JP6379604B2 - Mixing blade for molten metal - Google Patents

Description

  The present invention relates to a molten metal stirring blade for stirring molten metal (for example, molten iron).

Hot metal desulfurization is performed by the KR method (mechanical stirring type). Specifically, as shown in FIG. 3, after the hot metal 91 is put in the hot metal ladle 90, an impeller (stirring blade) 92 is immersed in the hot metal 91 from above the hot metal pan 90, so The desulfurizing agent is entrained in the hot metal 91 and efficiently dispersed by rotating the impeller 92 at a high speed while introducing the desulfurizing agent into the hot metal.
In general, as shown in FIGS. 4A and 4B, the impeller 92 has a Y-shaped (or V-shaped) metal stud (support) on the surfaces of the iron shaft core 93 and the blade core 94. ) 95 is attached, and a refractory (castable) 96 is poured and installed. Examples of the refractory 96 used for manufacturing the impeller 92 include materials such as Al ₂ O ₃ , 3Al ₂ O ₃ .2SiO ₂ (mullite), SiC, and SiO ₂ that are excellent in heat-resistant spalling properties.

With the impeller configured as described above, the corrosion resistance of the refractory does not affect the impeller life. Normally, the refractory provided on the blade core metal does not crack and peels off rather than the shaft core metal. Depending on the situation, the life of the impeller is determined.
This is because when the impeller is used, a large thermal shock is applied to the refractory (during use, the impeller is repeatedly immersed in the hot metal and removed from the hot metal, and the refractory is repeatedly heated and cooled (heat radiation cooling). ) And the difference in expansion between the metal stud and the refractory (the metal has a larger thermal expansion than the refractory, so the impeller is used hot) This is because stress is applied to the cracks and the refractories are peeled off. In addition, the hot metal is inserted from a crack generated in the refractory, and the metal stud and the blade core metal are melted.

In order to solve the above problems, the following impeller has been proposed.
For example, in Patent Document 1, a core (shaft core and blade core) of an impeller and a refractory covering the surface of the core, and a stud (anchor) attached to the core A thin forming material such as a sheet, a tape, and a paint is disposed between the refractory material surrounding the refractory material and disappears at a high temperature to correspond to the thickness of the thin forming material described above. And a desulfurization impeller in which stress is relaxed so as to absorb a difference in expansion due to thermal shock.
Further, in Patent Document 2, a structure having a metal stud extending from a cored bar to a lower outer edge of the blade part is used for stirring the molten metal to prevent the refractory covered with the cored bar from dropping off in the blade part. An impeller is disclosed.

Japanese Patent Laid-Open No. 2003-166011 JP 2011-184762 A

As described above, each of the impellers described in Patent Documents 1 and 2 describes a configuration for suppressing cracking and peeling of the refractory.
However, in the use of the impeller, since the refractory is immersed in the hot metal, as described in Patent Document 1, even if a micro gap is provided between the stud and the refractory, the refractory is sintered. Advances and the micro voids disappear.
In addition, although the impellers described in Patent Documents 1 and 2 have a certain effect in suppressing cracking and peeling of the refractory, they use a metal stud as a refractory support. Stress relaxation resulting from the differential expansion of the stud and the stud is insufficient. For this reason, the crack which generate | occur | produced in the refractory progresses, the hot metal penetrate | invades from the part and crack which the refractory peeled, and a metal stud becomes a runway, thereby damaging the core metal.
From the above, the impellers described in Patent Documents 1 and 2 cannot fundamentally solve the suppression of cracking and peeling of the refractory.

  The present invention has been made in view of such circumstances. Conventionally, the difference in expansion caused by a metal stud used as a refractory support is alleviated, and the occurrence of cracks in the refractory is reduced. It aims at providing the stirring blade for molten metal which can improve the durability of a thing.

The present inventors have in view of the shortcomings of metal studs to the support is used, it focuses on the fact differential expansion of the heat-resistant inorganic fibers and refractory is small, to apply the inorganic fibers on a support Thus, it was considered that the above-mentioned drawbacks could be solved.

The stirring blade for molten metal according to the present invention that meets the above-described object has a shaft cored bar and a bladed cored bar provided at the tip of the shaft cored bar, and the shaft cored bar and the bladed portion. In the stirring blade for molten metal where the surface of the metal core is covered with an irregular refractory,
At least the surface of the blade core metal is provided with a ring formed of an inorganic fiber rope using long fibers , and the ring is embedded in the amorphous refractory.

