JPH0620612B2 - Quenched metal manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a method for producing a solidifying material (ribbon, tape, flakes, etc.) in which molten metal is sprayed onto a rotating roll using a plurality of small-diameter nozzles to quench the molten metal. Related to the improvement of.

(Prior art and its problems) Compared with the conventional melt casting method (hereinafter abbreviated as I / M method), the method of rapidly solidifying molten metal and solidifying the obtained quench material to produce various products is , (1) The type and amount of addition of alloying elements can be significantly increased, and (2) the miniaturization of crystal grains and the fine dispersion of second phase grains are promoted. For this reason, new alloys, which cannot be obtained by the conventional I / M method, can be expected to be developed.

By the way, what is particularly important in promoting this type of rapid solidification technology is how to efficiently and stably produce a rapidly solidified material as a raw material, and answer such a request. Therefore, various methods and devices have been proposed.

At present, the single roll method and the twin roll method are relatively widely used. In particular, the single roll method is relatively simple in terms of equipment and is therefore most widely used.

The principle of this method and the outline of its usage are briefly described as follows.
As shown in the figure, first, the molten metal 1 melted in a closed crucible 4 having a heating device 5 such as an induction heating coil or a heating heater is fed with a gas introduction pipe (usually an inert gas such as Ar or N _2). The small diameter nozzle 2 (usually 0.2 to 1.0 mm) is pressurized by the inert gas introduced by the use 3).
φ), and a molten metal jet 6 is formed. The molten metal jet (hereinafter, jet) 6 is a nozzle 2
At the same time as being stretched in a thin strip shape on the surface of the rotating roll 7 arranged immediately below, it is rapidly cooled and solidified by a rapid heat absorbing effect from the roll to form a ribbon R, and then sent to a recovery container or a winding device. And collected (generally called the melt spinning method).

In such a single roll method, one of the important factors is how to form a stable jet in order to produce a uniform continuous ribbon by adopting the melt spinning method. It is normal to operate with the distance (l) as small as possible.

Further, in order to improve productivity, a plurality of nozzles may be provided to obtain a large number of ribbons R at the same time, as shown in FIG.

However, the nozzle diameter of this kind is 0.2-1.0 mmφ
Since it has such a small diameter, it is very easily clogged, and it is relatively frequently clogged by inclusions (oxide, refractory material, oxide film, etc.) contained in the molten metal. Other than the above, the cause of blockage is oxidation of the molten metal in the vicinity of the nozzle due to the atmosphere flowing through the nozzle during melting / holding in the crucible before the start of injection. Therefore, an inert gas atmosphere is used in the chamber and the crucible surrounding the entire device to prevent nozzle clogging.However, when quenching a metal, the temperature of the molten metal is considerably increased due to the melting point of the additive element for alloying. There is a case where the temperature is raised to a high level, and although a non-reactive graphite crucible is used, a reaction product with the crucible is often generated, and an oxide is often generated even in the inert gas atmosphere. Is hard to avoid.

When one nozzle is clogged (a part or all of the nozzle) due to such a cause, the jet to be jetted becomes unstable, and for example, fluctuation of the flow velocity, reduction of the flow diameter,
There are phenomena such as fluctuations in the jetting angle (Fig. 6 (a)), a jet is not formed and drops (Fig. 6 (b)), and jetting is impossible due to complete blockage. As a result, in the case of ~, a ribbon of a quality different from the initial purpose is produced, and in the case of ~, or in the case of severe, the ribbon is not formed, and as shown in FIG. The unstable jet or the dropped droplets are repelled and become small droplets. Such a destabilization or dropping phenomenon of the jet naturally occurs even when the number of nozzles is one, but when a plurality of nozzles are provided, an unspecified number of them occurs. Therefore, when a plurality of nozzles is adopted as in the case of FIG. 8, jet instability occurs in an unspecified number of nozzles, and the above-mentioned droplets are scattered,
Some of these scattered droplets will adhere to the adjacent sound ribbon, and some will be mixed in the collection container or the winding device. Such scattered droplets are not rapidly solidified on the roll surface, but are rapidly depleted and solidified by the ambient atmosphere gas during flight after reflection on the roll surface, so the cooling rate is very slow ( Hereinafter referred to as slowly cooled powder). The ribbon to which the slow-cooled powder adheres and mixes causes a structural nonuniformity in the solidified molding material thereafter, which causes characteristic deterioration and makes it impossible to obtain a good final product.

