JPH05182851A - Manufacture of rare earth elements-fe-b magnet - Google Patents

Abstract

PURPOSE:To search for manufacturing requirement to enhance magnetic properties in terms of hot working which uses metal capsules. CONSTITUTION:An alloy cast ingot, which contains at least a rare earth element, Fe and B, is sealed in a metal capsule. The alloy ingot is subjected to hot working at a specified hot working temperature ranging from 800 to 1100 deg.C in a state where the ingot contains liquid phase, and the hot working is carried out at a total working rate of above 70%. Furthermore, there is adopted a metal capsule whose strength exceeds 10kg/mm<2> at the working temperature, which forms a high orientation alloy structure. It is also more effective to select appropriate types of rare earth elements and addition elements, to add a water-cooling process during hot working, to add heat treatment during hot working, to specify the thickness of the capsule and to use a release agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rare earth element-Fe-B magnet having an alloy structure with excellent orientation, and more specifically, to a cast ingot formed from a rare earth element-containing alloy material in a metal capsule. The present invention relates to a method for producing a rare earth permanent magnet having excellent magnetic characteristics by defining the capsule strength and the like when performing hot working by encapsulating in.

[0002]

2. Description of the Related Art Rare earth magnets have been attracting attention as a third permanent magnet after ferrite magnets and alnico magnets. This rare earth magnet is expected to exhibit excellent magnetic performance that can contribute to miniaturization and high precision of electric products and precision instruments, and is actively making progress in both physical property research and production.

Of particular interest in recent years is the rare earth element-Fe-B system such as Nd-Fe-B or Pr-Fe-.
It is a permanent magnet such as B, and has recently come to contain Cu and Ag in the fourth
The addition of the element as the second constituent element, and addition of other trace elements in addition to the above are also being considered. The permanent magnet composition targeted by the present invention includes all of these cases and may also contain Ga, In, Sn, etc., the details of which will be described later, but in the following description, rare earth element-Fe-B. For convenience sake, a ternary magnet of a system (hereinafter, simply referred to as RE-Fe-B system magnet) will be representatively described.

The following two methods were initially studied as the method for producing the RE-Fe-B magnet. The first method is a sintering method, but this method requires powdering of the alloy prior to the sintering step, and since it is powdery, it is susceptible to oxidation and is brought into a sintered body. Oxygen has a negative effect on the magnetic performance, the magnetic performance deteriorates due to the incorporation of carbon content from the molding aids added during sintering, the green body before sintering has low strength, and is easy to handle. There are some drawbacks such as badness, so RE-
The characteristics expected of the Fe-B magnet have not been fully exhibited.

The second method is a method of forming a quenched thin piece and then forming a bonded magnet by using a thermoplastic resin or the like. Instead of the above-mentioned drawbacks, only a low productivity, in principle isotropic magnet is used. Therefore, the maximum energy product [hereinafter represented by (BH) max] represented by the product of the residual magnetic flux density and the coercive force is low, and the squareness (SQ) is not good. Therefore, as a means for positively anisotropy, it has been considered to subject the quenched thin piece to a two-step hot press treatment (mechanical orientation treatment). However, this is not a practical method considering the necessity of mass production, since the productivity will be lower.

Therefore, as a third method, hot working (rolling, forging, extrusion, etc.) is applied to the cast alloy to achieve the refinement of the crystal grains to increase the coercive force and the crystal axis. A means has been developed for lining up in a specific direction to draw magnetic anisotropy.

[0007]

Even if the hot working is performed, the alloy ingot is hot worked to refine the crystal grains to improve the coercive force and the magnetic anisotropy due to the mechanical orientation. In order to improve the hot rolling, it is necessary to carry out hot rolling under a high heat condition such that a liquid phase is generated in the ingot. However, if the alloy ingot is subjected to such a high melting state in a so-called semi-molten state and hot rolling is performed, the alloy ingot is fused to the surface of the rolling roll, and the operation becomes impossible. Therefore, it has been considered that the alloy ingot is enclosed in a metal capsule made of a material having a higher melting point than that of the alloy ingot to separate the two.

