°C is 1K / h to 100 K / h, preferably 4K / h to 50K / h, preferably 10K / h to 50 K / h.

[0021] In one embodiment, the temperature T1 of the heat treatment in the FCC phase region is more precisely defined such that T1 lies between TÜ2 and (TÜ2 + 100°C), i.e., the temperature T1 is only slightly higher than the transition temperature TÜ2 from the FCC / BCC two-phase region to the FCC region. In other embodiments, T1 lies between (TÜ2 + 2°C) and (TÜ2 + 100°C) or (TÜ2 + 2°C) and (TÜ2 + 50°C). Temperatures in this range can be used to improve the soft magnetic properties, for example, to achieve higher induction and lower coercivity.

[0022] If the pre-product has the shape of a sheet, it can deform during heat treatment, even at the specified heating and cooling rates, resulting in a wavy rather than flat sheet. This is undesirable in some applications, such as a stack of laminated parts. The additional weight can be used to prevent deformation of the pre-product and maintain the sheet's flatness.

[0023] The intermediate product can have the form of several stacked sheets or one or more sheet metal bundles. In this embodiment, the weight can be placed on the stack or on the top sheet of the stack during heat treatment.

[0024] InIn some embodiments, the intermediate product has the form of several stacked sheets, each coated with an electrically insulating coating. In In this embodiment, the weight can be arranged on the stack or on the top sheet of the stack during heat treatment.

[0025] In In one embodiment, the precursor is further coated with an oxide layer for electrical insulation. This embodiment can be used, for example, when the precursor is used in a laminated core. The precursor can be coated, for example, with a layer of magnesium methylate or zirconium propylate, which transforms into an insulating oxide layer during heat treatment.

[0026] The precursor can also be heat-treated in an oxygen- or water vapor-containing atmosphere to form the electrically insulating layer. This targeted oxidation can be carried out subsequently in a separate heat treatment after the heat treatment that establishes the magnetic properties.

[0027] InIn one embodiment, sheet metal sections punched, laser-cut, or eroded from the pre-product are further subjected to a final annealing, and the annealed individual sheets are then bonded together to form a sheet metal stack using an insulating adhesive, or the annealed individual sheets are superficially oxidized to create an insulating layer and then bonded, welded, or laser-welded together to form a sheet metal stack, or the annealed individual sheets are coated with an inorganic-organic hybrid coating such as Remisol-C5 and then further processed to form a sheet metal stack.

[0028] After heat treatment, the pre-product can undergo a further heat treatment in an oxygen- or water vapor-containing atmosphere. This additional heat treatment can be used to form the insulating layer or to increase the thickness of an existing insulating layer on the pre-product or sheets.

[0029] After heat treatment, at least one sheet metal stack can be manufactured from the stacked sheets by electrical discharge machining (EDM), laser cutting, or waterjet cutting. In this embodiment, the sheets therefore do not have their final contour during heat treatment, but can be rectangular.

[0030] In one embodiment, the sheets are first cut to length from a strip, stacked, and heat-treated as a stack. After heat treatment, the multiple sheets can be bonded together using an insulating adhesive, or their surface can be oxidized to create an insulating layer and then bonded, laser-welded, or coated with an inorganic-organic hybrid coating. This stack or composite is then further processed into a laminated core. The laminated core, with the outer contour required for a stator or rotor application, can be cut from the stack or composite, for example, by electrical discharge machining (EDM).

[0031] In further embodiments, additional parameters of the heat treatment are defined in more detail in order to further improve the soft magnetic properties and / or the shape of the pre-product.

[0032] In one embodiment, 960°C ≤ T 1 < T m .

[0033] In one embodiment, the pre-product is heat-treated above TÜ2 for a period of more than 15 minutes, and then cooled to T2.

[0034] In one embodiment, the precursor is cooled from at least T1 to room temperature and then heated from room temperature to T2. The heat treatment at T2 can be carried out as a separate heat treatment at a later time.

[0035] If the material is cooled to room temperature after annealing at T1, it is advantageous to then perform a post-annealing at T2. This particularly improves the soft magnetic parameters: permeability, which increases; Hc, which decreases; and hysteresis losses, which decrease. The effect of post-annealing on the induction values, however, is rather small. Alternatively, the temperature can be maintained at T2 during the cooling phase.

[0036] In one embodiment, the precursor is heat-treated at T1 for a time t1, where 15 minutes ≤ t1 ≤ 20 hours, and then cooled from T1 to T2. In another embodiment, the precursor is cooled from T1 to T2, heat-treated at T2 for a time t2, where 30 minutes ≤ t2 ≤ 20 hours, and then cooled from T2 to room temperature.

[0037] In embodiments where the precursor is cooled from T 1 to room temperature, the precursor can then be heated from room temperature to T 2 and heat-treated at T 2 according to one of the embodiments described herein.

[0038] Since the alloy, due to its low cobalt content, does not exhibit an order-disorder transition, quenching over the temperature range of 800°C to 600°C is omitted. The cooling rate from 800°C to 600°C can, for example, range from 100°C / h to 500°C / h. However, it can also be chosen to be even slower. The aforementioned cooling rates can also be carried out without problems until the alloy cools to room temperature.

[0039] According to the invention, the cooling rate over at least the temperature range from TÜ2 to TÜ1 is 1 K / h to 100 K / h, preferably 4 K / h to 50 K / h, preferably 10 K / h to 50 K / h. A cooling rate of 1 K / h to 100 K / h, preferably 4 K / h to 50 K / h, preferably 10 K / h to 50 K / h over the temperature range T1 to 900°C or T1 to T2 can also be used.

[0040] The cooling rate of T 2 to room temperature has less influence on the magnetic properties, so the precursor of T 2 can be cooled to room temperature at a rate of 10°C / h to 50,000°C / h, preferably 100°C / h to 1000°C / h.

[0041] In another alternative embodiment, the precursor is cooled from T1 to room temperature at a cooling rate of 4 K / h to 50 K / h. In embodiments with slow cooling from T1 to room temperature, for example at a cooling rate of less than 100 K / h, preferably less than 50 K / h, further heat treatment at temperature T2 can also be omitted.

[0042] After heat treatment, the pre-product or the soft magnetic alloy from which the pre-product is formed can be: a maximum permeability µmax ≥ 5,000, and / or an electrical resistance ρ ≥ 0.25 µΩm, hysteresis losses Phys ≤ 0.07 J / kg at an amplitude of 1.5 T, and / or a coercive field strength Hc of ≤ 0.7 A / cm and / or an induction B ≥ 1.90 T at 100 A / cm, or a maximum permeability µmax ≥ 10,000, and / or an electrical resistance ρ ≥ 0.25 µΩm, and / or hysteresis losses Phys ≤ 0.06 J / kg at an amplitude of 1.5 T, and / or a coercive field strength Hc of ≤ 0.6 A / cm and an induction B ≥ 1.95 exhibiting a T at 100 A / cm, or a maximum permeability µmax ≥ 12,000, preferably µmax ≥ 17,000, and / or an electrical resistance ρ ≥ 0.30 µΩm, and / or hysteresis losses Phys ≤ 0.05 J / kg at an amplitude of 1.5 T, and / or a coercive field strength Hc of ≤ 0.5 A / cm, preferably a coercive field strength Hc of ≤ 0.4 A / cm, preferably a coercive field strength Hc of ≤ 0.3 A / cm, and / or an induction B ≥ 2.00 T at 100 A / cm

[0043] The hysteresis losses PHyst are determined from the remagnetization losses P at an induction amplitude of 1.5 T across the y-intercept in a plot P / f against the frequency f by linear regression. The linear regression is performed using at least 8 measurements, which are distributed approximately evenly over the frequency range from 50 Hz to 1 kHz (e.g., at 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 Hz).

[0044] The intermediate product can be obtained from a cast block produced from a melt by vacuum induction melting, electroslag remelting, or vacuum arc remelting. The melt consists of 5 wt.% ≤ Co ≤ 25 wt.% 0.3 wt.% ≤ V ≤ 5.0 wt.% 0 wt.% ≤ Cr ≤ 3.0 wt.% 0 wt.% ≤ Si ≤ 3.0 wt.% 0 wt.% ≤ Mn ≤ 3.0 wt.% 0 wt.% ≤ Al ≤ 3.0 wt.% 0 wt.% ≤ Ta ≤ 0.5 wt.% 0 wt.% ≤ Ni ≤ 0.5 wt.% 0 wt.% ≤ Mo ≤ 0.5 wt.% 0 wt.% ≤ Cu ≤ 0.2 wt.% 0 wt.% ≤ Nb ≤ 0.25 wt.% 0 wt.% ≤ Ti ≤ 0.05 wt.% 0 wt.% ≤ Ce ≤ 0.05 wt.% 0 wt.% ≤ Ca ≤ 0.05 wt.% 0 wt.% ≤ Mg ≤ 0.05 wt.% 0 wt.% ≤ C ≤ 0.02 wt.% 0 wt.% ≤ Zr ≤ 0.1 wt.% 0 wt.% ≤ O ≤ 0.025 wt.% 0 wt.% ≤ S ≤ 0.025 wt.%

[0045] The remainder consists of iron, with Cr+Si+Al+Mn ≤ 3.0 wt%, and up to 0.2 wt% of other impurities. Other impurities include, for example, B, P, N, W, Hf, Y, Re, Sc, Be, and other lanthanides except Ce.

