JPH0325263B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to excitation of a high-frequency vibration mold for continuous casting (hereinafter abbreviated as vibration mold) used when continuously casting metal while applying high-frequency vibration to the mold. Regarding the method.

Japanese Patent Application No. 197617 describes a method of excitation of a vibrating mold equipped with multiple vibrators, in which the mold wall is subjected to high-frequency excitation with the excitation frequency difference between adjacent vibrators being equal to or higher than the beat generation limit frequency difference. This is a method of shaking. However, in this method, the excitation frequency of each vibrator is greatly different, making management of the vibrators difficult.

FIG. 10 is a diagram showing an example of frequency-amplitude characteristics of one vibrator. The excitation frequency of one vibrator can be changed by controlling the frequency setter. However, if the frequency of the vibration at which the maximum amplitude is obtained is fo, it becomes less than (fo-1) KHz or more than (fo+1) KHz, the amplitude decreases rapidly as shown in FIG.

In the method of Japanese Patent Application No. 60-197617, the excitation frequency of each vibrator is greatly different, but if all the vibrators are unified to vibrators with the same excitation characteristics, this method
As shown in the figure, it is undesirable because some of the vibrators must be excited with a small amplitude, and if multiple types of vibrators with different excitation characteristics are arranged in a vibrating mold, control and management becomes difficult. Become.

[Problems to be Solved by the Invention] For control and management purposes, it is desirable that the plurality of vibrators placed in the vibrating mold have the same performance. However, for example, when a vibrating mold is vibrated with a plurality of vibrators having the same excitation frequency and amplitude, the resulting vibration becomes a standing wave, and the vibrating mold is vibrated with this standing wave. Since this standing wave does not travel, the amplitude becomes extremely small on the wall of the vibrating mold at the position corresponding to the node of the standing wave.
For this reason, flux (a lubricant between the inner wall surface of the vibrating mold and the molten metal) does not flow smoothly at positions corresponding to the nodes, and seizure between the inner wall surface of the vibrating mold and the molten metal occurs.

As shown in FIG. 10, it is preferable to set the excitation frequency of each vibrator between (fo-1) KHz and (fo+1) KHz because the amplitude of each vibrator can be kept large. Set the frequency of each vibrator to (fo−1)KHz~
(fo + 1) KHz When the vibrating mold is excited at different frequencies, the standing waves are reduced, but because the difference in the excitation frequencies is small, a composite vibration is formed that will not progress rapidly unless special measures are taken. As a result, on the inner wall surface of the vibrating mold, there are parts that are vibrated with a large amplitude and parts that are always vibrated with a small amplitude, and in these parts that are vibrated with a small amplitude,
Seizure between the vibrating mold and the molten metal will occur.

In a vibrating mold in which a plurality of vibrators having the same excitation characteristics are arranged, the present invention applies the vibrating mold by setting the excitation frequency of each vibrator between (fo-1) KHz and (fo+1) KHz. To provide a vibrating method for a vibrating mold that vibrates all parts of the vibrating mold uniformly and with a large amplitude without causing localized parts of the vibrating mold where the amplitude is always small when vibrating.

[Means for Solving the Problems] The present invention provides (1) In a vibrating mold in which a plurality of vibrators having the same vibration characteristics are arranged, the excitation frequency of each vibrator is set within a range of 2 KHz, and adjacent vibrations are A vibrating mold excitation method characterized by setting the excitation frequency of each vibrator to be different, and changing the excitation frequency of each vibrator intermittently or continuously over time. be.

Hereinafter, (1) of the present invention will be specifically explained with reference to FIG. Figure 1 is a diagram showing an example of a cross section of a vibrating mold.
vibrates the inner wall of the The vibrators a to d will be explained below.

Assuming that each vibrator and its frequency at a specific time _T1 during excitation are a: νa, b: νb, c: νc, and d: νd, the frequency setter of each vibrator is controlled by the present invention. Then, νa to νd are set as follows.

νmax−νmin＜2KHz...(1) However, νmax: The frequency of the oscillator with the maximum frequency among νa to νd, νmit: The frequency of the oscillator with the minimum frequency among νa to νa. Further, in the present invention, νa to νd are set so that νa≠νb, νb≠νc, νc≠νd (2).

At time _T2 , which is t seconds after _T1, the excitation frequency of each vibrator is changed to a: νa', b: νb', c: νc', and d: νd'. Note that νa′ to νd′ are also set so as to satisfy equations (1) and (2), respectively.

