DE1408979A1 - Process for the production of sheet metal from magnetic alloys - Google Patents

Description

YfESTIEGEOUSE ELECTRIC Hanau, the

COFPOEATIOH Dr. Schz / H

East Pittsburgh, PA / USA.

Process for the production of metal sheets from magnetic alloys

1408979 -7. NOV, 1961

This invention relates to a method of making cobalt-iron alloys which have improved have magnetic properties «

Cobalt-iron magnet alloys with a relative pick Kobaite contents possess remarkable properties that make these alloys suitable for many applications, especially for • Making aircraft very suitable »These special properties are 1) a high saturation induction, which it enables the weight and size of the magnetic cores to be greatly reduced, 2.) a rectangular hysteresis loop, which results when the alloy has been produced and heat-treated in a suitable manner, so that di.e Alloys can be used, for example, for magnetic storage devices, 3>) a high Curie temperature, by .the alloy at increased ambient temperature?. "? · be used know »

The alloys with a high cobalt content currently used tend? however, to a well-trained organizational structure form ·; representing the physical properties' of the alloy to a considerable extent. About the formation of the red structures in the high cobalt content To avoid this, rather complicated heat treatments have been developed. In addition, since these alloys have a If they have a cobalt content of 50 and more percent, they are so expensive, if only because of the high iCobalt price, that they despite their better magnetic properties, have only a relatively limited field of application.

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It χει the object of the invention, a relatively simple Method to indicate according to which from a cobalt iron Alloy with generally less than 50 percent by weight cobalt by vacuum melting as well as by a selected one • Heating and processing program and a magnetic field annealing a cobalt-iron sheet with good magnetic properties is produced. A particular concern of the invention is to create a cobalt-iron sheet that, in the form of toroidal cores, creates a hysteresis loop with a high Degree of squareness and, with a high plus density, has low Yi'att losses at 400 Hz «

For a better understanding of the invention, reference is made to the following description and the drawing in which the plus density versus the Y / att losses of various Alloys is applied, both for alloys according to the invention, as well as for an alloy according to .der. previous JLrt.

The invention aims at a method that includes controlled melting and heat treatment. which, among other things, provides for cooling in a magnetic field; Furthermore, on sheets of high-purity cobalt-iron alloys, .d.i_§-, basically contain less than 50 fo cobalt and are good. have magnetic properties. The magnetic sheets according to the invention are used in particular with a thickness of 0.05 to 1.27 mm. :

According to the method of the invention, magnetic sheets are made from alloys consisting of 25 to 45 percent by weight cobalt, up to 5 percent by weight vanadium and / or chromium, the remainder being iron with small amounts, negligible impurities _o The most favorable amount of vanodine and / or chromium additives is 0.5 to 2 percent by weight ». Small amounts of normally unavoidable .impurities such as nickel, carbon, sulfur and phosphorus may appear in the alloys of this invention. On the one hand, nickel becomes common in these alloys

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Not considered a harmful impurity "and could be included in amounts up to $ 0.2 with some benefits. On the other hand, carbon, sulfur, and phosphorus are interfering impurities, and the total of these elements should not exceed 0.02" - traces of other impurities such as oxygen, nitrogen and the like may be present. The starting materials cobalt, iron, chromium and vanadium for the production of alloys according to the invention must be of a high degree of purity «

The method of this invention includes the following steps at: "

The melting of the various alloy constituents to form an alloy, while a negative pressure is maintained during the molten state in order to reduce the impurities. The alloy is then poured into a mold. Thereafter, the ingot is heated at 950 to 1200 ⁰ C under a protective atmosphere. The method further comprises hot rolling the ingot into strips 1.27 mm to 6.5 mm thick; a reheating of the thus deformed strip at tempereturen 850-1000 ⁰ C for 1 to 10 minutes; rapid stripping of the strip in order to produce a ductile structure and thereby facilitate the cold working of the strip; This method also includes a final annealing of the sheet or the cores at 850 to 95O ⁰ C for about 10 minutes to 4 hours in a dry hydrogen atmosphere, which has a dew point of -45 C or less. Thereafter, the heated sheets are cooled in a magnetic field with the field strength of at least 1.5 Oe at a rate of 1 ° to 5 ° C / LIinute a ^ temperature range of 550 to 75O ° C, then rapidly in about 10 minutes to 200 ⁰ C cooled. It has been shown that to carry out the expiry of the aforementioned

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Alloys such are particularly suitable with about 27 ^ ₃ 35? ° or 43 $ cobalt _a too binary alloys have been successfully produced, but showed this inferior physical properties, making their field of application is limited. The ternary alloys, which, in addition to cobalt and iron, also contain vanadium and / or chromium, on the other hand, have many possible uses because of their excellent physical properties.