[0046] The molten metal is poured and solidifies into a cast block. This cast block is then shaped to produce the semi-finished product. This shaping can be carried out by hot rolling, forging, and / or cold forming.

[0047] In one embodiment, the cast block is formed into a slab by hot rolling at temperatures between 900°C and 1300°C and subsequently into a hot strip with a thickness D 1.

[0048] In some embodiments, the hot strip is then formed into a strip with a thickness D 2 by means of cold rolling, where 0.05 mm ≤ D 2 ≤ 1.0 mm, and D 2 < D 1.

[0049] In one embodiment, a hot strip of thickness D 1 is first produced by continuous casting, which is then formed into a strip with a thickness D 2 by means of cold rolling, where 0.05 mm ≤ D 2 ≤ 1.0 mm, and D 2 < D 1.

[0050] In one embodiment, the degree of cold forming is >40%, preferably >80%, preferably >95%.

[0051] In one embodiment, the cast block is formed into a billet by hot rolling at temperatures between 900°C and 1300°C and then formed into a wire by cold drawing.

[0052] In one embodiment, the degree of cold forming is >40%, preferably >80%, preferably >95%.

[0053] In one embodiment, after heat treatment the mean grain size is at least 100 µm, preferably at least 200 µm, and most preferably at least 250 µm, and the soft magnetic alloy exhibits an induction B 100 (induction B at H = 100 A / cm) of at least 1.90 T, preferably at least 1.95 T. A mean grain size of at least 100 µm, 200 µm, or 250 µm promotes higher induction values, and, in particular, the coercive field strength H c decreases with increasing grain size dk.

[0054] Due to the lower cobalt content, the raw material costs of the alloy are reduced compared to an alloy based on 49 wt% Fe, 49 wt% Co, 2% V. According to the invention, an FeCo alloy with a maximum cobalt content of 25 wt% is created, which offers better soft magnetic properties, in particular a significantly higher permeability, than other FeCo alloys with a maximum cobalt content of 25 wt%, such as existing and commercially available FeCo alloys like VACOFLUX 17, AFK 18, or HIPERCO 15. These existing and commercially available alloys have a maximum permeability of less than 5000.

[0055] The alloy exhibits no order, meaning that, unlike alloys with over 30 wt% Co, it can be cold-rolled without a prior quenching process. A quenching process is particularly difficult to control with large quantities of material, as sufficiently rapid cooling rates are hard to achieve, potentially leading to ordering and subsequent embrittlement of the alloy. The absence of an order-disorder transition in this alloy thus simplifies large-scale production.

[0056] A noticeable order-disorder transition, such as that seen in CoFe alloys with a Co content exceeding 30 wt%, can be detected for an alloy using DSC (Differential Scanning Calorimetry) measurements, as it results in a peak in the DSC measurement. Such a peak is not detected for the alloy in a DSC measurement under the same conditions.

[0057] At the same time, this new alloy offers significantly lower hysteresis losses than previously known and commercially available alloys with Co contents between 10 and 30 wt%, as well as higher induction in addition to its higher permeability. The FeCo alloy can also be produced cost-effectively on an industrial scale.

[0058] Due to its higher permeability, the alloy can be used in applications such as the rotor or stator of an electric motor to reduce the size of the rotor or stator, and thus the electric motor, and / or to increase its performance. For example, higher torque can be generated with the same size and / or weight, which would be advantageous in electric or hybrid vehicles.

[0059] In one embodiment, the alloy exhibits a maximum permeability µmax ≥ 10,000, an electrical resistance ρ ≥ 0.28 µΩm, hysteresis losses Phys ≤ 0.055 J / kg at an amplitude of 1.5 T, a coercive field strength Hc of ≤ 0.5 A / cm, and an induction B ≥ 1.95 T at 100 A / cm. This combination of properties is particularly advantageous for use as or in a rotor or stator of an electric motor, in order to reduce the size of the rotor or stator and thus of the electric motor, and / or to increase the power output, or to generate higher torque with the same size and / or weight.

[0060] The soft magnetic alloy can thus be used in an electrical machine, such as in the stator and / or rotor of an electric motor and / or generator, and / or in a transformer and / or in an electromagnetic actuator. It can be supplied in the form of a sheet, for example with a thickness of 0.05 mm to 0.5 mm. Several sheets of the alloy can be stacked to form a laminated core, which is used as the stator or rotor.

[0061] The alloy has an electrical resistance of at least 0.25 µΩm, preferably at least 0.3 µΩm. Eddy current losses can be reduced to a lower level by selecting a slightly thinner strip.

[0062] In further embodiments, the composition of the soft magnetic alloy is defined in more detail, wherein 10 wt.% ≤ Co ≤ 20 wt.%, preferably 15 wt.% ≤ Co ≤ 20 wt.% and 0.3 wt.% ≤ V ≤ 5.0 wt.%, preferably 1.0 wt.% ≤ V ≤ 3.0 wt.%, preferably 1.3 wt.% ≤ V ≤ 2.7 wt.% and / or 0.1 wt.% ≤ Cr+Si ≤ 2.0 wt.%, preferably 0.2 wt.% ≤ Cr+Si ≤ 1.0 wt.%, preferably 0.25 wt.% ≤ Cr+Si ≤ 0.7 wt.%.

[0063] In one embodiment, the sum formula is defined in more detail, where 0.2 wt.% ≤ Cr+Si+Al+Mn ≤ 1.5 wt.%, preferably 0.3 wt.% ≤ Cr+Si+Al+Mn ≤ 0.6 wt.% applies.

[0064] The soft magnetic alloy may also contain silicon, wherein 0.1 wt.% ≤ Si ≤ 2.0 wt.%, preferably 0.15 wt.% ≤ Si ≤ 1.0 wt.%, preferably 0.2 wt.% ≤ Si ≤ 0.5 wt.%.

[0065] Aluminium and silicon can be exchanged for each other, so that in one embodiment the sum of Si and aluminium (Si+Al) 0 wt.% ≤ (Si + Al) ≤ 3.0 wt.%.

[0066] The alloys are virtually carbon-free and contain a maximum of up to 0.02 wt% carbon, preferably ≤ 0.01 wt% carbon. This maximum carbon content is to be considered an unavoidable impurity.

[0067] In these alloys, calcium, beryllium, and / or magnesium can be added in small amounts, up to 0.05 wt%, for deoxidation and desulfurization. To achieve particularly good deoxidation, up to 0.05 wt% cerium or cerium mischmetal can be added.

[0068] The Curie temperature of the alloy can be taken into account when selecting the temperatures T1 and / or T2. For example, TÜ1 can be > Tc, where Tc is the Curie temperature and Tc is ≥ 900°C. In one embodiment, TÜ1 > T2 > Tc is chosen.

[0069] In compositions where there is a separation of the phase transition from the BCC to the BCC+FCC two-phase region and the Curie temperature Tc, a further temperature range with high self-diffusion exists. Therefore, heat treatment in this region or cooling through this region enables a larger BCC grain structure and thus improved soft magnetic properties. Furthermore, the separation of the two-phase region and the Curie temperature Tc ensures that, during cooling, both the passage through the BCC / FCC two-phase region and the transition to the region of the pure BCC phase occur entirely in the paramagnetic state. By selecting the temperature T2 such that Tü1 > T2 > Tc, the soft magnetic properties can be further improved.

[0070] The improved magnetic properties can be achieved according to the invention by a heat treatment that is tailored to the composition as follows. In particular, it has been found that determining the phase transition temperatures for the selected compositions and determining the heat treatment temperatures and cooling rate with respect to these determined phase transition temperatures leads to improved magnetic properties. Furthermore, it is taken into account that the alloys with a cobalt content of a maximum of 25 wt% do not exhibit an order-disorder transition, so that no quenching is necessary in the manufacturing process to avoid ordering and the resulting embrittlement.

[0071] Traditionally, CoFe alloys are used in strip thicknesses ranging from 0.50 mm down to very thin dimensions of 0.050 mm. For strip processing, the material is conventionally hot-rolled and then cold-rolled to its final thickness. During cooling after hot rolling, an embrittlement of the grain order occurs at approximately 730°C, so that for sufficient cold rolling capability, an additional special intermediate annealing followed by quenching to suppress this order formation is necessary. This quenching step is omitted with this alloy because it does not exhibit an order-disorder transition, which simplifies its production.

