CN1854322A - High-purity ferroboron - Google Patents

Abstract

The present invention provides a high-purity ferro-boron alloy, which is characterized in that it contains P: 0.02% by mass or more, Al: 0.03% by mass or less, and the rest is composed of Fe, B and unavoidable impurities, and the high-purity ferro-boron alloy It is prepared by the following method. The method is to load a boron source, an iron source and a carbon-based reducing agent into a smelting reduction furnace to manufacture a ferroboron alloy. The iron source is steel obtained from a refining furnace, and the Al content of the steel is 0.03% by mass or less.

Description

High-purity boron-iron alloy

This application is a divisional application with the application date of March 27, 2003, the application number 03121186.0, and the invention name is high-purity boron-iron alloy, master alloy for iron-based amorphous alloy, iron-based amorphous alloy and its manufacturing method .

technical field

The present invention relates to a method for producing a high-purity iron-boron alloy used as a raw material for an amorphous alloy, a method for producing a master alloy for an iron-based amorphous alloy using the iron-boron alloy, and a method for producing an iron-based amorphous alloy using the master alloy manufacturing method.

technical background

Amorphous alloys have excellent magnetic and mechanical properties and are expected to become industrial materials with a wide range of uses. Among them, as the core material of power transformers and high-frequency transformers, iron-based amorphous alloys, such as Fe-B-Si series, Fe-B- Amorphous alloys such as Si-C series have been widely used.

These amorphous alloys can be produced by rapidly cooling and solidifying a master alloy from a molten state by a single-roll method or a double-roll method. In these methods, molten metal is sprayed from nozzles or the like onto the outer peripheral surface of a metal drum rotating at high speed, solidified rapidly, and cast into thin strips or filaments.

The master alloy is an alloy whose composition is adjusted to that of an amorphous alloy. The above-mentioned iron-based amorphous alloy is produced by adjusting the composition by mixing iron-boron alloy, diluted iron source, and auxiliary raw materials such as Si and C.

If there are impurities in the master alloy, it will not be able to stably form an amorphous state during rapid cooling and solidification, and cannot obtain excellent performance. Therefore, high-purity raw materials are used for the raw materials of the master alloy, and electrolytic iron is used for the diluted iron source.

Ferro-boron alloys have always been manufactured using boron sources such as boron oxide and boric acid, iron sources, and carbon-based reducing agents such as coke, charcoal, and fine powder carbon as raw materials, and are manufactured in smelting reduction furnaces such as electric furnaces. Electrolytic iron has been used as the iron source for high-purity ferroboron alloys.

The B content of the iron-based amorphous alloy is several mass %. Regarding the manufacture of the master alloy, two methods have been proposed. One method is to dilute the boron-iron alloy obtained by the electric furnace method with a B content of more than 10 mass %. , Another method is a method of fine-tuning the composition of ferroboron alloys with a B content of several mass % obtained by refining in a shaft furnace or ladle. In reality, the former method is used. The main reason is that the utilization rate of B in the former method is high and the cost is low. In addition, further increasing the B content will reduce the C content.

The solubility of C in ferroboron alloys is inversely correlated with the B content, and the solubility of C increases when the B content decreases. Therefore, when C is harmful as an impurity, increasing the B content is an effective means.

Japanese Patent Laid-Open No. 59-232250 discloses that the above anti-correlation relationship and the commercial production of ferroboron alloys with a B content ≥ 10 mass % and a C content ≤ 0.5 mass % are disclosed. However, in the case of producing boron-iron alloys by the electric furnace method, there are problems of high B content and high specific power consumption.

Furthermore, JP-A-59-126732 discloses a method of reducing the C content by bubbling oxygen into a ferroboron alloy melt. However, B is also oxidized by oxygen, and the utilization of B decreases accordingly. This is the problem with this method.

In addition, as a method of manufacturing a high-purity boron-iron alloy with low Al, the method of obtaining a boron-iron alloy with a B concentration of 10-20% by mass in an electric furnace has been disclosed in JP-A-59-232250 and JP-A-60-103151 public. However, when iron filings are used as an iron source, since the Al concentration contained in the iron filings is unstable, the guaranteed value of Al is <0.20% by mass. Therefore, the commercially obtained high-purity boron-iron alloys with low Al in the past are required to have a guaranteed value of Al < 0.025% by mass, so electrolytic iron is used as the iron source, so the price is expensive.

In order to obtain iron-boron alloys for iron-based amorphous alloys at low cost, a method of producing boron-iron alloys with a low B concentration without using an electric furnace has been disclosed. JP-A-58-77509 discloses a method of simultaneously reducing iron ore and boron oxide in a shaft furnace to obtain a ferroboron alloy having a B concentration of several mass %. JP-A No. 58-197252 discloses a method of adding boron oxide and a reducing agent into molten steel with a ladle refining furnace to reduce boron oxide to obtain a boron-iron alloy with a B concentration of several mass %.

However, when using these methods, unreduced boron oxide remains in the slag, and the utilization rate of B is low; and boron oxide is a relatively expensive raw material, so the use of these methods increases the cost instead. In addition, since environmental protection regulations have become stricter in recent years, high costs are required to dispose of B-containing slag, and these methods are becoming more and more expensive. These methods are considered to have an effect on reducing the Al content, but they cannot achieve the purpose of cost reduction originally envisioned. Therefore, these methods are not currently available for commercial application.

On the other hand, the current mass-produced steel can be manufactured through continuous casting process due to its high productivity and low cost. In the continuous steel casting process, in order to suppress the generation of gas, killed steel is produced. In mass-produced steel, Al is generally used as a deoxidizer, so the steel contains a considerable amount of Al. Therefore, it is considered that mass-produced steel cannot be used as an iron source for master alloys for iron-based amorphous alloys and high-purity iron-boron alloys as raw materials thereof.