Alloys of this invention show their best magnetic properties when the final anneal is done in the alpha region. The alpha range for these alloys is at a temperature that does not exceed 950 C. The ordering phenomenon in these alloys is also not quite as pronounced as in alloys that have 50 $ cobalt, because the orderly state decreases with decreasing cobalt content. However, an order in these alloys is usually occur if they are kept for a long time above about 300 or '35O ⁰ C and below the temperature range of 550 to 75O ⁰ C. The exact determination of these temperatures depends on the composition of the alloys = therefore higher cooling speeds are required? -; of at least 10 ⁰ C to 20 ° C / minute to be used if the sheets ^{are to be cooled after exposure at 550 to 750 0} C, 3CO to 55O ⁰ C or to room temperature. This suppresses the order and prevents the detrimental effect of this effect on ductility.

The amount of deformation in the hot and cold processing steps is not critical. It is only necessary to ensure correct handling of the Material and to ensure that the desired final dimension is achieved. As far as the melting process is concerned, will either inductive vacuum melting or vacuum light torch: - melting applied.

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With regard to the field strength in the magnetic field annealing, it is in principle necessary that the applied field strength exceeds the coercive field strength of the material «The amount of 1.5 Oe is satisfactory for these alloys, but 10 to 15 Oe or more can also be used with good results.

To illustrate the essence of the invention, alloys with cobalt contents of 27 ^° A ₃ 35 ^c p and 43 i> were produced. These cobalt contents related 1.) to binary cobalt-iron alloys, 2.) cobalt-iron alloys with about 1 ° p vanadium, and 3 =) cobalt-iron alloys with about 1 ^c ß> chromium »Further additions were made not added "The analysis of these cast-iron blocks can be found in Table I"

Table I.

Block _{Co Pe} Cr V Ki C '.SP

1522, 27.0 71.5 - - 0.08 Q, .0016 0.0042 0.0005

'15 .23 '25.9 71.1 0.95 - 0.11 0.0007 .0.0038 0.0005

1524 26.9 71.0 - 1.21 0.12 0.0009 0.0033 0.0005

1525 x 35.0 64.1 - - 0.09. 0.0006 0.0029 O ₅ OOO5

1526 33.7 63.4 0.97 - 0.04 0.0013 '0.0038 0.0005

1527 34.7 63.0 -. 1.42 0.11 0.0011 0.0033 0.0005

1741 43.0 56.9 - 0.06 0.0020 0.0005 0.0005

1566 42.5 56.4 0.97 - 0.13 0.0013 0.0007 0.0005

1567 42.5 56.2 - 1.03 0.14 0.0014 0.0009 0.0007

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In order to obtain the desired good properties of the magnetic materials, iron, cobalt, chromium and Vanadium of the highest purity from commercially available electrolyte grades used. The ITickel is as an impurity listed because it is not a desired part of the alloy, but difficult to do with cobalt is to be separated because it is always associated with this in the ores occurs.

- All alloys for the cast ingots listed above were melted inductively in a vacuum in magnesium oxide crucibles under reduced pressure in a helium-containing atmosphere. The batch was placed in the crucible before heating and the vacuum was maintained until shortly before the batch was melted. At the start of melting, a small amount of helium was let into the furnace space. The melt was poured into tabular molds in order to eliminate the soldering speed of any forging process before hot rolling. Once the lost head has been removed from the ingot, what remains is a tabular ingot that is suitable for further processing.

One part each of the ingots obtained in this way was hot-rolled into strips with a thickness of approximately 0.23 cm. In most cases this has been done without an intermediate anneal to avoid grain growth. Almost all cast ingots were heated prior to hot rolling up to 1000 ⁰ C, either under argon or under hydrogen as protective gas. · For some of the cast ingot, which tended to become brittle during subsequent stitches at Eeißwalzen was a temperature of 1100 ⁰ C applied.

After Eeißwalz.en all tapes were heated at 900 ⁰ C and quenched in ice-salt water in order to achieve a ductile structure. This intermediate annealing takes 2 to 5 minutes in a hydrogen or argon atmosphere. After quenching, the strips were prepared for cold rolling by placing them in a solution of hydrochloric acid and

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Nitric acid have been pickled cleanly. The - ^ changes were cold-rolled into sheets 0.01 cm thick and individually cut into strips 0.63 cm wide, the rest cut into 1.27 cm wide stripes. Every roll was done without pulling.

