JPS5842751A - Amorphous iron alloy having small iron loss and undergoing very slight change in magnetic characteristic due to aging - Google Patents

Abstract

PURPOSE:To obtain the titled alloy having reduced iron loss and enhanced thermal stability by adding prescribed amounts of Fe, Si, B and C. CONSTITUTION:The titled alloy has a composition represented by a formula FeaSibBcCd (where a=77-79 atomic%, b=8-12%, c=9-11%, d=1-3% and a+b+c+d=100%). The alloy is melted, spouted on a rotating roll or drum, and cooled to continuously obtain a thin strip by a single roll method, a centrifugal rapid cooling method, a twin roll method or other method. The thin strip is heat treated at a temp. below the crystallization starting temp. in a magnetic field or under tension. The iron loss of the iron core of a power transducer using the resulting thin film is reduced, and the core has enhanced thermal stability.

Description

[Detailed Description of the Invention] The present invention mainly relates to power transformers, current transformers,
This invention relates to an amorphous alloy with extremely low core loss and good thermal stability, which is used as the core of power converters such as high-frequency transformers and reactor bottles.

The magnetic properties required of iron core materials include low core loss and good excitation properties. In particular, iron loss is caused by heat in the core that is excited by alternating current.

It is said that the amount of electricity wasted day and night around the world is enormous.

In addition, in high-frequency transformers, heat due to iron loss increases the temperature of the magnetic core, resulting in many design constraints such as material selection and operating magnetic flux density. Currently, silicon steel sheets, thin silicon steel strips, ferrite,
Nodermalloy, iron powder, etc. have been used depending on the specific application, but there has been no material that satisfies the properties of glutinous properties and salmon-saving properties in a wide range of application fields.

However, in recent years, a method has been developed to create alloy ribbons with a random (asynchronous) structure similar to that of liquids by ultra-rapidly cooling metals from a high-temperature molten state called amorphous metals. This material has attracted attention because it has no anisotropy in principle, has high electrical resistance, can be easily made thin, has low iron loss over a wide frequency band, and has good excitation characteristics. However, for electrocadrence applications, the saturation magnetic flux density is B.

It has disadvantages such as being considerably lower than that of silicon steel sheets and having poor thermal stability, which has been considered a problem for practical use. Therefore, various studies have been made on the component composition in order to increase the saturation magnetic flux density.
Inventions such as Japanese Patent No. 58251 and Japanese Patent No. 54-148122 have been proposed.

However, the value of B at room temperature is still slightly higher than 17 KG, which is lower than the 20 KG of silicon steel.Furthermore, all known alloys with high B compositions have a B value of 17 KG at room temperature. The rate of decline is large at temperatures ranging from 150°C to 150°C, and the magnetic flux density at the temperature used drops to about 15-16 kg, and the difference with silicon steel widens again. Furthermore, currently known alloy systems such as those mentioned above have the disadvantage of low thermal stability. Therefore, in order to take advantage of the characteristics of amorphous alloys, it is practical to find an alloy system that further lowers the core loss, which is low in principle, and improves thermal instability, which is a common drawback of amorphous alloys. It is.

The present inventors investigated the magnetic properties and thermal stability of many alloy compositions and found that there is a correspondence between compositions with low iron loss and compositions with excellent thermal stability. A composition with high thermal stability can stabilize the amorphous structure by heat treatment, and at the same time improve iron loss. It was discovered that a higher heat treatment temperature can be used than with thermally unstable compositions, which has a large effect on iron loss improvement.
The application was filed as No. 32345. These are F., 81bB
, Cd, in which a, b, a, and d are each in the following range in terms of the number of atoms.

11-74~79 b; 8~19 C-σ~13 dxQ~3.5 However, a + b + a + d = 100 The present inventor has evaluated the thermal stability of amorphous alloys in these composition ranges. After further investigation, we discovered an alloy composition that can guarantee stable magnetic properties for several years.

That is, the present invention is F., 51bB1! A substantially amorphous alloy represented by the chemical formula cd, &@b
# amd is in the following range with the number of atoms -.

a Engineering 77-79 b-8-12 e=9-11 a-1-3 However, h + b + e + d -100 Especially preferably F.7! The composition is l''1°B,.C2.