The present invention was completed by searching for manufacturing requirements for further improving magnetic properties in hot working using metal capsules.

[0009]

The method of the present invention, which has been completed as a result of the above-mentioned research, has at least a rare earth element, Fe and B.
In a method for producing a RE-Fe-B magnet, which comprises a step of hot working an alloy ingot containing a metal capsule, the alloy ingot having a hot working temperature of 800 to 1100 ° C. While performing hot working in a state containing a liquid phase,
At this time, hot working is performed so that the total working rate is 70% or more, and the strength at the working temperature is 10 kg / mm ²
The point is to form a highly oriented alloy structure by using the above metal encapsulant.

As a result, a highly oriented alloy structure was successfully formed, and the RE-Fe-B magnet provided here exhibits excellent magnetic properties. Also, as an alloy ingot,
One or more rare earth elements selected from Pr and Nd, F
In addition to containing e and B, an alloy ingot containing at least one element selected from the group consisting of Ga, In and Sn as an essential component is used, and the capsule surface is water-cooled at any time during hot working. It is also effective to do so, and by imparting such requirements, the effects of the present invention can be more effectively exhibited.

After the hot working is completed, 800 to 11
Heat treatment at 00 ℃, then 400-600 ℃
It is also effective to heat-treat, and the magnetic characteristics can be further improved by adding such a step.

As described above, the present invention makes it essential to enclose the alloy ingot in a metal capsule having a predetermined strength and perform hot working. However, the effect of the metal capsule is most effective. In order to exert the effect, it is preferable to perform hot working so that the upper and lower plate thicknesses of the metal capsules are 0.5 to 5 mm as the rolling finish thickness.

As the material of the metal capsule used in the present invention, any of stainless steel, high manganese steel, carbon steel and the like can be used, but a metal material having high strength such as stainless steel or high manganese steel is used. When used, sufficient strength can be obtained without water cooling, but when a metal material having relatively low strength such as carbon steel is used, it is effective to increase the strength by water cooling. Whichever metal material is used, boron nitride and thin plate Al
It is effective to interpose a release agent for the ₂ O ₃ -SiO ₂ complex oxide between the metal capsule and the alloy ingot (specifically, after applying boron nitride, a thin plate-shaped Al ₂ O ₃ -SiO _{2 (2} ) Wrap with complex oxide), which avoids the reaction between the alloy ingot and the metal capsule, and makes it possible to easily take out a magnet material having a good shape after hot working.

The time of water cooling is not limited, and it may be performed at any time of hot working as described above, but the most effective time is immediately before hot working and the condition is "alloy." After heating the metal capsule containing the ingot, 0-30
Cooling with water at 0 ° C for 0.5 to 3 seconds per 1 mm of metal capsule plate thickness.

[0015]

The present invention is constructed as described above, but in short,
By defining the strength of the metal capsule, the work deformation of the magnet material inside the capsule is increased, the crystal orientation of the magnet material is increased, and the high (BH) max is achieved. The alloy composition of the RE-Fe-B magnet of the present invention will be described.

First, as rare earth elements, in addition to Y, La,
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
Lanthanum series rare earth elements such as y, Ho, Er, Tm, Yb and Lu are commonly used, but if necessary, actinium series elements can be used, and one or more of them can be used in combination. To use. Particularly effective among these are Pr and / or Nd.