[0072] CoFe alloys undergo a final heat treatment, also known as magnetic annealing, to achieve their magnetic properties. For this process, the material is heated to its annealing temperature, held at this temperature for a specific time, and then cooled at a defined rate. It is advantageous to perform this final annealing at the highest possible temperatures and under a dry, pure hydrogen atmosphere. At high temperatures, the reduction of impurities by the hydrogen is more efficient, and the grain structure becomes coarser, thus improving soft magnetic properties such as coercivity and permeability.

[0073] In practice, the annealing temperature of the CoFe system is limited because a phase transition occurs in the binary system at approximately 950°C, transforming the magnetic and ferritic BCC phase into the non-magnetic and austenitic FCC phase. When alloying occurs, a two-phase region forms between the FCC and BCC phases, in which both phases coexist. The transition between the BCC phase and the two-phase or BCC / FCC mixed region occurs at a temperature TÜ1, and the transition between the two-phase region and the FCC phase occurs at a temperature TÜ2, where TÜ2 > TÜ1. The position and size of the two-phase region further depend on the type and extent of the alloying. If annealing takes place in the two-phase region or in the FCC region, residual FCC phases can impair the magnetic properties after cooling and incomplete reconversion.Even with complete reconversion, a damaging effect remains across the newly formed grain boundaries, since the coercive field strength is inversely proportional to the grain diameter. Consequently, the known, commercially available alloys with Co contents around 20 wt.% are final annealed at temperatures below the two-phase region BCC+FCC. For example, the recommended annealing time for AFK 18 is 3h / 850°C, for AFK 1 it is 3h / 900°C, and for VACOFLUX 17 it is 10h / 850°C. At such low final annealing temperatures and due to the relatively high magnetocrystalline anisotropy (K1 approx. 45,000 J / m3 at 17 wt.% Co), the potential for particularly good soft magnetic properties in these FeCo alloys is limited. For example, with VACOFLUX 17-band, maximum permeabilities of around 4,000 can only be achieved, with a coercive field strength of typically 1 A / cm, which limits its use, especially with regard to motor and generator applications.

[0074] In contrast to these known final annealing processes, the composition enables a heat treatment that produces better magnetic properties than the single-stage annealing with furnace cooling typically used for FeCo alloys, regardless of the temperature range in which the single-stage annealing takes place. The alloying elements are selected to shift the lower boundary of the two-phase region and the BCC / FCC phase transition upwards, thus enabling annealing at high temperatures, for example, above 925°C in the pure BCC region. Annealing at such high temperatures is not possible with previously known FeCo alloys.

[0075] Furthermore, due to the composition, the width of the two-phase region, i.e., the difference between the lower transition temperature TÜ1 and the upper transition temperature TÜ2, is kept as narrow as possible. Thus, by performing a final annealing above the two-phase region, combined with cooling through the two-phase region and subsequent holding time or controlled cooling in the pure BCC region, the advantages of a high final annealing temperature—i.e., the elimination of potentially magnetically unfavorable textures, the cleaning effect under H2, and the growth of large grains—are preserved without the risk of magnetically harmful residues of the FCC phase.

[0076] It has been found that compositions with a phase transition between the pure BCC region and the BCC / FCC mixed region exhibit significantly improved magnetic properties at higher temperatures, for example above 925°C, and with a narrow two-phase region, for example of less than 45K. According to the invention, compositions with this specific combination of phase diagram features are selected and heat-treated accordingly to ensure a high maximum permeability of more than 5000, more than 10,000, or even more than 15,000.

[0077] Vanadium has been identified as one of the most effective elements in Fe-Co alloys, increasing electrical resistance and simultaneously shifting the two-phase region to higher temperatures in alloys with low Co content. The increase in transition temperatures by vanadium is more effective with lower Co content. In the Fe-17Co alloy, the addition of approximately 2% vanadium can even raise the transition temperatures above those of the binary FeCo composition.

[0078] In the binary Fe-Co system, the BCC / FCC phase transition occurs at lower temperatures than the Curie temperature when the cobalt content is approximately 15% or higher. Since the FCC phase is paramagnetic, the magnetic phase transition is no longer determined by the Curie temperature, but rather by the BCC / FCC phase transition. Sufficiently high amounts of vanadium shift the BCC / FCC phase transition above the Curie temperature Tc, thus revealing the paramagnetic BCC phase.

[0079] However, if the vanadium content is too high, the width of the mixing region increases. These compositions exhibit lower maximum permeability values, even though the phase transition between the BCC / FCC mixing region and the pure BCC region occurs at higher temperatures. Consequently, it has been found that the composition influences both the temperatures at which the phase transitions occur and the width of the mixing region, and this should be considered when selecting the composition. The heat treatment temperatures can be selected with respect to the temperatures at which the phase transitions occur for this composition in order to achieve the highest permeability values.

[0080] It was thus found that a more precise determination of the temperatures at which the phase transitions occur is advantageous for a given composition when optimizing the manufacturing process. These temperatures can be determined using differential scanning calorimetry (DSC). The DSC measurement can be performed with a sample mass of 50 mg and a DSC heating rate of 10 Kelvin per minute, and the phase transition temperatures determined during heating and cooling of the sample can be used to determine the temperatures for heat treatment.

[0081] Chromium and other elements can be added to improve, for example, electrical resistance or mechanical properties. Chromium, like most other elements, lowers the two-phase region of the binary Fe-17Co alloy. Therefore, the proportion of the alloying element, in addition to vanadium, is preferably chosen so that, together with the vanadium, it results in an increase in the two-phase region compared to the binary FeCo alloy. To achieve this, the levels of impurities and elements that strongly stabilize austenite (e.g., nickel) must be kept as low as possible.

[0082] The following concentrations have proven preferable for achieving very good magnetic properties: cobalt of 5 wt.% ≤ Co ≤ 25 wt.%, and preferably concentrations of 10 wt.% ≤ Co ≤ 20 wt.%, and especially preferred concentrations of 15 wt.% ≤ Co ≤ 20 wt.%

[0083] Vanadium of 0.3 wt.% ≤ V ≤ 5.0 wt.% and preferably contents of 1.0 wt.% ≤ V ≤ 3.0 wt.% and the following molecular formula: 0.2 wt.% ≤ Cr + Si + Al + Mn ≤ 3.0 wt.%.

[0084] The alloys are virtually carbon-free and contain a maximum of up to 0.02 wt% carbon, preferably ≤ 0.01 wt% carbon. This maximum carbon content is to be considered an unavoidable impurity.

[0085] In these alloys, calcium, beryllium, and / or magnesium can be added in small amounts, up to 0.05 wt%, for deoxidation and desulfurization. To achieve particularly effective deoxidation and desulfurization, up to 0.05 wt% cerium or cerium mischmetal can be added.

[0086] The composition allows for further improvement. Cobalt has a higher diffusion coefficient in the paramagnetic BCC phase than in the ferromagnetic BCC phase. Therefore, by separating the two-phase region and the Curie temperature Tc, vanadium enables a wider temperature range with high self-diffusion. This allows for a larger BCC grain structure and thus improved soft magnetic properties through heat treatment in this region or through cooling via this region. Furthermore, the separation of the two-phase region and the Curie temperature Tc ensures that during cooling, both the passage through the two-phase region BCC / FCC and the transition to the region of the pure BCC phase occur entirely in the paramagnetic state. This also has a positive effect on the soft magnetic properties.

[0087] In one embodiment, the measured density of the annealed alloy ρ(alloy) is more than 0.10% lower than the density ρ(alloy[calc]) calculated by proportion from the mean atomic weight of the metallic elements (including Si) of the alloy MAG(alloy), from the mean atomic weight of the metallic elements of the corresponding binary FeCo alloy MAG(binary alloy) and from the measured density ρ(binary alloy) of this annealed binary FeCo alloy.

[0088] As a formula: ρ alloy < 0 , 999 × ρ alloy calc with ρ alloy calc = ρ binary alloy × MAG alloy MAG binary alloy

[0089] Due to heat treatment, the sulfur content in the finished alloy can be lower than in the melt. For example, the upper limit of the sulfur content in the melt can be 0.025% by weight, while in the finished soft magnetic alloy the upper limit is 0.015% by weight.

