JPH07179926A - Metallic capsule additive - Google Patents

Abstract

PURPOSE:To obtain a metallic capsule additive for refining or casting of metal which can be stably and easily added at a high yield by sealing metals and alloys, such as alkaline earths, having extremely high oxidability into a metallic capsule having a specific sheath thickness. CONSTITUTION:An additive to be used in the refining process for irons, steels and nonferrous metals, such as for ladles, vacuum degassing devices, tundishes and casting molds for continuous casting or in production of spheroidal graphite cast irons is produced by adding the additive 1 consisting of >=1 kinds among alkaline earth metals, alkaline earth metal-contg. alloys, rare earths and rare earth-contg. alloys into the metallic capsule 2 having the sheath thickness of 1.3 to 5.0mm. As a result, the metallic capsule additive which prevents the oxidation of the additive having the extremely high oxidability is obtd. When the additive is added into molten metal, the metallic capsule melts while settling and the additive comes into contact with the molten metal at depth sufficient for preventing oxidation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an additive used for deoxidation, desulfurization and alloy addition for refining and casting of steel and non-ferrous metals such as copper and aluminum.

[0002]

2. Description of the Related Art In refining nonferrous metals such as steel, copper and aluminum, powdery or granular additives are used for deoxidation, desulfurization and alloy addition, ladle, vacuum degassing equipment or tundish for continuous casting. Add to template. Further, in the production of spheroidal graphite cast iron, the additive is added to the molten metal in the form of powder or granules.

Further, a composite wire having a metal outer shell containing an additive such as Ca, Mg or an alloy thereof as disclosed in Japanese Patent Publication No. 55-48570, or a metal wire coated with the additive in a bulk or One cut into chips, or C described in JP-A-55-97419
Various additives such as those in which a granular material of additives such as a and Al are coated with iron by thermal spraying are added to the molten metal in the refining process or the molten metal in the manufacturing process of spheroidal graphite cast iron. . Further, JP-A-4-350112 discloses an additive in which Ca, Mg or an alloy containing these and iron powder or iron particles are mixed in a coating material to increase the density.

[0004]

However, among the additives of various alloying elements, alkaline earth metals, rare earth metals or their alloys are very easy to oxidize, so if they are added to molten metal in the form of powder or lumps. The loss as an oxide is large, the yield in the metal is low, and the yield is unstable. Therefore, it is necessary to add a large amount, the cost becomes high, and since the addition amount of these alloy elements is a minute amount of 1% or less, the hit rate of the target component also becomes low due to the variation of the yield.

A composite wire having a metal outer shell containing an additive as described in JP-B-55-48570 usually has an outer skin thickness of less than 0.3 mm, and the wire near the surface of the molten metal is short in time. The metal shell melts, the additive contained therein floats up on the surface of the molten metal, comes into contact with air and is oxidized, and the yield is low. Further, in some cases, the wire-shaped additive cannot be used because of the structure of the device such as a vacuum degassing device.

When the additive is coated with a metal and cut into lumps or chips, it oxidizes from the exposed surface of the cut surface during storage before addition, and when added to molten metal, it oxidizes from the exposed surface of the cut surface. It happened and the yield was still low. Further, in the additive described in JP-A-55-97419 described above in which the granular material is coated with iron by thermal spraying, the thermal spray coating layer is thinly added to the molten metal and oxidation is prevented in the thermal spray coating layer when the temperature becomes high. Effect is lost, oxidation also occurs from the cut portion, the yield is lowered, and the manufacturing cost of the additive is high. Further, the additive disclosed in the above-mentioned JP-A-4-350112 has a large difference in specific gravity between Ca, Mg or an alloy containing these and iron powder or iron particles during the production, making uniform mixing difficult. Therefore, variations in contained components occur and the manufacturing cost increases.

The present invention relates to a ladle, a vacuum degassing device, a tundish or a mold for continuous casting, such as iron and steel, a non-ferrous metal refining process and an alkaline earth metal having a very high oxidizing property used in the production of spheroidal graphite cast iron, In rare earth metals or additives of these alloys, the yield to molten metal is high,
And can be added with a stable yield, moreover, easy with conventional powdery and granular additive device and addition method,
It is an object to provide an additive that can be easily added.

[0008]

The gist of the present invention is to provide an alkaline earth metal, an alkaline earth metal-containing alloy,
A metal capsule additive for metal refining or casting, characterized by encapsulating one or more rare earth or rare earth metal-containing alloys in a metal capsule having an outer skin thickness of 1.3 to 5.0 mm.