However, in some mass-produced steels, Si, Mn, etc. are used as deoxidizers. In addition, with the improvement of refining technology, steels with low Al content can also be mass-produced with Al deoxidation.

JP-A No. 9-263914 and JP-A No. 2001-279387 disclose methods for producing low-cost master alloys that use steel obtained through ordinary steelmaking processes as a source of diluted iron without using expensive electrolytic iron. . That is, as impurities, expressed in mass %, when P: 0.008-0.1%, Mn: 0.15-0.5%, and S: 0.004-0.05% are contained, due to the existence of this trace amount of P, even if the contents of Mn and S reach such To a certain extent, the performance of the cast thin strip will not deteriorate.

In addition, Japanese Unexamined Patent Application Publication No. 2002-220646 discloses a method for producing an iron-based amorphous alloy thin strip. Although this method targets the thin strip after casting, it actively incorporates a specific range within a limited composition range. Even if the temperature of each part of the iron core is uneven during annealing, it can also exert excellent magnetic properties with small fluctuations in a large temperature range. This alloy can also tolerate the above-mentioned levels of Mn and S, and can also use ordinary steel as a dilute iron source.

Contents of the invention

The object of the present invention is to cheaply manufacture a high-purity iron-boron alloy that improves the recovery rate of B from boron sources such as boron oxide and reduces the C content. It is also possible to use inexpensive electrolytic iron as an iron source. The steel produced in large quantities, and the object of the present invention is also to use the obtained iron-boron alloy as a raw material to manufacture a master alloy for an iron-based amorphous alloy and an iron-based amorphous alloy with excellent properties.

In addition, the present invention provides, in particular, in iron-boron alloys used as raw materials for iron-based amorphous alloys containing P and having excellent magnetic properties, instead of using expensive electrolytic iron, cheap mass-produced steel is used as iron. source, and a way to be able to supply it stably. The gist of the present invention is as follows.

(1) The manufacture method of high-purity ferro-boron alloy, this method is the method that boron source, iron source and carbon system reductant are packed into smelting reduction furnace to manufacture ferro-boron alloy, it is characterized in that, said iron source is obtained with refining furnace steel having an Al content of 0.03% by mass or less.

(2) The method for producing a high-purity ferroboron alloy as described in item (1) above, wherein the above-mentioned smelting reduction furnace is an electric furnace.

(3) A method for producing a master alloy for an iron-based amorphous alloy, characterized in that a diluted iron source and auxiliary raw materials are added to the high-purity ferroboron alloy produced by the method described in the above item (1) or (2).

(4) The method for producing a master alloy for an iron-based amorphous alloy as described in item (3) above, wherein the diluted iron source is steel obtained from a refining furnace, and the Al content of the steel is 0.006% by mass or below.

(5) The manufacture method of iron-based amorphous alloy, it is characterized in that, by using the rapid cooling and solidification method, the molten metal of the iron-based amorphous alloy raw material manufactured according to the method described in (3) or (4) is rapidly cooled and solidified to manufacture.

(6) A high-purity boron-iron alloy characterized by containing P: 0.02% by mass or more, Al: 0.03% by mass or less, and the remainder consists of Fe, B and unavoidable impurities.

(7) The high-purity iron-boron alloy as described in the above item (6), which contains 0.03% by mass or less of Ti.

(8) The manufacture method of high-purity ferro-boron alloy, this method is the method that boron source, iron source and carbon-based reducing agent are loaded into smelting reduction furnace to manufacture ferro-boron alloy, it is characterized in that, said iron source is obtained with refining furnace A steel containing 0.01% by mass or more of P and 0.03% by mass or less of Al.

(9) The method for producing a high-purity iron-boron alloy as described in the above item (8), wherein the steel contains 0.03% by mass or less of Ti.

(10) A method for producing a high-purity ferro-boron alloy, characterized in that, after the ferro-boron alloy is produced in a smelting reduction furnace, oxygen is blown into the molten metal of the above-mentioned ferro-boron alloy under the condition that the temperature of the molten metal is 1600° C. or above to decarburize.

(11) The method for producing high-purity ferroboron alloys as described in item (10) above, wherein the above-mentioned molten metal is obtained by putting boron source, iron source and carbon-based reducing agent into an electric furnace for smelting reduction molten metal.

(12) The manufacture method of high-purity boron-iron alloy as described in item (10) above, it is characterized in that, above-mentioned molten metal is to carry out smelting reduction by putting boron source, iron source and carbon-based reducing agent into electric furnace, and then Metal melt obtained by melting boron-iron alloy solidified after smelting reduction.

(13) The method for producing a high-purity ferroboron alloy as described in the above item (11) or (12), wherein the B content in the molten metal is 10% by mass or less.

(14) The manufacturing method of high-purity ferroboron alloy as described in any one of above-mentioned (11)-(13), it is characterized in that, above-mentioned iron source is the steel that obtains with refining furnace, and the Al content of this steel is 0.03 mass % or less.

(15) A method for producing a master alloy for an iron-based amorphous alloy, characterized in that, by adding iron for dilution to the high-purity iron-boron alloy produced by the method described in any one of the above-mentioned (10)-(14) The composition of the source and auxiliary raw materials is adjusted.

(16) The method for producing a master alloy for an iron-based amorphous alloy as described in item (15), wherein the above-mentioned diluted iron source is steel obtained from a refining furnace, and the Al content of the steel is 0.006% by mass or below.