[0090] In one embodiment, a laminated core is provided consisting of several stacked, electrically insulated sheets of a soft magnetic alloy. The soft magnetic alloy consists of 5 wt.% ≤ Co ≤ 25 wt.% 0.3 wt.% ≤ V ≤ 5.0 wt.% 0 wt.% ≤ Cr ≤ 3.0 wt.% 0 wt.% ≤ Si ≤ 3.0 wt.% 0 wt.% ≤ Mn ≤ 3.0 wt.% 0 wt.% ≤ Al ≤ 3.0 wt.% 0 wt.% ≤ Ta ≤ 0.5 wt.% 0 wt.% ≤ Ni ≤ 0.5 wt.% 0 wt.% ≤ Mo ≤ 0.5 wt.% 0 wt.% ≤ Cu ≤ 0.2 wt.% 0 wt.% ≤ Nb ≤ 0.25 wt.% 0 wt.% ≤ Ti ≤ 0.05 wt.% 0 wt.% ≤ Ce ≤ 0.05 wt.% 0 wt.% ≤ Ca ≤ 0.05 wt.% 0 wt.% ≤ Mg ≤ 0.05 wt.% 0 wt.% ≤ C ≤ 0.02 wt.% 0 wt.% ≤ Zr ≤ 0.1 wt.% 0 wt.% ≤ O ≤ 0.025 wt.% 0 wt.% ≤ S ≤ 0.015 wt.%

[0091] The remainder is iron, with Cr+Si+Al+Mn ≤ 3.0 wt.% and up to 0.2 wt.% of other impurities. The soft magnetic alloy has a maximum permeability µmax ≥ 10,000, an electrical resistivity ρ ≥ 0.28 µΩm, hysteresis losses Phys ≤ 0.055 J / kg at an amplitude of 1.5 T, a coercive field strength Hc ≤ 0.5 A / cm, and an induction B ≥ 1.95 T at 100 A / cm. The laminated core has a fill factor F ≥ 90%, preferably > 94%.

[0092] In the production of the alloy and the process according to the invention, the two-phase region is traversed twice, causing a phase transformation twice. This phase transformation results in a volume jump in the sheets, leading to plastic deformation, which in practice manifests as a wave-like shape. Consequently, the original planarity of the sheets is not maintained, and the fill factor of the laminated core is reduced. However, the planarity of the sheets and the fill factor of the laminated core can be ensured if the heating rate and / or the annealing temperature are adjusted according to the invention. Optionally, additional weight can also be placed on the sheets during heat treatment to ensure the planarity of the sheets and to achieve the desired fill factor of the laminated core.

[0093] In one embodiment, the soft magnetic alloy of the laminated core has a maximum permeability µ max ≥ 12,000, preferably µ max ≥ 17,000.

[0094] In one embodiment, the soft magnetic alloy has hysteresis losses P Hys ≤ 0.05 J / kg, and / or a coercive field strength H c of ≤ 0.4 A / cm, preferably H c of ≤ 0.3 A / cm, and / or an induction B ≥ 2.00 T at 100 A / cm.

[0095] In one embodiment, the composition of the soft magnetic alloy is defined in more detail, wherein 10 wt.% ≤ Co ≤ 20 wt.%, preferably 15 wt.% ≤ Co ≤ 20 wt.% applies, or 0.5 wt.% ≤ V ≤ 4.0 wt.%, preferably 1.0 wt.% ≤ V ≤ 3.0 wt.%, preferably 1.3 wt.% ≤ V ≤ 2.7 wt.% applies, or 0.1 wt.% ≤ Cr ≤ 2.0 wt.%, preferably 0.2 wt.% ≤ Cr ≤ 1.0 wt.%, preferably 0.3 wt.% ≤ Cr ≤ 0.7 wt.% applies, or 0.1 wt.% ≤ Si ≤ 2.0 wt.%, preferably 0.15 wt.% ≤ Si ≤ 1.0 wt.%, preferably 0.2 wt.% ≤ Si ≤ 0.5 wt.% applies and / or the sum formula 0.1 wt.% ≤ Cr+Si+Al+Mn ≤ 1.5 wt.%, preferably 0.2 wt.% ≤ Cr+Si+Al+Mn ≤ 0.6 wt.% applies.

[0096] The laminated core can contain a varying number of laminations depending on the application. For example, it can contain at least two laminations, such as for actuators, or at least 50 or 100 laminations for rotors and stators. The laminations can each have a thickness of 0.05 mm to 0.50 mm, and the electrical insulation between adjacent laminations can have a thickness of 0.1 µm to 2.0 µm.

[0097] The laminated core according to one of the embodiments described herein can be used in an electrical machine, such as, for example, as a stator and / or rotor of an electric motor and / or a generator, and / or in a transformer and / or in an electromagnetic actuator.

[0098] In an alternative embodiment, the temperatures of the heat treatment, in particular the temperature T1 in the FCC phase region, are defined more precisely in a process for producing a soft magnetic alloy, whereby the heating rate and cooling rate can be set as described above. In this embodiment, a precursor is provided which has a composition consisting of 5 wt.% ≤ Co ≤ 25 wt.% 0.3 wt.% ≤ V ≤ 5.0 wt.% 0 wt.% ≤ Cr ≤ 3.0 wt.% 0 wt.% ≤ Si ≤ 3.0 wt.% 0 wt.% ≤ Mn ≤ 3.0 wt.% 0 wt.% ≤ Al ≤ 3.0 wt.% 0 wt.% ≤ Ta ≤ 0.5 wt.% 0 wt.% ≤ Ni ≤ 0.5 wt.% 0 wt.% ≤ Mo ≤ 0.5 wt.% 0 wt.% ≤ Cu ≤ 0.2 wt.% 0 wt.% ≤ Nb ≤ 0.25 wt.% 0 wt.% ≤ Ti ≤ 0.05 wt.% 0 wt.% ≤ Ce ≤ 0.05 wt.% 0 wt.% ≤ Ca ≤ 0.05 wt.% 0 wt.% ≤ Mg ≤ 0.05 wt.% 0 wt.% ≤ C ≤ 0.02 wt.% 0 wt.% ≤ Zr ≤ 0.1 wt.% 0 wt.% ≤ O ≤ 0.025 wt.% 0 wt.% ≤ S ≤ 0.015 wt.%

[0099] The remaining iron consists of Cr+Si+Al+Mn ≤ 3.0 wt.%, and up to 0.2 wt.% of other melt-related impurities, and has a cold-rolled or fibrous texture. Other impurities include, for example, B, P, N, W, Hf, Y, Re, Sc, Be, and other lanthanides except Ce.

[0100] The precursor exhibits a phase transition from a BCC phase region, to a BCC / FCC mixed region, to an FCC phase region, with ascending

[0101] The phase transition temperature between the BCC phase region and the BCC / FCC mixing region is a first transition temperature TÜ1, and with a further increasing temperature, the transition between the BCC / FCC mixing region and the FCC phase region takes place at a second transition temperature TÜ2, wherein TÜ2 > TÜ1 and the difference TÜ2 - TÜ1 is less than 45K, preferably less than 25K.

[0102] The pre-product undergoes the following heat treatment: Heating the precursor to a temperature T 1, then heat-treating the precursor at temperature T 1 for a period of time t 1, and then cooling from T 1 to room temperature.

[0103] Alternatively, the pre-product is subjected to the following heat treatment: Heating the precursor to a temperature T 1, then heat-treating the precursor at temperature T 1 for a time period t 1, then cooling the precursor to a temperature T 2, then heat-treating the precursor at temperature T 2 for a time period t 2, and then cooling the precursor from T 2 to room temperature, where T 1 > T 2.

[0104] In these two methods, the temperature T1 is set such that T1 lies between TÜ2 and (TÜ2 + 100°C), and T2 lies below TÜ1, where 700°C ≤ T2 ≤ 1050°C and T2 < T1. In further embodiments, T1 lies between (TÜ2 + 2°C) and (TÜ2 + 100°C), or between (TÜ2 + 5°C) and (TÜ2 + 100°C).

[0105] In another embodiment, the degree of cold forming is increased to achieve improved soft magnetic properties, in particular high induction B and low coercivity Hc. In this embodiment, the heating rate and the cooling rate can be adjusted as described above.

[0106] In this embodiment, a cast ingot can be produced from a melt provided, for example, by vacuum induction melting, electroslag remelting, or vacuum arc remelting, wherein the melt consists of 5 wt.% ≤ Co ≤ 25 wt.% 0.3 wt.% ≤ V ≤ 5.0 wt.% 0 wt.% ≤ Cr ≤ 3.0 wt.% 0 wt.% ≤ Si ≤ 3.0 wt.% 0 wt.% ≤ Mn ≤ 3.0 wt.% 0 wt.% ≤ Al ≤ 3.0 wt.% 0 wt.% ≤ Ta ≤ 0.5 wt.% 0 wt.% ≤ Ni ≤ 0.5 wt.% 0 wt.% ≤ Mo ≤ 0.5 wt.% 0 wt.% ≤ Cu ≤ 0.2 wt.% 0 wt.% ≤ Nb ≤ 0.25 wt.% 0 wt.% ≤ Ti ≤ 0.05 wt.% 0 wt.% ≤ Ce ≤ 0.05 wt.% 0 wt.% ≤ Ca ≤ 0.05 wt.% 0 wt.% ≤ Mg ≤ 0.05 wt.% 0 wt.% ≤ C ≤ 0.02 wt.% 0 wt.% ≤ Zr ≤ 0.1 wt.% 0 wt.% ≤ O ≤ 0.025 wt.% 0 wt.% ≤ S ≤ 0.025 wt.%

[0107] The remainder consists of iron, with Cr+Si+Al+Mn ≤ 3.0 wt.%, and up to 0.2 wt.% of other impurities.