In the RE-Fe-B system magnet of the present invention, the rest is substantially Fe in addition to the above-mentioned rare earth element and B,
Ga, In, Sn, Co, Al, C instead of part of Fe
It is also effective to contain u, Ag, Nb, V and the like.
In particular, 1 selected from the group consisting of Ga, In and Sn
The inclusion of one or more species is extremely effective in improving the magnetic properties. That is, the addition of Ga, Sn, In, etc. is such that R ₂ —Fe ₁₄ —B (atomic ratio, for example, Pr ₂ Fe ₁₄ B) is added during hot working.
The first phase consisting of (hereinafter sometimes simply referred to as the first phase)
A RE-rich thin film phase or grain boundary phase is formed around the alloy, and as a result, the crystal orientation of the first phase is extremely well aligned during rolling, which contributes to the improvement of magnetic flux density (Br) and coercive force (iHc). .. Further, Co has an effect of improving temperature characteristics of magnetism, Al has an effect of suppressing a decrease in coercive force, and C
u has the effect of increasing the coercive force, and Ag, Nb, V, etc. have the effect of refining the structure.

The composition ratio of each element in the RE-Fe-B system magnet according to the present invention is not particularly limited,
Generally, it is recommended to select according to the following criteria. The composition range of rare earth elements is 10 to 35 in total or in total.
An appropriate amount is 10% by weight, and if it is less than 10% by weight, a cubic crystal structure having the same structure as that of α-iron will be formed, resulting in lowering of iHc, and good magnetic properties cannot be obtained. Further, the hot workability is deteriorated, and cracks are likely to occur during hot working. On the other hand, when the upper limit is more than 35% by weight, the RE-rich phase becomes excessive and the volume fraction of the first phase becomes insufficient, which appears as a decrease in magnetic flux density, and good magnetic properties can be exhibited. Disappear.

B is preferably 0.8 to 1% by weight, and if it is less than 0.8% by weight, the volume fraction of the first phase is insufficient and the magnetic flux density is lowered. On the other hand, regarding the upper limit, RE that does not bear magnetic characteristics
1 wt% from the viewpoint of preventing a decrease in iHc due to the emergence of ₁ -Fe ₄ -B ₄ phase may be a standard.

The magnet according to the present invention, in addition to the above essential components,
The balance basically consists of Fe and inevitable impurities. As described above, it is particularly effective to contain elements such as Ga, In and Sn in place of part of Fe, but when these are added, the total amount is 0.2 to 0.8% by weight. If less than 0.2% by weight (Ga, S
The n-, In-containing R-rich phase is reduced, and the crystal orientation of the first phase is insufficient. On the other hand, when it exceeds 0.8% by weight, excess of (Ga, Sn, In) -containing RE rich phase and insufficient volume ratio of the first phase are caused, resulting in reduction of magnetic flux density.

It has been reported that Ga has been added to a conventional powder sintered magnet, but if it is not added in an amount of about 2 wt.
c ≧ 15 KOe was not obtained. Also, a powder sintered magnet containing Sn has been reported, but in this case, it is added to lower the sintering temperature, Dy is added in combination to increase iHc, and the magnetic properties of grain boundaries are further added. Which enhances
Has also been added. That is, Ga, I in the present invention
With an appropriate total addition amount of n, Sn, etc. of about 0.2 to 0.8% by weight, sufficient effects have not been obtained with the conventional powder sintered materials.

On the other hand, in the present invention, by adding the manufacturing steps described above and in detail later, even if the addition range is within the above range, the effect is maximized. Thus, it is one of the features of the present invention that the additive effect of Ga, In, Sn, etc. is maximized.

The alloy ingot having the composition as described above is housed in a metal capsule and hot-worked. The hot-working of the present invention is carried out at such a high temperature that a liquid phase is formed in the alloy ingot. In view of the above, as the metal capsule, a material having a higher melting point than the alloy ingot, for example, mild steel having a melting point of 1500 ° C. or higher, structural steel, stainless steel, high alloy steel, or the like is used. Further, in the present invention, as shown in Examples described later, the strength of the metal capsule at the heating temperature needs to be 10 kg / mm ² or more. At 10 kg / mm ² or less, the alloy ingot has a higher strength than the metal capsule, and the metal capsule undergoes more deformation during hot working, which is said to improve the crystal orientation. Is smaller. Therefore, from such a viewpoint, it is preferable to use a material having sufficiently high strength such as stainless steel or high manganese steel for the metal capsule. However, even if a low strength material such as carbon steel is used as the metal capsule, by adding a water cooling step described later,
A sufficient strength required for processing can be achieved. Even if stainless steel or high manganese steel is used, a water cooling step may be added, but if cooling is excessive, it may cause inconvenience of cracking, and water cooling should be kept to the minimum necessary. Should be.

