JP2002086251A - Method for continuously casting alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for continuously casting copper alloy, etc., at a high productivity and a low cost with which the additional composition having high melting point is fully melted into an alloy at high concentration and can uniformly diffuse it. SOLUTION: A wire rod 29 having additional alloy composition is continuously melted or semi-melted by arc-discharge, and the molten or semi-molten material 31 is added into the flow of the molten metal 34 of the base alloy component to melt the additional alloy component into the molten metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting method of an alloy, and more particularly to a continuous casting method of a copper alloy or the like, which is characterized by a method of adding an additional alloy component.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional continuous casting apparatus of a copper alloy or the like generally used. The continuous casting apparatus includes a continuous melting furnace 1, a transfer gutter 2, a holding furnace 3, a casting gutter 4, a tundish 5, a downcomer 6, a mold 7, a shower 9, a water tank 10, a pinch roll 11, and a flying saw 12. The alloy component melted (hereinafter, melted) in the continuous melting furnace 1 is stored in the holding furnace 3 through the transfer gutter 2, poured into the tundish 5 through the casting gutter 4, and passed through the downcomer 6. It is poured into a mold 7 and an ingot 8 is continuously formed. The ingot 8 is cooled by a shower 9 and a water bath 10, the cross-sectional dimension is adjusted by a pinch roll 11, and cut into a required length by a flying saw 12.

[0003] A continuous casting apparatus such as a copper alloy is used for casting not only the same kind of alloy but also various alloys in order to use the equipment efficiently. If elements other than the basic constituent elements common to the alloy to be cast are added in a melting furnace or a holding furnace, they remain there and contaminate the subsequently cast alloy. To avoid this contamination, the added metal is generally added in a casting gutter or tundish further downstream from the holding furnace.

[0004] However, when a metal having a high melting point is added in a high concentration, it is common to add an alloy component in a crucible type melting furnace and perform semi-continuous casting.

FIG. 8 shows a conventional semi-continuous casting apparatus generally used. The semi-continuous casting apparatus includes a crucible type melting furnace 19,
It comprises a casting gutter 4, a tundish 5, a downcomer 6, a mold 7, a shower 9, and a water tank 10. The alloy component melted in the crucible type melting furnace 19 passes through the casting trough 4 and the tundish 5
To the mold 7 through the downcomer 6 to form an ingot 8. The ingot 8 is cooled by the shower 9 and the water bath 10 and solidified.

[0006]

However, in semi-continuous casting in which an alloy component is added in a melting furnace, it is necessary to either interrupt the casting after each batch of casting or to switch between and use a plurality of melting furnaces. As a result, a reduction in production efficiency or an increase in equipment costs is inevitable. In addition, when the type of the cast alloy is changed, it is necessary to remove the slag of the melting furnace and to perform melting for cleaning.

[0007] In the continuous casting method in which the additive is added in a casting gutter or a tundish further downstream from the holding furnace, it is extremely difficult to completely dissolve the added component having a high melting point in the alloy at a high concentration and uniformly diffuse it.

[0008] It is an object of the present invention to provide a continuous casting method for a copper alloy or the like, in which an additive having a high melting point can be completely dissolved in an alloy at a high concentration and diffused uniformly.

Another object of the present invention is to provide a continuous casting method having a high production efficiency and a low equipment cost, such as a copper alloy to which an alloy component having a high melting point is added at a high concentration.

[0010]

According to the present invention, there is provided a continuous casting method of a copper alloy or the like for continuously casting a molten metal comprising a basic alloy component and an additional alloy component.
The wire composed of the additive alloy component is continuously melted (hereinafter, melted) or semi-molten by arc discharge, and the molten or semi-molten additive alloy component is added to the flowing molten metal of the basic alloy component. It is characterized by obtaining a molten melt.

A typical wire is a wire. The wire may be composed only of the additive alloy component, or may be a master alloy wire containing the additive alloy component. The wire may be coated or plated.

For supplying a wire such as a wire, a wire feeder or the like may be used to control the supply speed. A wire such as a wire may be preheated before melting or semi-molten by arc discharge.

The present invention is particularly useful for continuous casting of a copper alloy (the basic alloying component is copper). The additive alloy component may be any as long as it can form a wire such as a wire that can be continuously melted or semi-melted by arc discharge. The present invention is particularly useful for continuous casting using a continuous casting apparatus, but is also applicable to casting using a semi-continuous casting apparatus.

[0014] The alloy additive component melted or semi-molten by arc discharge is preferably added to the molten metal downstream of the holding furnace. It is preferable that the molten metal after addition is sufficiently stirred so that the additional components are uniformly diffused.

The apparatus used for arc discharge in the present invention may be either a consumable electrode type using a wire such as a wire itself as an electrode, or a type using a non-consumable electrode. Further, either a direct current or an alternating current may be used. As usual, an inert gas such as argon is supplied to the discharge unit to generate arc plasma. The electric capacity is determined by the supply speed of the wire, the specific heat, the latent heat of melting, the efficiency of the apparatus, and the like. A single plasma torch may be used, or a small torch may be provided in series or in parallel, or a double torch system provided in series / parallel. When long-time continuous operation is required, the double torch method is preferable.