In particular, when producing a continuous ribbon with a multi-hole nozzle, even if one of the nozzles is clogged as described above and the jet becomes unstable (Fig. 8), it is manufactured from the remaining normal nozzles. The quality of even the ribbon will deteriorate. Therefore, until now, we have taken all measures such as discarding all the products obtained by the charge, or immediately stopping the operation when blockage (or instability of the jet) is found. It was a major cause of sex deterioration. Such a decrease in productivity was especially remarkable in active metals such as Al and Mg which are highly oxidizable.

(Problems to be solved by the invention) Therefore, in order to prevent a decrease in productivity, it is necessary to close the nozzle in which the jet becomes unstable, but a slide nozzle or an immersion type stopper is used to open and close the molten metal nozzle. In that case, the former must attach a nozzle that drives to a small gap between the nozzle and roll (usually 10 mm or less), and requires advanced stopper processing technology and its driving technology, if not technically impossible. , Which will lead to soaring equipment costs. Particularly in recent years, in order to suppress the oxidation of the ribbon due to the demand for quality improvement, it is necessary to manufacture the ribbon in an inert gas atmosphere in the airtight chamber. In this case, the above drive stopper is provided in the airtight chamber. It is needless to say that it becomes more difficult to provide and control it, and expensive equipment is required. In order to further improve the productivity, it is obvious that mounting the drive stoppers independently on a large number of nozzles, such as 10 holes and 20 holes, also causes the equipment price to rise.

In the latter case as well, it is complicated to install a large number of vertical drive type stoppers for each nozzle independently.
This will lead to high prices.

Further, in both the former case and the latter case, it is undeniable that the productivity is lowered due to the troublesome maintenance such as the replacement of the stopper after the operation is completed.

Furthermore, in both methods, when trying to improve productivity with a very large number of nozzles such as several tens of holes, the nozzle gap must be widened to 10 mm and 20 mm due to the arrangement of the stopper, which is why There is also a disadvantage that the crucible, the melting furnace, etc. are increased in size.

The present invention is a melt spinning method or the like, in which a molten metal in a crucible is jetted as a molten metal jet from a plurality of small-diameter nozzles, and rapidly solidified on a rotating roll arranged immediately below the nozzles to solidify material such as ribbons, tapes, and flakes. In manufacturing the product, it is possible to prevent the production of defective ribbons due to jet instability caused by blockage of an unspecified number of nozzles among multiple nozzles with extremely simple and low-cost equipment, thus improving productivity and yield. The purpose is to provide superior technology.

(Means for Solving the Problem) The present invention is to inject a metal melt in a crucible as a melt jet from a plurality of small-diameter nozzles, and rapidly solidify the melt on a rotating roll arranged immediately below the nozzles to form ribbons, tapes, flakes, and the like. When manufacturing the solidified material of No. 1, we detected the instability or droplet formation of the molten metal jet that occurred in an unspecified number of nozzles among the multiple nozzles, and provided multiple nozzles corresponding to each nozzle. The gas injection pipe of is selectively operated to inject gas between the nozzle and the rotating roll in the direction opposite to the direction of flight of the solidified material, and the unstable molten metal jet or droplets jetted from the nozzle is cooled to rapidly cool the solidified material. If it is blown away in the direction opposite to the flight direction to remove it and separate it from the normal solidified material, the slow cooling powder adheres and mixes due to jet instability caused by nozzle clogging. The present invention has been completed by finding that it is possible to prevent the occurrence of such defective ribbons with extremely simple and low-priced equipment.

Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings.