In encapsulating the alloy ingot in various metal capsules as described above, it is preferable to interpose a release agent at the contact interface between the alloy ingot and the metal capsule. That is, when the alloy ingot is encapsulated in a metal capsule and rolled, the melt of the alloy ingot is fused to the inner surface of the metal capsule, and further diffusion of alloy components occurs to cause alloy ingot and metal The problem that the capsules are integrated may occur, but such a problem can be solved by using the release agent. When the integration as described above occurs, it is not possible to divide the two after the rolling is completed, and it is necessary to separate them by cutting by machining, which leads to a decrease in yield due to cutting loss, and because of the change in physical properties due to the diffusion. Part of the semi-molten alloy ingot inside may be caused by cracking of the metal capsule, or the alloy ingot may undergo surface dilution due to dilution of the alloy composition,
Fragment adheres to the metal capsule side, and the yield is reduced due to cutting of the rare earth magnet to remove the cracked part.When cracking becomes noticeable, it is remelted as a defective product. Many drawbacks arise, such as having to turn around. As such a release agent, it is desirable to use various release agents such as glass-based release agents, boron nitride, alumina, sialon, and zirconia that can stably exhibit their action even under high heat. However, it becomes a semi-molten state containing a liquid phase. As long as the alloy ingot and the metal capsule exhibit a protective action so as not to be integrated under the hot rolling condition, they are all applicable to the present invention. A particularly preferred form of the stripping agent is a thin plate-like Al ₂ O ₃ − after applying boron nitride.
It is to wrap it with a SiO ₂ composite oxide.

In the present invention, the metal capsule may be water-cooled during hot working, which increases the strength of the metal capsule and increases the working osmotic pressure to increase the working deformation of the magnet material inside, as described above. The crystal orientation of the magnet material is increased to a high (B
H) This is for maximization. The time of water cooling at this time is not particularly limited, and an appropriate time may be selected according to the hot working schedule, but from the standpoint of exhibiting the above effect from the initial stage of hot working, Immediately before hot working, that is, after heating until hot working is preferable. The optimum water cooling condition at this time is that the metal capsule is heated to a predetermined temperature and then cooled with water at 0 to 30 ° C. for 0.3 to 3 seconds per mm plate thickness of the capsule. If the time is less than 0.5 seconds, the effect of hydrostatic pressure on the alloy ingot cannot be expected because the strength of the surface of the metal capsule is increased, and if the time exceeds 3 seconds, the temperature of the alloy ingot in the capsule decreases and the crystal orientation. This is not preferable because the deterioration of the film quality and the occurrence of cracks increase.

If the capsule upper and lower plates are too thick, only the capsule upper and lower plates will be deformed during hot rolling, the processing pressure will not easily penetrate into the inside, and the fine granulation of the magnet material will be difficult to achieve. From this point of view, it is preferable that the upper and lower plate thicknesses of the capsules are hot worked so that the finished thickness is 5 mm or less. On the other hand, if the thickness of the upper and lower plates of the capsule is too thin, the capsule will bulge during hot working, and the magnet material in the middle part will not be easily deformed, so that improvement of magnetic properties cannot be expected. From this point of view, the lower limit of the upper and lower plate thickness of the capsule is preferably 0.5 mm. Further, the upper and lower plate thickness before hot working may be set in consideration of the rolling reduction and the finishing thickness, but 5 to 50 mm may be used as a guide.