  In the molten metal stirring blade according to the present invention, the inorganic fiber rope preferably has a diameter of 5 mm to 30 mm.

In the molten metal stirring blade according to the present invention, the support for supporting the amorphous refractory on the core metal (at least the blade core metal) is composed of an inorganic fiber rope. In comparison, the difference in expansion from the amorphous refractory can be reduced, and the generation of cracks in the refractory can be drastically reduced.
In addition, since the above-mentioned inorganic fiber rope is formed in a ring, unlike the case where this rope is made linear, the pull-out of the rope from the amorphous refractory can be suppressed and further prevented. It can be securely held on the mandrel via a rope.
Furthermore, since the ring is embedded in the irregular refractory, direct contact between the ring and the molten metal can be prevented, and deterioration of the ring can be suppressed and further prevented. In addition, when using the stirring blade for molten metal, the ring may be partially exposed from the surface of the irregular refractory. However, since the ring is made of the above-mentioned material, the ring is damaged as compared with a conventional metal stud. (In the case of a metal stud, the stud melts due to the molten metal, and the core metal melts due to the molten metal that has penetrated.)
Therefore, as compared with a molten metal stirring blade using a conventional metal stud, it is possible to suppress the peeling of the irregular refractory and the core metal from being melted, thereby extending the life of the molten metal stirring blade.

  Further, when the diameter of the inorganic fibrous rope is 5 mm or more and 30 mm or less, a rope having sufficient strength to support the irregular refractory can be formed in the ring with good workability.

It is explanatory drawing which shows the lining structure of the irregular refractory material of the stirring blade for molten metals which concerns on one embodiment of this invention. (A)-(C) is explanatory drawing which shows the lining structure of the irregular-shaped refractory of the stirring blade for molten metals which concerns on a modification, respectively. It is explanatory drawing which shows the hot metal desulfurization method. (A) is explanatory drawing which shows the lining structure at the time of carrying out the cross-sectional view of the stirring blade which concerns on the conventional example used by the desulfurization method of the hot metal, (B) shows the lining structure at the time of carrying out the cross-sectional view of the stirring blade. It is explanatory drawing.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIG. 1, a molten metal stirring blade (hereinafter also simply referred to as a stirring blade) according to an embodiment of the present invention is provided at a shaft cored bar 10 and a tip of the shaft cored bar 10. A blade core metal 11 and a shaft core metal 10 and a surface 12 of the blade core metal 11 covered with an indeterminate refractory (hereinafter also simply referred to as refractory) 13 (FIGS. 3 and 4). (Refer to (A) and (B)), which reduces the occurrence of cracks in the refractory 13 and improves the durability of the refractory 13. This will be described in detail below.

The stirring blade is an impeller used in a hot metal desulfurization KR apparatus, but is not particularly limited as long as the molten metal is stirred. In addition, the magnitude | size and shape (blade part shape) of a stirring blade are not specifically limited, According to the use application (for example, the kind and purpose of molten metal), it can change variously.
The shaft core metal 10 and the blade core metal 11 constituting the stirring blade are made of, for example, iron, the shaft core metal 10 is columnar (or cylindrical), and the blade core metal 11 is plate-shaped. Yes. A plurality of (for example, four) blade cores 11 (blade portions) are provided on the shaft core 10 at equal angles with the shaft core 10 as the center. The number of blade cores 11 can be variously changed to one or a plurality of two or more depending on the use application of the stirring blade.

A plurality of rings 14 formed of an inorganic fiber rope are provided on the surface 12 of the shaft core metal 10 and the blade core metal 11, and the rings 14 are embedded in the refractory 13. That is, the ring 14 has a stud function used in place of a conventional metal stud.
For example, the thermal expansion coefficient at 800 ° C. is 11 × 10 ⁻⁶ / K (SS400) for a conventionally used metal stud, while 7.2 × 10 ⁻⁶ / K (Al ₂ O ₃ ). As described above, since the thermal expansion coefficients of the respective materials are greatly different, the number of occurrences of cracks in the refractory can be drastically reduced when an inorganic fiber rope is used instead of the metal stud.
In addition, since the above-mentioned rope is manufactured by knitting inorganic fibers, for example, in the form of braids, even if it is thermally expanded, it does not expand so as to cause cracks in the refractory like a metal stud. . Further, the rope can be easily deformed. Furthermore, even if the refractory around the inorganic fiber is deformed at a high temperature, the inorganic fiber inside the refractory is deformed following the deformation of the refractory, so that the internal stress can be relieved.