(17) A method for producing an iron-based amorphous alloy, which is characterized in that the molten metal of the iron-based amorphous alloy raw material produced by the method described in the above item (15) or (16) is prepared by using a rapid solidification method For casting.

A brief description of the drawings

Fig. 1 is a graph for illustrating the method of the present invention.

preferred embodiment

The manufacturing method of the high-purity boron-iron alloy of the present invention adopts the steel obtained in the ordinary steelmaking process as the iron source of the raw material, and the Al content of the steel is 0.03% by mass or less. Other raw materials are boron sources such as boron oxide and boric acid, and carbon-based reducing agents such as coke, charcoal, and fine powder carbon. These raw materials are charged into a smelting reduction furnace to manufacture ferroboron alloys. As the smelting reduction furnace, it is preferable to use an electric furnace from the viewpoint of production efficiency and cost.

Since inexpensive mass-produced steel can be used as an iron source instead of expensive electrolytic iron, an inexpensive iron-boron alloy can be produced. The steel used may be a slab cast by continuous casting after being refined in a refining furnace such as a converter or an electric furnace, or a steel plate that is further hot-rolled or cold-rolled. Even steel deoxidized with Al can be used as an iron source as long as the Al content is 0.03% by mass or less. Steels with lower Al content deoxidized with Si, Mn, etc. can also be used.

Experimental results show that even if Mn-deoxidized steel with an Al content of 0.001% by mass is used as an iron source, the Al content of the obtained ferroboron alloy may sometimes be as high as 0.02% by mass due to the mixing of Al from a reducing agent or the like. As long as the high-purity boron-iron alloy using steel with an Al content of 0.03 mass% or less as the iron source is used as a raw material, an iron-based amorphous alloy with excellent magnetic and mechanical properties can be stably produced.

In addition to the above, the high-purity boron-iron alloy obtained by the method of the present invention can also be used as a raw material for magnetic materials and a steelmaking additive.

Secondly, the manufacturing method of the iron-based amorphous alloy master alloy of the present invention is a method of adjusting the composition by adding a diluted iron source and auxiliary raw materials to the high-purity boron-iron alloy manufactured by the above-mentioned method of the present invention. As the diluted iron source, instead of expensive electrolytic iron, mass-produced steel obtained from a refining furnace of a steelmaking process may be used, and in this case, the Al content of the steel is preferably 0.006% by mass or less. The auxiliary raw materials are raw materials of Si, C, etc., and constituent components of the target iron-based amorphous alloy. The high-purity boron-iron alloy can be obtained in a molten state by the above-mentioned method, or can be melted in a solid state. High frequency induction furnace can be used for melting.

The composition of the master alloy should be substantially the same as that of the target iron-based amorphous alloy. At the time of manufacture, raw materials whose composition is known are blended to obtain a predetermined composition. The experimental results show that the analysis results of the fabricated master alloy hardly deviate from the pre-set specified composition.

When setting the component composition of the master alloy, the raw material mixing ratio is determined based on the main components such as Fe and B. At this time, the Al content should be set below the allowable amount for stably obtaining an amorphous alloy with excellent properties. In this case, since the Al content of the high-purity ferro-boron alloy will not exceed the maximum content of 0.03% of the steel used as the iron source, it is possible to make the Al content of the master alloy after dilution within the above-mentioned tolerance by determining the Al content of the diluted iron source. below the amount.

Experimental results have shown that even if Al is contained in the diluted iron source steel, as long as it is 0.006% by mass or less, excellent properties can be stably obtained for almost all iron-based amorphous alloys targeted.

The high-purity ferro-boron alloy production method of the present invention is a method for decarburizing the ferro-boron alloy metal melt by blowing oxygen into the melt at a temperature above 1600° C., without reducing the B content, but reducing the C content.

The present inventors have carried out in-depth thermodynamic studies and experimental studies on the conditions for reducing the C content without reducing the B content in the method of blowing oxygen into a molten boron-iron alloy with a high C content, The present invention has thus been accomplished.

The Ellingham phase diagram is widely used when easily judging the ease of reduction of an oxide, and conversely, the ease of oxidation of a pure substance. On this figure, B and C intersect at about 1900°K. Accordingly, metal B is more stable on the high temperature side, and C turns into CO; while on the low temperature side, C is more stable, and B turns into boron oxide. In fact, the temperature of the intersection point of the stability reversal depends on the activity of B and C in Fe-B-C, oxygen partial pressure, and CO partial pressure, and it is difficult to obtain it thermodynamically.

The inventors of the present invention obtained the temperature of the intersection point at which the stability reverses by experimenting with an actual molten metal of a boron-iron alloy, and obtained conditions suitable for actual operation, thereby completing the above-mentioned method for producing a boron-iron alloy of the present invention.

In the above-mentioned method of the present invention, the molten boron-iron alloy is preferably obtained by smelting reduction in an electric furnace. The reason for this is that the expensive B has a high utilization rate and high productivity. The molten metal may also be a molten metal obtained by smelting reduction in an electric furnace and then remelted after being solidified. Remelting is useful in situations where it is desired to manufacture certain ferroboron alloys with reduced C content separately from other ferroboron alloys.

In addition, in the electric furnace method, when the B content in the molten metal is high, the unit power consumption increases; since the unit power consumption rises sharply when the B content exceeds 10 mass%, the B content is preferably 10 mass% or less.

The high-purity boron-iron alloy of the present invention may contain 0.03% by mass or less of Al in addition to 0.02% by mass or more of P as described above. In addition, 0.03% by mass or less of Al and 0.03% by mass or less of Ti may be contained. The B content is not limited, and the B content in commercially available common ferroboron alloys is not less than 10% by mass, which is enough.