After t seconds after T ₂ , the excitation frequencies of each vibrator are set to a: νa'', b: νb'', c: νc'', d: νd'', and νa'', νb'', νc'', νd ``Similar to the above, equations (1) and (2)
Set each expression so that it is satisfied. In this case, νa=νa″, νb=νb″, νc=νc″, νd=νd″
You can also use it as

Thereafter, similarly, the vibration mold is vibrated by changing the excitation frequency of each vibrator intermittently or continuously as time passes.

The above description has been made for the vibrators a to d, but the same applies to the vibrators e to l. In addition, (2) of the present invention is a method of setting the excitation frequencies of adjacent vibrators to be different, such as by arranging them on one side or both sides of the reference vibrator with respect to a specific vibrator (reference vibrator). The excitation frequency of each vibrator is set to become smaller as it moves away from the reference vibrator, or the excitation frequency of other vibrators placed on one or both sides of the reference vibrator is set as the reference vibrator. It is a setting (setting) that gradually increases as it moves away from the vibrator, and the method of excitation by changing the excitation frequency of each vibrator intermittently or continuously over time is to change the setting from the setting as time passes. Next, there is a method of excitation of a high-frequency vibration mold for continuous casting as described in (1) above, which is a method of excitation while changing settings intermittently or continuously.

(2) of the present invention will be explained with reference to FIG. The reference vibrator may be any vibrator from a to d. For example, if oscillator a is used as the reference oscillator, the frequency of each oscillator at a specific time _T1 is a setting, and the above (1)
The equation becomes 0<νa−νd<2KHz...(1') (1') equation, and equation (2) becomes νa>νb>νc>νd...(2') (2') equation.

At time _T2 , which is t seconds after _T1 , the excitation frequency of each vibrator is changed to a setting that satisfies the following expressions (1)'' and (2)''.

0＜ν′d−ν′a＜2KHz……(1″) ν′a＜ν′b＜ν′c＜ν′d……(2″) Each oscillator after t seconds after T ₂ The excitation frequencies νa″, νb″, νc″, and νd″ are νa: νa″, νb: νb″, νc: νc″, and νd: νd″.
Therefore, for νa″, νb″, νc″, and νd″, (1)′
Equations and (2') hold true.

Thereafter, the vibrating mold is similarly vibrated intermittently or continuously as time passes, from setting to setting, and then from setting to setting.

[Operations and Examples] Figure 2 shows the vibration status of mold 1 when each of the vibrators a, b, c, and d in Figure 1 vibrates mold 1 at the following excitation frequencies. FIG.

a: νaKHz, b: (νa-1)KHz, c: νaKHz,
d: (νa-1) KHz In Figure 2, A is between 0 and t seconds after the start of vibration, B is between t and 2t seconds, C is between 2t and 3t seconds, and D is between 3t and 3t seconds.
During 4t seconds, Ho is the vibration situation between 4t and 5t seconds. The dotted line in the figure is the range of maximum amplitude within each time period. As seen in FIG. 2, the vibrations of each vibrator overlap to form a wave packet shown by a dotted line. This wave packet changes from A to B to C to D as time passes, and reaches E, completing one cycle. After that, repeat I-ho as time passes. FIG. 3 is a diagram showing the outer periphery of the diagram when I to E of FIG. 2 are superimposed on the same diagram, and is a diagram showing the maximum amplitude at each position of the vibrating mold during one cycle. In Figure 3, for example, position P ₁ of the vibrating mold is always vibrated with a large amplitude during one cycle, so it is always desirable to have a large amplitude, but position Q ₁ is always vibrated with only a small amplitude. Become. Therefore, at the position _Q1 , seizing of the vibrating mold and the molten metal is likely to occur.

Figure 4 shows a: νaKHz, b: (νa+1)KHz,
When set to c: νaKHz, d: (νa+1)KHz,
It is a figure which shows the maximum amplitude in each position of a mold during one period.

When the excitation frequency of each vibrator is changed, the position of a large amplitude in the vibrating mold becomes, for example, P ₂ in FIG. 4, and the position of a small amplitude becomes, for example, Q ₂ . Fifth
The figure is a diagram showing the outer periphery of FIG. 3 and FIG. 4 by overwriting them in the same manner. In other words, the frequency of each vibrator is
If we set t for ₁ second as explained in the figure, then change it as explained in figure 4 and set t for ₂ seconds, t ₁ +
As shown in FIG. 5, the maximum amplitude applied to the vibrating mold during t ₂ seconds is made uniform at each position of the vibrating mold, and the positions that are always vibrated with a small amplitude disappear.

