JPH0472015A - Production of soft-magnetic foil having high saturation magnetic flux density and excellent in workability - Google Patents

Abstract

PURPOSE:To produce a soft-magnetic foil having high saturation magnetic flux density and excellent in workability by forming a molten Fe-Co alloy having specific Co content into a foil by means of rapid solidification, exerting reheating, and then carrying out rolling while specifying the initiating temp. and finishing temp. of rolling. CONSTITUTION:A molten Fe-Co alloy containing 25-65% Co is continuously supplied onto a cooling body having a cooling surface renewably moving at high speed to undergo rapid solidification, and the resulting foil is subjected, successively or after reheating, to rolling at >=600 deg.C rolling initiating temp. and <=550 deg.C rolling finishing temp. Further, it is preferable that a couple of cooling bodies having cooling surfaces renewably moving at high speed in a state in contact with each other, respectively, is used as the above cooling body and the temps. of respective cooling surfaces just before these cooling surfaces become in contact with the molten alloy are regulated to >=100 deg.C, and it is also preferable to apply forced cooling to the foil immediately after the finishing of rolling.

Description

[Detailed description of the invention] (Industrial application field) This invention has high saturation magnetic flux density and good soft magnetism,
Moreover, the present invention relates to a method for producing a high saturation magnetic flux density soft magnetic ribbon with excellent workability.

(Prior Art) In recent years, there has been an increasing demand for higher performance and smaller size of electrical equipment, and along with this, there has been a demand for improvements in the characteristics, particularly magnetic flux density, of magnetic materials used in such electrical equipment.

Conventionally, soft magnetic materials with high saturation magnetic flux density include
Fe=Co alloys containing about 30 to 50-t% (hereinafter referred to simply as %) of CO are known (e.g., Japanese Patent Application Laid-Open No. 132424/1982), but this alloy system has particularly good soft magnetic properties. Because it has a good composition centered on 50% Co and is formed into an ordered lattice, it is extremely brittle, and therefore has the disadvantage that cold working such as rolling, shearing, punching, and bending that is performed during commercialization is extremely difficult. Therefore, efforts have been made to improve workability by adding V, Cr, etc. and rapidly cooling by water quenching to suppress the formation of regular lattices, but even so, cracks are likely to occur during processing due to the above-mentioned embrittlement. This resulted in a significant decrease in yield.

In addition, in recent years, a method of directly thinning difficult-to-process materials by the so-called liquid quenching method has been implemented, but even the Fe-Co alloy ribbon obtained by this liquid quenching method has problems such as cracking during processing. I couldn't escape it.

(Problems to be Solved by the Invention) The present invention advantageously solves the above-mentioned problems, and is capable of rolling, shearing, The purpose of the present invention is to propose an advantageous manufacturing method of FeCo-based soft magnetic ribbon with high saturation magnetic flux density, which has excellent workability such as punching and bending.

(Means for solving problems) First, the background to the elucidation of this invention will be explained.

Now, Fe-Co alloys have a maximum temperature of about 730"C in the composition region centered on Fe - 50% Co, and as the composition deviates from 50% Co, an order/disorder transition occurs at a temperature that decreases. Below the temperature, the B2 type ordered phase becomes stable. However, this ordered phase is extremely brittle and is extremely difficult to cold work, not only when using the steel ingot rolling method, but also when directly making plates by applying liquid phase and cold processing. Difficult.In order to avoid the formation of this ordered phase, rapid cooling from a temperature above the order/disorder transition point is considered effective, but since the rate of formation of the ordered phase is extremely fast, embrittlement cannot be completely suppressed. This results in frequent plate cracking during machining.

Therefore, the inventors conducted extensive research to improve the workability of such alloy ribbons, and as a result, they obtained the knowledge described below.

(1) The degree of ordering is relatively small below the ordered/irregular transition temperature and up to around 600°C. In this temperature range, processing such as rolling is not only possible, but also an ordered lattice is formed due to plastic deformation caused by this processing itself. is suppressed, making it possible to process at even lower temperatures.

(2) When manufacturing a ribbon using the liquid quenching method, the above rolling process may be performed either immediately after liquid quenching or after reheating, and during liquid quenching, the ribbon is solidified by the cooling body itself. Equivalent results can be obtained by adding rolling.

(3) In any of the above cases, the effect on rolling workability can be improved by increasing the temperature of the cooling surface of the cooling body.

(4) Better workability can be obtained by forcibly cooling the ribbon immediately after rolling.

This invention is based on the above knowledge.