In terms of B content, in the case of iron-based amorphous alloys, since it can be diluted by the addition of auxiliary materials such as Si, it can be set higher than the B content of the target amorphous alloy. When aiming at the Fe-B-Si-P system with a low B content, it should just be 5 mass % or more. Furthermore, sometimes it is used as a high-B amorphous alloy and other uses, that is, as an auxiliary raw material for steelmaking or as a raw material for magnetic materials; For these uses, the B content is preferably 10% by mass or more.

The P content is required to be 0.02% by mass or more. When producing boron-iron alloys by the electric furnace method, since boron sources such as boron oxide or reducing agents such as charcoal are also mixed with P, as described in the following embodiment 1, the P content of the iron source is allowed to be slightly higher than that of the iron source. However, the weight of the iron source in the electric furnace method is the largest, and only a small amount of P is mixed from other raw materials. In the case of using electrolytic iron as the iron source, P that is inevitably mixed is usually 0.005-0.019% by mass. Therefore, the P content of the ferroboron alloy of the present invention is specified to be 0.02% by mass or more. In addition, although there is no upper limit on the P content, it is usually at most 5% by mass.

Al can be tolerated up to 0.03% by mass. The experimental results show that, in the iron-based amorphous alloy with positive addition of P, as described in Examples 2 and 3, even if such a level of Al is contained in the iron-boron alloy, the Al content of the master alloy is also reduced, and it is possible to stably obtain Amorphous alloy with excellent magnetic and mechanical properties.

The Ti content can also be tolerated up to 0.03% by mass for the same reason. Ti and Al may be contained at the same time, and their respective contents are allowable up to 0.03% by mass.

Secondly, the method of the present invention does not use electrolytic iron when manufacturing the above-mentioned ferroboron alloy of the present invention, and uses steel obtained by ordinary steelmaking processes as an iron source, and limits the content of P, Al and Ti in the steel. As the refining furnace, a converter and an electric furnace can be used; and the steel can be continuously cast steel.

P is an impurity element that has a great influence on the properties of steel; there are steel types that completely remove P to less than 0.01% by mass, such as dozens of ppm, and steel types that allow P to reach 0.01% by mass or more. The former steel requires more slag than the latter steel in order to prevent the phenomenon of P returning to the molten steel as oxides entering the slag during oxidation and refining, so the cost of removing P is high. For this reason, steel grades that dephosphorize to less than 0.01% by mass are not suitable for the purpose of cost reduction of ferroboron alloys. Therefore, the P content of the iron source steel should be 0.01% by mass or more. Furthermore, as mentioned above, when ferroboron is produced, other raw materials are also mixed in, and P becomes 0.02% by mass or more.

Al and Ti are used as deoxidizers during refining of steel, and are added as essential components in some types of steel. Ferro-boron alloys using low-Al steel deoxidized by Si and Mn as the iron source will also increase the Al content due to the incorporation of other raw materials. In addition, in the iron-boron alloy in which Al-deoxidized steel with an Al content of 0.03% by mass was used as an iron source, a slight decrease in the Al content was confirmed. Ti also has the same tendency. Therefore, the Al and Ti contents of steel as an iron source can be tolerated up to 0.03% by mass, respectively.

Next, the production method of the iron-based amorphous alloy of the present invention is a method of casting the molten metal of the master alloy produced by the above-mentioned method of the present invention by the rapid solidification method. The molten metal of the master alloy may be obtained by re-melting the master alloy in a high-frequency induction furnace or the like, or may be in a molten state produced as described above.

According to the method of the present invention, for example, a thin strip having an Al content of 0.005% by mass or less in a Fe-B-Si-C-P-based iron-based amorphous alloy can be produced. This thin strip has excellent magnetic properties.

As the rapid cooling and solidification method, a single-roll method and a double-roll method can be used.

Example 1

The 4 kinds of iron sources shown in Table 1, boron oxide and carbon-based reducing agent were melted in an electric furnace to produce boron-iron alloy. Various iron sources are steels produced from blast furnace pig iron through de-S process, de-Si process, and de-P process and de-C process by converter oxygen blowing. Steel type A is deoxidized with Si and Mn, steel types B and D are deoxidized with Mn, and steel type C is deoxidized with Al. All kinds of steel are made into slabs through continuous casting, and then hot-rolled into hot-rolled coils with a thickness of about 3 mm, and square sheets with a side length of several centimeters are cut out from various hot-rolled coils with a shearing machine. Put it into the electric furnace.

As the electric furnace, a 3-phase Heroult type electric furnace with an electric power of 600 KVA was used. The operation of the electric furnace is carried out continuously for 8 days, and the iron source is replaced in the order of B, D, A, and C every two days. The drain interval is about 2 hours, and the boron-iron alloy that is not at the time of iron source replacement is used for analysis.

For the matching of raw materials, start the operation according to the initial ratio shown in Table 2; when the operation is stable, change to the stable ratio.

The analytical values of the manufactured ferroboron alloys are shown in No.1-No.4 of Table 3. The ferroboron alloys with low Al steel types A, B, and D as the iron source increase the Al content due to the mixing of Al from the reducing agent, but it is still 0.03% by mass or less. In the ferroboron alloy using steel C with an Al content of 0.03% by mass as an iron source, the Al content slightly decreases due to the entry of Al into the slag. T.Al in the table represents the total value of metal Al and compound Al.

The various boron-iron alloys of No.1-No.4 in Table 3 all contain Al as an impurity, the content of which is 0.03% by mass or less, and are used as raw materials to manufacture master alloys and then cast iron-based amorphous alloys; Regardless of which alloy is used, a thin strip having excellent magnetic properties as described below can be formed.