[0108] The molten metal is poured, solidifies into a cast block made of a soft magnetic alloy, and the cast block is then shaped.

[0109] The cast block is hot-rolled at temperatures between 900°C and 1300°C to form a slab, then a hot-rolled strip with a thickness D1, and subsequently cold-formed to a strip with a thickness D2, wherein the degree of cold forming is >40%, preferably >80%, preferably >95%, and 0.05 mm ≤ D2 ≤ 1.0 mm, and D2 < D1, wherein the strip has a cold-rolled texture or a fiber texture.

[0110] As in the above-mentioned methods, the soft magnetic alloy of the strip exhibits a phase transition from a BCC phase region to a BCC / FCC mixed region to an FCC phase region, wherein, with increasing temperature, the phase transition between the BCC phase region and the BCC / FCC mixed region takes place at a first transition temperature TÜ1 and, with further increasing temperature, the transition between the BCC / FCC mixed region and the FCC phase region takes place at a second transition temperature TÜ2, wherein TÜ2 > TÜ1 and the difference TÜ2 - TÜ1 is less than 45K, preferably less than 25K.

[0111] The belt undergoes the following heat treatment: Heating the precursor to a temperature T1, then heat-treating the precursor at temperature T1 for a duration t1, and then cooling from T1 to room temperature. or subjected to the following heat treatment: Heating the precursor to a temperature T 1, then heat-treating the precursor at temperature T 1 for a time period t 1, then cooling the precursor to a temperature T 2, then heat-treating the precursor at temperature T 2 for a time period t 2, and then cooling the precursor from T 2 to room temperature, where T 1 > T 2.

[0112] In this embodiment, T1 is above T1 and T2 is below T1, where 920°C ≤ T1 < Tm, and 700°C ≤ T2 ≤ 1050°C, where T2 < T1 and Tm is the solidus temperature.

[0113] A cooling rate of 10 to 50K / h between T 1 and e.g. 900°C is advantageous for achieving good soft magnetic properties and can eliminate the need for separate after-annealing or longer holding at temperature T 2.

[0114] Exemplary embodiments of the invention will now be explained in more detail with reference to the drawings and the following examples. Figure 1 shows a schematic representation of the heat treatment according to the invention. Figure 2 shows a diagram of the coercive field strength Hc as a function of the cooling rate. Figure 3 shows a diagram of the induction B at 20 A / cm as a function of the cooling rate. Figure 4 shows metallographic sections for determining the grain size of two examples. Figure 5 shows metallographic sections of a Si-containing example 93 / 0505 after annealing in the gamma region. Figure 6 shows a diagram of the induction B20 (B at H = 20 A / cm) as a function of the grain size. Figure 7 shows a diagram of the coercive field strength Hc as a function of the grain size. Figure 8 shows a diagram of the remanence Br and B20 (B at H = 20 A / cm). Figure 9 shows a diagram of the coercive field strength Hc as a function of cold working. Figure 10 shows a representation of the induction B(20 A / cm) as a function of cold forming.

[0115] According to the invention, a precursor made of a soft magnetic alloy with a composition consisting of 5 wt.% ≤ Co ≤ 25 wt.% 0.3 wt.% ≤ V ≤ 5.0 wt.% 0 wt.% ≤ Cr ≤ 3.0 wt.% 0 wt.% ≤ Si ≤ 3.0 wt.% 0 wt.% ≤ Mn ≤ 3.0 wt.% 0 wt.% ≤ Al ≤ 3.0 wt.% 0 wt.% ≤ Ta ≤ 0.5 wt.% 0 wt.% ≤ Ni ≤ 0.5 wt.% 0 wt.% ≤ Mo ≤ 0.5 wt.% 0 wt.% ≤ Cu ≤ 0.2 wt.% 0 wt.% ≤ Nb ≤ 0.25 wt.% 0 wt.% ≤ Ti ≤ 0.05 wt.% 0 wt.% ≤ Ce ≤ 0.05 wt.% 0 wt.% ≤ Ca ≤ 0.05 wt.% 0 wt.% ≤ Mg ≤ 0.05 wt.% 0 wt.% ≤ C ≤ 0.02 wt.% 0 wt.% ≤ Zr ≤ 0.1 wt.% 0 wt.% ≤ O ≤ 0.025 wt.% 0 wt.% ≤ S ≤ 0.015 wt.%

[0116] The remainder consists of iron, with Cr+Si+Al+Mn ≤ 3.0 wt.%, and up to 0.2 wt.% of other melt-related impurities. These impurities may include, for example, one or more of the elements B, P, N, W, Hf, Y, Re, Sc, Be, or other lanthanides besides Ce. To increase electrical resistance, in addition to the alloying element vanadium, one or more of the elements Cr, Si, Al, and Mn may be added to the extent that the following formula is satisfied: 0.05 wt.% ≤ Cr + Si + Al + Mn ≤ 3.0 wt.%

[0117] The alloy can be supplied in the form of a semi-finished product with a cold-rolled or fiber texture. The semi-finished product can be a strip or one or more sheets suitable for manufacturing a laminated core.

[0118] The soft magnetic alloy or precursor exhibits a phase transition from a BCC phase region (also called α region), to a BCC / FCC mixed region (also called α + γ region) to an FCC phase region (also called γ region), wherein, with increasing temperature, the phase transition between the BCC phase region and the BCC / FCC mixed region takes place at a first transition temperature TÜ1, and with further increasing temperature, the transition between the BCC / FCC mixed region and the FCC phase region takes place at a second transition temperature TÜ2, wherein TÜ2 > TÜ1 and the difference TÜ2 - TÜ1 is less than 45K, preferably less than 25K.

[0119] The alloy is preferably melted in vacuum induction furnaces. However, processing via vacuum arc remelting and electroslag remelting is also possible. The molten metal first solidifies into a block, which is then stripped of its oxide layer and subsequently forged or hot-rolled at temperatures between 900 °C and 1300 °C. Alternatively, the oxide layer can also be removed from bars that have been forged or hot-rolled first. The desired dimensions can be achieved by hot forming strips, billets, or bars. Hot-rolled material can be freed from surface oxides by blasting, grinding, or peeling. Alternatively, the desired final dimensions can also be achieved by cold forming strips, bars, or wires. For cold-rolled strips, a grinding process can be inserted to remove oxide roots from the hot-rolling process.If excessive work hardening occurs after cold forming, one or more intermediate annealing processes can be carried out at temperatures between 400 °C and 1300 °C for recovery and recrystallization. The thickness or diameter for the intermediate annealing should be selected such that a cold working reduction of > 40% to the final thickness is preferably achieved, and a cold working reduction of > 80% and > 95% is particularly preferred.

[0120] This is followed by a heat treatment according to one of the embodiments of the invention, which is also referred to as magnetic final annealing. The final annealing is preferably carried out under a pure, dry hydrogen atmosphere. Annealing under protective gas or in a vacuum is also possible.

[0121] In one embodiment, the precursor is heated to a temperature T1 and then heat-treated at temperature T1 for a duration t1, and subsequently cooled from T1 to room temperature. In an alternative embodiment, the precursor is heated to a temperature T1 and then heat-treated at temperature T1 for a duration t1, then cooled to a temperature T2 and subsequently heat-treated at temperature T2 for a duration t2, and subsequently cooled from T2 to room temperature. Temperature T1 is higher than temperature T2. Furthermore, T1 is above TÜ2, i.e., in the FCC phase region, and T2 is below TÜ1, i.e., in the BCC phase region, and 920°C ≤ T1 < Tm, where Tm is the solidus temperature, and 700°C ≤ T2 ≤ 1050°C.

[0122] For both processes, the heating rate over at least the temperature range from T Ü1 to T Ü2 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h, and the cooling rate over at least the temperature range from T Ü2 to T Ü1 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h.

[0123] In one embodiment, a laminated core is produced from several sheets of an alloy. The following process is used. The soft magnetic alloy, in the form of a strip coated with an electrically insulating layer, for example, an oxide, is provided. The strip is cut to length, and sheets are produced. These sheets are stacked, and the stacked sheets are annealed or heat-treated in a bell furnace according to one of these embodiments. Afterward, the sheets can be oxidized.

[0124] After heat treatment, the sheets are glued together, with the coated sheets being stacked with an adhesive layer to form a composite, cleaned, and then a sheet metal stack is formed from the composite into a shape for an application such as a rotor or a stator, for example by EDM.

[0125] In one embodiment, stacks of 50 or 100 sheets (210 x 140 x 0.15 mm³) were annealed. A ceramic plate weighing approximately 2 kg (244 x 213 x 10 mm³) served as a flat base in almost all trials. The cut sheets are then annealed to ensure flatness and increase the fill factor in the finished sheet stack. Specifically, the heating and cooling rates are adjusted to prevent plastic deformation of the initially flat sheets and thus achieve sufficient flatness through heat treatment.