The surface of the molten metal at the site where the molten or semi-molten additive alloy component is added is preferably covered with an inert gas such as argon or a reducing gas to prevent oxidation.

[0017]

Embodiments of the present invention will be described below. FIG. 1 shows an alloy continuous casting apparatus used for carrying out the present invention. The alloy continuous casting apparatus shown in FIG. 1 has the same configuration as the alloy continuous casting apparatus shown in FIG. 7 except for the arc plasma melting device 13 and the stirrer 14. A copper alloy containing iron is continuously cast by adding the copper-containing iron melted by the arc plasma melting device 13 to a position 4a of the casting gutter 4 close to the holding furnace 3. A stirrer 14 is provided downstream of the casting gutter 4 to stir the molten metal uniformly.

FIG. 2 shows an example of an arc plasma melting apparatus. The arc plasma melting device includes a plasma torch 22,
It comprises a DC power supply 26, an additive metal wire 29, a wire feeder 30, a copper plate 25, and a cooling water pipe 36. The plasma torch 22 includes a cathode 23, an anode 24a, an auxiliary electrode 24b, a plasma gas 27, and a shield gas 28. The arc plasma melting apparatus is provided on a gutter lid 33 above the casting gutter 32 (the casting gutter 4 in FIG. 1).

The plasma torch 22 for generating the arc plasma 21 comprises a central cathode 23, an auxiliary electrode 24b and an anode 24a surrounding it. The anode 24a is connected to a copper plate 25 provided on the gutter lid 33. The cathode 23 is connected to the negative side of the DC power supply 26, the anode 24a is connected to the positive side of the DC power supply 26 together with the copper plate 25, and the auxiliary electrode 24b is connected to the positive side of the power supply 26 via the resistor 26a. A plasma gas 27 flows between the cathode 23 and the auxiliary electrode 24b, and a shield gas 28 flows between the auxiliary electrode 24b and the anode 24a. Arc plasma 21 is generated at the tip of plasma torch 22. The wire 29 of the added metal is supplied from the wire feeder 30 to the arc plasma 2.
1 and dissolved into droplets 31. Drops 31 of the additive fall into a melt 34 flowing in a casting gutter 32. The molten metal 34 is covered with a coating gas 35 to prevent oxidation. The copper plate 25 is cooled by a cooling water pipe 36.

FIG. 3 shows another example of the arc plasma melting apparatus. The reference numerals are the same as those in FIG. 2 except for the plasma torch 42, but this apparatus does not include the copper plate 25 and the auxiliary electrode 24b. The plasma torch 42 includes a central cathode 23,
A plasma gas 27 flows between the cathode 23 and the anode 24a. The anode 24a is water-cooled. Others are the same as the apparatus of FIG.

FIG. 4 shows another example of the arc plasma melting apparatus. The reference numerals are the same as those in FIG. In this device, an additional metal wire 29 is used.
Are inserted into the center of the plasma torch 52 integrally with the power supply unit 53, and they are surrounded by a water cooling jacket 54.
The plasma gas 27 flows between the wire 29 of the additional metal and the water cooling jacket 54. The power supply 53 of the plasma torch 52 is connected to the negative side of the DC power supply 26. The copper plate 25 serving as an anode provided on the gutter lid 33 is
It is connected to the positive side of DC power supply 26. At the tip of the plasma torch 52, between the copper plate 25 and the arc plasma 2
1 results. The copper plate 25 is cooled by a cooling water pipe 36. Others are the same as the apparatus of FIG.

[0022]

EXAMPLES Examples of the present invention will be described below together with comparative examples. [Embodiment 1] In the continuous casting apparatus shown in FIG.
2 as an arc plasma melting device 13 installed on
Was used. With this continuous casting apparatus, 2.2
A copper alloy containing iron by weight was continuously cast. The copper-coated pure iron wire was supplied to the arc plasma melting apparatus at a supply rate of 2.2 kg / min using a wire feeder. Five plasma torches with an output of 100 kW were prepared, one of which was sequentially stopped, and four were constantly operated, and operated continuously for about 20 hours.
Argon gas was used as a coating gas.

The appearance of the ingot was good and no abnormality was observed. When the macrostructure and microstructure of the ingot were observed, no insoluble residue of iron or coarse precipitation was found. No backflow of iron into the holding furnace was observed.

FIG. 5 shows the results of measuring the change in iron concentration in the longitudinal direction of the ingot. The horizontal axis shows the position of the ingot in the longitudinal direction as a value converted to the time from the start of casting (up to 3 hours).
It takes about 30 minutes from the start of the addition until the iron concentration is stabilized. After the addition of iron, it took about one hour for the iron concentration in the casting gutter to drop to 10 ppm or less. 120 iron-containing copper alloy
When the ton casting was performed, the rod with a defective component generated before and after the casting was about 12 tons.