Example 2

An example of producing boron-iron alloys using an induction melting furnace will be described below. Put 950g of steel type A shown in Table 1 as the iron source, 20g of CaO as the slagging agent and 300g of carbon material as the reducing agent into the crucible, heat it in an induction furnace and keep it at 1700°C. Then, 600 g of boron oxide was added into the crucible from above and kept at 1700°C. From the time of adding boron oxide, stop the induction heating after 60 minutes, and analyze the boron-iron alloy obtained after cooling. The results are shown in No. 5 of Table 3.

Both Al and Ti impurities are very small in this example. Although the B content is lower and the C content is higher than that of No.1-No.4 manufactured by electric furnace, it can still be used as a raw material for iron-based amorphous alloys after being combined with high B-low C boron-iron alloys, etc. use.

Example 3

The No.1-No.4 ferroboron alloy of Table 3 obtained in Example 1, the diluted iron source and FeP, carbon-based materials and Si as auxiliary raw materials are melted with a high-frequency induction furnace to produce Fe-B-Si- Master alloy for P-based iron-based amorphous alloys. The product released and solidified in Example 1 was pulverized and used as a boron-iron alloy. Diluted iron sources are the steel grades A-D of Table 1 used in Example 1.

In the high-frequency induction furnace, the main components of the master alloy are formulated into the specified value, the mixed raw materials are heated until they are completely melted, and the heat preservation reaches a uniform state. After solidification and crushing, a part of it is taken as a sample for analysis.

Table 4 shows an example of raw material blending when ferroboron alloy FeB-A No. 1 in Table 3 is used as a raw material. Master alloy A-A is an example of the case where steel grade A is used as the diluted iron source, and master alloy A-C is an example of the case where steel grade C is used as the diluted iron source.

Table 5 shows the component analysis values of the master alloy obtained in this compounding example. The main component analysis values in Table 5 hardly deviated from the preset values, and it was confirmed that a composition consistent with the blending of raw materials was obtained.

The content of Al as an impurity in the master alloy A-A is 0.0050% by mass or less, and is suitable for use as an iron-based amorphous alloy. However, master alloys A-C have high Al content and high Ti content, and are not suitable for use as iron-based amorphous alloys.

When steel type A, steel type B, and steel type D are used as the diluted iron source, when any of No.1, No.2, No.4, and No.5 in Table 3 of ferroboron alloy The contents are all at or below 0.0050% by mass, and are suitable for use as iron-based amorphous alloys. However, when steel type C (No.3) is used as the diluted iron source, the obtained master alloy has a high Al content, which is not suitable for use as an iron-based amorphous alloy.

Example 4

The master alloys A-A in Table 5 obtained in Example 3 were melted again, quenched and solidified by the single-roll method, and thin strips were produced, and their magnetic properties as core materials were evaluated. In addition, the results of analysis of the composition of the ribbon showed no deviation from the composition of the master alloy. In addition, even in the case of adjusting the components by adding auxiliary raw materials when remelting, it is possible to obtain a thin ribbon consistent with the compounded components.

When evaluating the magnetic properties, the thin strip was cut into 120 mm long, placed in a nitrogen atmosphere at 360°C for 1 hour, annealed in a magnetic field, and B ₈₀ and iron loss were measured with SST (Single Plate Magnetic Tester). B ₈₀ is the maximum magnetic flux density when the maximum applied magnetic field is 80A/m, and the iron loss is the value when the maximum magnetic flux density is 1.3T. The measurement frequency is 50 Hz.

The measurement results show that the high magnetic flux density of B ₈₀ =1.44 is obtained, the iron loss is as low as 0.063W/kg, and has excellent AC soft magnetic properties, fully meeting the practical requirements.

Table 1 steel type Composition (mass%) Fe C Si mn P S T.Al Ti A Balance 0.0033 0.7660 0.2550 0.0334 0.0051 0.0040 0.0003 B Balance 0.0026 0.0050 0.4300 0.0120 0.0190 0.0010 0.0003 C Balance 0.0010 0.0100 0.1000 0.0050 0.0050 0.0300 0.0300 D. Balance 0.0040 0.0040 0.3400 0.0160 0.0080 0.0010 0.0004

Table 2 raw material Mixing ratio (parts by mass) initial after stabilization boron oxide 657 657 iron source 820 820 charcoal 190 368 lime 84 67 Metallurgical coke 214 -

table 3 No. Ferroboron Raw material iron source Composition (mass%) Fe B C Si mn P S T.Al Ti 1 FeB-A A Balance 15.3 0.3500 0.8580 0.2400 0.0350 0.0090 0.0230 0.0060 2 FeB-B B Balance 15.5 0.3300 0.3500 0.4500 0.0180 0.0220 0.0240 0.0050 3 FeB-C C Balance 15.1 0.3700 0.4500 0.1800 0.0150 0.0070 0.0290 0.0310 4 FeB-D D. Balance 15.7 0.3200 0.4200 0.3900 0.0240 0.0140 0.0240 0.0080 5 FeB-A2 A Balance 3.42 4.7800 0.7700 0.2100 0.0240 0.0036 0.0040 0.0003

Table 4 raw material Mixing ratio (parts by mass) Master Alloy AA Master Alloy AC FeB-A 929 929 dilute iron source 5665 5622 FeP 3300 3300 Carbon-based materials 16.5 16.4 Si 90.2 133

table 5 Master Alloy Composition (mass%) Fe B C Si mn P S T. Al Ti AAA Balance 1.4200 0.2450 1.4200 0.1550 5.9600 0.0050 0.0047 0.0011 AC Balance 1.4200 0.2430 1.4200 0.0840 5.9500 0.0050 0.0190 0.0180