[0126] In some embodiments, in addition to the set heating and cooling rates, a weight is placed on the stacked sheets or panels. The weight was varied, with a solid NCT3 cover plate (1.4841) weighing 6.5 kg (270 x 150 x 20 mm) being used in most cases. The dead weight of the sheet stacks was 1.7 kg (50 sheets) or 3.4 kg (100 sheets), depending on the stack height.

[0127] Figure 1 Figure 1 shows a schematic progression of the test annealing processes. The dashed lines indicate the expected range for the two-phase region. This two-phase region depends on the alloy composition.

[0128] The transition temperatures TÜ1 and TÜ2 can be determined for a specific composition using DSC measurements. Table 1 shows the composition and transition temperatures for four examples. Table 1 Batch 93 / Co wt. % V wt. % Cr wt. % Si Weight % 1. Onset heating (T ü2 ) Peak heating 1. Onset Cooling (T ü1 ) Peak Cooling T c Peak heating T c Peak Cooling 7604988 16,81 2,29 0,01 0,02 989 995 962 957 939 929 7605180 17,11 1,47 0,01 0,28 967 974 949 942 938 881 7605267 17,20 1,54 0,02 0,23 965 974 944 936 938 875 7409992 17,25 1,49 0,02 0,23 964 972 945 937 939 875

[0129] The annealing program was selected such that the holding temperature T1, at 1000°C to 1030°C, lies above the two-phase region and within the FCC phase region, as shown in Figure 1 The temperature of the batch used, 7605180A, is shown in the diagram. According to the DSC, this temperature ranges between 949°C and 967°C (first onsets during cooling and heating, respectively). The passage through the two-phase region was varied; that is, during heating, a ramp from T0 to T1 was applied, and during cooling, a ramp from T1 to T3 was applied, each with heating and cooling rates between 10 K / h and 100 K / h.

[0130] Figure 2 shows a diagram of the coercive field strength H c and Figure 3 A diagram of the induction B at H=20A / cm as a function of the cooling rate.

[0131] Table 2 shows a summary of the coercive field strength Hc and induction B at 20 A / cm and 100 A / cm for three examples heat-treated with different heating and cooling rates. The induction values ​​are similar in all cases, with the advantage of the slower heating and cooling rates being the improved flatness of the sheets. Table 2 # Heating rate Holding step Cooling rate B(20 A / cm) in T B(100 A / cm) in T Hc in A / cm 1 of 920°C 4h of 1000°C 1,706 2,009 0,432 at 1000°C 1000°C with 4 K / h at 920°C with 4 K / h 2 of 920°C 4h of 1000°C 1,717 1,984 0,378 at 1000°C 1000°C at 20 K / h at 920°C at 20 K / h 3 of 920°C 4h of 1000°C 1,722 1,987 0,433 at 1000°C 1000°C at 100 K / h at 920°C at 50 K / h Batch 7605180A, tape thickness 0.20 mm

[0132] The measured coercive field strength is somewhat lower at slower cooling rates, and the measured induction is somewhat higher at slower cooling rates. Consequently, the soft magnetic properties of these alloys can be improved by using cooling rates of less than 100 K / h, preferably less than 50 K / h or less than 25 K / h.

[0133] The experiments show that excessively rapid heating or cooling leads to severely corrugated sheets, which also exhibit a kind of plastic deformation within the sheet. During heating, the body-centered α-phase transforms into the more densely packed face-centered γ-phase as it passes through the two-phase region. This results in a shortening of the sheets. During cooling, a reversion occurs, ideally restoring the original geometry. It can be assumed that this observed deformation is due to an incomplete forward or reverse conversion. The best results were achieved at heating and cooling rates of 20 K / h and 10 K / h, respectively. At higher rates, e.g., 50 K / h each, slight corrugations already appeared in 50 sheets, and rates as low as 35 K / h in 100 sheets rendered them unusable.

[0134] It was found that, in addition to the weight, the heating and cooling rates can be adjusted to obtain flat sheets. If the stacks of sheets are not weighted or only minimally weighted, significant waviness can occur. If the annealing is carried out under the same conditions, i.e., with the same low heating and cooling rates of 10 K / h, but with a substantial weight of 6.5 kg, a perfectly flat stack of sheets is obtained. Despite the high weight, all sheets could be easily separated from one another.

[0135] The results of the experiments are summarized in Table 3, using the following evaluation of the annealing processes: Very good: The sheets are perfectly flat and show no edge waviness. Good: The sheets are flat overall and show minimal edge waviness. Poor: The sheets show plastic deformation on at least one half. Very poor: The sheets show plastic deformation across the entire sheet. #Sheets Complaint dT / dt heating dT / dt Cooling Evaluation T 0 T1 Tmax T 2 = T 0 in kg in K / h in K / h in °C in °C in °C 50 0 without 10 10 very bad 900 1000 900 50 0,3 1) 50 25 very bad 930 1030 930 50 8,0 2) 10 10 very good 900 1000 900 50 6,5 3) 50 50 good 900 1000 900 50 6,5 3) 50 25 good 900 1000 900 50 6,5 3) 100 25 bad 900 1000 900 50 6,5 3) 100 50 bad 900 1000 900 100 6,5 3) 20 20 very good 920 1000 920 100 6,5 3) 35 35 bad 930 1000 930 100 6,5 3) 100 50 very bad 900 1000 900 1) Uneven, very light weighting using 4 small ceramic plates 2) Uniform weighting using 4 large ceramic plates, each weighing 2 kg 3) Uniform weighting using 1 solid NCT3 plate weighing 6.5 kg Table 3

[0136] In one of the annealing tests (100 sheets, 20 K / h), a solid NCT3 plate was used for both the support and the weighting. The sheets emerged from the annealing process in very good quality. These results show that slowly passing through the two-phase region is beneficial for achieving good soft magnetic properties.

[0137] In another group of examples, the influence of the annealing temperature T1, which is specified in the Figure 1 This has been shown and examined in more detail. Table 4 shows the composition of the examples.

[0138] It has been found that precise temperature control can be used to improve magnetic properties, particularly induction values. Furthermore, grain size can be adjusted by appropriately setting the annealing temperature.

[0139] A positive influence of annealing in the γ-region on the induction values ​​B20 = B(20 A / cm), on the coercive field strength H c, and on the maximum permeability µ max was observed. Furthermore, an influence on the resulting grain size was noted.

[0140] Four compositions in a strip thickness of 0.35 mm with different compositions were investigated, see Table 4, whereby all elements not listed are present with a maximum of 0.02 wt.% each. Table 4 Charge Nominal composition Actual composition (wt%) Fe Co V Cr Si 93 / 0328 Fe-17Co-1.0V-1Cr rest 17,08 0,98 1,04 - 93 / 0329 Fe-17Cr-1.5V-0.5Cr rest 17,12 1,46 0,54 - 93 / 0330 Fe-17Co-2.0V rest 17,19 1,97 - - 93 / 0505 Fe-17Co-1.4V-0.4Si rest 16,97 1,39 - 0,40

[0141] These examples contain approximately 17% Co and additives of 1 to 2% V, where: Batches 93 / 0328 and 932 / 0329 have an additional 0.5% to 1.0% Cr added, batch 93 / 0330 is a purely ternary Fe-Co-V alloy without additions of Cr or Si, and batch 93 / 0505 contains 0.4% Si in addition to Fe-Co-V.

[0142] The annealing was carried out at various temperatures between 850°C and 1150°C. The majority of the annealing took place at high temperatures of at least 1000°C in the γ-region, but some samples were also annealed at lower temperatures in the α-region. The precise location of the two-phase region is shown in Table 5. It can be seen that there is considerable variation; that is, the upper phase boundary α+γ→α lies between 928°C with a high addition of Cr and 970°C with the addition of Si. The width of the two-phase region also varies considerably, ranging from 17°C to 35°C.

