JPS6057414B2 - Mold for continuous metal casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the method of attaching a vibration generator to a mold for applying high frequency vibrations to the mold in a mold for continuously casting molten metal.

Conventionally, when continuously casting molten metal, in order to prevent seizure or promote lubrication on the contact surface between the mold and the solidified metal, the mold was cast several tens to hundreds of meters per minute. How to perform reciprocating motion with a swing width (
The reciprocating vibration method (hereinafter referred to as the reciprocating vibration method) is generally practiced.

In addition, there is a method of reciprocating in the direction intersecting the slab, that is, the circumferential direction of the round bar block (hereinafter referred to as the rocking method).
There is also a West German patent 896988; 105 yen). moreover,
A method of applying vibration to a mold at a rate of 5 to 30 cycles/second (hereinafter referred to as the "vibration method") has also recently been developed. On the other hand, the present inventors have previously devised a method of promoting lubrication by applying high frequency vibration of 5 to 50 KHz to the mold. Now, the advantages and disadvantages of such a method are as follows.

First, in the reciprocating vibration method, striped patterns (usually referred to as oscillation marks) are formed on the surface of the solidified metal lump due to the reciprocating vibration of the mold, causing surface defects.

However, this method is widely practiced because it is easy to implement and can be applied to flat molds and round molds. Furthermore, the locking method is not general because its application is limited to round molds. The vibration method has the disadvantage that the slab also vibrates, which affects the quality of the slab and limits its applications. Furthermore, in the method of applying high-frequency vibrations of 5 to 50 KHz to the mold, conventionally, vibration energy was applied to the entire mold including the cooling box and attached parts such as cooling piping, so a large amount of incident energy was required.
The present invention was made to solve these problems, and it can reduce the oscillation marks on slabs, reduce surface flaws, and can be applied to a variety of mold shapes.
Moreover, it provides a mold that can reduce the amount of incident energy.

That is, the present invention provides a mold with open ends for continuously casting molten metal, which has a structure in which the part of the mold that comes into contact with the metal to be cast (hereinafter referred to as the mold moving part) is divided against high-frequency vibrations. The present invention relates to a metal casting mold which is divided into a plurality of parts, and vibrations of 5 to 50 K pressure are applied to one or more of the divided parts.

In the present invention, the mold moving parts to which high-frequency vibrations are applied are distributed at several locations, for example, in the height direction and the width direction, and the frictional force between the mold moving parts and the slab is averaged. The unique feature is that you can freely choose whether to reduce the frictional force to the maximum or apply vibration to the area where the frictional force is greatest. ．． Further, in the mold for continuous casting of metal according to the present invention, the frequency of vibration applied to the moving parts of the mold is limited to a range of 5 to 50 KHz for the following reason.

In the low frequency range of less than 5KHz, it generates audible noise and cannot be used in the working environment, and in the frequency range of more than 50KHz, it works as mechanical vibration to reduce the friction between the mold and the metal to be cast. I can't.

The present invention will be explained in detail below using the drawings.

FIG. 1 shows a mold that generates high-frequency vibrations, in which a vibrator 1 receives high-frequency electricity oscillated from a high-frequency vibration generating electric equipment 3 and vibrates, and this vibration is passed through a vibrating connecting rod 2 to cast molten metal. It is a figure which shows giving vibration to the casting mold 4. In this case, the mold has an integral structure in terms of high-frequency vibration between the cooling box and the mold moving part, and the applied high-frequency vibration force is transmitted not only to the mold moving part but also to the cooling box, etc., and the energy is The consumption power is high. Now, as equipment for generating high frequency vibrations, there is a high frequency vibration generator, which is
There are major technical difficulties in designing for a KW capacity.
．． In addition, the larger the capacity, the worse the energy efficiency.Furthermore, if vibrations from multiple oscillators are applied to one continuous solid body, such as a mold, they will interfere with each other, and the mold will not be able to sufficiently vibrate. In some cases, this is not done.

The present invention has been made to solve these problems.

Next, examples of the present invention will be described.

2, 3, and 4 are diagrams illustrating a specific example of the present invention, in which 6 is a cooling water passage, and 7 is a means for vibrationally isolating the divided mold into 4 parts and connecting them. 8 is a mold portion to which high frequency vibration is applied, 9 is molten metal, 10 is a lubricant, and 11 is a solidified shell.

