JPS646862B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to the dip forming method, which is known as a method for continuous casting and rolling of copper. Prior Art Conventionally, the so-called dip forming method has been put to practical use in the production of copper rough drawn wire, but this dip forming method will be explained with reference to Fig. 1.
A molten copper supply port 4 is inserted from a melting furnace 3 into a crucible 2 made of a refractory material such as graphite, which has a seed wire insertion port 1 formed at the bottom.
Molten copper 5 is supplied through the crucible 2, and a seed wire 6 of a predetermined diameter also made of copper is supplied from below the crucible 2
The molten copper 5 is continuously inserted into the seed wire through the seed wire insertion port 1.
The seed wire 6 is then continuously pulled up vertically from the molten copper 5 in the crucible 2 to the cooling tower 7.
In this way, molten copper adheres and solidifies around the seed wire 6 as a core, thereby continuously obtaining a cast wire having a diameter larger than the diameter of the seed wire 6.
Further, the copper wire is processed into a rough drawn copper wire of a desired diameter using a hot rolling device (not shown), and then wound onto a winding device (not shown). By the way, when manufacturing a clad material in which the seed wire and the deposited solidified part are made of different materials, such as by adhering and solidifying a copper alloy around the copper seed wire using the method described above, it is necessary to separate the seed wire and the deposited solidified part depending on the application. It is necessary to set the area ratio, that is, the cladding ratio, to an appropriate value. By doing so, for example, in the case of a copper-coated steel wire where the seed wire is made of steel and the deposited solidified part is made of copper,
The strength of the steel wire and the conductive copper wire can be varied depending on the application, and a wide range of materials can be selected with characteristics suitable for the application. In that case, the ratio of the cross-sectional area of the adherent solidified portion can be increased by repeating the step of continuously soaking the seed wire 6 in the crucible 2, which is part of the step of the dip forming method described above. ,
Further, the ratio of the cross-sectional area of the adhered and solidified portion can be reduced by shortening the immersion time of the seed wire 6 in the crucible 2. However, these methods have problems such as being limited by the balance with other equipment, and it is not possible to easily adjust the cladding ratio. Purpose of the Invention The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object of the present invention to provide a dip forming method that can easily adjust the cladding ratio and produce a cladding material. It is something. Basic facts regarding the invention When performing the above-mentioned dip forming method, when the seed line 6 is passed through the crucible 2, the amount of molten metal in the crucible 2 that adheres to the seed line 6 and solidifies is the same as the amount that the seed line 6 is in the crucible 2. It is determined by the amount of heat exchanged between the seed wire 6 and the molten metal in the crucible 2 during the process of passing through the crucible. That is, the amount of heat that increases the temperature of the seed wire 6 while passing the seed wire 6 from below to above the crucible 2;
In other words, the total heat amount of the heat received by the seed wire, the amount of heat released while the molten metal is cooled to the freezing point, and the latent heat generated when the molten metal solidifies, that is, the total amount of heat that is imparted to the seed wire when the molten metal adheres to the seed wire and solidifies. When the amount of heat is balanced, an amount of adhesion and coagulation corresponding to the balanced amount of heat is generated on the seed line. Further, in this case, the amount of heat that the seed wire 6 can receive is enough to raise the temperature of the seed wire 6 from the temperature of the seed wire 6 at the entrance of the crucible 2 to a temperature that does not reach the melting point of the seed wire 6. Therefore, the upper limit of the amount of molten metal that can be solidified on the seed wire 6 while the seed wire 6 passes through the crucible 2 once is determined by the diameter and material of the seed wire 6. For example, when molten copper is deposited and solidified on a copper seed wire, the upper limit of the amount of molten copper deposited and solidified per 1 kg of seed wire with a diameter of 12.7 mm is approximately 1.7 kg, and in that case, the total weight of the cast wire is approximately 2.7 kg. . Therefore, the adhesion ratio, or cladding ratio, is γ = 2.7/1 = 2.7, and when converted to the ratio of the cross-sectional area of the adhered solidified portion to the entire cross-sectional area of the cast wire, it is 1.7/2.7×
100=63(%). Furthermore, based on the above-mentioned fact, if the temperature of the seed wire 6 passing through the crucible 2 is set variously, the amount of heat that the seed wire 6 can receive can be set, and the amount of molten metal that adheres to and solidifies on the seed wire 6 can also be varied. Can be set. In other words, from a phenomenon perspective, if the temperature of the seed wire is low, solidification of the molten metal will proceed quickly on the seed wire when the seed wire is pulled up from the molten metal, and as a result, a large amount of molten metal will adhere and solidify. On the other hand, if the temperature of the seed wire is high, the solidification of the molten metal on the seed wire will be delayed when the seed wire is pulled up from the molten metal, and as a result, the amount of molten metal that will stick and solidify will decrease. By controlling the preheating temperature, the amount of solidified molten metal deposited on the seed line can be adjusted. Structure of the Invention In other words, the deep forming method of the present invention involves continuously immersing a core seed wire into a molten metal different from the material of the seed wire, and then continuously dipping the seed wire upward from within the molten metal. In the dip forming method, in which the molten metal is attached and solidified around the seed wire, the seed wire is preheated in a non-oxidizing atmosphere before being immersed in the molten metal, and the preheating temperature is controlled. This method is characterized by controlling the amount of metal adhesion and solidification around the seed wire. This invention will be explained in more detail below. FIG. 2 shows an apparatus for carrying out the present invention, in which a vacuum vessel 8 is provided which is connected to the lower inlet 1 of the crucible 2 to form a non-oxidizing atmosphere, and the vacuum vessel 8 is equipped with a peeling die 9. Seed line introduction port 1 with
0 and an exhaust port 11 are provided. Further, inside the vacuum vessel 8, a preheater 12 is provided above, and a capstan 13 is provided below. The seed wire 6 introduced from the inlet 10 while the surface layer is removed by the peeling die 9 is taken up by the capstan 13, passes through the preheater 12, and is supplied upward from the lower inlet 1 of the crucible 2. Ru. In this invention, as mentioned above, the seed wire 6 is connected to the preheater 12.
While passing through, the seed wire 6 is preheated to the required temperature. Further, the inside of the vacuum container 8 is exhausted from the exhaust port 6, thereby preventing the preheated seed wire 6 from being oxidized. Here, the preheating temperature for the seed wire 6 needs to be less than the melting point of the material of the seed wire, and at the same time it needs to be less than the freezing point of the solidified metal attached, so as a result, the preheating temperature for the seed wire 6 is Limited to temperatures below the melting point. Preferably, the preheater 12 uses an electrical heating method that allows the preheating temperature of the seed wire 6 to be set with high precision, such as high-frequency induction heating, electrical heating, or the like. Furthermore, the inside of the vacuum container 8 is desirably 20 torr or less.
It is best to set the pressure to 10 torr; if it exceeds it, the seed wire will be oxidized and the quality of the product will deteriorate.
Note that the inside of the vacuum container 8 does not necessarily need to be in a vacuum state, and an atmosphere may be formed using a reducing gas such as argon gas, for example. Examples Examples and comparative examples of the present invention will be described below. Example A steel wire with a diameter of 12.7 mm was used as the seed wire, copper was used as the deposited solidified molten metal, and the preheating temperature by the preheater 12 was varied in the apparatus shown in FIG. Copper-coated steel wire was manufactured. At that time, the immersion time of the steel wire in the molten copper was varied by changing the feed rate of the steel wire and the height of the molten copper in the crucible 2. Comparative Example A copper-coated steel wire was manufactured by performing the conventional dip forming method using the same steel wire and molten copper as in the example. The copper area ratio of the deposited solidified portion was measured for each of the copper-coated steel wires obtained as above. The results are shown in Table 1.