(Embodiment) FIG. 1 and FIG. 2 are schematic elevational views of an apparatus for carrying out the present invention. Like the conventional single roll method shown in FIG. 5, a closed crucible 4 having a heating device 5 is provided. The molten metal 1 melted inside is pressurized by the inert gas introduced through the gas introduction pipe (usually using an inert gas such as Ar or N ₂ ) 3,
Although not shown in the drawing, the molten metal jet (hereinafter, jet) formed in the same manner as in FIG. 5 is injected through a plurality of small diameter nozzles 2 (usually 0.2 to 1.0 mmφ).
At the same time as being stretched in the shape of a ribbon on the surface of the rotating roll 7 arranged immediately below the nozzle 2, it is rapidly cooled and solidified by the effect of abrupt heat removal from the roll, and then collected in a recovery container (not shown) or a winding device (not shown). (Omitted) to be collected. However, although FIG. 1 shows an example in which a plurality of nozzles are used, only one nozzle 2 can be seen due to the field of view.

In the present invention, as shown in FIG. 1 and FIG.
Between each of the nozzles 2, ... And the rotating roll 7 in parallel with the ribbon flight direction shown in FIG. 1, that is, perpendicular to the roll rotation axis direction, and the jet port is opposite to the ribbon flight direction. While arranging the small-diameter gas injection pipes 8, ..., A container 9 is provided facing the gas injection pipe 8 to receive and store the splashed droplets.

The diameter of the injection pipe 8 is, of course, smaller than the nozzle / roll distance 1 set during operation, but it hinders the ribbon from flying while the ribbon is normally formed from the target nozzle. Select the pipe diameter within the range that does not exist.

Regarding the mounting position, it is preferable to mount it on the side of the nozzle 2 as much as possible so as not to hinder the flight of the ribbon, and in short, it may be arranged between the nozzle and the roll within a range that does not hinder it. Further, the tip position and the injection pressure of the injection pipe 8 will be described. First, in order to blow off the unstable jet or the dropped droplet efficiently and surely, the tip position is the nozzle 2 as much as possible.
However, if it is necessary to secure a certain distance due to restrictions such as the pipe diameter, the structure of the device, the mounting method, and the monitoring of the nozzles for operation, then the injection gas from the injection pipe However, it may be retracted to a range that does not disturb the stability of the jet by acting on the jet of the adjacent nozzle. Further, it is advantageous to increase the pressure of the gas introduced into the injection pipe 8 in order to surely blow the unstable jet or the dropped droplets to the side opposite to the ribbon flight direction. Since the waste, the adverse effect on the adjacent jet, and the mixing of the blown fine powder into the ribbon due to unnecessary gas convection in the chamber, etc. occur, it is sufficient to select a pressure that can be reliably sent to the storage container 9. However, if the pressure is too low, the blow-off is insufficient, and some or all of the jet or the dropped droplets drop on the roll surface, causing the above-mentioned inconvenience.

On the other hand, in order to detect the state in which the molten metal jet becomes unstable (fluctuation of the injection angle shown in FIG. 6 (a)) or dropletized (FIG. 6 (b)), the gas injection pipe 8 is used. While the photoelectric switch projector 10 is arranged on the side, the photoelectric switch receiver 12 is arranged on the side of the storage container 9 so as to face it. When the molten metal jet becomes liquid droplets, such a state is detected as a change in the amount of light, and the electromagnetic valve 14 provided in the gas injection pipe 8 is opened via the control device 13 to release the inert gas from the gas injection pipe 8. The droplets are ejected and blown off into the container 9 to be stored. In the drawing, in order to avoid cooling of the projector and the light receiver and adhesion of splashed powder, the light projector 10 is built in the gas injection pipe, and a pipe 15 for supplying an inert gas is provided on the front surface of the light receiver 12. In addition, 11 is a power supply for light projection.

Instead of the above photoelectric detection, an infrared imaging device 20 may be used as shown in FIGS. 3 (a) and 3 (b). In this case, when the camera unit is arranged above the front of the roll and the temperature of the plurality of ribbons is constantly measured, when a droplet is generated (the third
In the figure (b), when the roll surface temperature (usually lowered to 200 to 250 ° C due to the water cooling effect) is measured, the surface temperature of the flying ribbon (usually 300 to 500 ° C) is measured (Fig. 3 ( Since the temperature is lower than that in a)), it is possible to detect the time of droplet generation by image analysis.