The temperature for carrying out the hot working may be appropriately determined in consideration of the hot working schedule, but the lower limit temperature is required to generate a liquid phase in the alloy ingot for the reason described above. In order to prevent the occurrence of cracks during hot working, the temperature must be 800 ° C or higher, preferably 850 ° C or higher. On the other hand, regarding the upper limit, 11
If the temperature exceeds 00 ° C, the alloy magnet will melt and become sherbet-shaped, making hot working impossible.
Must be:

The hot working schedule in the present invention is
It is a method of reheating for each processing of one pass to stabilize the temperature (hereinafter referred to as multi-heat / multi-pass), or a method of not heating again during multi-pass after heating once when hot working is started. Either can be adopted.

In the case of multiple heat and multiple passes, the metal capsule is reheated for each pass, so that the processing resistance is small.
Although it has the advantage that the processing effect is stable, it has the drawback of being inferior in productivity. On the other hand, in the case of 1-heat / multi-pass, the above effects are slightly reduced, but the desired multi-pass can be completed promptly by so-called reverse processing, so the temperature before hot working is set to be slightly higher. If so, the desired processing temperature can be maintained even after the latter stage of the processing schedule, and excellent productivity can be exhibited. In addition, it is desirable that the number of passes is at least two or more in both multi-heat / multi-pass and one-heat / multi-pass. The upper limit of the number of passes is not particularly limited, and hot working may be completed with the number of passes that can reach the desired plate thickness.

The multi-pass processing in the above description will be described, for example, in terms of rolling. A unidirectional rolling method in which the metal capsule is always guided from one direction to the rolling apparatus, a so-called reverse rolling in which the metal capsule is alternately reciprocated for each pass, etc. It is meant to include both.

Next, the working rate by hot working is not determined from the standpoint of reaching the desired plate thickness, but as shown in FIG.
As shown in (B), when the total rolling processing rate exceeds 70%, (BH) max becomes the minimum desired value (20) for a permanent magnet.
70% is set as the lower limit from the viewpoint of exceeding MGOe) and iHc exceeding a sufficiently high value (10 KOe) as a permanent magnet. It is desirable that each pass be processed so as to exceed 15%.

The RE-Fe-B system magnet obtained by the present invention is not limited to the plate width direction in the long plate material,
Good crystal axis orientation is obtained also in the longitudinal direction, and magnetic anisotropy is exhibited in the entire width direction and length direction.

In the present invention, as described above, after hot working, heat treatment is performed at 800 to 1100 ° C., and further 400 to 60.
A preferred embodiment is heat treatment at 0 ° C. This will be clarified in Examples described later, but this is because the two-step heat treatment achieves a finer structure and further improves the characteristics of the magnet. In relation to the temperature condition of the hot working, by adopting this heat treatment, even if the hot working temperature is lowered and the magnetic properties are slightly inferior, it is possible to recover it, and conversely, it is adopted in the present invention. RE-Fe
In the case of -B type alloy system, iHc is increased by performing this heat treatment when the hot rolling is completed at less than 850 ° C, rather than when the hot rolling is completed at 850 ° C or more. The present inventors have also found that this is possible, and in some cases, the adoption of this heat treatment may open the way to low-temperature processing at 800 to 950 ° C. Such heat treatment may be performed after cooling to room temperature after the hot working is completed, or may be directly transferred to the heat treatment step after the hot working is finished and the temperature is lowered to some extent. Further, it is preferable to perform this heat treatment a plurality of times, whereby spheroidization of the eutectic structure is achieved, which contributes to the improvement of iHc.

[0034]

Example 1 An ingot having the composition shown in Table 1 was produced.

[0035]

[Table 1]

The obtained ingot was cut along a cutting line S shown in FIG. 6 to obtain a plurality of alloy ingots 4. The direction of formation of columnar crystals P in the ingot is as shown in the figure.