[0143] Heating from 600°C was typically carried out at a rate of 150 K / h. The cooling phase was performed using furnace cooling (approximately 100 to 150 K / h), with an even slower cooling rate to be expected at temperatures below 600°C. Table 5 Charge Nominal composition α+γ→γ 1)< in °C α+γ→α 2< ) in °C Latitude α+γ in °C 93 / 0328 Fe-17Co-1.0V-1Cr 893 928 35 93 / 0329 Fe-17Cr-1.5V-0.5Cr 925 945 20 93 / 0330 Fe-17Co-2.0V 950 973 23 93 / 0505 Fe-17Co-1.4V-0.4Si 953 970 17 1) 1. Onset heating in DSC, 2) 1. Onset cooling in DSC

[0144] As expected, the annealing in the α-region (850°C, 910°C) resulted in relatively low induction values ​​B20 = B(20 A / cm) of less than 1.7 T, high Hc values ​​greater than 0.6 A / cm, and lower maximum permeabilities µmax below 5100 for both batches (see Tables 6 and 7). Table 6 shows the magnetic values ​​and grain sizes dK for alloy 93 / 0328 with added Cr (Fe-17Co-1V-1Cr). Table 7 shows the magnetic values ​​and grain sizes for alloy 93 / 0329 with added Cr (Fe-17Co-1.5V-0.5Cr). Table 6 93 / 0328 Glowing TMax in °C B20 in T B100 in T Hc in A / cm µ max Br in T dk in µm α 4h 850°C 850 1,656 1,918 0,93 3.890 0,95 63-76 10h 910°C 910 1,623 1,887 0,63 4.902 1,02 107-125 10h 910°C + 70h 930°C 930 1,771 2,036 0,47 6.912 1,16 >1500 4h 1000°C 1000 1,768 2,011 0,66 5.130 1,16 210-430 Y 4h 1050°C 1050 1,767 2,012 0,63 5.387 1,18 180-350 4h 1100°C 1100 1,726 1,980 0,68 4.958 1,10 210-350 4h 1150°C 1150 1,692 1,956 0,68 4.863 1,09 180-350 B20=B(20 A / cm), B100 = B(100 A / cm) Table 7 93 / 0329 Glühung TMax in °C B20 in T B100 in T Hc in A / cm µ max Br in T d k in µm α 4h 850°C 850 1,651 1,911 1,04 3.584 0,88 75 10h 910°C 910 1,620 1,881 0,62 5090 1,13 151 h 1000°C (+10h 910°C) 1000 1,803 (1,807) 2,035 (2,038) 0,51 (0,38) 7.929 (16.658) 1,38 (1,53) 250 γ 4h 1050°C 1050 1,809 2,039 0,50 7.943 1,39 302 4h 1100°C 1100 1,797 2,031 0,52 7.497 1,35 214 4h 1150°C 1150 1,778 2,018 0,47 7.860 1,35 254 B20=B(20 A / cm), B100 = B(100 A / cm)

[0145] After annealing in the gamma region (up to 1050°C), significantly higher B20 values ​​of greater than 1.75T are obtained. A further increase in the annealing temperature (1100°C, 1150°C) leads, in the example with 1% Cr (Table 6), to a significant decrease in the B20 induction of up to 80 mT compared to the best annealing at 930°C. The example with 0.5% Cr (Table 7), however, is considerably more stable in this respect; the decrease compared to the best annealing at 1050°C is only about 30 mT.

[0146] Figur 4 Shows metallographic sections for determining grain size of batch 93 / 0328. Left: 10h 910°C (α), right: 10h 910°C+70h 930°C (γ).

[0147] Regarding the grain size dk, the only finding for both batches is that annealing in the γ-region results in larger grains (> 180 µm) than annealing in the α-region (<180 µm). Furthermore, no other correlation between B20 and grain size can be determined, since, for example, annealing at 1050°C and 1150°C of batch 93 / 0328 results in the same grain sizes of 180 µm to 350 µm, but very different B20 values ​​of 1.767 T and 1.692 T.

[0148] However, a correlation between coercive field strength H c and grain size can be observed in the sample that was annealed for a very long time at 930°C, since in this state both the lowest H c of the batch (0.47 A / cm) and by far the largest grains (>1500 µm) occurred.

[0149] For the ternary alloy 93 / 0330 with Fe-17Co-2V (Table 8), two annealing cycles were performed in the α-region (850°C, 910°C) and four in the γ-region (1000°C, 1050°C, 1100°C, 1150°C), see Table 8. It is confirmed here as well that the stroke in the B20 induction coil only occurs after an annealing cycle in the γ-region. Furthermore, this value also decreases again at very high annealing temperatures of 1100°C or more. Table 8 93 / 0330 Glühung TMax in °C B20 in T B100 in T Hc in A / cm µ max Br in T d k in µm α 4h 850°C 850 1,648 1,906 1,05 3.533 0,87 - 10h 910°C 910 1,615 1,873 0,68 4.868 1,11 - h 1000°C 1000 1,801 2,038 0,41 10.618 1,44 300-350 γ 4h 1050°C 1050 1,812 2,040 0,35 12.670 1,50 250-350 4h 1100°C 1100 1,786 2,028 0,38 10.051 1,41 300-430 4h 1150°C 1150 1,756 2,005 0,36 10.568 1,44 300-430 B20=B(20 A / cm), B100 = B(100 A / cm)

[0150] In this batch it also becomes clear that the Br remanence increases significantly due to annealing in the γ-region, i.e. the loop becomes significantly more rectangular (Br > 1.4 T).

[0151] In the example 93 / 0505 with added silicon (Fe-17Co-1.5V-0.5Cr), only the annealing in the gamma region was considered (1000°C, 1050°C, 1100°C). Table 9 shows the magnetic properties and grain sizes for alloy 93 / 0505.

[0152] As with the other batches, very high induction values ​​B20 of up to 1.79 T were measured, which, however, drop significantly again at 1100°C. The very low Hc values ​​of approximately 0.3 A / cm² and the very high permeability of greater than 10,000 compared to the other compositions examined can possibly be explained by the relatively coarse-grained microstructure (see Table 9). Figur 5 . Table 9 93 / 0505 Glühung TMax in °C B20 in T B100 in T Hc in A / cm µ max Br in T d k in µm 4h 1000°C 1000 1,787 2,029 0,32 12.668 1,32 350-710 γ 4h 1050°C 1050 1,760 2,020 0,26 14.272 1,24 300-360 4h 1100°C 1100 1,692 1,969 0,33 10.819 1,20 inhomogen, bis >1500 B20=B(20 A / cm), B100 = B(100 A / cm)

[0153] In all batches examined, the high induction values ​​(B20 > 1.75 T) only occur during annealing in the γ-region (FCC).

[0154] It was observed that the induction values ​​are highest after annealing just above the phase transition α+γ→γ (FCC+BCC→FCC). This correlates with a significant coarsening of the microstructure.

[0155] Table 10 shows a summary of the measured grain sizes of the investigated batches, taking into account all annealing processes with a duration between 4 and 10 hours. Figur 6 shows a diagram of the induction B 20 (B at H=20 A / cm) as a function of the grain size. Figur 7 shows a diagram of the coercive field strength H c as a function of grain size. Figur 8 This shows a relationship between remanence B r and B 20 (B at H=20 A / cm) for all investigated states. The filled symbols correspond to annealing in the γ-region (FCC), the unfilled symbols to annealing in the α-region (BCC). Table 10 Korngrößen nach Glühung (4 - 10h) in µm Glühung im α-Gebiet (BCC) Glühung im γ-Gebiet (FCC) Charge von bis von bis 93 / 0328 63 125 210 350 93 / 0329 75 151 214 302 93 / 0330 - - 300 430 93 / 0505 - - 300 >1500

[0156] Excessive increases in the annealing temperature (1100°C or higher) resulted in a decrease in the observed induction values. The four batches behaved differently in this regard; that is, while batches 93 / 0329 and 93 / 0330 still exhibited very high B20 values ​​greater than 1.75 T even at 1150°C, this value had already dropped to 1.69 T at 1150°C and 1100°C, respectively, for batches 93 / 0328 and 93 / 0505. No direct correlation between this effect and grain size could be established.

[0157] The alloy 93 / 05050 with added silicon exhibits significantly larger grains than the compositions without silicon. Accordingly, the Hc values ​​are also the lowest, although the ternary Fe-Co-V melt 93 / 0330, despite its significantly smaller grain size, shows almost equally high Hc values.

[0158] If one excludes the states with very coarse grains of 1 mm or larger, direct correlations emerge between the magnetic properties and the grain size, compare Figur 4 (B 20 ) and Figur 5 (H c ). Furthermore, one can see in Figur 6 A high induction B20 is associated with a high remanence B r. Above a remanence of 1.3 T, all states in this study exhibit an induction B20 of at least 1.75 T. The increase in induction is therefore accompanied by the formation of a hysteresis loop.

[0159] Further embodiments examine the influence of the degree of cold forming on the magnetic properties. From a soft magnetic perspective, low Hc and high B values ​​are advantageous.

[0160] During rolling, the strip width can be neglected and the degree of cold forming KV of the final thickness D 2 is defined as the percentage reduction in thickness relative to a non-cold-formed initial thickness D 1 . The following applies: KV % = D 1 − D 2 D 1 ⋅ 100

[0161] The initial thickness not cold-formed D 1 This can be achieved, for example, by hot rolling or by intermediate annealing (ICE). Both D 1 varies in the range of 1.9mm to 6.4mm, as well as D 2 in the range of 0.35 mm to 0.10 mm. Three different heat treatments were used, corresponding to the annealing variants 1st stage + 2nd stage or 1st stage + controlled cooling. The cooling rate for the 4h annealing at 1050°C is 150°C / h. OK means furnace cooling, which also corresponds to a cooling rate of 150°C / h. RT means room temperature.

[0162] Figur 9 shows a diagram of the coercive field strength H c as a function of cold forming. Figur 10 shows a diagram of the induction B 20 (B at H=20A / cm) as a function of cold forming.