[Table] As is clear from Table 1, as the preheating temperature of the seed wire increases, the cross-sectional area ratio of copper attached to the seed wire decreases, and by changing the immersion time of the seed wire, In this example, the copper cross-sectional area ratio is set variously in the range of 10% to 42%. Note that the embodiments of the present invention are not limited to the above, and for example, a seed wire 6 that is not preheated is passed through the molten metal in the crucible 2, and the wire rod obtained thereby is preheated as the seed wire 6 and placed in the crucible 2. By passing through the molten metal, the cladding ratio can be easily set not only when decreasing the cladding ratio but also when increasing the cladding ratio. Effects of the Invention As described above, according to the present invention, the seed wire is preheated in a non-oxidizing atmosphere before being immersed in molten metal to perform the dip forming method, and the seed wire is controlled by controlling the preheating temperature. Since the amount of adhesion and coagulation of metal around the wire is adjusted, the cladding ratio can be freely set, and a clad wire having material properties suitable for the purpose can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of equipment for carrying out the conventional dip forming method, and FIG. 2 is a schematic diagram showing an example of equipment for carrying out the dip forming method of the present invention. 1... seed wire insertion port, 2... crucible, 5... molten copper, 6... seed wire, 8... vacuum container, 9... peeling die, 11... exhaust port, 12... preheater.

Claims (1)

[Claims] 1 The core seed wire is continuously immersed in a molten metal different from the material of the seed wire, and then the seed wire is continuously pulled upward from the molten metal, and the molten metal is poured around the seed wire. In the deep forming method, the seed wire is preheated in a non-oxidizing atmosphere before being immersed in molten metal, and by controlling the preheating temperature, the metal around the seed wire is deposited and solidified. Deepforming method characterized by controlling the amount.