JPH04200905A - Continuous casting/rolling method - Google Patents

Abstract

PURPOSE:To manufacture high-quality rough drawing wire free from indentation defect of oxide film, therefore, excellent in wire drawing properties by making the oxide film on the surface of an ingot with a skin pass rolling mill into splinters and injecting high pressure water to remove the oxide film. CONSTITUTION:An ingot 5 having oxide film 6 on its surface is rolled down slightly alternately at least by two-way roll stands 1, 2, 3 from two directions which are orthogonally crossed such as vertical and lateral directions, etc., to make the oxide film 6 into splinters 7. High pressure water 8 is injected to a surface of a ingot 5 under slight rolling reduction covered with easily separable splintered oxide film 7 where does not come in contact with the roll to remove the oxide film splinters 7. Consequently, the oxide film 6 can be removed surely and easily all over the surface of the ingot 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous casting and rolling method that can easily produce rough drawn wire of copper or the like having a good surface M shape and excellent workability.

[Prior Art] Copper rough wire used as a raw material for electric wires, for example, is made by casting molten copper using the continuous held boiling method, that is, by endless held running, and by I'1! ! Molten metal is continuously injected into a mold formed by the grooves of a rotating wheel provided with grooves and solidified to form an ingot, and then the ingot is continuously rolled. This continuous casting and rolling method is called the SCR method, Blopelch method, etc.

[Problem to be solved by the invention]

However, an ingot cast by the above-mentioned continuous IH casting machine has a thick oxide film formed on its surface, and when this ingot is rolled as it is, the oxide film is pushed into the inside of the ingot, resulting in The surface quality of the rough drawn wire deteriorates, and such indentation defects cause wire breakage when drawing into ultra-fine wire.

[Means to solve problems]

In view of this situation, the present invention has conducted extensive research, and has found that when the oxide film on the surface of a metal material is rolled down, for example, from above and below,
It was discovered that this aspect makes it extremely easy to peel off, and after further research, the present invention was completed.

That is, the present invention casts molten metal into an ingot using a continuous casting machine, and then continuously rolls the ingot using a groove-type continuous rolling mill placed in front of the continuous casting machine to form a rough wire. In the continuous casting and rolling method, a skin pass rolling mill in which at least two two-way roll stands are arranged so that their rolling directions alternately intersect at right angles is disposed between the continuous casting machine and the groove-type continuous rolling mill, and By skin pass rolling machine,
The ingot is lightly reduced to break the oxide film on the ingot surface into pieces, and at the same time, high-pressure water is sprayed on the surface of the ingot that is not in contact with the rolls in each of the two-way roll stands to remove the ingot. It is characterized in that after removing the oxide film particles on the surface, it is processed into a rough drawn wire using the groove type continuous rolling mill.

That is, the method of the present invention removes the oxide film from an ingot produced from a continuous casting machine by subjecting the ingot to light pressure, for example, alternately from the top and bottom and from the left and right to break the oxide film into small pieces. At the same time, high-pressure water is injected onto the left and right sides or the top and bottom surfaces of the ingot that are not covered by the rolls of the ingot under light pressure to remove the oxide film over the entire circumference of the ingot.

The method of the present invention will be specifically explained below with reference to the drawings.

FIG. 1 is a side view showing an example of the method of the present invention.

A skin pass rolling mill 4 is constructed by sequentially arranging two-way roll stands 1゜2.3 in tandem with rolls mounted so that the roll faces are oriented horizontally, vertically, and horizontally, respectively. An ingot 5 cast by a continuous casting machine is supplied, and this ingot 5 is first lightly rolled down in the vertical direction by a two-sided roll stand 1 to reduce the oxide film 6 on the surface of the ingot 5 into small pieces. , spraying high-pressure water 8 with a spray 9 on both left and right sides of the lightly rolled part of the ingot 5 that are not touched by the rolls to remove the oxide film fragments 7;
Next, the ingot 5 is lightly rolled down from the left and right directions using the two-way roll stand 2 to break the oxide film on the top and bottom surfaces of the ingot into small pieces, and the top and bottom surfaces of the ingot 5 that are not touched by the rolls are sprayed with 1
9, high-pressure water 8 is injected to remove the oxide film particles.

Furthermore, the ingot 5 is lightly rolled down from above and below by the two-way roll stand 3, and high-pressure water 8 is sprayed from the spray 29 onto both left and right sides of the ingot that are not touched by the rolls, thereby forming an oxide film on both the left and right sides of the ingot 5. Remove the strips 7 more completely. The ingot 5 from which the oxide film has been removed in this way is then passed through a groove-type continuous rolling mill 10 in which groove roll stands are arranged in tandem.
It is rolled and processed into a rough wire J1 having a predetermined shape.