The 0.01 cm thick strips were deburred, degreased and isolated with magnesium oxide. ^R were prepared from the strip then "-ingkerne wound The Kerne.wurden in dry hydrogen having a dew point of -45 ° to 0 or heated lower ,, The heat treatment was carried out at temperatures of 850 to 95O ⁰ G, and indeed in some while" a Duration of about 10 minutes and for others a period of 3 hours. ! laughing heating was the core ait a controlled rate of 2 ° C / minute in a field of 10 Oe cooled, had fallen to the temperature between 550 and 75O ⁰ C. The cores were then rapidly cooled to room temperature at such a rate that a temperature of 100 ^° C. was reached in 10 minutes or less. The rapid cooling "also took place in a magnetic field of about 10 Oe.,

The saturation induction, which for pure i-isene is about 21,000 Gauss, is approximately 24,000 Gauss for the alloys of this invention and is therefore of great practical importance for them. The high saturation induction enables the size of magnetic elements to be reduced noticeably. The magnetic properties of the nuclei were examined numerically, both under static conditions as gz- even when Freq.uenz of 400, ■ the core losses to determine ₅ the checks carried out with direct current showed that for all samples the hysteresis loops through the magnetic annealing had obtained good squareness. The amount of squareness of the hysteresis loops - ~ is at least 70; S. Here, B ₁ means the remanent induction and 3 _m the induction at the maximum field strength applied in each case. The ternary 45 ^ ige cobalt alloy shows the best magnetic properties, namely for 3 _m at a field strength of

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'50 Oe an induction of 22.63 to 22.99 kilogauss, for B ₁ -. a value of 16.08 to 17.16 kilogauss, and for E _c a value of 0.216 to 0.259 Oe, Table II provides further information on the static magnetization properties due to various heat treatments »

Table II

Static magnetic! Properties of cores

Block annealing 3 at 50 Oe 3 _r .Ii ₀ ITr. _ time_ ± n_ic & i2_ * S ^ iE_2 ^

15.84 0.398

'16.47 0.573

14.50 0.571 15.39 0.663

13.60 0.602

16.02 0.6l9

13.51 0.24 '■ 15.60 0.4'i'i

14.83 0.350

17.08 0.394

15.52 0.396 16.56 0.378

14.29 0.281

1522 3
10 hours
Minutes hours
Minutes 19.96
19.97 1523 3
10 hours
Minutes hours
Minutes 19.56
18.90 1524 3
10 hours
Minutes 19.76
19.19 1525 3
10 hours
Minutes 21.00
22.16 1526 3
10 hours
Minutes 21.99
22.67 1527 3
10 hours
Minutes 21.25
22.00 1741 10 mins
(1.27 cm
Stripes
2.5 χ 1.9
Core) 22.27
cm 1566 ■ ζ.
10 22.87
22.63 1567 3
.10 22.99
22.93

16.08 0.238 16.36 0.216

16.63 0.259 17.16 0.216

The first core of every alloy, with the exception of Ur, -174'ί, had an outer diameter of 2.22 cm and an inner diameter of 1.90 cm, while the second core had a; Outside diameter of 2.54 cm and an inside diameter of one 1.90 cm. All kernels were sue 0.63 cm wide Strip made, '"

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In the alloys according to the invention the treated .wurden _/} showed a coercive force of '.naχ 1 times C, 7 Oe ..

When these materials were annealed without a magnetic field, the static properties were significantly inferior. For example, the coercive field strength in the alloy with 43 f 'cobalt increased from 0.216 to 0.958 Oe and the remanence fell from 17.16 to 6.8 kilogauss. Alloy concentrations measured> The annealing treatment in a magnetic field is essential if the best properties are to be achieved Coercive field strength was lower in the case of constant annealing, while the remanence was higher after annealing for 10 minutes. The above static properties of high-purity, magnetically annealed alloys have been significantly improved compared to the usual commercial alloys. Alloy with a cobalt content of $ 27 and 1.80 Oe for a cobalt-iron alloy with a cobalt content of 355 »· Lie commercially available materials are not annealed in a magnetic field and contain substantial amounts of the usually disruptive. Impurities, which then react unfavorably to the magnetic field annealing »

Also the dynamic properties of the ternary alloys v / earth is significantly improved by the method according to the invention ο This is shown in Table III »

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Table III

Core losses from cores made of Kob ^ lt-Eieen alloys at 400 Hz after an increase of 10 minutes

Block-core losses_inJ ^ att / k ^ _in_an_induktiOn_of

ilro 10 TzG 12 IcCr "14 IcG 16 IcG 17 IcG 18 IcG

1522 14.57 23.02 30.38 40.30 43.28 52.33 1523 14.04 21, 11 27.16 38.05 1524 12.19 19.62 26.32 38.03 50.57 1525 18.01 25.15 44.40 53.22 1526 10.91 13.60 16.27 21.65 28.26 1527 11.33 19.73 24.74 33.53 1741 17.75 24.16 33.33 42.81 50.18 1566 10.60 13.18 16.31 18.28 25.88 1567 10.63 15.60 16.69 19.86 25.39

These cores had an outside diameter of approx. 2.54 an inside diameter of 1.90 cm with a strip width of 0.63 cm, except for the batch Hr. 1741, in which the Strip width was 1.27 cm.