Example 5

In order to obtain the lower limit temperature at which de-B does not occur in the manufacture of low-C ferroboron alloys, an oxygen blowing experiment was carried out with an induction melting furnace. The iron-boron alloy and the carbon-based material with steel types A and B shown in Table 6 with a content of 18% by mass were put into a crucible and melted in an induction melting furnace. According to the requirement that the weight of the initial molten metal is 1000g, the B content of the initial composition is 4.0% by mass, and the C content is 2.4% by mass. The molten metal temperature was maintained at three levels of 1500°C, 1600°C and 1700°C, and oxygen was blown from the upper part of the furnace at a flow rate of 1 liter/min. Samples were taken from the molten metal every 5 minutes for chemical analysis.

Figure 1 shows the variation of B content and C content in molten metal with oxygen blowing time. At 1500°C, both B and C decrease simultaneously. It can be seen that the temperature at which the thermodynamic stability of B and C reverses is around this temperature. At 1600°C and 1700°C, the de-C proceeds continuously, but the B content is fixed, and the de-B reaction does not proceed.

Example 6

In order to confirm that boron steel with low C and Al content can be manufactured at low cost, ferroboron alloys were manufactured by electric furnace method and oxygen blowing was carried out.

Four kinds of iron sources shown in Table 6, boron oxide and carbon-based reducing agent were melted in an electric furnace to produce ferroboron alloy. The various iron sources are steels obtained by subjecting blast furnace pig iron to desulphurization process, desiliconization process, deP and C depletion processes by oxygen blowing in the converter. Steel type A is deoxidized with Si and Mn, steel types B and D are deoxidized with Mn, and steel type C is deoxidized with Al. All steel types are made into slabs through continuous casting, and then hot-rolled into hot-rolled coils with a thickness of about 3mm, and then cut into square pieces with a side length of several centimeters from various hot-rolled coils by shearing machine , put it into the electric stove.

As the electric furnace, a 3-phase Heroult type electric arc furnace with a capacity of 600KVA was used. The operation of the electric furnace was carried out continuously for 16 days. Manufacture ferroboron alloy with B content of 15-16% by mass in the first 8 days, and replace the iron source in the order of B, D, A, and C every 2 days. Manufacture ferroboron alloys with a B content of about 9% by mass in the latter 8 days; replace the iron sources in the order of B, D, A, and C every 2 days. The iron ladle is used to receive the boron-iron alloy metal melt flowing out of the electric furnace, and then the high-frequency induction furnace is used to maintain 1600°C for oxygen blowing.

The average operating conditions in the first 8 days are voltage 45V, current 4000-5000A, drain interval about 2 hours, daily output 2t/day, unit power consumption 4.3kwh/kg-FeB. The average operating conditions for the latter 8 days are voltage 45V, current 4000-5000A, drain interval about 1.5 hours a little longer, daily output 2.2t/day, unit power consumption 3.9kwh/kg-FeB.

The analysis results of the ferroboron alloy before oxygen blowing are shown in Table 7, and the analysis results of the ferroboron alloy after oxygen blowing are shown in Table 8. The C content decreased in all samples. In addition, the incidental effect that the content of Al and Ti was also reduced was also confirmed. In addition, T.Al in the table shows the total value of metal Al and compound Al.

It can be known from this example that the method of reducing the C content by blowing oxygen is applicable to the boron-iron alloy molten metal provided by the electric furnace. As the iron source used in the electric furnace method, any one of steel grades A to D produced by the converter method can be used. In addition, it can be seen from the unit power consumption per unit product weight that a product with a low B concentration in the ferroboron alloy is advantageous in terms of power cost.

Example 7

It has been confirmed that even if the iron-boron alloy obtained by the electric furnace method is released and solidified for a while, it can be decarburized by melting again and blowing oxygen. That is, the eight kinds of boron-iron alloys shown in Table 7 obtained in Example 6 were melted again, kept at 1600° C., and blown with oxygen. Even in this case, the C content can be reduced to 0.1% by mass or less without reducing the B content in the ferroboron alloy.

Example 8

In order to confirm that the ferroboron alloy produced by the method of the present invention is suitable for producing the master alloy for the iron-based amorphous alloy, and then manufacture the iron-based amorphous alloy, the diluted iron source and auxiliary raw materials are added to the ferroboron alloy to produce the master alloy.

The ferroboron alloy obtained in embodiment 6, the diluted iron source, Fep as auxiliary raw materials, carbon-based materials and Si were melted with a high-frequency induction furnace, and the iron-based amorphous alloy of Fe-B-Si-P system was manufactured. master alloy. The boron-iron alloy is the pulverized product of the drain solidification in Example 6. Steel types A to D in Table 6 were used as the diluted iron source.

In a high-frequency induction furnace, the main components of the master alloy are mixed to a specified value, the temperature is raised until it is completely melted, the temperature is maintained until the mixture is uniform, and then the product is solidified and pulverized, and a part of it is taken as a sample for analysis.

Table 9 shows an example of ingredients when using the iron-boron alloy FeB-A9-O in Table 8 as a raw material. Master alloy FeB-A9-O-A is an example when steel grade A is used as the diluted iron source; master alloy FeB-A9-O-C is an example when steel grade C is used as the diluted raw material.

Table 10 shows the compositional analysis results of the master alloy obtained with this compounding example. The analysis values in Table 10 have almost no deviation from the preset values, and it was confirmed that a composition consistent with the ingredients was obtained.