[0163] One can recognize from Figur 9The induction B increases with the degree of cold working at a field strength H of 20 A / cm. The maximum realized kV is 98%. The B values ​​can be improved with increasing cold working, and the deterioration of the Hc with increasing cold working can be compensated for by suitable cooling after the first stage over the two-phase region.

[0164] In summary, a highly permeable soft magnetic alloy is provided, exhibiting improved soft magnetic properties, such as significantly higher permeability and lower hysteresis losses, while simultaneously offering higher saturation than existing and commercially available FeCo alloys. At the same time, this new alloy offers significantly lower hysteresis losses than previously known and commercially available alloys with Co contents between 10 and 30 wt.%, and, most importantly, a significantly higher permeability level, previously unattainable for such alloys. The alloy can also be produced on an industrial scale and cost-effectively, particularly in the form of flat sheets and a laminated core, which, due to the flatness of the sheets, can have a fill factor greater than 90% or 94%.

Claims

1. A method of producing a soft magnetic preliminary product, comprising: providing an alloy having a composition of 5 % by weight ≤ Co ≤ 25 % by weight 0.3 % by weight ≤ V ≤ 5.0 % by weight 0 % by weight ≤ Cr ≤ 3.0 % by weight 0 % by weight ≤ Si ≤ 3.0 % by weight 0 % by weight ≤ Mn ≤ 3.0 % by weight 0 % by weight ≤ Al ≤ 3.0 % by weight 0 % by weight ≤ Ta ≤ 0.5 % by weight 0 % by weight ≤ Ni ≤ 0.5 % by weight 0 % by weight ≤ Mo ≤ 0.5 % by weight 0 % by weight ≤ Cu ≤ 0.2 % by weight 0 % by weight ≤ Nb ≤ 0.25 % by weight 0 % by weight ≤ Ti ≤ 0.05 % by weight 0 % by weight ≤ Ce ≤ 0.05 % by weight 0 % by weight ≤ Ca ≤ 0.05 % by weight 0 % by weight ≤ Mg ≤ 0.05 % by weight 0 % by weight ≤ C ≤ 0.02 % by weight 0 % by weight ≤ Zr ≤ 0.1 % by weight 0 % by weight ≤ O ≤ 0.025 % by weight 0 % by weight ≤ S ≤ 0.015 % by weight the remainder iron, wherein Cr+Si+Al+Mn ≤ 3.0% by weight and up to 0.2% by weight consisting of other impurities due to melting, wherein the preliminary product has a phase transition from a BCC-phase region, to a BCC / FCC mixed region to an FCC phase region, wherein, with increasing temperature, the phase transition between the BCC phase region and the BCC / FCC mixed region occurs at a first transition temperature Tt1, and, with further increasing temperature, the transition between the BCC / FCC mixed region and the FCC phase region occurs at a second transition temperature Tt2, wherein Tt2 > Tt1 and the difference Tt2 - Tt1 is less than 45K, preferably less than 25K, wherein the preliminary product is subjected to the following heat treatment, wherein, prior to the onset of the heat treatment, the preliminary product has a cold-rolled texture or a fibrous texture: heating the preliminary product to a temperature T1, and subsequently heat treating the preliminary product at the temperature T1 for a duration t1, and subsequently cooling from T1 to room temperature, or the preliminary product is subjected to the following heat treatment: heating the preliminary product to a temperature T1, and subsequently heat treating the preliminary product at the temperature T1 for a duration t1, and subsequently cooling the preliminary product to a temperature T2, and subsequently heat treating the preliminary product at the temperature T2 for a duration t2, and subsequently cooling the preliminary product from T2 to room temperature, wherein T1 > T2, T1 is above Tt2 and T2 below Tt1, wherein 920°C ≤ T1 < Tm, 700°C ≤ T2 ≤ 1050°C, and Tm is the solidus temperature, wherein 15 minutes ≤ t1 ≤ 20 hours, and 30 minutes ≤ t2 ≤ 20 hours, wherein the heating rate across at least the temperature range from Tt1 to Tt2 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h, and the cooling rate across at least the temperature range from Tt2 to Tt1 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h, wherein the preliminary product has the form of multiple stacked metal sheets or one or more metal sheet packages and is loaded with an additional weight, and the preliminary product with the weight is subjected to the heat treatment, wherein the weight of the loading is at least 20%, preferably at least 50% of the weight of the preliminary product.

2. The method of claim 1, wherein the heating rate across at least the temperature range from 900°C to T1 is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h, and / or wherein the cooling rate across at least the temperature range from T1 to 900°C is 1 K / h to 100 K / h, preferably 10 K / h to 50 K / h.

3. The method according to claim 1 or claim 2, wherein T1 is between Tt2 and (Tt2 + 100°C).

4. The method according to one of claims 1 to 3, wherein the preliminary product is heat treated for a duration of over 15 minutes above Tt2, and subsequently cooled to T2, or the preliminary product is heat treated for a duration of over 15 minutes above Tt2, and subsequently cooled to room temperature.

5. The method according to one of claims 1 to 4, wherein the preliminary product is cooled at least from T1 to room temperature, and subsequently heated from room temperature to T2.

6. The method according to one of claims 1 to 5, wherein the preliminary product is heat treated under a hydrogenous atmosphere, wherein, after heat treating, the soft magnetic alloy: has a maximum permeability µmax ≥ 5,000, and / or an electric resistance ρ ≥ 0.25 µΩm, hysteresis losses Phys ≤ 0.07 J / kg at an amplitude of 1.5 T, and / or a coercitivity Hc of ≤ 0,7 A / cm and / or induction B ≥ 1.90 T at 100 A / cm, or has a maximum permeability µmax ≥ 10,000, and / or an electric resistance ρ ≥ 0.25 µΩm, and / or hysteresis losses Phys ≤ 0.06 J / kg at an amplitude of 1.5 T, and / or a coercitivity Hc of ≤ 0,06 A / cm and induction B ≥ 1,95 T at 100 A / cm, or has a maximum permeability µmax ≥ 12,000, preferably µmax ≥ 17,000 and / or an electric resistance ρ ≥ 0.30 µΩm, and / or hysteresis losses Phys ≤ 0.05 J / kg at an amplitude of 1.5 T, and / or a coercitivity Hc of ≤ 0.5 A / cm, preferably a coercitivity Hc of ≤ 0.4 A / cm, preferably a coercitivity Hc of ≤ 0.3 A / cm, and / or induction B ≥ 2.00 T at 100 A / cm.

7. The method according to one of claims 1 to 6, further comprising: providing a melt by vacuum induction melting, electroslag remelting or vacuum arc remelting, consisting of 5 % by weight ≤ Co ≤ 25 % by weight 0.3 % by weight ≤ V ≤ 5.0 % by weight 0 % by weight ≤ Cr ≤ 3.0 % by weight 0 % by weight ≤ Si ≤ 3.0 % by weight 0 % by weight ≤ Mn ≤ 3.0 % by weight 0 % by weight ≤ Al ≤ 3.0 % by weight 0 % by weight ≤ Ta ≤ 0.5 % by weight 0 % by weight ≤ Ni ≤ 0.5 % by weight 0 % by weight ≤ Mo ≤ 0.5 % by weight 0 % by weight ≤ Cu ≤ 0.2 % by weight 0 % by weight ≤ Nb ≤ 0.25 % by weight 0 % by weight ≤ Ti ≤ 0.05 % by weight 0 % by weight ≤ Ce ≤ 0.05 % by weight 0 % by weight ≤ Ca ≤ 0.05 % by weight 0 % by weight ≤ Mg ≤ 0.05 % by weight 0 % by weight ≤ C ≤ 0.02 % by weight 0 % by weight ≤ Zr ≤ 0.1 % by weight 0 % by weight ≤ O ≤ 0.025 % by weight 0 % by weight ≤ S ≤ 0.015 % by weight the remainder iron, wherein Cr+Si+Al+Mn ≤ 3.0% by weight and up to 0.2% by weight other impurities due to melting, solidifying the melt to a cast block, forming the cast block to produce the preliminary product, wherein the forming is performed by hot rolling and / or forging and / or cold forming, wherein the cast block is formed by hot rolling to a slab at temperatures between 900°C and 1300°C and subsequently to a hot strip with a thickness D1, and subsequently formed by cold rolling to a strip with a thickness D2, wherein 0.05 mm ≤ D2 ≤ 1.0 mm, and D2 < D1.

8. The method according to claim 7, wherein initially, a hot strip of thickness D1 is produced by continuous casting, which is then formed by cold rolling to a strip with a thickness D2, wherein 0.05 mm ≤ D2 ≤ 1.0 mm, and D2 < D1, wherein the degree of cold deformation by cold rolling is > 40%, preferably > 80%, preferably > 95%, or the cast block is formed by hot rolling to a billet at temperatures between 900°C and 1300°C, and subsequently formed to a wire by cold drawing, wherein the degree of cold deformation by cold drawing is > 40%, preferably > 80%, preferably > 95%.