HU202431B - Method for continuous producing wire - Google Patents

Abstract

A method for the continuous production of wire is characterised in that a continuously supplied core wire is subjected to surface cleaning, that the core wire with the cleaned surface is introduced into a duct with an atmosphere consisting of an inert gas or a gas with a slight reducing action, at a pressure above the ambient pressure, that the core wire is passed out of the duct into a bath of molten metal, through which it is passed in order to take up the molten metal onto the wire to form a cast rod consisting of the core wire and a coating which is formed around it and results from the solidified metal taken up, and that the cast rod is hot-rolled to give a wire with a reduced cross-section.

Description

FIELD OF THE INVENTION The present invention relates to a process for continuous firing of wires by dipping casting, wherein the core wire is passed through a feed chamber and then through a metal melt by cleaning or removing the surface of the core wire prior to introduction into the metal melt. roll hot.

Such dipping casting methods for wire production have long been known and are widely used. A description of the impulse is found, inter alia, in pages 39-18204. JP. In this arrangement, the core wire is led through a drawing ring into an inlet chamber, from which the cleaned core wire is then introduced into the casting crucible. The casting crucible is made of graphite and the core wire enters the molten metal through an arrow on its bottom and then exits through an arrow from the casting chamber and enters between rolls and, if appropriate, a cooling unit.

During casting, a vacuum is formed in the inlet chamber and optionally in the rolling chamber to prevent oxidation of the surface of the wire, thereby weakening the bond between the core wire and the deposited metal, and forming surface defects.

It has been found that when the dehumidifiers of the core wire are filled with dry air, the above adverse effects do not occur. Consequently, the belief that the reduction of bonding security and the formation of surface defects result from surface oxidation has not been substantiated and further investigations have shown that the cause of these defects lies in the moisture content of the air.

Thus, the present invention is based on the realization that in order to produce a product of the correct quality, it is not a vacuum but a dry atmosphere.

The object of the present invention has been solved by directing the core wire during the dipping casting in the inlet chamber and optionally during the rolling in a neutral or reducing gas atmosphere above atmospheric pressure.

In the inlet chamber, the core wire is heated to an optimum temperature, thereby determining the thickness of the cast rod coating.

In some cases, the core wire may be made of an alloy other than the metal to be laid.

Prior to introduction into the inlet chamber, the surface of the core wire should be cleaned with a wire brush or shot blasting.

After core casting, hot rolling reduces the product cross-section by up to 40%. Preferably, a pair of ovals and a pair of semicircular cylinders are used.

An advantage of the present invention is that the operating steps, operating conditions and equipment required for the dipping molding process are significantly simpler than those previously employed and provide good control over the ratio of core wire to coating layer and surface quality of the product.

In addition, the use of the method of the invention is significantly cheaper, both during the investment and during operation.

The product obtained is of unimpaired quality with no inclusions, cracks or other surface defects.

Further details of the invention are provided

examples drawing. THE drawing is Figure 1 Outline of a known apparatus for performing a dipping molding process, a Figure 2 Schematic of apparatus for carrying out the process of the invention, a Figure 3 a diagram of a device for carrying out a further embodiment of the invention, and a Figure 4 3 is a schematic diagram of a procedure similar to that shown in FIG.

In the embodiment shown in Figure 1, the core wire 11 is passed through a pulling ring 14 by means of a pulling roller 12. The core wire 11 then enters the deflection roller 16 as it enters the inlet chamber 18b enclosed by the jacket 18. Upon entry, it passes through 20 peeling rings which remove the surface layer and thereby provide a clean metal wire surface. From the inlet chamber 18b, the core wire 11 is guided by the conveyor rollers 22 into the casting crucible 24 through the inlet port 24a. The crucible 24 is formed of a refractory material, such as graphite, and is filled with molten metal M, such as copper, through a channel 28 from a melting pot 26.

The core wire 11 continues to move upward, whereby a layer of molten metal is deposited on a clean metal peripheral surface. In this way, the diameter of the cast wire 13 exiting the die 24 is larger than that of the core wire 11.

The cast wire 13 passes from the crucible 24 to the cooling unit 30a enclosed by a sheath 30, where it passes along the guide rolls 31 to the hot rolling unit 32a enclosed by the sheath 32. Here it is formed with 34 and 36 pairs of rollers. The profile of the pairs of rollers 34 is preferably oval, while the pairs of rollers 36 are provided with a semi-circular profile.

After forming, the wire 13 passes through the cooling zone 38 and leaves the apparatus as a finished product 40.

In the figure, the inlet chamber 18b is provided with a suction nozzle 42 through which the aforementioned 39-18204 in the inlet chamber 18b. Vacuum can be applied as described in JP. This vacuum assumes 3 that the cleaned surface of the core wire 11 in the husk ring -20 is not oxidized before it enters the casting crucible 24 and thus achieves the desired surface quality.