Example 2 Using the same apparatus as in Example 1, a copper alloy containing 2.5% by weight of nickel was cast.
However, three plasma torches having an output of 100 kW were prepared, one of which was sequentially stopped, and two were constantly operated. A copper / nickel alloy wire containing 50% by weight of nickel was supplied to an arc plasma melting apparatus by a wire feeder at a supply rate of 2.5 kg / min. The wire was preheated with Joule heat before melting.

The appearance of the ingot continuously cast for about 20 hours was good, and no abnormality was observed. When the macro structure and micro structure of the ingot were observed, the structure was uniform and no abnormality was observed. No backflow of nickel into the holding furnace was observed.

FIG. 6 shows the result of measuring the change in the nickel concentration in the longitudinal direction of the ingot. The horizontal axis shows the position of the ingot in the longitudinal direction as a value converted to the time from the start of casting (up to 3 hours). It takes about 30 minutes from the start of the addition until the iron concentration is stabilized. After the nickel addition, it took about one hour for the nickel concentration in the casting gutter to drop to 10 ppm or less. When 120 tons of an iron-containing copper alloy was cast, about 12 tons of poor component rods were generated before and after casting.

Comparative Example 1 Using a semi-continuous casting apparatus as shown in FIG. 8, about 5 tons of deoxidized copper was melted in a crucible-type melting furnace 19, and then electrolytic iron was added to produce 2.2% by weight of iron. Copper alloy containing was cast. The appearance of the ingot was good and no abnormality was observed. Observation of the macro structure and micro structure of the ingot revealed no insoluble residue or coarse precipitation of iron. However, the cost of casting per kg of alloy was about 5 times that of casting according to Example 1.

Comparative Example 2 Electrolytic iron was added to the molten metal of the holding furnace 3 while using the continuous casting apparatus shown in FIG. Was continuously added and melted, and a copper alloy containing 2.2% by weight of iron was continuously cast. When the macrostructure and microstructure of the ingot were observed, insoluble residues of iron and coarse precipitation were observed.

[0030]

According to the continuous casting method of the present invention, an additive having a high melting point can be completely dissolved in an alloy at a high concentration, and can be uniformly diffused. Particularly useful for copper alloys.

Further, according to the present invention, a copper alloy or the like containing a high concentration of an alloy component having a high melting point can be obtained without using semi-continuous casting.
Continuous casting is possible with high production efficiency and low equipment cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a continuous casting apparatus used in the present invention.

FIG. 2 is an explanatory view of an arc plasma melting apparatus used in the present invention.

FIG. 3 is an explanatory view of an arc plasma melting apparatus used in the present invention.

FIG. 4 is an explanatory view of an arc plasma melting apparatus used in the present invention.

FIG. 5 is a graph showing a change in iron concentration in a longitudinal direction of an ingot.

FIG. 6 is a graph showing a change in nickel concentration in a longitudinal direction of an ingot.

FIG. 7 is an explanatory view of a conventional general continuous casting apparatus.

FIG. 8 is an explanatory view of a generally used semi-continuous casting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Continuous melting furnace 2 Transfer trough 3 Holding furnace 4 Casting trough 4a Position (of arc plasma melting apparatus) 5 Tundish 6 Downcomer 7 Mold 8 Ingot 9 Shower 10 Water tank 11 Pinch roll 12 Flying saw 13 Arc plasma melting apparatus 14 Stirrer DESCRIPTION OF SYMBOLS 19 Crucible melting furnace 21 Arc plasma 22 Plasma torch 23 Cathode 24a Anode 24b Auxiliary electrode 25 Copper plate 26 DC power supply 26a Resistance 27 Plasma gas 28 Shield gas 29 Wire of added metal 30 Wire feeder 31 Drop (additional component) 32 Casting gutter 33 Gutter lid 34 Molten metal 35 Coating gas 36 Cooling water pipe 42 Plasma torch 52 Plasma torch 53 Power supply unit 54 Water cooling jacket

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C22C 1/02 503 C22C 1/02 503B (72) Inventor Hajime Sasaki 5 Hidaka-cho, Hitachi City, Ibaraki Prefecture 1-chome F-term in Hitachi Cable, Ltd. Research Institute of Technology 4E004 MB14 NC07

Claims (3)

[Claims] 1. A continuous casting method for an alloy, comprising continuously casting a molten metal comprising a basic alloy component and an additive alloy component, wherein the wire comprising the additive alloy component is continuously melted or semi-melted by arc discharge. A continuous casting method for an alloy, characterized by adding the molten additive alloy component to a flowing molten metal of the basic alloy component to obtain a molten metal in which the additive alloy component is melted. 2. The continuous casting method for an alloy according to claim 1, wherein the molten or semi-molten additive alloy component is added to a molten metal of the basic alloy component downstream of a holding furnace. 3. The continuous casting method for an alloy according to claim 1, wherein said base alloy component is copper.