The alloy ingot 4 is enclosed in metal capsules 5 made of stainless steel, high manganese steel and carbon steel,
Rolled material 6 as shown in FIG. 7 was formed. At this time, as a release agent, (boron nitride + thin plate-like Al ₂ O ₃ -SiO ₂
A composite oxide) was used and was interposed between the alloy ingot 4 and the metal capsule 5. Roll the rolling material 6 at a rolling temperature of 1000
℃, 1 pass, rolling reduction of 30%, 4 passes, total reduction of 76
% Hot rolling was performed. At this time, the rolling material 6 encapsulated in the carbon steel capsule was cooled with water at 25 ° C. for 13, 10 and 7 seconds, respectively, before rolling for 1 to 3 passes. The strength of the metal capsule during hot working, as 15 kg / mm ² made of stainless steel, of also made high manganese steel 20 kg / mm ^2,
Those 20 kg / mm ² made of carbon steel (water cooling) was 2.5 kg / mm ² made of carbon steel (without water cooling). After hot working, 1050
Two-step heat treatments of ℃ (first step) and 475 ° C (second step) were performed, and the magnetic properties of the obtained magnet material were investigated. The results are shown in Table 2, and it can be seen that those satisfying the requirements of the present invention have excellent magnetic properties.

[0038]

[Table 2]

Example 2 An ingot having the composition shown in Table 3 was produced.

[0040]

[Table 3]

From the obtained ingot, in the same manner as in Example 1,
A plurality of alloy ingots 4 were obtained. After coating the outer surface of the alloy ingot 4 with boron nitride, it is enclosed in a metal capsule made of S10,
Rolled material 6 as shown in FIG. 7 was formed. The rolled material 6
Was held at 1000 ° C. for 10 hours, then immersed in water to cool the surface of the capsule with water (about 15 seconds), various reduction ratios for one pass were set, and hot rolling was performed for several passes. Further, similar hot rolling was performed even when water cooling was not performed.

The changes over time in the capsule surface temperature, load and rolling torque current during hot rolling are shown in FIGS. 1 (A) to 1 (C).
Note that FIG. 1A shows the case where the ratio (D / T) of the diameter D of the rolling roll and the wall thickness T of the rolled capsule material is 5/25.
(B) is the case of 6/1, and FIG. 1 (C) is the case of 6/9. Also, the numerical values in the figure (for example, 170H, 130H
Etc.) shows the thickness (unit: mm) after rolling, and the load and rolling torque current are values converted into a width of 300 mm. From these results, it can be seen that by performing surface water cooling, the rolling osmotic pressure on the rolling material can be increased.

Example 3 Ingots hot-rolled to various thicknesses according to Example 2 were cooled to room temperature, and then the metal capsules 5 were peeled off to obtain 7 mmφ × 7 mm
A magnetic measurement sample of ^h was cut out and the magnetic characteristics were measured with a DC magnetic recorder. For comparison, the magnetic properties of the Cu-added R-Fe-B alloys having the compositions shown in Table 4 below were also measured.

[0044]

[Table 4]

The results are shown in FIGS. 2 (A) to 2 (D). Figure 2
The heat resistant temperature (HR) shown in (D) is a value obtained by the following mathematical formula. HR = -112.1 + 10.4 × iHc + 0.8 × S. Q. As is clear from the results of FIG. 2, it is extremely effective to add Ga to the magnet material in carrying out the method of the present invention.

Example 4 Using the ingots shown in Table 3 above, hot rolling was performed according to the procedure shown in Example 2 until the rolling reduction reached 70% or more, and the magnetic properties were obtained according to the procedure shown in Example 3. Was measured. At this time, the same measurement was carried out for those that were not water-cooled, and the influence of the presence or absence of water cooling on the magnetic properties was investigated.

The results are shown in FIGS. 3 (A) to 3 (C). It is understood that adding a water cooling step during hot working is extremely effective in improving the magnetic characteristics. This is shown in Fig. 1 (A)-
As shown in (C), it is considered that the rolling load can be effectively applied to the rolling material by performing the capsule water cooling.