As described above, if the excitation frequency of each vibrator is changed during excitation, there will be no localized areas in the vibrating mold where the amplitude is always small.

FIG. 6 shows an example of the present invention (2), where the reference oscillator is a, a: νaKHz, b: (νa−0.3)KHz,
It is a figure showing the maximum amplitude at each position of the mold during one cycle when setting c: (va-0.6) KHz and d: (va-0.9) KHz. In this setting, the wave packet becomes a beat wave with a group velocity traveling from oscillator a to oscillator d, so the maximum amplitude at each position of the mold during one period is more equalized than in Fig. 3. Ru. After setting the excitation frequency of each vibrator for t ₂ seconds as shown in Fig. 6, change the setting. At this time, the excitation frequency of each vibrator is a: νaKHz, b: (νa + 0.3)
KHz, c: (νa + 0.6) KHz, d: (νa + 0.9) KHz. The setting is held for t ₄ seconds, and the distribution of the maximum amplitude at each position of the mold at this time is shown in Figure 7.

FIG. 8 is a diagram showing the outer periphery of FIG. 6 and FIG. 7 overlaid on the same diagram. That is, it shows the maximum amplitude applied to each position of the vibrating mold during t ₃ +t ₄ seconds. FIG. 8 shows a more uniform vibration distribution than FIG. 5.

Fig. 9 is a diagram showing an example in which the reference oscillator is used as another oscillator. In this example, the solid line is the setting and the dotted line is the setting.

[Effects of the Invention] According to the present invention, in a vibrating mold in which a plurality of vibrators are arranged, all the vibrators can be made of the same type of vibrator with the same vibration characteristics in order to prevent the frequency of each vibrator from greatly differing. This makes it easier to control and manage the transducer. Furthermore, according to the present invention, there are no localized areas in the vibrating mold where the amplitude is always small, and all parts of the vibrating mold are uniformly vibrated with a large amplitude. Therefore, the flow of flux is smooth, the casting surface of the slab is excellent, and since seizure etc. do not occur, casting accidents can be prevented.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a cross section of the vibration mold, Figure 2 is a diagram showing a cross section of the vibration mold.
The figure shows the maximum amplitude of each part of the vibrating mold at each period, Figure 3 shows the maximum amplitude at each position of the vibrating mold in the excitation pattern of Figure 2, and Figure 4 shows other excitation patterns. A diagram showing the maximum amplitude at each position of the vibrating mold in the pattern, Figure 5 shows the maximum amplitude at each position of the vibrating mold when the excitation pattern in Figure 3 and the excitation pattern in Figure 4 are intermittently changed and combined. 6 is a diagram showing the maximum amplitude of each position of the vibrating mold in the setting of the present invention (2). FIG. 7 is a diagram showing the maximum amplitude of each position of the vibrating mold in the setting. Figure 8 is a diagram showing the maximum amplitude at each position of the vibration mold when the settings are changed and combined intermittently, and Figure 9 is an example of the excitation frequency of each vibrator when the reference vibrator is changed. Figure 10 shows 1
FIG. 3 is a diagram showing frequency-amplitude characteristics of individual vibrators.

Claims (1)

[Claims] 1. In a high-frequency vibration mold for continuous casting in which a plurality of vibrators with the same vibration characteristics are arranged, the excitation frequency of each vibrator is within a range of 2 KHz, and the excitation frequency of adjacent vibrators is A method for exciting a high-frequency vibrating mold for continuous casting, characterized in that the vibration frequency of each vibrator is set to be different, and the vibration frequency of each vibrator is changed intermittently or continuously over time. 2 The method of setting the excitation frequency of adjacent vibrators to be different is to set the excitation frequency of other vibrators placed on one side or both sides of the reference vibrator for a specific vibrator (reference vibrator). is set so that it becomes smaller as it moves away from the reference transducer, or the excitation frequency of each other transducer placed on one side or both sides of the reference transducer is set to gradually increase as it moves away from the reference transducer. The method of excitation by changing the excitation frequency of each vibrator intermittently or continuously over time is to change it from setting to setting over time, and then from setting to setting. A method of exciting a high-frequency vibration mold for continuous casting according to claim 1, which is a method of exciting a high-frequency vibration mold for continuous casting, which is a method of exciting a high-frequency vibration mold by changing settings intermittently or continuously.