In the above, if the reduction area per pass by the skin pass rolling mill is less than 5%, the oxide film will not be sufficiently fragmented, and if it exceeds 15%, the oxide film will be deeply embedded in the ingot. Since it becomes difficult to remove even if high-pressure water is applied, the reduction area ratio is preferably in the range of 5 to 15%.

Further, the number of two-way roll stands constituting the skin pass rolling mill is required to be at least two in order to remove the oxide film over the entire surface of the ingot. However, if the number of bases is too large, the temperature of the ingot will drop sharply due to high-pressure water injection, resulting in poor workability in groove rolling in the subsequent process, so a maximum of about four bases is preferred.

In addition, it is preferable to use the same coolant used in continuous rolling in the subsequent process for the high-pressure water injected into the ingot, and the amount, pressure, and injection angle of the high-pressure water to be injected are determined depending on the type of ingot and its It is appropriately selected depending on the thickness of the oxide film, etc. In addition, a sprayer that injects high-pressure water has a plurality of nozzles arranged in the width direction of the ingot so that the high-pressure water is applied to the entire width direction of the ingot, and the spray is also applied to the front and back of the ingot. It can also be used by arranging multiple rows in the direction.

Since the ingot from which the oxide film has been removed is re-oxidized before it reaches the next step, the groove-type continuous rolling mill, it is preferable to encapsulate the ingot in a non-oxidizing atmosphere during that time.

A method of encapsulating the ingot in a non-oxidizing atmosphere is to run the produced ingot in a heat-resistant tube filled with an inert gas such as Nz or Ar or a reducing gas such as Co or H2. methods etc. are applied. The temperature of the ingot from which the oxide film has been removed is lowered by high-pressure water injection. Therefore, in order to process the ingot homogeneously in the subsequent rolling process, it is preferable to perform a prescribed heat treatment on the ingot before it reaches the continuous rolling mill to recover the ingot temperature. .

In the above, as a method for heat-treating the produced ingot, induction heating or a heating method using a liquefied gas such as butane gas is suitable because of its fast temperature increase rate. Particularly, liquefied gas heating is preferable because it is possible to create a reducing atmosphere by adjusting the mixture ratio of fuel and air, and atmosphere preparation and heating can be performed at the same time.

Continuous casting methods used in the method of the present invention include, in addition to the above-mentioned belt-wheel continuous casting method, twin-held continuous casting methods in which casting is performed using the space between two running Entresspel I sheets as a mold, etc. The continuous casting method, which is relatively fast and involves continuously rolling the produced ingot as it is, is mainly applied.

The method of the present invention can also be applied to the case where an ingot or a rolling mill or the like having an oxide film formed on its surface is rolled into a hatch. In addition, the method of the present invention can be applied to copper, copper alloys, steel materials, etc.
It is effective when applied to metal materials that are easily oxidized and whose oxide film peels off relatively easily.

(Function) In the method of the present invention, an ingot with an oxide film formed on its surface is
At least two two-way roll stands are used to reduce the oxide film into pieces by alternating light reduction from two perpendicular directions such as up and down, left and right, and the ingot is subjected to light reduction so that the fragmented oxide film is easily peeled off. Since the oxide film fragments are removed by spraying high-pressure water onto the surface not touched by the rolls, the oxide film can be reliably and easily removed over the entire surface of the ingot.

〔Example〕

The present invention will be explained in detail below using examples.

Example 1 A copper rough drawn wire was manufactured using an SCR continuous casting and rolling mill. That is, the cross-sectional area is 5100 mm by using a heald wheel type continuous casting machine.
- A square ingot was cast at a speed of 14 m/mjn, and the continuously produced ingot was subjected to oxide film removal treatment by light pressure and high-pressure water injection as explained in Fig. 1. Thereafter, it was rolled using a groove-type continuous rolling mill to form a copper rough drawn wire having a diameter of 81III1φ.

As the above-mentioned groove type continuous rolling mill, a tandem rolling mill was used in which 12 two-way rolls of two types of groove types, oval and round, were arranged alternately.

In addition, since the size of the ingot subjected to light reduction was smaller, the rolling rate of the first roll of the groove-type continuous rolling mill was lowered, or the roll passed free. For high-pressure water, the amount of water per spray is 5 j2/min.