The inorganic fiber constituting the rope is a fiber having heat resistance, and the chemical component (material) to be configured is, for example, Al ₂ O ₃ quality, SiO ₂ quality, Al ₂ O ₃ —SiO ₂ quality, It is a long fiber (inorganic long fiber) which is any one or two or more of Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ .
This inorganic fiber has heat resistance and strength even in an environment in which the strength of the metal stud is reduced (for example, at a high temperature of 600 ° C. or higher, or even 1000 ° C. or higher). If it is comprised with said chemical component, it is preferable from satisfying such heat-resistant conditions.

Among the above materials, in particular, Al ₂ O ₃ —SiO ₂ is more preferable because it is excellent in high temperature resistance and cost performance.
Among these Al ₂ O ₃ —SiO ₂ materials, inorganic fibers having a composition in which Al ₂ O ₃ is 70% by mass or more (for example, Al ₂ O ₃ : 72% by mass, SiO ₂ : 28% by mass) are easily available. In addition, the cost performance is good, and inorganic fibers having a composition of Al ₂ O ₃ of 90% by mass or more (for example, Al ₂ O ₃ : 90% by mass, SiO ₂ : 10% by mass) are more excellent in heat resistance. .
In addition, even if other materials are used, the rope can be used at a location where the temperature does not become too high if the rope is manufactured using inorganic fibers that can be formed into a rope shape with heat-resistant fibers. For example, carbon fiber, fibers such as Al ₂ O ₃ —SiO ₂ —CaO, CaO—SiO ₂ , etc. are applicable.

A plurality of inorganic fibers used for the rope can be twisted into a yarn, and it is necessary that a plurality of the yarns can be bundled to form a braid and processed into a rope shape. In addition, what has a diameter of about 0.2-1 mm can be used as a yarn, for example, It is preferable to use what has a diameter of about 5-30 mm as a rope, for example.
Thereby, a rope can be manufactured.
In addition, examples of the type of braid processing described above include 8 strokes, 16 strokes, and hammering, but the types are not particularly limited. The rope may have a hollow shape such as a sleeve, but preferably the rope has as little space as possible.

In order for the rope to exhibit strength as a stud function within the irregular refractory, it is essential to use long fibers (continuous fibers) as the material of the rope as described above. On the other hand, even when short fibers are used, it is possible to process the braid into a rope shape, but since the fibers are easily pulled out, they do not perform the stud function.
In addition, when using a long fiber, adjustment of tensile strength required as a stud function is possible by changing the diameter of the above-mentioned rope. This long fiber has a fiber length of m (meter) or more (usually more than km (kilometer) order) and is easily distinguished from a short fiber having a fiber length of about 1 to 50 mm. .

As described above, the rope having the stud function in the amorphous refractory has an improved tensile strength as the diameter thereof increases, and thus can improve the refractory peeling prevention effect. In particular, it is preferable that the diameter of the rope is 5 mm or more because the above-described effect is stabilized.
On the other hand, as the diameter of the rope increases, it becomes difficult to form the rope into a ring (bend into a ring). In particular, when the diameter exceeds 30 mm, it tends to be difficult to form a ring.
Therefore, it is preferable that the rope has a diameter of 5 mm or more and 30 mm or less (more preferably 20 mm or less).

As shown in FIG. 1, the ring 14 is attached to the surface 12 of the shaft core 10 and the blade core 11 using a metal ring (connecting member) 15.
The ring 15 is an annular metal member having a through-hole inside, and the both ends of the ring-shaped rope are aligned and inserted into one side of the through-hole of the ring 15. The rope can be formed on the ring 14 by caulking. Then, the ring 15 is pressed to form a pressure-bonding portion 16, and the rope and the ring 15 are pressure-bonded to prevent the rope from being pulled out from the ring 15.
In addition, this ring 15 is arranged so that its axis is perpendicular to the surface 12 of the shaft core 10 and the blade core 11, and the periphery of the ring 15 is welded to the surface 12. Thus, the ring 14 is provided on the surface 12 of the shaft core 10 and the blade core 11.