Example 5 According to Example 2, hot rolling was performed by changing the finishing thickness of the capsule upper and lower plates during hot rolling (hot working rate was 80 to 87%), and the magnetic properties of the obtained magnet material were obtained. Was investigated for the effect on. The results are shown in FIGS. 4 (A) to 4 (C), and it is understood that in carrying out the present invention, it is preferable to make the finishing thickness of the capsule upper and lower plates as thin as possible. However, as described above, the thickness should be 0.5 mm or more so that the capsule does not bulge during rolling.

Example 6 According to the method described in Example 2, except that after hot rolling, the temperature was held at 1000 ° C. for 6 hours, air-cooled to room temperature, and then held at a temperature of 400 to 600 ° C. for 2 hours. A magnet having the composition shown in Table 3 was manufactured.

The change in magnetic characteristics of this magnet before and after heat treatment is as shown in FIG. In addition, FIG. 5 also shows the magnetic characteristics of only holding at 1000 ° C. for 6 hours.

As is apparent from FIG. 5, after the heat treatment at a high temperature is performed at a temperature of 1000 ° C., the heat treatment at a low temperature is performed at 40 ° C.
It can be clearly seen that the magnetic properties are remarkably improved when the heating is performed in the temperature range of 0 to 600 ° C.

Example 7 Ingots having the respective compositions shown in Table 5 below were produced, hot-rolled according to Example 2 to obtain hot-worked magnets, and magnetic properties were determined in the same manner as in Example 3. investigated. The results are also shown in Table 5. It can be clearly seen that particularly those containing Ga, In, Sn, etc. exhibit excellent magnetic characteristics.

[0053]

[Table 5]

[0054]

As described above, according to the present invention, by using a metal capsule having high strength during hot working, it is possible to increase the degree of compounding of the easy axis of magnetization of the crystal in the pressing direction, Rare earth element-Fe with excellent magnetic properties
-It has become possible to stably produce B magnets. In addition, adding a water cooling step to the metal capsule can also contribute to the improvement of magnetic properties.

[Brief description of drawings]

FIG. 1 is a graph showing changes with time in capsule surface temperature, load, and rolling torque current during hot rolling.

FIG. 2 is a graph showing the relationship between the product thickness of each magnet material and the magnetic characteristics.

FIG. 3 is a graph showing the influence of the presence or absence of water cooling on the magnetic characteristics.

FIG. 4 is a graph showing the relationship between the finished thickness of the capsule upper and lower plates and the magnetic characteristics of the magnet material during hot rolling.

FIG. 5 is a graph showing changes in magnetic properties after heat treatment.

FIG. 6 is a perspective view showing a cutting line of a cast piece.

FIG. 7 is a perspective sectional view showing a concept when an alloy ingot is enclosed in a metal capsule.

FIG. 8 is a graph showing the relationship between the total rolling rate and magnetic properties.

[Explanation of symbols]

 4 Alloy ingot 5 Metal capsule 6 Rolled material

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[Procedure amendment]

[Submission date] January 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 Diameter D of rolling roll and thickness T of capsule rolled material
6 is a graph showing changes with time in capsule surface temperature, load, and rolling torque current during hot rolling when the ratio (D / T) is 5/25.

[Fig. 2] Diameter D of rolling roll and thickness T of capsule rolled material
3 is a graph showing changes with time in capsule surface temperature, load, and rolling torque current during hot rolling when the ratio (D / T) is 6/1.

[Fig. 3] Diameter D of rolling roll and thickness T of rolled capsule material
3 is a graph showing changes with time in capsule surface temperature, load, and rolling torque current during hot rolling when the ratio (D / T) is 6/9.

FIG. 4 is a graph showing the relationship between the product thickness of each magnet material and (BH) _max .

FIG. 5 is a graph showing the relationship between the product thickness of each magnet material and iHc.

FIG. 6 shows the product thickness of each magnet material and S.I. Q. It is a graph which shows the relationship of.

FIG. 7 is a graph showing the relationship between the product thickness of each magnet material and HR.