The water pressure was 150 atm and the injection angle was 45 degrees at the injection angle θ shown in Figure 1.The number of light pressure drops and the number of high pressure water injections were varied as shown in Table 1. The distance between the machine and the groove-type continuous rolling mill was approximately 4 m, and during that time the ingot was placed in one of three atmospheres: in the atmosphere, in an SOS vibe filled with N2 gas, or in a reducing flame of butane gas. Furthermore, the rough wire coming out of the continuous rolling mill was run inside a pink ring pipe, washed with isopropyl alcohol, subjected to a reduction treatment, and then wound into a tight coil.

Comparative Example 1 In Example 1, light reduction was performed only once from the top and bottom directions, and high-pressure water was applied to the surface of the ingot that was not touched by the rolls during the light reduction and the surface under light reduction immediately after the light reduction, that is, the upper and lower surfaces. Inject,
A rough drawn wire was produced in the same manner as in Example 1, except that the ingot after the oxide film removal treatment was run in the atmosphere as it was and supplied to a groove-type continuous rolling mill.

Comparative Example 2 Copper rough drawing wire was produced in the same manner as in Example 1, except that in Example I, the produced ingot was run in the atmosphere as it was without being subjected to oxide film removal treatment and was supplied to a groove-type continuous rolling mill. was manufactured.

For each of the copper wires obtained in this way, the presence or absence of indentation of oxide film pieces was investigated by SEM observation, and the rough wires were heated to 0.03 mm with appropriate intermediate annealing.
The wire was drawn to φ and the wire drawability was investigated. The results are shown in Table 1.

As is clear from Table 1, the product produced by the method of the present invention (N.

1 to 9) have good surface quality with no oxidation film stress, and the wire drawability is 15 wire drawing per wire breakage.
The weight was as high as ~25 kg.

Among them, No. 4.5 was obtained by encapsulating the ingot after light reduction with a reducing flame of N2 gas or butane gas to prevent the regeneration of the oxide film before reaching the channel continuous rolling mill. The surface quality of the rough drawn wire was extremely good, and the amount of wire drawn per wire breakage was also high. Especially no,
In No. 5, the ingot temperature, which had decreased due to high-pressure water, was recovered by heating with a butane gas flame, and as a result, the ingot was uniformly processed during channel continuous rolling, and the wire drawability was significantly improved.

In addition, for No. 8.9, the wave front ratio during light reduction is too small, making the oxide film fragmented somewhat insufficiently, and the latter has a too large area reduction ratio, causing the oxide film fragments to form inside the ingot. Because the wires were embedded somewhat deeply, indentation defects remained on the surface of the rough drawn wires, and wire drawability was also slightly reduced.

On the other hand, for comparison method product No. 10, light reduction was performed only once from the top and bottom directions, so the oxide film fragments on the bottom surface of the ingot-L were difficult to peel off, and even when high-pressure water was sprayed, the oxide film fragments did not come off. A considerable amount remained, and in No. 1.1, no oxide film removal treatment was performed at all, so the oxide film remained on the entire surface of the ingot, and as a result, a large amount of oxide film fragments were pushed into the rough drawing line. ,
In both cases, the surface quality deteriorated, and the amount of wire drawn per wire breakage became extremely low.

[Effects] As described above, according to the method of the present invention, it is possible to produce high-quality rough drawn wire with no oxide film indentation defects, etc. and excellent wire drawability, and it has an industrially significant effect. play.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the method of the present invention. 1.2.3... Two-way roll stand, 4... Skin pass rolling mill, 5... Ingot, 6... Oxide film, 7...
・Oxide film fragments, 8...High pressure water, 9,19.29...
- Spray, 10... Channel type continuous rolling mill, 11... Rough line. Patent applicant Furukawa Electric Co., Ltd.

Claims (1)

[Claims] A continuous casting and rolling method in which molten metal is cast into an ingot using a continuous casting machine, and then the ingot is continuously rolled into a rough drawing wire using a groove-type continuous rolling mill disposed in front of the continuous casting machine, Between the continuous casting machine and the groove type continuous rolling machine,
A skin pass rolling mill is provided in which at least two two-way roll stands are arranged so that their rolling directions alternately intersect at right angles, and the skin pass rolling mill lightly rolls down the ingot to remove the oxide film on the surface of the ingot. At the same time as the ingot is cut into pieces, high-pressure water is injected onto the surface of the ingot that is not in contact with the rolls in each two-way roll stand to remove fine oxide film on the surface of the ingot, and then the groove-type continuous rolling is carried out. A continuous casting and rolling method characterized by processing into rough lines using a machine.