JPS648691B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a ribbon of a high magnetic permeability alloy called Sendust. Fe-Si-Al gold (sendust), which consists of 4 to 7% Al, 8 to 11% Si, and the remainder mainly iron, or Ni to improve the magnetic and mechanical properties of this alloy.
Alloys containing small amounts of Co, Ti, B, rare earth elements, and other elements have excellent magnetic properties and are highly hard and wear resistant, so they are used in magnetic heads for magnetic recording. used as a core. However, for this purpose, the mother alloy is mechanically cut to obtain thin pieces, which are then laminated to form the core, but Sendust alloy is not only hard but also brittle. The problem was that machining was difficult. Recently, as a method to solve this problem, the sendust master alloy is heated and melted, the molten material is fed onto a single roll or twin rolls rotating at high speed, and the molten material is ultra-quenched on the rolls and solidified into a single piece to produce a ribbon. However, a method has been proposed in which this ribbon is formed into a core shape by etching or punching. According to this method, since it is only necessary to process the continuously manufactured high permeability Sendust alloy thin strip, there is no need for cutting into the thin section compared to the method of directly cutting the core thin section from the Sendust alloy block. It has the advantage of being extremely easy to work with. However, in this method of obtaining a ribbon by rapidly cooling and solidifying a molten material, if the temperature of the molten material is far higher than the melting point when the molten material is supplied onto the moving surface of the moving body, the material may be rapidly solidified. The degree of cooling differs greatly between each part of the supplied material, for example, the part in contact with the moving surface and the part not in contact with it, and heat shrinkage is not performed uniformly.
For this reason, there was a problem that microcracks were generated in the ribbon, and these microcracks had a fundamental defect that could not be removed even by heat treatment. The present invention was made in view of such conventional problems, and involves heating and melting an alloy base material consisting of 4 to 7% Al, 8 to 11% Si, and the remainder mainly iron, and applying this molten alloy base material to the roll of a moving body. In a method for manufacturing a high magnetic permeability alloy ribbon, which is supplied onto a surface and rapidly cooled on a roll surface to solidify into a ribbon, the temperature immediately before supplying the molten alloy base material onto a moving surface is the melting point of this alloy base material. The temperature is set at a temperature range that is directly above or does not exceed 100°C above the melting point, and the viscosity immediately before being supplied onto the moving surface of the molten alloy base material is 6.5 × 10 ^-2 to 4 × 10 ^-2 dyne.sec/cm ² together with the surface temperature of the moving object from room temperature to 460℃
By maintaining the molten base material at a temperature of 920° to 1350°C between the molten base material and the cooling roll, non-uniformity in the degree of cooling during rapid cooling is suppressed, and a ribbon without microcracks is produced. This provides a method to do so. The invention will be explained in detail below. The alloy base material has a so-called sendust composition, that is, Al4~7%, Si8~11%, and the remainder is mainly iron, with V, Nb, Ta, Cr, and Mo added as necessary to improve mechanical and magnetic properties. ,W,Ni,
Co, Cu, Ti, Mn, Ge, Zr, Sb, Sn, Be, B,
Those with small amounts of Bi, Pb, Y, and rare earth elements added are also used. The melting point of this molten base material varies slightly depending on the composition, but is around 1280°C. FIG. 1 shows a manufacturing apparatus used in the method of the invention. With this device, the master alloy 1 is first heated and melted in a non-oxidizing gas atmosphere such as argon gas in the heating cylinder 3 by the heating means 2 using a resistor or coil, and then the heating temperature of the heating means 2 is adjusted to the master alloy. Near the melting point of 1, preferably above the melting point, about 10%
twin rolls 4a, which rotate the molten base material 1 at high speed from the nozzle 3a by lowering the temperature to a range of
4b, and is rapidly cooled by contact with twin rolls 4a and 4b, and simultaneously rolled and solidified to obtain a ribbon 5. Here, the temperature when heating and melting the master alloy 1 is around 1500℃, and if you lower the temperature to just above the melting point just before ejecting, the heating time will be shorter, but it is better to heat and melt it at a low temperature from the beginning. You can also take it. Also rolls 4a, 4b
The material should preferably have a smooth surface with high heat resistance, such as stainless steel, cast iron, or chrome steel. The heating cylinder 3 needs to avoid reaction with the base material 1, and is made of a highly heat-resistant material such as silica or high-purity alumina. Also, the nozzle 3a of the heating cylinder 3
The shape of the strip should be determined depending on the size of the ribbon to be obtained, but if a wide and porous one as shown in Fig. 2 is used, the molten material can be sprayed over a wide range onto the rolls 4a and 4b. The uniformity of the cooling degree can be further improved. Furthermore, in the case of a multi-hole nozzle, if the distance between each hole is increased,
You can get multiple thin strips at once. FIG. 3 shows another manufacturing apparatus, which has a configuration in which a molten material 1 is supplied between an endless belt 6 and a roll 7, and is ultra-quenched and rolled. Even with this device, the belt 6
The material of the roll 7 and the material and shape of the heating tube 3 are almost the same as the apparatus using the twin rolls 4a and 4b shown in FIG. 1 above. In the case of the ribbon obtained in this way, the temperature of the base material immediately before it is supplied by the moving body is just above its melting point (temperature not exceeding 100°C above the melting point), so the supply Immediately afterward, there is no significant difference in the degree of cooling between the parts that come into contact with the moving surface of the moving body and the parts that do not, and as a result, the molten base material is cooled relatively slowly, causing thermal contraction due to rapid cooling. This process occurs relatively uniformly throughout, making it possible to obtain a ribbon free of microcracks. In addition, the temperature just above the melting point of the base material is:
From the inventor's experiments, it is about 10% above the melting point, about 100
The effect is obtained in a range of approximately 50°C, and the effect is particularly remarkable in a range of about 50°C, which is about 5% above the melting point. Please note that the temperature of the roll, which is a moving body, is between room temperature and 460℃.
By holding the material at a temperature of 0.degree. C., the thermal shrinkage caused by ultra-rapid cooling is alleviated, and the thermal shrinkage occurs relatively uniformly throughout the material, which has the remarkable effect of preventing the generation of microcracks. The preferred temperature range for the roll, which is a moving body, is
The temperature is between 100℃ and 300℃. The temperature just before ejection of the molten base material is determined from the melting point of the base material.
It is necessary to keep the temperature within a range of not exceeding 100°C and to maintain a relatively high viscosity, and the viscosity is preferably 6.5×10 ^-2 to 4×10 ^-2 dyne.sec/cm ² . However, if the viscosity of the molten base material is higher than the above-mentioned upper limit, the viscosity will be too high and the extrusion pressure will be too high, making it difficult to implement, so this is not necessary. In addition, if the viscosity is less than the lower limit mentioned above, the viscosity will become too small, and if the extrusion pressure is too high, it will become mist-like, blind-like, or wave-like, which is undesirable. is preferred. Temperature difference between molten base material and cooling roll: 920℃~
Better results can be obtained if the temperature is not too high, around 1350°C. This is because microcracks do not occur when thermal contraction due to ultra-rapid cooling occurs relatively uniformly throughout the material. The roll rotation speed is preferably 650 to 10,000 RPM. If the roll rotation speed is low, a thick ribbon of about 100μ can be obtained,
If the rotation speed of the roll is high, a thin ribbon of about 50μ to 10μ can be obtained. When the jetting temperature of the molten base material is as high as about 1500°C, a higher rotation speed has the same effect as reducing the temperature difference between the molten base material and the cooling roll, making it difficult for microcracks to occur. If the temperature difference between the molten base material and the cooling roll is below the lower limit, ultra-rapid cooling cannot be obtained even if the rotational speed of the roll is variously changed, which is not preferable. Furthermore, if the temperature difference is above the above-mentioned upper limit, thermal contraction due to ultra-rapid cooling occurs unevenly throughout the material, producing microcracks in the central portion. Since these microcracks cannot be eliminated by subsequent heat treatment, the material becomes brittle and its workability deteriorates, making it impossible to obtain the desired flexibility. When twin rolls are used as a moving body, columnar crystals develop inward from the surface in contact with the rolls. This is heated at 600°C to 950°C, preferably around 850°C.
Heat treatment for 5 minutes to 5 hours will cause the crystals to become coarse and the flexibility will be slightly inferior, but the coercive force will improve, so it is better to perform heat treatment. The present invention will now be described in detail based on Examples. Example 1 2 g of master alloy block 1 having a composition of Al5.38, Si9.37, and Fe85.25 was placed in the heating cylinder 3 of the apparatus shown in Fig. 1, and heated by a SiC heater in an Ar gas atmosphere. The material is heated and melted at approximately 1450°C by means 2, and then the amount of power supplied to heating means 2 is reduced to lower the temperature to approximately 1320°C, the Ar gas pressure is increased to 0.5 atm, and the molten material 1 is transferred from the nozzle 3a to the twin roll 4a. , 4b, and was rapidly cooled and rolled with twin rolls 4a and 4b to obtain a ribbon 5. Here, the heating cylinder 3 is made of silica with an outer diameter of 8 mm and an inner diameter of 6 mm, and the nozzle is
It was 0.5mm in diameter. Further, the rolls 4a and 4b are made of chrome steel with a diameter of 65 mm, and the rolls 4a and 4b are brought into close contact with each other, and the nozzle 3a and the roll 4 when the material 1 is ejected are
The test was carried out at a rotational speed of 1000 rpm with the distance between a and 4b being as close as possible to approximately 0.2 mm or less. The obtained ribbon is 100 μm thick, about 2 mm wide, and about 10
It was heat-treated in vacuum at about 850° C. or less, and then a core thin piece 5a was punched out and its surface condition and magnetic properties were measured. Example 2 2 g of a master alloy having the same composition as in Example 1 was placed in a heating cylinder made of high purity alumina, and the experiment was carried out using the same apparatus as in Example 1. However, the nozzle diameter is 1.0 mm, the roll rotation speed is 650 rpm, and the temperature just before ejecting the molten material is approximately 1380.
℃. The obtained ribbon is 100 μm thick, about 2 mm wide, and about 5
This was heat-treated under the same conditions as in Example 1, and a core thin piece 5b was punched out to measure its surface condition and magnetic properties. Comparative Example A test was carried out using 2 g of a master alloy having the same composition as in Example 1 and using the same apparatus as in Example 1. However, the heating temperature of the master alloy was approximately 1450°C and it was ejected at that temperature. The obtained ribbon is 80 μm thick, approximately 2 mm wide, and approximately 10 m long.
After heat treating it under the same conditions as in Example 1, a core thin piece 5c was obtained, and its surface condition and magnetic properties were measured. The measurement results of the surface condition and magnetic properties in the above Examples and Comparative Examples are as shown in the following table and FIG. 4.