The casing 30a and 32b of the refrigeration unit 30a and the hot rolling mill unit 32a and 32a, respectively, are provided with gas inlet ports 30b and 32b, through which slightly reducing gas is introduced into the work space during process operations, also to ensure surface quality.

As mentioned above, its investigations have revealed that the use of a vacuum is not necessary to ensure the surface quality of the product, since surface defects are not due to oxidation but to moisture. When the inlet chamber 18b was filled with dry air, the product quality was as good as under vacuum. At the same time, however, it was no longer necessary to ensure reliable sealing of the intake chamber, which significantly reduced costs. In addition, the disadvantage of using a vacuum to allow a metal melt to leak into the inlet chamber 18b through the inlet port 24a of the die 24 could also be eliminated.

However, it has also been found that when operating the inlet chamber 18b with pressurized dry air, the high temperature causes the casting crucible 24 to undergo a very strong oxidation effect in the vicinity of the inlet port 24a, which results in a short life and continuous operation. This necessitates the use of a neutral gas or a slightly reducing gauze in the inlet chamber 18b.

Figure 2 is a schematic diagram of a device for practicing the process of the invention.

The structure of the casting apparatus 10 is in principle similar to that shown in FIG. The core wire 11 is passed through a peeling ring 20 into the inlet chamber 18b, which at one end is provided with a gas inlet port 46. The gas inlet 46 has a valve 48.

In this embodiment, the housing 18 also has a suction nozzle 42 for venting the inlet chamber 18b prior to gas introduction. The remainder of the casting apparatus 10 is substantially the same as that shown in FIG.

In the process, at start-up of the apparatus, the inlet chamber 18b is evacuated through the suction nozzle 42 and, after the valve 48 is opened, the inhaled or slightly reducing gas is introduced through the inlet nozzle 46. In this way, the core wire 11 passes through the inlet arm 18b to retain the clean metal surface formed after the peeling ring 20. Passing through the deflection roller 16, the core wire 11 passes through the casting crucible 4

At its inlet 24a, and then the cast wire 13 coming out of it, enters the cooling unit 30a.

During operation of the device, the inlet chamber 18b is pressurized slightly above atmospheric pressure, so that no outside air can enter, even if the jacket 18 is not airtight. Accordingly, the surface of the core wire 11 retains its good quality and oxidation of the casting crucible 24 can also be avoided.

The peeling ring 20 may optionally be replaced by another cleaning element, such as a shotgun or a wire brush or chemical agent.

In the apparatus shown in Figure 2, the process was carried out as follows.

A mixture of 95% nitrogen by weight and 5 volumes of carbon monoxide was introduced into the inlet chamber 18b at a pressure of 10 Pa and a flow rate of 5 m ³ / h. Thus, a slightly reducing atmosphere and a slight overpressure were created. The core wire used was copper wire with a diameter of 12.7 mm leaving the peeling ring 20. The cast wire 13 was hot-rolled to an 8 mm diameter product.

The above technology was also accomplished by connecting the inlet chamber 18b to a vacuum source. Both products obtained by parallel technology were tested. The data obtained during the test are given in the table below.

Table 1 is a sample sample of the invention by vacuum technology

tensile stress (kN / m ² ) 230 464 228 503 elongation (X) 40 41 twist no no test* waste waste cross- no no * section the boundary layer does not waste the boundary layer does not waste

* Each wire is twisted 10 times in one direction and then 10 times in the other direction.

* The cross-section of each wire was examined under a microscope.

As shown in Table 1, the quality of the wire formed by the process of the present invention is substantially the same as that of the state of the art.

Figure 3 illustrates another embodiment of apparatus 10a for carrying out the process of the present invention. This differs from the die 10 shown in Fig. 2 in that the peeling ring 20 was replaced by a surface cleaning device 50 and that only a pair of rollers 34 and a pair of rollers 36 were used. With the pair of rollers 34, the cast wire 13 is formed to an oval cross section and then with the pair of rollers 36 to a circular cross section.

The surface cleaning device 50 comprises a wire brush in the illustrated embodiment, but may also be a shot blasting or chemical cleaning device. The latter are particularly advantageous if the core wire 11 is made of steel rather than copper, which would require the snow ring 20 to be replaced very frequently. This would impede continuous operation, whereas, if cleaning is done with the aforementioned means, the equipment can be operated virtually continuously and no cleaning tools need to be replaced.

There is no metallurgical bond between the core wire 11 and the layer of melt M in the casting crucible 24. This bond is formed during hot rolling.

In cases where the core wire and the deposited coating layer are of different compositions, providing a uniform cross-section of the cast wire during hot rolling is relatively difficult. Thus, for example, when a copper core is coated with a copper coating, it is a composite material of various strengths which is not easy to produce in a hot rolled product of a uniform cross-section. Cross-sectional reduction with oval cylinders increases the unevenness of the copper plating thickness, which is not favorable for the finished product. Therefore, in the embodiment shown, for example, the cast wire is rolled only once between rollers of oval profile. The total weight of cast wire between different pairs of rolls is generally no more than 40%. In this way, the unevenness of the finished product produced by rolling can be minimized.