That is, in this invention, a molten Fe-Co alloy containing 25 to 65% of co is continuously supplied onto a cooling body whose cooling surface is updated and moved at high speed, and is rapidly solidified into a thin ribbon. This is a method for producing a high saturation magnetic flux density soft magnetic ribbon with excellent workability, which comprises performing a rolling treatment at a rolling start temperature of 600° C. or higher and a rolling end temperature of 550° C. or lower, subsequently or after reheating.

In this invention, a pair of cooling bodies whose cooling surfaces are in contact with each other and move to update at high speed is used as the cooling body, and molten alloy is continuously supplied to the joint of the cooling bodies and rapidly solidified, and at the same time, the cooling body The thin strip that is being solidified by the pair,
Rolling may be performed at a rolling end temperature of 550° C. or lower.

Further, in the present invention, it is preferable that the temperature of the cooling surface immediately before contacting the molten alloy is 100° C. or higher.

Further, in the present invention, it is preferable that the ribbon is forcedly cooled immediately after rolling is completed.

Furthermore, in this invention, the Fe-Co alloy material contains Co: 25 to 65%, and also contains V, Cr, Nb, Mo, Ta, W and N.
i17) At least one selected from among: 0.05~
Particularly advantageously suitable are those containing 5.0%.

(Function) First, the reason for limiting the composition of the alloy material will be explained.

Pe-Co alloys have the highest soft magnetic properties, with the highest saturation magnetic flux density at a composition around 35-40% Co, and the highest magnetic permeability and lowest coercive force at a composition around 50% Co. Becomes good. Therefore, the composition around this can be selected for the Co content depending on the purpose, but if the Co content is less than 25% or more than 65%, it will not be possible to satisfy both the requirements of high saturation magnetic flux density and good soft magnetism. , Co content was limited to a range of 25 to 65%.

In addition, V, Cr, Nb, Mo, Ta, W, and Ni are all useful elements that suppress the formation of an ordered lattice in Fe-Co alloys and improve workability, but when added alone or in combination of the five, Even in cases where the amount added is 0.
If it is less than 0.05%, the effect of the addition will be poor, while if it exceeds 5.0%, it will not only result in a significant decrease in saturation magnetic flux density and soft magnetism, but may even deteriorate workability. It was limited to a range of 0%.

Furthermore, the Fe--Co alloy may contain the following elements.

That is, T5 Zr+ AI+ St+ Ga, Ge
and Sn is an α-phase forming element and is effective in improving magnetic properties as well as increasing electrical resistance and improving alternating current magnetic properties. In addition, "n+" Cu and Zn have the effect of improving electrical resistance as well.However, if either of these elements is added in an amount exceeding 5%, it causes a significant decrease in saturation magnetic flux density and also impairs mechanical properties. Therefore, whether added alone or in combination, the amount added must be 5% or less.

Next, the manufacturing process according to the present invention will be specifically explained.

As mentioned above, Fe-Co alloys form an ordered lattice at temperatures below about 730°C, resulting in poor cold workability, but even below the ordered/disorder transition temperature, the degree of formation of an ordered lattice is small. When rolling is started at a temperature of 600°C or higher, rolling is relatively easy, and by setting the rolling end temperature to 550°C or lower, the effect of suppressing the formation of regular lattices due to rolling can be fixed. Because you can
The rolling start temperature is 600″C or higher, and the rolling end temperature is 5
The temperature was limited to 50°C or lower.

Such rolling is carried out at a plate temperature of 600℃ following liquid quenching and solidification.
Even if you start from a temperature of 600°C or above, you can also cool the board to any temperature below 600°C and then reheat it to a temperature of 600°C.
It may be performed after the above steps, and the effect will be the same.

In the former case, any known method such as the single roll method, twin roll method or double belt method is suitable for liquid 2 and coldness, and for the ribbon obtained by rapidly solidifying the molten alloy by these methods, Rolling may be performed under the above conditions using a rolling mill provided downstream of the cooling body. Further, the melt pouring position on the roll may be directly above the roll rotation axis or not, and the melt overflow method may be used. Further, the liquid quenching roll can also serve as a rolling body; for example, in a single roll method, a planetary roll can be provided in contact with the main cooling roll to roll the ribbon immediately after quenching and solidifying. Next, when the ribbon obtained by cooling and solidifying the liquid is reheated and then rolled, the reheating and rolling after reheating may be performed on a line continuous with the liquid quenching device or on a separate line. May be processed.

The above rolling may be performed by a pair of cooling bodies at the same time as the molten alloy is rapidly solidified. In this case, the rolling start temperature is not particularly limited, but solidification must be completed by the time the ribbon reaches the end of rolling. The rolling end temperature must be 550° C. or lower for the same reason as above. As the liquid quenching method in this case, a twin roll method, a twin belt method, etc. are suitable.