[0009]

The present invention will be described in detail below. The metal capsule additive of the present invention is a highly-oxidizable alkaline earth metal, rare earth metal or alloy thereof, which is encapsulated in a metal capsule, so that it does not oxidize from the end and is added to the molten metal. Then, the metal capsule shell melts while settling inside the molten metal, and the additive comes into contact with the molten metal at a depth sufficient to prevent oxidation. Therefore, the yields of alkaline earth metals, rare earth metals or their alloys are high, and they are stable, and the hit ratio of the target component is also high. Furthermore, since it is not in a wire form, it can be easily used in any refining process such as addition in a vacuum degassing vessel, or in the process of producing spheroidal graphite cast iron.

Examples of metal capsule additives of the present invention are shown in FIGS.
As shown in FIG. 1A is a side view, FIG. 1B is a front view, and FIG. 1C is a plan view, and the upper half shows a cross section. In the figure, 1 indicates an additive and 2 indicates a metal capsule. At both ends of the metal capsule 2, a metal tube filled with an additive is pressed out by a guillotine type cutter or a press, and the end 3 is crushed to encapsulate the additive.

FIG. 2 shows an example in which the end portion of the metal capsule is bent after pressing and pressing, and FIG. 3 shows an example in which the pressing end portion is pressed by heating while being energized or heated with high frequency, and 4 is a welded portion.

As the outer material of the metal capsule, in principle, the same kind of metal as the metal to be added is used. For carbon steel, a carbon steel capsule is used. The same applies to stainless steel, aluminum or aluminum alloy, copper or copper alloy. Is selected according to the metal to be added. From the viewpoint of the refining effect or the spheroidizing effect of graphite, it is possible to use a metal different from the metal to be added as a shell material for the capsule in order to adjust the melting temperature and the melting speed of the capsule.

Further, when a welded tube or a hot-pressing tube is used, these metal capsule outer material can have a form in which the side surface of the metal capsule is completely airtight as shown in FIG. When a metal strip is used as the outer skin material of the metal capsule, the metal capsule 2 is used as shown in FIG.
It is also possible to enclose the tube while forming a tube by bending the side surface of the tube. The structure of these metal capsules is selected according to the type of additive to be encapsulated. For example, an alkaline earth metal having a strong reactivity with water has the completely sealed structure shown in FIG. 3, and an alloy stable at room temperature has the structure shown in FIG. 1 or 4.

The outer wall thickness of the metal capsule is 1.3 mm to
5.0 mm is suitable. If it is less than 1.3 mm, the capsule is melted near the surface in the molten metal bath and the coating effect of the outer shell is lost, and the encapsulated alloying agent easily comes into contact with air, resulting in a large oxidation loss. Further, when it exceeds 5.0 mm, the capsule is not completely melted and remains as a foreign substance in the solidified ingot or billet or the like. Further, in the production of spheroidal graphite cast iron, the reaction between the alloying agent and the molten metal is delayed and the spheroidizing effect of graphite is lost.

The size of the metal capsule additive has a length indicated by L in FIG. 1 of 5 mm to 500 m depending on the method of adding the additive.
It is suitable that the outer diameter shown by W in FIG. 1 is about 5 mm to 50 mm. When the length L and the outer diameter W are 5 mm or less, the weight of one additive becomes light, and when it is added to the molten metal, it does not easily pass through the slag layer on the bath surface, and it is difficult to sink in the molten metal bath and near the surface. Therefore, the additive melts and the effect of the present invention cannot be exhibited.

The additive material to be encapsulated in the metal capsule additive of the present invention is Mg, Ca or the like for alkaline earth metal, Mg-Al alloy or Ca-Si alloy for alkaline earth metal-containing alloy, Y for rare earth metal, etc. The rare earth metal-containing alloy such as Ce means misch metal, Y-Ni alloy, Y-Al alloy, or the like. The particle size of these additives is generally suitable to be 5 mm or less, but wire-like particles such as misch metal can be enclosed.

[0017]

【Example】

Example 1 The outer diameter of the metal capsule shell material is 15 mm and the wall thickness is 1.4.
mm C: 0.08%, Si: 0.31%, Mn: 0.
Ca: 41 as an additive material in 43% carbon steel welded pipe
%, Si: 54%, and a Ca-Si alloy having a particle size of 1 to 3 mm is filled with a guillotine type cutter, and the length is 100 mm.
It was cut into pieces to obtain the metal capsule additive of the form shown in FIG.