If the rate of weight loss is greater than 40%, it has been found that the unevenness of the thickness of the copper plating layer on the steel core wire is greater than the allowable tolerance.

Thus, when a copper coating was cast on a steel core wire using the apparatus shown in Figure 3, the following procedure was followed.

After vacuuming and then creating a slightly reducing gas atmosphere, the dipping casting process was performed. The core wire used was a 9.5 mm diameter spring steel wire which was cleaned with a wire brush. The core wire was introduced into the feed chamber at a speed of about 70 m / min, from which a cast wire of about 13 mm diameter was guided.

The cast wire consisted of steel core and copper plating, and after cooling and hot rolling, a wire with a diameter of 11 mm was obtained as a finished product.

The weight loss during hot rolling was 13%. The thickness of the final copper plating ranged from 1.45 to 1.5 mm and the average thickness was 1.48 mm. This means a practically constant coating thickness. The weight ratio of the coating layer to the finished product was about 50%, however, as said above, it can be varied depending on the rate of passage of the core wire through the casting crucible.

Figure 4 shows a variant of the invention according to the embodiment shown in Figure 3. This differs in particular from the other embodiment in that the inlet chamber 18b is provided with heating units 54. The introduced core wire 11 can thus be heated to a temperature before it reaches the casting crucible 24, which is desirable in technology.

It has been discovered that the amount of metal melt deposited on the core wire depends on the temperature of the core wire introduced into the casting crucible. Generally, the greater the amount of metal melt that is loaded onto the core wire, the more heat the core wire absorbs from the metal melt in the casting crucible. Accordingly, if the core wire temperature is relatively low, the coating layer is relatively thick. However, if the temperature of the core wire is increased by heating, the coating layer will be thinner. In this way, the thickness of the coating layer can be controlled by actuating the heater. The ratio of core wire to coating layer can be varied within the range of 10 to 70%.

The heating of the core wire is also advantageous in cases where the dipping casting is carried out on a non-circular cross-section wire, e.g. In this case, heating provides a uniform temperature of the core portion, which in turn allows the coating to develop at equal thickness.

In the apparatus shown in Figure 4, a shielding gas containing 2% hydrogen and 98% nitrogen was used. The slightly reducing gas mixture was introduced into the apparatus at a pressure higher than atmospheric pressure to create a slightly reducing and slightly pressurized atmosphere in the inlet chamber. The same gas mixture was used during hot rolling.

The starting material used was a 9.5 mm diameter mild steel wire which was cleaned and corroded using a wire brush. The cleaned core wire was passed through a copper melt to form a cast rod, which was then hot-rolled.

Three core diameters of different diameters were used in the experiments and led at different temperatures to the

-47 HU 202431 B 8 gelyle. The thickness and weight ratio of the copper plating on the finished products were determined. The results of the test are shown in the table below.

Table 2 maghuzal- -temperature (° C) product- -diameter (Mm) copper coating avg. thickness (mm) weight ratio (%) room temperature 11.5 2.02 61 200 10.0 1.05 38 400 9.0 0.44 21

As can be seen from the table, the weight ratio of the resonant coating is significantly dependent on the core wire temperature.

It will be apparent from the examples presented that the present invention provides a simpler and safer technology for producing wire by dipping casting than conventional solutions. However, the equipment used is simpler and less expensive to operate. By controlling the core wire temperature in accordance with the present invention, the thickness or weight ratio of the coating layer can be varied within wide limits.

Of course, the examples presented are merely illustrative of the invention and are not to be construed as limiting the scope of the invention as defined in the appended claims.

Claims (7)

PATENT CLAIMS A process for continuously producing wire by dipping casting comprising passing the core wire through an inlet chamber and then melting the metal wire prior to being introduced into the metal melt and removing the molten wire from the metal melt and depositing the solid material onto the surface. characterized in that between the cleaning or removal of the surface of the wound (11) and its passage through the metal melt (M), and optionally, the cast wire (13) is pressurized with neutral or reducing pressure at atmospheric pressure during hot rolling gas circle. We drive it in 35 atmospheres. (3/12/1984). Method according to claim 1, characterized in that the surface cleaning of the core wire (11) is carried out by wire brushing. (01.03.1984). 40 Method according to claim 1, characterized in that the surface cleaning of the core wire (11) is carried out by blowing a shot. (01.03.1984) 4. A process according to any one of claims 1 to 4, characterized in that during hot rolling, the cross-section of the cast wire (13) is reduced by up to 40%. (01.03.1984) 5. A process according to any one of claims 1 to 6, characterized in that the hot-rolled wire (13) is hot-rolled first to an oval and then to a circular cross-section (01.03.1984). 6. Process according to any one of claims 1 to 4, characterized in that the core wire (11) is heated before being introduced into the metal melt (M). (3/12/1984). 7. A method according to any one of claims 1 to 3, characterized in that the core wire (11) is coated with a coating (M) of a different metal or alloy melt. (01.03.1984).