Here, the installation interval of the ring 14 (ring 15) is not particularly limited, and may be appropriately determined based on the same concept as a conventional metal stud.
Further, the plurality of rings 14 are arranged so that the axial center of the through hole 17 is different from the axial center of the through hole 17 of the adjacent ring 14 (here, the axial center of the through hole 17 is horizontal with the vertical direction). Arranged alternately in the direction). Thereby, although the stud function of the refractory 13 to the surface 12 of the shaft core metal 10 and the blade core metal 11 is enhanced, the axial center of the through hole 17 of each ring 14 can be made the same.

Further, as described above, the ring 14 is preferably installed on the entire surface 12 of the shaft core metal 10 and the blade core metal 11, but at least a portion where the number of cracks is large, that is, the blade core metal 11 ( In particular, it is preferable to install it on the surface 12 of the lower part of the blade core 11 and further on the lower corner) from the viewpoint of workability and economy. In this case, a conventionally used metal stud (V-type or Y-type) can be installed at a portion where the ring 14 is not installed.
In addition, although the site | part with many generation | occurrence | production of the above-mentioned crack can be grasped | ascertained by the past operation performance etc., it can also grasp | ascertain by numerical analysis, for example.

Moreover, the attachment structure of the ring to the core metal surface is not limited to the above-described structure, and for example, the structure shown below can be used.
As shown in FIG. 2 (A), a metal ring (connecting member) 20 having a through-hole inside is used, and end portions of the rope are respectively inserted from both sides of the through-hole of the ring 20 so that the rope is Make a ring. Next, both ends of the rope are aligned in the ring 20, and the ring 20 is pressed to form a crimping portion 21, and the rope and the ring 20 are crimped to prevent the rope from being pulled out of the ring 20.
In addition, by arranging the ring 20 so that the axial center thereof is parallel to the surface 12 of the shaft core metal 10 and the blade core metal 11, and welding the side surface of the ring 20 to the surface 12, A ring 22 can be provided on the surface 12 of the shaft core 10 and the blade core 11.

Further, as shown in FIG. 2B, a through hole 23 (for example, a diameter of about 10 to 20 mm) is formed on the surface 12 side of the shaft core metal 10 and the blade core metal 11. Both ends of the rope are pushed in from both sides, and both ends of the rope are fixed in the through hole 23. Thereby, the ring 24 can be provided on the surface 12 of the shaft core metal 10 and the blade core metal 11.
And as shown in FIG.2 (C), the L-shaped locking pin 25 was provided in the surface 12 of the axial part metal core 10 and the blade | wing part metal core 11, and this locking pin 25 was formed with the rope. The ring 26 can be provided on the surface 12 of the shaft core 10 and the blade core 11 by hooking (or connecting) the ring 26.

The ring 14 described above (the same applies to the rings 22, 24, and 26) needs to be embedded in the amorphous refractory 13 as shown in FIG. 1. The irregular refractory 13 is constructed by pouring. Examples of the material of the amorphous refractory 13 include Al ₂ O ₃ , 3Al ₂ O ₃ .2SiO ₂ (mullite), SiC, and SiO ₂ .
As described above, the ring 14 is embedded in the amorphous refractory 13 if a part of the ring 14 is exposed on the surface (working surface) of the amorphous refractory 13, which causes the ring 14 to be cut. This is because the effect of the irregular refractory 13 as a stud decreases.

The ring 14 is embedded in the irregular refractory 13 with respect to the thickness T2 of the irregular refractory 13 covering the surface 12 of the vane core 11 (same as the shaft core 10). The ratio of the projection length X of the ring 14 from the surface 12 of 11 (= X / T2) is 1/5 (20%) or more and 9/10 (90%) or less (preferably, the lower limit is 30%, 40%, the upper limit is 80%, and even 70%), the durability of the amorphous refractory 13 is stabilized.
Here, the protrusion length X of the ring 14 is the shortest distance from the surface 12 of the blade core metal 11 to the tip position of the ring 14.

In addition, when constructing the irregular refractory 13 on the surface 12 of the shaft core 10 and the blade core 11, the rope forming the ring 14 has flexibility, so the ring 14 is irregular refractory 13. There is a possibility that the load will hang down in the load direction, bend in the irregular refractory 13, bend, or the through-hole 17 may be crushed. These phenomena reduce the role of the ring 14 as a support material.
Therefore, it is preferable that the inorganic fibers constituting the rope are cured with a curing material in advance and the strength of the ring 14 is expressed at room temperature during construction.