It can be seen from Table III that the "core losses at 400 Hz for all alloys are less than 54 W / kg at the flux density of 16 to 18 kilogauss of particular interest. In the case of the ternary cobalt-iron alloy, 27 I fall> cobalt all core losses at 400 Ez below 51 W / kg. With the ternary cobalt-iron alloy with 35 ^ cobalt, all core loss values fall below 34 W / kg. With the ternary cobalt-sisen alloy with 45 ⁰ A cobalt, all core loss values fall below 26 W / kg

The core losses at 400 Hz. For some alloys according to of the invention are given in the graphical representation of the drawing. For comparison, the graphic

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Representation of the watt loss of two commercially available alloys. The three curves for the alloys according to the invention relate to ternary alloys which each contain an addition of 1 ^ chromium. In the case of the ternary cobalt alloy with 27 $ cobalt, the improvement achieved by the invention is special clearly seen ο the drawing further shows that the vacuum molten magnetfeldgeglühte cobalt-iron alloy prof ^ has 27 ^c ß> cobalt core losses, which are half as large as the open molten, not magnetfeldgeglühte ₅ commercially available cobalt-iron alloy with 27 "p Cobalt-comparable improvements have been obtained for the cobalt-iron alloys of the invention rait 35 i" cobalt "and 43 ';' * 3'zobait / 'igen cobalt-Zicen alloys lower losses than the commercially available silicon-sisen alloys with a preferred magnetic direction.

The time for the intermediate annealing after the ice processing also has a certain influence on the cold working. workability from. A disordered structure is necessary in order to obtain a good ductility ^{after quenching the intermediate annealed 1 strip} In the temperature range of disordered structure, this structure is retained even at temperatures of cold rolling. However, if the material remains too long in this range, the ductility is impaired, although a disordered structure was achieved. As mentioned earlier, an intermediate anneal of 1 to 10 minutes gives good results, and an annealing time longer than this should be avoided.

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Me made according to the invention from magnetic sheets Cobalt-i-isene alloys can be processed in such a way that they can be used as components in electrical equipment. These magnetic sheets can with advantage used in magnetic core assemblies for transformers and rotors. The high induction available This alloy reduces the size and weight of the magnetic components Example achieved a size reduction by more than 25? S which is of particular advantage with regard to the construction of plug-in tools »The one after the process Magnetic sheets produced according to the invention have good properties even at elevated temperatures, which allow them to work in an environment where most other lagging alloys already seriously to be harmed »

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Claims (1)

Claims 1 _; Process for the production of metal sheets from magnetic alloys, characterized in that alloys of 25 to 45 percent by weight cobalt, up to 5 / 'vanadium and / or chromium and a residual content of iron and harmful impurities such as C, S and P ₉ do not exceed O ₃ 02 ^c / j , preferably melted in vacuo and the cast ingots obtained are subjected to a heat treatment under protective gas at 950 to 1200 ⁰ C, so that a hot orphan is then carried out under protective gas, which is subjected to intermediate annealing. Protective gas of 1 to 10 minutes duration at 850 to 100O ⁰ C and a quenching of the alloy with subsequent pickling and cold rolling with degrees of degradation of at least 50 ^c 'o , followed by a final annealing at 850 to 95O ⁰ C for a period of 10 minutes for 4 hours in a - ^ tT ocphere of dry hydrogen with a dew point of -45 ° C or less, and that the alloy from the temperatures of the final annealing in a magnetic field with a field strength of up to 10 Oe or more and a speed cooled from 1 ° to 5 ° C / minute up to temperatures of 550-750 ⁰ C and then at speeds of more than 10 ^o-C / i \ iinute is cooled ο 2, method according to claim 1, characterized in that the melting!; · ?! Suppression takes place in a helium-containing atmosphere. 3 »Process according to claims 1 and 2, characterized in that that argon or hydrogen is used as a protective gas will ο 4. Process according to Claims 1 to 3, characterized in that preferably for the intermediate annealing a period of 2 to 5 minutes' is selected » 8 0 9 8 0 3/0 4 9 7 ^ 0 \ ΛΟ pRlGiNL .If process according to claims 1 to 4, "characterized in that the heat treatment yo.i the Eeißwolsen at about 1000 C and the intermediate annealing before the cold rolling at about 900 ⁰ C made" ο Method according to claims 1 to 5>. characterized in that the degree of deformation ^{: <in the} case of cold rolling, preferably 80 to 98 ^c ß> selected, v / ir.d. 7 «Process according to claims 1 to 6, characterized in that the cooling takes place in the magnetic field. ·· at a field strength of at least 1.5 Oe. '· ■' ■ 809803 ^ 0 ^ 9 ^ _r .