In the above-mentioned liquid phenomenon, in order to improve the contact between the molten alloy supplied onto the cooling body and the cooling method, the cooling body is heated to increase the cooling surface temperature, and roll crown control is better. Although there are disadvantages such as complexity, it improves the surface properties of the rapidly solidified zone to make rolling more effective, which in turn improves the processability of the ribbon and ensures uniformity of mechanical and magnetic properties. preferred above. in this case,
If the temperature immediately before the cooling surface contacts the molten alloy is less than 100"C, the improvement effect of cooling body heating on the workability of the ribbon after rolling is small;
It is preferable to set it as above degreeC. The upper limit is not particularly limited as the applicable range varies depending on the methods described above and the material of the cooling body, etc., but it should be within the temperature range in which the molten alloy is effectively rapidly solidified and the rolling conditions described above are satisfied. Needless to say.

Further, after the rolling is completed, it is desirable to forcibly cool the ribbon immediately after the rolling is completed in order to prevent the formation of regular lattices and embrittlement due to aging. (If the rolling process is not performed immediately after the ribbon is produced by the liquid quenching method,
In order to avoid embrittlement due to aging, it is preferable to cool to 400° C. or lower, preferably 200° C. or lower. When carrying out this method, any cooling method may be used, such as air cooling, water cooling, and belt cooling.

(Example) 2 tests ± 1 Each molten alloy having the composition shown in Table 1 was made from 50 mm to a plate thickness of 0.20 to 0.48 mm by the twin roll method.
A thin ribbon was made. Then, for each steel type, the plate thickness is 20.4
Cut a thin strip of 0 mm or more and heat it at 590″C in an Ar atmosphere.
Immediately after taking out the ribbon from the furnace while keeping it warm, rolling was started, and immediately after the rolling was completed, cold water mist was sprayed onto the ribbon to cool it to room temperature.

The plate thickness after rolling was 0.20 to 0.25 mm (average rolling reduction: 50%). When the ribbon surface temperature was measured using a contact thermometer, almost no temperature drop was observed from the time the ribbon was taken out of the furnace until the start of hot rolling. The rolling completion temperature is as listed in Table 1. After this treatment, the ribbon was pickled, and an Epstein specimen with a width of 30 mm and a length of 280 mm was sheared and sampled so that the longitudinal direction coincided with the rolling direction, and the thickness without rolling was 0.20 to 0. It was subjected to repeated bending tests and magnetic measurements together with a .24 mm sample.

The repeated bending test was conducted in accordance with JIS C2550 using the sheared ribbon as a test piece.

In addition, magnetic measurements were conducted on a sheared thin strip at 87° C. in an Ar atmosphere.
After finishing annealing at 5° C. for 5 hours, the measurement was performed using a DC magnetization measuring device.

These results are shown in Table 1.

As is clear from the same table, it can be seen that by rolling the Fe--Co alloy ribbon at an appropriate temperature, the bending workability is significantly improved and excellent magnetic properties are obtained after annealing.

EXAMPLE 1 The ribbon samples of steel No. 6 prepared in Example 1 were rolled by varying the rolling start temperature and end temperature. At that time, a cooling water mist was sprayed from the exit side of the rolling roll toward the lower part of the ribbon to perform rolling, followed by cooling to room temperature. After this treatment, the Epstein test piece was sheared and sampled from the pickled ribbon and subjected to repeated bending tests, and a portion of the sample was separately sampled and rolled to a thickness of 0.1 om at room temperature.

The results obtained are shown in FIG.

As is clear from the figure, particularly good repeated bending properties and cold rollability are obtained when rolling is carried out according to the present invention at a rolling end temperature of 2,600°C or higher and a rolling end temperature of 550°C or lower. There is.

For comparison, it has the same component composition as Steel No. 6,
Similar repeated bending and rolling tests were conducted on a pickled sample of a thin strip with a plate thickness of 0.23 mm after rapid solidification, and the number of repeated bending was 0, and the number of repeated bending was 0 and 1 stroke. Rolling up to that point was impossible due to plate cracking.

It is clear from this example that the improvement in bending properties and cold rollability is not simply due to the reduction in plate thickness, but is due to the hot rolling effect according to the invention.

It was confirmed that the same results as above were obtained for other steel types as well.

Example 1 Thin strips were produced from 30 molten alloys having the same composition as the steel Nα6 of Main Example 1 by a twin roll method using a pair of rolls whose cooling bodies were made of Fe. At this time, the heating element provided close to the cooling roll is controlled so that the temperature of the cooling surface immediately before contacting the molten metal is 70 to 250°C, and
Rolling was carried out by applying a reduction blade of 1.5 ton/cm to the roll joint.
A comparison was made with a case where a rolling blade of 5 ton/cm was applied. The pouring position was directly above the joint of the cooling roll. The rapidly solidified ribbon was cooled to room temperature by being sprayed with cooling water after being separated from the twin rolls.