The above-described strength means that the ring 14 can withstand deformation such as drooping, bending, bending, or crushing due to the load of the irregular refractory 13 during construction.
Examples of the curing material include phenolic resin, coal tar pitch, phosphoric acid, phosphate, silicate, silica sol, alumina sol, oil varnish, and organic adhesive that form a vitreous network at high temperatures. Preferably, a resin such as a commercially available oil varnish that volatilizes during the temperature rising process is suitable.
Furthermore, the arrangement | positioning position and shape of the ring 14 can also be fixed by fixing the ring 14 using a formwork etc. and hardening the ring 14 using a hardening | curing material.

Then, the manufacturing method of the stirring blade for molten metal which concerns on one embodiment of this invention is demonstrated, referring FIG.
First, the ring 14 formed of an inorganic fiber rope is attached to the surface 12 of the blade core metal 11 (further, the shaft core metal 10, the same applies hereinafter). At this time, the ring 14 may be cured by a curing material as necessary.
Next, a formwork is arranged on the surface 12 of the blade core metal 11 with an interval. Note that the installation position of the mold is set in consideration of the thickness of the desired amorphous refractory 13 and that the ring 14 is embedded in the irregular refractory 13.

Then, the kneaded amorphous refractory 13 is poured into the mold, and after curing and curing the amorphous refractory 13, the mold is removed and further dried in a drying furnace or the like. The obtained molten metal stirring blade is used by being attached to, for example, a KR apparatus.
As described above, the ring 14 is provided on the surface 12 of the blade core metal 11, and the ring 14 is embedded in the cast refractory 13 that has been cast, so that the refractory 13 is also provided in the through hole 17 of the ring 14. Therefore, there is no possibility that the ring 14 slides out of the refractory 13 and is pulled out.

Next, examples carried out for confirming the effects of the present invention will be described.
Here, as a stirring blade for molten metal used in the test, it has a shaft core and a blade core, the surface of which is an irregular refractory (Al ₂ O ₃ : 60% by mass, SiO ₂ : 30% by mass, An impeller covered with SiC (6 mass%, remaining impurities) was used. Four blade cores are attached to the shaft core at an equal angle with the shaft core in the center.

  The impeller described above has an axial length (length from the upper end of the impeller shaft portion to the lower end of the blade portion) H1 of 3000 mm, a shaft core metal diameter D1 of 300 mm, and an outer diameter of the shaft portion (including a refractory). D2 is 500 mm. The blade core metal has a thickness T1 of 120 mm, an axial width (height) H2 of the shaft core metal of 600 mm, and a radial protrusion width W of the shaft core metal of 400 mm. The thickness T2 of the refractory disposed on the gold surface is 300 mm (see FIGS. 4A and 4B).

As an impeller, as Comparative Example 1, an impeller in which a metal stud was attached to the surfaces of the shaft core and the blade core, and as Comparative Example 2, only the surface of the blade core was used in Comparative Example 1. An impeller with a straight rope attached instead of a metal stud, as Examples 1 to 8, only the surface of the blade core metal, an impeller with a ring attached instead of the metal stud used in Comparative Example 1, Each was used (see FIG. 1).
With respect to the blade cores of each impeller, metal studs, linear ropes, or rings were attached at 36 locations per blade core (total: 144 locations = 36 locations × 4). Note that three straight ropes were attached at one place.

The impellers described above were used for hot metal desulfurization and the impeller lifetimes were compared. The amount of treatment per day was 25 to 30 charges, the hot metal temperature was 1330 to 1370 ° C., and the treatment time was about 15 to 20 minutes.
Table 1 shows the test conditions described above and the results. In addition, from the viewpoint of workability and economy, the impeller life is determined to be acceptable when 200 charges or more can be used. The results of visual observation are shown in Table 1. For Comparative Examples 1 and 2, the results when peeling occurred and the impeller life was reached are shown in Table 1.