In FIG. 2, the mold moving part is divided into three parts on one side, and the central part is the mold moving part to which high frequency vibrations are applied. Such vibrating mold moving parts are provided on each of the four sides of the square mold. For example, if the electric equipment that applies vibration to each surface has a power of 10 KW, a total of 40 KW of input can be applied to this mold system as a whole. Of course, there is no limit to the number of movable parts of the mold to which independent vibrations are applied, and it is important to consider the technical and economical conditions arising from the capacity of the vibration system, and from the high-frequency vibration power that should be applied to the mold system. , is to be determined.

FIG. 3 shows an example in which a large mold is provided with a large number of vibrating parts. This example shows a mold for manufacturing rectangular slabs.
This mold has a total of six vibration-applied parts, two on each long side and one on each short side. Also, among those divided into several parts in the height direction,
For example, as shown in FIG. 4, it is of course possible to apply high frequency vibration only to a limited portion that contacts the metal to be cast. ”
In this way, the friction between the mold and the metal to be cast can be reduced with less excitation energy. In FIG. 4, reference numeral 2 denotes a connecting rod that transmits bulk frequency vibration from a high frequency vibration generation source to a mold portion 8 in contact with the metal to be cast.

7 is a backing material that vibrationally isolates the molds divided in the height direction of the mold.

12 is a part of the mold to which high frequency vibration is not applied.

13 is the back plate of the water cooling box of the mold.

Next, using the mold system shown in Figure 3, cross-sectional dimensions of 900 x 25
An example of manufacturing a steel slab of 0wn is shown.

The mold surface dimensions of the part to which high-frequency vibration was applied were 20"φ on the wide side and 10"φ on the narrow side. The power supply equipment corresponding to one high frequency vibration part was each 2KW.

With such equipment, if high frequency input is not applied,
A comparison was made between the case where the high frequency input was applied to the entire mold and the case where the high frequency input was applied to the divided portion according to the present invention, and the results shown in the attached table were obtained. These results show that by applying high frequency input to the mold, especially to the divided mold sections, surface defects on the slab can be more effectively reduced.
The mold moving part to which the high-frequency vibrations were applied, shown in FIG. 3, is a part of all the working parts of the mold, but it can be seen that the effect of the vibration extends to the entire surface of the slab. The reason for this is that when high-frequency vibrations are applied from the mold to several places on the surface of the slab, unavoidably,
The vibrations are also transmitted to the solidified shell, and these vibrations are also transmitted to the surrounding area, so the vibrations also reduce the frictional force between the mold and the solidified shell. In this way, defects on almost the entire surface of the slab are reduced. This effect is not limited to continuous casting of steel, and similar effects can be expected in casting of other metals.

In addition, since the formation of surface defects is slight, even if the drawing speed of the slab is increased, breakout (a condition in which the solidified shell of the slab is damaged and molten metal flows out from inside, making it impossible to continue casting) ), which leads to a reduction in the risk of accidents and an increase in productivity.

Surface flaw determination: number and size of microcracks on the surface of the slab
Evaluate it based on the amount of maintenance required.

[Brief Description of the Drawings] Fig. 1 is a conceptual diagram showing a situation in which vibrations from a high-frequency vibration generator are applied to a metal casting mold, and Figs. 2, 3, and 4 show the mold according to the present invention. 2 is a sectional view, FIG. 3 is a perspective view, and FIG. 4 is a partially sectional view. 1: Vibrator, 2: Vibrating connecting rod, 3: High frequency vibration generator electrical equipment, 4: Mold, 5: Slab, 6: Cooling water passage, 7: Backing, 8: Mold part to which high frequency vibration is applied. 9;
Molten metal, 10; Lubricant, 11; Solidification shell, 12; Mold copper plate, 13; Mold water box back plate.

Claims (1)

[Claims] 1. In a mold with both ends open for continuously casting molten metal, the part of the mold that comes into contact with the metal to be cast is divided into a plurality of parts, and each part is connected by vibration isolation means, A mold for continuous casting of metal, which is formed by connecting a vibration generator that applies vibrations of 5 to 50 KHz to any one of the plurality of divided molds in contact with the metal to be cast.