The master alloy FeB-A9-P-O-A has a low Al content as an impurity, and is suitable for use as an iron-based amorphous alloy. However, the master alloy FeB-A9-O-C, which uses the steel type C with high Al content as the diluted iron source, has high Al content and high Ti content, which is not suitable for iron-based amorphous alloys.

In the case of steel type A, steel type B, and steel type D as the diluted iron source, no matter which ferroboron alloy in Table 8 is used, the Al content of the obtained master alloy is 0.0050% by mass or less, which is suitable as an iron source. Base amorphous alloys are used. However, when the steel type C is used as the diluted iron source, the obtained master alloy has a high Al content, which is not suitable for use as an iron-based amorphous alloy.

Example 9

In order to confirm that the master alloys for boron-iron alloys and iron-based amorphous alloys produced by the method of the present invention are suitable for the manufacture of iron-based amorphous alloys, the amorphous alloys are made from the master alloys by rapid cooling and solidification.

The master alloy FeB-A9-O-A in Table 10 obtained in Example 8 was melted again, quenched and solidified by the single-roll method, and made into a thin strip, and its magnetic properties as a core material were evaluated. The analytical results of the strip composition did not deviate from the composition of the master alloy. Moreover, when adding auxiliary raw materials to adjust the composition during remelting, a thin ribbon consistent with the composition of the ingredients can also be obtained.

When evaluating the magnetic properties, cut the thin strip into 120mm long, place it in a nitrogen atmosphere at 360°C for 1 hour, anneal in a magnetic field, and measure B ₈₀ and iron loss with SST (Single Plate Magnetic Tester). B ₈₀ is the maximum magnetic flux density when the maximum applied magnetic field is 80A/m, and the iron loss is the value when the maximum magnetic flux density is 1.3T. The measurement frequency is 50 Hz.

The measurement results show that the high magnetic flux density with B ₈₀ =1.44T, the iron loss as low as 0.063w/kg, excellent AC soft magnetic properties, fully meet the practical requirements.

Table 6 steel type Composition (mass%) Fe C Si mn P S T. Al Ti A Balance 0.0033 0.7660 0.2550 0.0334 0.0051 0.0040 0.0003 B Balance 0.0026 0.0050 0.4300 0.0120 0.0190 0.0010 0.0003 C Balance 0.0010 0.0100 0.1000 0.0050 0.0050 0.0300 0.0300 D. Balance 0.0040 0.0040 0.3400 0.0160 0.0080 0.0010 0.0004

Table 7 Ferroboron Raw material iron source Composition (mass%) Fe B C Si mn P S T. Al Ti FeB-A A Balance 15.3 0.3500 0.8580 0.2400 0.0350 0.0090 0.0230 0.0060 FeB-B B Balance 15.5 0.3300 0.3500 0.4500 0.0180 0.0220 0.0240 0.0050 FeB-C C Balance 15.1 0.3700 0.4500 0.1800 0.0150 0.0070 0.0290 0.0310 FeB-D D. Balance 15.7 0.3200 0.4200 0.3900 0.0240 0.0140 0.0240 0.0080 FeB-A9 A Balance 9.2 0.6500 0.8350 0.2100 0.0250 0.0080 0.0220 0.0050 FeB-B9 B Balance 8.7 0.7000 0.3400 0.4300 0.0140 0.0210 0.0230 0.0050 FeB-C9 C Balance 9.1 0.6600 0.4600 0.1500 0.0130 0.0070 0.0290 0.0290 FeB-D9 D. Balance 8.6 0.7400 0.4300 0.3600 0.0230 0.0120 0.0230 0.0070

Table 8 Ferroboron Raw material iron source Composition (mass%) Fe B C Si mn P S T. Al Ti FeB-AO A Balance 15.4 0.0500 0.8450 0.2300 0.0290 0.0060 0.0080 0.0030 FeB-BO B Balance 15.3 0.0600 0.3420 0.4600 0.0170 0.0180 0.0120 0.0040 FeB-CO C Balance 15.4 0.0700 0.4200 0.2000 0.0150 0.0070 0.0090 0.0140 FeB-DO D. Balance 15.6 0.0600 0.4120 0.4200 0.0220 0.0120 0.0100 0.0040 FeB-A9-O A Balance 9.1 0.0800 0.8240 0.1700 0.0240 0.0070 0.0070 0.0030 FeB-B9-O B Balance 8.8 0.0600 0.3260 0.3900 0.0120 0.0180 0.0090 0.0040 FeB-C9-O C Balance 8.9 0.0700 0.4460 0.1800 0.0110 0.0060 0.0080 0.0090 FeB-D9-O D. Balance 8.7 0.0500 0.4200 0.3200 0.0180 0.0090 0.0070 0.0050

Table 9 raw material Mixing ratio (parts by mass) Master Alloy FeB-A9-OA Master Alloy FeB-A9-OC FeB-A9-O 1560 1560 dilute iron source 5035 4990 FeP 3295 3305 Carbon-based materials 18.3 18.4 Si 89.9 128

Table 10 Master Alloy Composition (mass%) Fe B C Si mn P S T.Al Ti FeB-A9-OA Balance 1.4200 0.2400 1.4200 0.1450 5.9500 0.0050 0.0034 0.0009 FeB-A9-OC Balance 1.4200 0.2400 1.4200 0.0820 5.9600 0.0050 0.0160 0.0160

Implementation 10

Two kinds of iron sources, boron oxide, and carbon-based reducing agent in Table 11 were melted in an electric furnace to produce ferroboron alloy. The various iron sources are steels produced from blast furnace pig iron through de-S process, de-Si process, and oxygen-blowing de-P and C-removal processes in the converter. Steel type A is deoxidized with Si and Mn, and steel type B is deoxidized with Mn. All kinds of steel are made into slabs through continuous casting, and then hot-rolled into hot-rolled coils with a thickness of about 3 mm, and then cut out square sheets with a side length of several centimeters from the hot-rolled coils by a shearing machine, to This is used as an iron source.