As a result of introducing this metal capsule additive into the tundish of the continuous casting apparatus, the Ca yield was 85%. For comparison, the wall thickness of the metal capsule is 0.2
An additive test of 5 mm and 7 mm was also conducted, and when the outer skin thickness was 0.25 mm, the Ca yield was 63%.
Further, when the outer skin thickness was 7 mm, undissolved capsules remained in the slab after casting and it was not possible to make a steel product. The Ca yield cannot exceed 50% by the conventional method of directly adding the massive Ca—Si alloy, but the use of the metal capsule additive of the present invention provided a significant yield improvement effect.

Example 2 As a metal capsule outer material, a hoop made of SUS304 stainless steel having a width of 25.4 mm and a plate thickness of 1.5 mm was formed into a semi-circular shape in the middle of forming a tubular shape by a pipe forming apparatus, and the additive was added. As a material, a misch metal wire having a diameter of 4 mm was inserted into the tube and formed into a tube. High-frequency electric resistance welding of the seam in the length direction of the pipe, and then the outer diameter of the pipe is 5 mm
After the diameter was reduced to 10 mm, a guillotine cutter was used to cut each 10 mm in length to obtain a metal capsule additive. These steps were continuously performed in one line from forming-electric resistance welding-cutting without interruption.

The metal capsule additive is Cr: 25%,
As a result of adding Ni: 20% to the vacuum tank of the vacuum degassing apparatus in the refining process of stainless steel, the yield of the misch metal was 92%. As a comparison, the yield of the misch metal was 64% when the wire in which the misch metal wire was coated with the outer skin of SUS304 stainless steel having a thickness of 0.1 mm was added to the ladle of the vacuum degassing device.

Example 3 As a metal capsule skin material, the outer diameter is 35 mm and the wall thickness is 4 m.
m, length 1,200 m, C: 0.08%, Si: 0.3
Carbon steel welded pipe of 0%, Mn: 0.44%, Mg: 80% and Ca: 20% with a particle size of 3 to 6 mm as an additive material
After filling with the mixture consisting of, the end portion of the capsule was crushed, and copper electrodes were further pressed above and below the portion and pressed while being energized and cut to obtain a metal capsule additive with a length of 250 mm each. .

The molten iron in the ladle was first charged with a metal capsule additive containing Mg and Ca, and then Fe- was used as an inoculant.
Si was added. Compared with the conventional method in which a Mg alloy such as Mg-Ni is pushed into molten iron with a steel cup and Fe-Si is charged, the amount of Mg used is 60% of that of the conventional method and the graphite spheroidization rate is exactly the same. It was possible to produce castings.
In the conventional method, since Mg and Ca have low boiling points and large evaporation loss, they cannot be used alone and are used as alloys.

[0023]

As described in detail above, according to the metal capsule additive of the present invention, ladle, vacuum degassing device or tundish or mold for continuous casting, such as smelting process of ferrous steel or non-ferrous metal or spheroidal graphite cast iron When adding alkaline earth metals, rare earth metals or their alloys with extremely high oxidizability used in the production of, it is possible to add them to the molten metal with high yield and stability, and to add conventional powdery or lumpy additions. The agent can be added by an adding device or an adding method.

[Brief description of drawings]

FIG. 1 is an example of a metal capsule additive of the present invention, (a) is a side view, (b) is a front view, (c) is a plan view, and each upper half shows a cross section.

FIG. 2 is a cross-sectional view showing an example of treatment of the outer edge portion of the metal capsule additive of the present invention.

FIG. 3 is a cross-sectional view showing an example of treatment of the outer end portion of the metal capsule additive of the present invention.

FIG. 4 is a cross-sectional view of an example in which a strip plate is used as a skin material of the metal capsule of the present invention.

[Explanation of symbols]

 1 Additive 2 Metal Capsule 3 End 4 Weld Part L Length W Outer Diameter

Claims (1)

[Claims] 1. An alkaline earth metal, an alkaline earth metal-containing alloy, a rare earth, or a rare earth metal-containing alloy is enclosed in a metal capsule having an outer skin thickness of 1.3 to 5.0 mm. Additives for metal capsules for refining or casting metals.