Among the ribbon samples prepared in this way, those prepared under conditions in which the cooling roll release temperature, that is, the rolling end temperature, was 480 to 530°C were cut, and after pickling, the Epstein test pieces were collected by shearing. It was subjected to repeated bending tests and magnetic measurements. The repeated bending test was performed in the same manner as in Example 1, and the magnetic measurement was performed after the test piece was annealed at 875° C. for 15 hours in an Ar atmosphere.

The results are shown in Table 2.

As is clear from the table, heating the cooling roll improves the bending resistance and magnetic properties after annealing, and rolling the thin strip that is solidifying with the cooling roll also improves the bending resistance and the magnetic properties after annealing. Later magnetic properties could be improved.

Implementation ■ 2000k each of molten alloys with the composition shown in Soil Table 3
Thickness: 0.30-0.33 from g by twin roll method
A thin strip of Peng was made. A pair of rolls made of Fe is used as the cooling body, and the heating body placed close to the cooling roll allows
The temperature of the cooling surface immediately before contact with the molten metal was controlled to an average of 200°C. The rapidly solidified ribbon is immediately rolled to 0.22 to 0.25 Mn (average reduction rate 2) by a rolling mill installed in the same line.
5%). At that time, the rolling start temperature is set at 620 to 670°C by spraying a cooling water mist onto the ribbon that has left the twin rolls, and the rolling end temperature is set by spraying cooling water from the exit side of the rolling rolls toward the lower part of the ribbon. 530
℃ or below, and continue cooling to 150℃.
Reeled below.

Next, the ribbons obtained as described above and the ribbons having a thickness of 0.21 to 0.25 mm after rapid solidification and wound up at 150°C or less without being rolled were pickled and then rolled out. 410 ring-shaped test pieces with a diameter of 45 mm and an inner diameter of 33 mm were continuously punched out for each coil, and after degreasing the 1st to 10th test pieces and the 401st to 410th test pieces, they were heated at 900°C for 110 hours in a hydrogen atmosphere. Annealing was performed.

The maximum magnetic permeability measured by stacking 10 test pieces thus obtained is also listed in Table 3.

From the same table, it is clear that the rolled samples exhibit better magnetic properties than the unrolled samples.

Further, in the rolled sample, almost no deterioration was observed even after repeated punching, whereas in the unrolled sample, the punching performance deteriorated significantly.

From the above results, it is clear that rolling the ribbon significantly improves its punching workability, and that it exhibits excellent soft magnetic properties after final annealing.

(Effects of the Invention) Thus, according to the method of the present invention, it is possible to significantly improve the cold workability of Fe-Co alloy ribbons having particularly excellent magnetic properties and in the composition range, thereby preventing a decrease in yield during processing. can be prevented, and its industrial benefits are enormous.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between rolling start temperature and rolling end temperature on the number of repeated bending times and cold rollability.

Claims (5)

[Claims] 1. A molten Fe-Co alloy containing 25 to 65 wt% of Co is continuously supplied onto a cooling body whose cooling surface is updated and moved at high speed, and then rapidly solidified into a thin ribbon, either continuously or after reheating. , rolling start temperature:
A method for producing a high saturation magnetic flux density soft magnetic ribbon with excellent workability, which comprises rolling at a temperature of 600°C or higher and a rolling end temperature of 550°C or lower. 2. In claim 1, the cooling bodies are a pair of cooling bodies whose cooling surfaces are in contact with each other and move for renewal at high speed, and the molten alloy is continuously supplied to the joint portion of the cooling bodies to rapidly solidify it, and at the same time A method for producing a high saturation magnetic flux density soft magnetic ribbon with excellent workability, in which a solidified ribbon is rolled by a pair of cooling bodies, and the rolling end temperature is 550°C or less. 3. 3. The method for producing a high saturation magnetic flux density soft magnetic ribbon with excellent workability, wherein the temperature of the cooling surface immediately before contacting the molten alloy is 100° C. or more according to claim 1 or 2. 4. 4. The method for producing a high saturation magnetic flux density soft magnetic ribbon with excellent workability, wherein the ribbon is forcibly cooled immediately after rolling. 5. In Claim 1, 2, 3 or 4, the Fe-Co alloy contains Co: 25 to 65 wt% and at least one selected from V, Cr, Nb, Mo, Ta, W and Ni: A method for producing a high saturation magnetic flux density soft magnetic ribbon containing 0.05 to 5.0 wt% and excellent workability.