FIG. 8 is a graph showing the influence of the presence or absence of water cooling on (BH) _max .

FIG. 9 is a graph showing the effect of water cooling on iHc.

FIG. 10 shows the presence or absence of S. Q. It is a graph which shows the influence which it has on.

FIG. 11 is a graph showing the relationship between the finished thickness of the capsule upper and lower plates and (BH) _max of the magnet material during hot rolling.

FIG. 12 is a graph showing the relationship between the finished thickness of the capsule upper and lower plates and iHc of the magnet material during hot rolling.

FIG. 13: Finished thickness of capsule upper and lower plates during hot rolling and S. Q. It is a graph which shows the relationship with.

FIG. 14 is a graph showing changes in magnetic properties after heat treatment.

FIG. 15 is a perspective view showing a cutting line of a cast piece.

FIG. 16 is a perspective view showing the concept of encapsulating an alloy ingot in a metal capsule.

FIG. 17 is a graph showing the relationship between the total rolling processing rate and (BH) _max .

FIG. 18 is a graph showing the relationship between the total rolling rate and iHc.

[Explanation of code] 4 Alloy ingot 5 Metal capsule 6 Rolled material

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 6]

[Figure 1]

[Figure 9]

[Fig. 2]

[Figure 3]

[Figure 10]

[Figure 4]

FIG. 16

[Figure 5]

[Figure 7]

[Figure 8]

FIG. 11

[Fig. 12]

[Fig. 13]

FIG. 14

FIG. 15

FIG. 17

FIG. 18

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tsutsuaki Oki 1-7-7 Karibadai, Nishi-ku, Kobe (72) Inventor Yuji Yuji 4-6-23-C301, Fukuda, Tarumi-ku, Kobe (72) Inventor Hanaki Atsushi 2-6-10-W6608 Kitaoki, Higashinada-ku, Kobe-shi (72) Inventor Eiji Iwamura 2-2-5, Minami-cho, Nara-ku, Nada-ku, Kobe

Claims (6)

[Claims] 1. A method for manufacturing a rare earth element-Fe-B magnet, comprising a step of hot working an alloy ingot containing at least a rare earth element, Fe and B in a metal capsule. Hot working is performed in a state where the working temperature is 800 to 1100 ° C. and the alloy ingot contains a liquid phase, and hot working is performed so that the total working rate at this time is 70% or more, and 10kg strength at processing temperature
/ rare earth element characterized by forming a highly oriented alloy structure by using a metal capsule of / mm ² or more-
Method for manufacturing Fe-B magnet. 2. The alloy ingot contains at least one rare earth element selected from Pr and Nd, Fe and B, and is selected from the group consisting of Ga, In and Sn.
The alloy ingot containing at least one element as an essential component is used, and the capsule surface is water-cooled at an arbitrary time of hot working to form a highly oriented alloy structure. Production method. 3. The method according to claim 1, wherein after the hot working is completed, heat treatment is performed at 800 to 1100 ° C., and then heat treatment is further performed at 400 to 600 ° C. 4. The hot working is carried out so that the upper and lower plate thicknesses of the metal capsule at the time of hot working finishing are 0.5 to 5 mm.
The manufacturing method in any one of -3. 5. A stainless steel or a high manganese steel is selected as the material of the metal capsule, and a release agent composed of boron nitride and a thin plate-shaped Al ₂ O ₃ —SiO ₂ composite oxide is interposed in the metal capsule. The manufacturing method according to claim 1, wherein the alloy ingot is encapsulated by a method. 6. Carbon steel is selected as the material of the metal capsule, and an alloy ingot is formed in the metal capsule with a release agent consisting of boron nitride and a thin plate of Al ₂ O ₃ —SiO ₂ composite oxide interposed. 5. Encapsulation, heating the metal capsule encapsulating the alloy ingot, cooling with water at 0 to 30 ° C. for 0.5 to 3 seconds per 1 mm plate thickness of the metal capsule, and then hot working. The manufacturing method described in.