The apparatus structure may be appropriately determined according to the type of metal and operating conditions (nozzle diameter, nozzle / roll distance, distance between adjacent nozzles, etc.).

Although the present invention has been described above in the case of the single roll method, the double roll method can be applied as shown in FIG. 4 when the nozzle is arranged above the upper surface of the roll. . The same members are designated by the same reference numerals and the description thereof is omitted.

(Production Example) While using the Al-8% Fe-8% (La, Ce) alloy to produce a ribbon by the method of the present invention, the ribbon production situation and the quality of the ribbon can be determined in the case where the present invention is not applied. The results of the comparative investigation are shown in the table below.

The main conditions for the implementation of this study are as follows.

(A) Ribbon manufacturing conditions: Dissolved amount = 3 kg Nozzle diameter = 0.5 mmφ Nozzle number, nozzle spacing = Table above Roll diameter = 300 mm φ Roll rotation number = 2500 rpm Nozzle / roll distance = 7 mm (b) Implementation conditions of the present invention: gas Injection diameter = 3 mm Gas injection pipe tip position = 2 mm from nozzle center Injection pressure = 2.0 kg / mm ² Injection gas = Ar (Function and effect of the invention) As is clear from the above description, according to the present invention, the nozzle Unstable jets or dripping droplets resulting from blockage were blown away in the direction opposite to the ribbon flight direction, and it was possible to prevent inferior ribbons or slow-cooled powders from mixing into high-quality ribbons with a very simple facility. Even if the operation had to be stopped, it was possible to continue the operation as it is and to collect only high-quality ribbons. It can be significantly increased.

[Brief description of drawings]

FIG. 1 is an elevational view showing the outline of an apparatus for carrying out the method of the present invention, FIG. 2 is an elevational view as seen in the direction of the arrow along the line II-II in FIG. 1, and FIG. 3 is an infrared imaging apparatus. FIG. 4 is an elevational view showing the outline of the apparatus when the present invention is applied to the twin roll method, and FIG. 5 is the apparatus configuration of the conventional single roll method. Fig. 6 (a) is an elevational view showing
And (b) are explanatory views showing a jetting angle variation state of a molten metal jet and a droplet dripping phenomenon, FIG. 7 is an explanatory diagram showing a droplet formation state due to droplet formation, and FIG. 8 is a droplet (slow cooling powder). It is explanatory drawing which shows the phenomenon which an adjacent ribbon deteriorates by formation. 1 ... Metal melt, 2 ... Small diameter nozzle, 4 ... Sealing crucible, 6 ... Metal melt jet, 7 ... Rotating roll, 8 ... Gas injection pipe, 10 ... Emitter, 12 ... Receiver, 20 ...... Infrared imager, R ... Ribbon, L ... Splash.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Kawabata 2-3-2, Jinryodai, Tarumi-ku, Kobe-shi, Hyogo Prefecture 2-406 (72) Inventor Yuichi Ando 14-87-502, Edagawa-cho, Nishinomiya-shi, Hyogo Prefecture

Claims (1)

[Claims] 1. A method for producing a solidified material such as ribbons, tapes, flakes, etc. by injecting a metal melt in a crucible as a melt jet from a plurality of small-diameter nozzles and rapidly solidifying the melt on a rotating roll arranged immediately below the nozzles. When any of the molten metal jets ejected from the plurality of nozzles becomes unstable or drops, it is detected and the above among the plurality of gas injection pipes provided corresponding to each nozzle. The gas is sprayed in the direction opposite to the flight direction of the solidified material between the nozzle and the rotating roll by the gas injection pipe corresponding to the nozzle in which the jet is destabilized or liquefied, and is injected from the nozzle while manufacturing the normal solidified material. A method for producing a quenched metal, characterized in that an unstable molten metal jet or droplets are blown away in a direction opposite to the flight direction of the normally solidified material to be excluded.