As the electric furnace, a 3-phase Heroult type electric furnace with a capacity of 600 KVA was used. The operation of the electric furnace continued for 4 days, and the iron source was replaced every 2 days in the order of B and A. The draining interval is about 2 hours; the boron ferroalloy that is not in the iron source replacement is used for analysis. For the blending of raw materials, start the operation with the initial blending ratio shown in Table 12, and replace it with the stabilized blending ratio when the operation is stable.

The analytical values of the obtained ferroboron alloy are shown in Table 13. When steel type A is used as the iron source and when steel type B is used as the iron source, the Al content is 0.024% by mass or less, and the Ti mass is 0.008% by mass or less; high purity. The analytical values of Al and Ti of the boron-iron alloy are higher than the corresponding values of the iron source steel grades shown in Table 12, which is due to the incorporation of boron oxide and reducing agent. T.Al in the table is the total value of metal Al and compound Al.

Example 11

The iron-boron alloy in Table 13 obtained in Example 10, the diluted iron source, FeP as auxiliary raw materials, carbon-based materials and Si were melted in a high-frequency induction furnace to produce a master alloy for iron-based amorphous alloys. The product released and solidified in Example 10 was pulverized and used as a boron-iron alloy. Each steel type in Table 11 was sheared in the same manner as in Example 10, and the resulting product was used as a diluted iron source.

In the high-frequency induction furnace, the main components of the master alloy are made into a specified value, the temperature is raised to complete melting, and the temperature is kept until the mixture is uniform, then solidified and crushed, and a part of it is taken as a sample for analysis.

Table 14 shows an example of raw material blending when FeB in Table 13 is used as the ferroboron alloy and steel type A in Table 11 is used as the diluted iron source (combination A-A). In addition, the component analysis values of master alloy A-A obtained in this compounding example are shown in Table 15. It was confirmed that the main component analysis values in Table 15 had almost no deviation from the predetermined value, and that a composition consistent with the ingredients was obtained.

The master alloy A-A shown in Table 15 has low Al content and Ti content, and is suitable for use as an iron-based amorphous alloy. In addition, the combination B-A using FeB-B as the boron-iron alloy and steel type A as the diluted iron source can also obtain a master alloy with Al and Ti content suitable for iron-based amorphous alloys.

When the steel type B is used as the diluted iron source, the Al content of the master alloys of combination A-B and combination B-B is 0.0050% by mass or less, and are also suitable as master alloys for iron-based amorphous alloys.

Example 12

The master alloy A-A obtained in Example 11 was melted again, quenched and solidified by the single-roll method to form a thin strip, and the magnetic properties of the iron core material were evaluated. In addition, the results of analysis of the composition of the ribbon showed that there was no deviation from the composition of the master alloy, and even when the composition was adjusted by adding auxiliary raw materials during remelting, a ribbon with the same composition as the blend could be obtained.

When evaluating the magnetic properties, the thin strip was cut into 120mm long, placed in a nitrogen atmosphere at 360°C for 1 hour, and after annealing in a magnetic field, B ₈₀ and iron loss were measured with SST (single plate magnetic tester), B ₈₀ is the maximum magnetic flux density when the maximum applied magnetic field is 80A/m, and the iron loss is the value when the maximum magnetic flux density is 1.3T. The measurement frequency is 50 Hz.

The measurement results show that the high magnetic flux density of B ₈₀ =1.44T is obtained, the iron loss is as low as 0.063W/kg, and has excellent AC soft magnetic properties, fully meeting the practical requirements.

Table 11 steel type Composition (mass%) Fe C Si mn P S T.Al Ti A Balance 0.0033 0.7660 0.2550 0.0334 0.0051 0.0040 0.0003 B Balance 0.0040 0.0040 0.3400 0.0160 0.0080 0.0010 0.0004

Table 12 raw material Mixing ratio (parts by mass) initial after stabilization boron oxide 657 657 iron source 820 820 charcoal 190 368 lime 84 67 Metallurgical coke 214 -

Table 13 Ferroboron Raw material iron source Composition (mass%) Fe B C Si mn P S T. Al Ti FeB-A A Balance 15.3 0.3500 0.8580 0.2400 0.0350 0.0090 0.0230 0.0060 FeB-B B Balance 15.7 0.3200 0.4200 0.3900 0.0240 0.0140 0.0240 0.0080

Table 14 raw material Mixing ratio (parts by mass) FeB-A 929 Dilute iron source (steel type A) 5665 FeP 3300 Carbon-based materials 16.5 Si 90.2

Table 15 Master Alloy Composition (mass%) Fe B C Si mn P S T. Al Ti AAA Balance 1.4200 0.2450 1.4200 0.1550 5.9600 0.0050 0.0047 0.0011

Claims (2)

1. high-purity ferroboron, it is characterized in that, contain P:0.02 quality % or above, Al:0.03 quality % or following, remainder is made up of Fe, B and unavoidable impurities, and this high-purity ferroboron prepares by the following method, described method is to be that the reductive agent fusion reducing furnace of packing into is made ferro-boron with boron source, source of iron and carbon, and described source of iron is the steel that obtains with refining furnace, and the Al content of this steel is 0.03 quality % or following.

2. high-purity ferroboron as claimed in claim 1 wherein also contains 0.03 quality % or following Ti.