【table】

[Table] As can be seen from the above table and FIG. 4, there is no difference in magnetic properties between the Examples and Comparative Examples, but the core of Example 1 of the present invention has a lower surface temperature at the time of material ejection. There were almost no micro-cracks in the core of Example 2 of the present invention, which had a slightly higher temperature, but a few micro-cracks 8 were generated in the core of Example 2 of the present invention. Therefore, according to the present invention, a core with an extremely good surface condition and no influence on magnetic properties could be obtained.

[Brief explanation of drawings]

Fig. 1 is an overall view of the device used in one embodiment of the present invention, Fig. 2 is a perspective view of a multi-hole nozzle used in the same device, and Fig. 3 is an overall view of the device used in another embodiment of the present invention. , FIG. 4 is a cross-sectional view of a ribbon core piece obtained by an example of the present invention and a conventional example. 1... Master alloy material, 2... Heating means, 3... Heating tube,
3a... Nozzle, 4a, 4b... Roll, 5... Thin strip,
6...belt, 7...roll, 8...micro crack.

Claims (1)

[Claims] 1 An alloy base material consisting of Al4~7%, Si8~11%, and the remainder mainly iron is heated and melted, this molten alloy base material is supplied onto the roll surface of a moving body, and is rapidly cooled on the roll surface to solidify into one piece. In the method for producing a high magnetic permeability alloy ribbon, the temperature immediately before supplying the molten alloy base material onto the moving surface is set to a temperature range that is immediately above the melting point of the alloy base material or does not exceed 100 ° C above the melting point,
The viscosity of the molten alloy base material immediately before being supplied onto the moving surface is set to 6.5×10 ^-2 to 4×10 ^-2 dyne.sec/cm ² and the surface temperature of the moving body is maintained at room temperature to 460°C,
and the temperature difference between the molten base material and the cooling roll.
A method for producing a high magnetic permeability alloy ribbon, characterized in that the temperature is 920° to 1350°C.