As shown in Table 1, in Comparative Example 1, since the metal stud was attached to the surface of the blade core metal, the stress relaxation caused by the difference in expansion between the refractory and the metal stud was insufficient. For this reason, many cracks occurred in the refractory, and most of the refractory was peeled off, so that the impeller could not be used for 200 charges (150 charges or more and less than 200 charges).
Moreover, since the linear rope was attached to the surface of the blade | wing part core metal in the comparative example 2, a rope was easy to pull out from a refractory material and the support of the refractory material by a rope became weak. For this reason, peeling of the refractory occurred, and the impeller could not be used for 200 charges (150 charges or more and less than 200 charges).

  On the other hand, since all of Examples 1 to 8 had the ring attached to the surface of the blade core metal, pulling out of the ring from the refractory could be suppressed and further prevented, and the refractory could be supported by the ring. For this reason, generation | occurrence | production of the crack to a refractory was able to be reduced (crack generation | occurrence | production: less than 10 in 10 cm square), and since the generation | occurrence | production time of peeling could be delayed, the impeller was able to be used 200 charges or more.

  Here, the results of changing the diameter of the rope used for forming the ring with the protrusion ratio (hereinafter also referred to as occupation ratio) of the ring being constant (2/3) will be described with reference to Examples 1 to 4. To do. The ring occupancy ratio is an index indicating the position of the ring embedded in the irregular refractory, and is relative to the thickness T2 (here, 300 mm) of the irregular refractory covering the surface of the blade core metal. The ratio of the protrusion length X of the ring from the surface of the blade core metal (= X / T2).

In Example 1, since the rope diameter was less than the lower limit (3 mm) of the optimum range (5 to 30 mm), the tensile strength of the rope was lowered. For this reason, although the impeller was able to be used for 200 charges or more, cracks occurred in the refractory (crack generation: medium (5 cm or more and less than 10 in 10 cm square)).
On the other hand, in Examples 2 and 3, since the rope diameter was within the above-described optimum range, the tensile strength of the rope was sufficient. For this reason, generation | occurrence | production of the crack to a refractory material was able to be reduced rather than Example 1 (crack generation | occurrence | production: few (less than 5 in 10 cm square)).
In Example 4, since the rope diameter was more than the upper limit (40 mm) of the optimum range described above, it took time and effort to form the rope into the ring.

Then, the diameter of the rope used for formation of a ring was made constant (5 mm), and the result of having changed various occupation ratios of a ring is demonstrated referring Example 2, 5-8.
In Example 7, since the occupation ratio of the ring was less than the lower limit (1/6) of the optimum range (1/5 to 9/10), the stud function with respect to the refractory tended to be lowered. For this reason, the impeller could be used for 200 charges or more, but cracks occurred in the refractory (crack generation: medium).
On the other hand, in Examples 2, 5, and 6, since the occupation ratio of the ring was within the above-described optimum range, the stud function with respect to the refractory was sufficiently exhibited. For this reason, generation | occurrence | production of the crack to a refractory material was able to be reduced rather than Example 7 (occurrence | production of a crack: few).

  In Example 8, since the occupation ratio of the ring was more than the upper limit (93/100) of the optimum range described above, the ring was partially exposed from the surface of the amorphous refractory when using the impeller. It was. For this reason, the molten metal contacted the ring and the ring melted, and the effect as a stud of the refractory was reduced. However, the metal with the protrusion length X from the surface of the blade cored bar set to 280 mm as in Example 8 Compared with the stud made, the effect of suppressing cracking was obtained.

  From the above, it has been confirmed that by using the stirring blade for molten metal of the present invention, the occurrence of cracks in the amorphous refractory can be reduced and the melting loss of the cored bar can be suppressed as compared with the prior art.

  As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, a case where the molten metal stirring blade of the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the scope of the right of the present invention.

10: Shaft core, 11: Blade core, 12: Surface, 13: Indeterminate refractory, 14: Ring, 15: Ring, 16: Crimp part, 17: Through hole, 20: Ring, 21: Crimp Part, 22: ring, 23: through hole, 24: ring, 25: locking pin, 26: ring

Claims (2)

A molten metal having a shaft cored bar and a vane cored bar provided at the tip of the shafted cored bar, the surfaces of the shafted cored bar and the bladed cored bar covered with an irregular refractory In the stirring blade for
At least on the surface of the blade core metal, a ring formed of an inorganic fiber rope using long fibers is provided, and the ring is embedded in the amorphous refractory, the stirring for molten metal Feathers.   2. The molten metal stirring blade according to claim 1, wherein the inorganic fibrous rope has a diameter of 5 mm to 30 mm.

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