Amorphous alloys that meet these chemical requirements are listed in Tables 1 and 2.
As shown in the table, even at 200°C, which is much higher than the normal operating temperature of a transformer, the change in magnetic properties over time is extremely small compared to those outside the composition range of the present invention. At the same time, the amorphous alloy has a high ability to form an amorphous state (ease of becoming amorphous), so it is easy to make a thick line, and there is no change in properties in the longitudinal direction of the gun. It also has the characteristic of being small, which is extremely advantageous in practice.

Method for manufacturing the amorphous alloy of the present invention As mentioned earlier, a molten alloy is injected and collided with the outer or inner wall of a rotating roll or drum, so that one side is formed.

Any of the known methods of continuous production may be used, such as a method of cooling from a single roller (single roll method and a centrifugal quenching method) or a method of cooling from both sides between a pair of four rolls (a twin roll method).

The rapidly cooled ribbon is generally left as is (as Ca5t)
Since it does not exhibit sufficient properties in this state, it is usually heat treated at a temperature below the crystallization initiation temperature to improve magnetism.

To make the heat treatment more effective, rounding is preferably carried out in a magnetic field or under tension.The characteristics of the alloy of the present invention also appear in the effect of heat treatment. That is, since the crystallization initiation temperature is much higher than that of conventional high magnetic flux density alloys, high heat treatment temperatures can be used. A high heat treatment temperature makes it possible to sufficiently remove the strain remaining after cooling, and as a result has the advantage of a large reduction rate in iron loss. For example, for conventional materials, Tokukai Sho! 38 as disclosed in Publication No. 55-158251
Whereas it was necessary to heat treat at a temperature below 5℃,
The alloy of the present invention allows heat treatment at high temperatures up to 430'C.

Next, examples of the present invention will be shown.

Example 1 Chemical formula F.yas'. B. An alloy designated by C2 was heated to 1100°C, which is approximately 100°C higher than the liquidus temperature of this alloy, and rapidly cooled on the surface of a single steel roll for cooling. The obtained thin strip is! Charge 2C)is width was about 3001. Magnetic properties of the obtained ribbon after annealing in a magnetic field and 20
Table 1 shows the magnetic properties after 2000 hours at 0°C. However, the annealing conditions were a magnetic field of 300Φ, 390°C for 30 minutes in hydrogen. tt magnetic properties are sample size 20 width x 1
The distance was 20 m, and measurements were taken using a single plate measuring device. 21st M! It can be seen that the change in magnetic properties is extremely small compared to the 9th comparative example.

Example 2 After melting the raw materials blended to have each composition in Table 2,
It was rapidly cooled from a temperature 50 to 150° C. higher than the liquidus temperature in the same manner as in Example 1 to obtain an amorphous alloy ribbon. The magnetic properties of the obtained ribbon and the magnetic properties after 2000 hours at 200°C are shown together with comparative examples. As is clear from these results, the core loss and stability of the amorphous alloys having compositions within the range of the present invention are extremely superior to those of the comparative examples. % deterioration of iron loss is small.

As explained above, according to the present invention, the change in magnetic properties over time is extremely small and stable properties can be obtained over a long period of time.

Procedural amendment (voluntary) November 26, 1980 Commissioner of the Japan Patent Office Shima 1) Spring Tree Membrane 1. Display of the case 1982 Patent Application No. 140263 2 Title of the invention Low core loss iron-based amorphous alloy with extremely small change in magnetic properties over time 3 Person making the amendment Relationship to the case Patent applicant Chiyoda-ku, Tokyo 2-6-3 Otemachi (665) Nippon Steel Corporation Representative Takeshi 1) Toyo 4, Agent Published by O 2-4-1 Marunouchi, Chiyoda-ku, Tokyo

Claims (2)

[Claims] (1) A low core loss iron-based amorphous alloy with a composition of F@, 81bB, and Cd, which exhibits minimal changes in magnetic properties over time. However, "*b*6*d" is the number of atoms - a-77 to 79 b-s to 12 6 w 9 to 11 d depth 1 to 3 a + b + e + d = 100. (2) A low core loss iron-based amorphous alloy with extremely small changes in magnetic properties over time as claimed in claim 1, which has a composition of F.78"1°"1Oc2.