JPH10216905A - Method for continuously casting active element-containing copper alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To add the active elements of Ti, Zr, Cr, Al, etc., in high yield and to obtain an ingot having high quality. SOLUTION: This casting method is constituted so as to flow molten copper 10 of low oxygen tapped from a melting so as to flow molten a trough 30, continuously add the active element 32 at a prescribed position in the trough 30 and to flow the molten copper alloy 11 after adding the active element 32 into a mold 50 through a tundish 40 to execute the continuous casting. In such a case, at least the surrounding of the molten copper alloy 11 after adding the active element is made to an Ar gas atmosphere. Therefore, since the surrounding of the molten copper alloy after adding the active element into the molten low oxygen copper, is made to the Ar gas atmosphere having non- activity with the active element, the adding yield of the active element is improved, and since oxide and nitride are not generated, the quality of the ingot is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to Ti, Zr, C
The present invention relates to a continuous casting method of an active element-containing copper alloy which can add an active element such as r or Al at a high yield and can obtain a high quality ingot.

[0002]

2. Description of the Related Art Copper, which has excellent electrical and thermal conductivity, is widely used as a basic material in the electronics field such as lead frame materials, terminal materials and connector materials. In recent years, demands for higher density of LSIs and weight reduction of mounted parts have increased the demand for high strength and high conductivity for the basic materials. Accordingly, Ti, Zr, and Cr have been used as alloying elements for copper alloys. , A
Active elements such as 1, Mg, Ca, Si, and Ce have come to be used. Conventionally, such an active element has been added to the molten copper in a melting furnace or a holding furnace in an inert gas atmosphere. However, the oxidation loss due to oxygen in the molten metal is large, and the generated oxide is contained in the ingot. To deteriorate the quality of the ingot.

[0003]

In view of the above, a method has been considered in which a melting furnace, a holding furnace, a gutter, a tundish, a mold, and the like are added in a CO + N ₂ reducing gas atmosphere to reduce the amount of oxygen in the molten copper. However, in this method, the active element reduces the CO gas in the atmosphere to an oxide, and reacts with the N ₂ gas to form a nitride, so that the yield of alloying elements decreases, and There has been a problem that the nitride is mixed into the ingot and causes an ingot defect. Here, there is a method in which the active element is added into the molten metal together with the Ar gas injection. In the case of an active element having a specific gravity lower than that of the molten copper, the undissolved element floats on the molten metal and reacts with the atmosphere gas after the addition. It has no effect. An object of the present invention is to provide a continuous casting method of an active element-containing copper alloy in which an active element is added at a high yield and a high-quality ingot is obtained.

[0004]

According to the first aspect of the present invention,
The low-oxygen copper melt discharged from the melting furnace is transferred to a gutter, an active element is continuously added at a predetermined location of the gutter, and the copper alloy melt after the addition of the active element is transferred to a mold via a tundish. And continuously casting an active element-containing copper alloy, wherein at least the periphery of the copper alloy melt after the addition of the active element is set in an Ar gas atmosphere.

According to a second aspect of the present invention, there is provided an active element-containing copper according to the first aspect, wherein an atmosphere separating weir is provided at a predetermined location of the gutter, and an active element is added at a downstream side (a tundish side). This is a continuous casting method for alloys.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the reason for adding an active element to a low-oxygen copper melt is to reduce the amount of the active element consumed by oxygen in the copper melt and cause ingot defects. This is for reducing the amount of oxide generated. Here, the low-oxygen copper melt preferably has an oxygen content in the copper melt of not less than ten PPM, particularly preferably not more than several PPM. Such low-oxygen copper is obtained by setting the surroundings of the molten copper before adding the active element in the melting furnace, the holding furnace, and the gutter to a reducing gas atmosphere. Here, the reducing gas is a gas obtained by mixing an inert gas such as a nitrogen gas and an Ar gas with a CO gas, and may be any gas that can remove oxygen from the molten copper. In the present invention, it is economical to add the active element in the form of granules, but the active element may be added in another form such as a linear form.
Elements other than the active element may be added in a melting furnace or a holding furnace, or may be added together with the active element. In the present invention, A around the copper melt after adding the active element
The reason for using the r gas atmosphere is that the active element does not react with Ar, and therefore, it is possible to suppress a decrease in the yield of addition of the active element and generation of a reactant.

Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 is an explanatory side view showing an example of the continuous casting method of the present invention. The molten copper 10 melted in the melting furnace 20 is held in a holding furnace.
After being held at 21, it is transferred to a cylindrical gutter 30, and a granular active element 32 is fed from an alloy element addition device 31 attached in the middle of the gutter 30.
, And then the molten copper alloy 11 to which the active element 32 has been added.
Is transferred to a tundish 40 and straightened, and then continuously cast into a billet 60 by a mold 50. At the upstream side (holding furnace side) of the alloy element addition device 31, a plate-shaped atmosphere separation weir (hereinafter, abbreviated as separation weir) 33 is provided in close contact with the inner wall of the gutter, and CO + N upstream of the separation weir 33 is provided. _{The two} gases and the Ar gas on the downstream side are not mixed. A molten metal passage 34 is opened in a lower part of the separating weir 33 immersed in the molten copper (copper alloy) 10,11. The Ar gas is introduced from the through hole 41 of the tundish 40 and is discharged from above the alloying element adding device 31. In the figure, reference numeral 12 denotes a raw material. The CO + N ₂ gas inlet and exhaust holes are omitted.

[0008]

The present invention will be described below in detail with reference to examples. (Example 1) Cu-0.3 was obtained by the continuous casting method shown in FIG.
A wt% Ti alloy billet (250 mmφ, weight 4 tons) was continuously cast. A wooden cork (not shown) is arranged in the molten metal passageway 34 of the separation weir 33, and the upstream of the separation weir 33 is CO + CO
_An atmosphere of ₂ + N ₂ gas was used, and an atmosphere of Ar gas was used on the downstream side. In this state, the molten copper 10 at 1300 ° C. was transferred from the holding furnace 21 to the gutter 30. The wooden cork is quickly burned down by the heat of the molten copper, and the molten metal passage 34 is opened. At the same time as the opening, spherical particles of Ti (about 0.5 mm in diameter) are continuously added from the alloying element adding device 31. Copper alloy melt 11 in tundish 40
, And was continuously cast into a billet 60. The atmosphere before the separation weir 33 was changed in two ways.

(Comparative Example 1) In Example 1, the separation from the melting furnace 20 to the mold 50 was carried out with CO + C
A Cu-0.3 wt% Ti alloy billet was continuously cast in the same manner as in Example 1 except that the atmosphere was changed to an O ₂ + N ₂ gas atmosphere.

Comparative Example 2 In Example 1, the inside of the melting furnace 20 was set to a CO + CO ₂ + N ₂ gas atmosphere without a separation weir on the gutter, and the Ar gas atmosphere was used from the holding furnace to the mold 50. Otherwise, the same method as in Example 1 was used to prepare Cu-0.3wt% T
An i-alloy billet was continuously cast.

The yield of Ti addition and the number of ingot defects were investigated for each of the billets thus obtained.
Table 1 shows the results.

[0012]

[Table 1] (Note) * Volume percentage. #Reducing atmosphere of CO: CO ₂ : N ₂ (20: 5: 75) in the melting furnace.

As is clear from Table 1, No. 1 of the present invention example
In each of Examples 1 and 2, the yield of addition of Ti was high, and therefore, ingot defects were small. On the other hand, No. 3 of the comparative example had a reducing gas atmosphere containing CO from the melting furnace to the mold, and most of the Ti became oxide or nitride.
The yield of addition of i decreased, and the oxides or nitrides were mixed in the billet to generate many ingot defects. In Comparative Example No. 4, since the atmosphere after the holding furnace was Ar gas and the oxygen in the molten metal was slightly increased, Ti became a considerable amount of oxide, the Ti addition yield decreased, and many ingot defects occurred. .

[0014]

As described above, in the continuous casting method according to the present invention, the active element is added to the low-oxygen copper molten metal in the gutter serving as the molten metal transfer path, after the active element is added thereto, and the active element is not mixed with the active element. Since a reactive Ar gas atmosphere is used, the yield of addition of the active element is improved, and the quality of the ingot is also improved because no oxide or nitride is generated. The low oxygen copper melt can be easily obtained by setting the surroundings of the copper melt before adding the active element to a reducing gas atmosphere containing CO. The reducing gas and the Ar gas are
Mixing can be prevented by providing a separation weir at a predetermined location in the gutter. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a continuous casting method of the present invention.

[Explanation of symbols]

 10 Molten copper 11 Molten copper alloy 12 Raw material 20 Melting furnace 21 Holding furnace 30 Gutter 31 Alloy element addition device 32 Active element 33 Atmosphere separation weir 34 Molten passage opened in atmosphere separation weir 40 Tundish 41 Ar gas introduction hole 50 Mold 60 billet

Claims (2)

[Claims] 1. A low-oxygen copper melt discharged from a melting furnace is transferred to a gutter, an active element is continuously added at a predetermined position of the gutter, and the copper alloy melt after the addition of the active element is tundished. In the method of continuous casting by transferring to the mold through
A continuous casting method for an active element-containing copper alloy, characterized in that at least the periphery of the copper alloy melt after the addition of the active element is in an Ar gas atmosphere. 2. The continuous casting method for an active element-containing copper alloy according to claim 1, wherein an atmosphere separating weir is provided at a predetermined location of the gutter, and an active element is added downstream (tundish side) thereof.