JPH0481253A - Method for detecting abnormality of oscillation in continuous casting mold oscillating device - Google Patents

Abstract

PURPOSE:To surely detect abnormality of an oscillating frame at early time by measuring amplitudes at the times of oscillating the oscillating frame at high velocity and at low velocity in a continuous casting mold oscillating device, obtaining displacing ratio based on the formula and deciding as the abnormality in the oscillation when the displacing ratio exceeds the fixed value. CONSTITUTION:Under empty condition, which molten steel is not supplied in the mold 1, the oscillating frame 2 is oscillated at the high velocity and successively, this is oscillated at the low velocity to obtain the displacing ratio in the oscillation with the formula. At this time, if some abnormality of wear and breakage, etc., to link mechanism in the mold oscillating device is developed, transmission of vertical movement of a rod 12 for driving with driving mechanism to the oscillating frame 2 becomes imperfect. In this result, the amplitude at the time of oscillating in the high velocity is not so large difference as that at the normal time, but the amplitude at the time of oscillating in the low velocity becomes remarkably smaller than that at the normal time and the displacing ratio in the oscillation becomes remarkably large compared with the displacing ratio at the normal time. Therefore, in the case the displacing ratio at the time of developing the abnormality in the link mechanism is set, e.g. to 10%, when the displacing ratio exceeds this, the development of abnormality in the oscillation can be surely detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a method for detecting vibration abnormalities in a vibration frame that supports a mold and moves it up and down at a constant amplitude in a mold vibration device of a continuous casting machine. It is about the method.

[Conventional technology]

In a continuous casting machine, the powder added to the surface of molten steel in the mold flows smoothly between the inner surface of the mold and the solidified shell, and prevents the solidified shell from seizing on the inner surface of the mold. In order to improve the surface quality of the piece, the mold was
It vibrates vertically at a constant pitch.

FIG. 2 is a schematic side view showing an example of a mold vibration device. As shown in FIG. 2, the mold vibration device includes a vibration frame 2 that supports a mold 1, and a support frame 4 fixed on a base 3.
, a first link 7 which is pivotally connected to the support frame 4 by a horizontal shaft 5 and a first link 7 which is pivotally connected to one end 2a of the vibrating frame 2 by a connecting shaft 13; A second link 8 is pivotally attached to the second link 8 by a connecting shaft 14, and one end is connected to the first link 7 by a pin 9, which connects the first link 7 and the second link 8.
A turnbuckle-type connecting rod 11 whose other end is connected to the second link 8 by a pin] 0, and whose upper end is connected to the end of the first link 7 opposite to the connecting rod 11, not shown. A driving mechanism such as an eccentric cam is used to move the immediate action rod 1-2 downward at a constant pitch in the axial direction. A connecting shaft 16 that connects the intermediate portion of the link 8 is an air spring that supports the lower surface of the other end portion 2b of the vibrating frame 2.

When the driving mechanism (not shown) moves the rod 12 up and down at a constant pitch, the first link 7 and the connecting rod 11
Vibrating frame 2 moves up and down via second link 8 . Thus, the mold supported on the vibrating frame 2 is
It vibrates in an arc in the vertical direction with a constant amplitude.

[Problem to be solved by the invention]

As described above, in the mold vibration device, the vibration of the vibration frame 2 that supports the mold 1 causes the vertical movement of the driving rod 12 to be transmitted to the vibration frame 2 via the first link 7, the connecting rod 11, and the second link 8. This is done by communicating to the

The link mechanism of such a mold vibration device includes a horizontal shaft 5.
, 6, connecting shaft 1.3, 14. ．． 15. There are many connection points such as pins 9° and 10. Therefore, it is difficult to avoid wear at each of the above-mentioned connecting points, and in particular, the pin 10 that connects the connecting rod 11 and the second link 8, the horizontal shaft 6 that connects the second ring 8 and the support frame 4, etc. is large, pin 10, horizontal axis 6
And the holes through which these are inserted are prone to wear and damage.

In this way, if wear or damage occurs to the link mechanism of the mold vibrating device, the drive rod 1 relative to the vibrating frame 2
Since the transmission of the second downward motion is insufficient, vibration abnormality occurs in the mold 1.

If abnormal vibration occurs in the mold 1, the powder will not flow smoothly between the inner surface of the mold 1 and the solidified shell, and the mold 1
The solidified shell seizes on the inner surface of the slab, causing problems such as deterioration of the surface quality of the slab and occurrence of breakouts.

-I- In order to prevent the above-mentioned problem, conventionally, a displacement detection sensor 17 such as an optical distance sensor is provided close to the other end 2b of the vibrating frame 2. Detection of vibration abnormalities was carried out.

However, with this method, it is only possible to detect when an abnormality in vibration of the vibrating frame 2 has occurred, and by the time an abnormality in vibration has been detected, the above-mentioned deterioration of the surface quality of the slab has already occurred. Problems such as breakouts and breakouts occurred.

Therefore, an object of the present invention is to provide a method for early and accurately detecting vibration abnormalities in a vibration frame that supports a mold and moves it up and down at a constant amplitude in a mold vibration device of a continuous casting machine. be.

[Means to solve the problem]

The present inventors have conducted extensive research in order to solve the above-mentioned problems. As a result, we obtained the following knowledge. That is, the vertical movement of the vibration frame in the mold vibration device is Asjn2 xft
(where A: amplitude, f: frequency, and shi=time) is expressed by a simple harmonic motion. And its acceleration is (2π
f) 2A, which increases in proportion to the square of the frequency f.

Therefore, there is a difference in amplitude between low-speed vibration and high-speed vibration.

If an abnormality such as wear or damage occurs in the link mechanism of the mold vibrating device, the amount of vibration during low-speed vibration will be smaller than the amount of amplitude during normal vibration. However, the amount of amplitude during high-speed vibration does not differ much from the normal time because the inertial force is larger than the amount of vibration 1lIW during low-speed vibration. Therefore, when an abnormality such as wear or damage occurs in the link mechanism, the difference in the amplitude of vibration IW during low-speed vibration and the amplitude during high-speed vibration becomes large.

This invention has been made based on the above findings, and provides for a vibration frame in a continuous casting mold vibration device for supporting a mold and moving it downward at a constant amplitude during high-speed vibration and low-speed vibration. Measure the amplitude at , and use the obtained amplitude to determine the displacement rate based on the formula (amplitude during low-speed vibration), and when the displacement rate calculated in this way exceeds a certain value, This is characterized in that it is detected as a vibration abnormality of the vibration frame.

From many actual operational experiences, the displacement rate during normal operation is 2-8%. Therefore, by setting the constant value of the displacement rate to 10%, it is possible to accurately detect vibration abnormalities in the vibrating frame.

In order to produce a difference in the amplitude as described above, for example, the vibrating frame may be vibrated at a high speed with a frequency of 180cρ1n, and then vibrated at a low speed with a frequency of loocpm.

[Effect]

In this invention, when the mold 1 is empty and no molten steel is supplied into the mold 1, the vibration frame 2 is
It is vibrated at a high speed with a frequency of 80 cpm, and then vibrated at a low speed with a frequency of, for example, I Q Ocpm, and the displacement rate of the amplitude is determined using the above-mentioned formula.

If an abnormality such as wear or damage occurs in the link mechanism of the mold vibrating device, the vertical movement of the drive rod 12 by the drive mechanism will not be transmitted to the vibrating frame 2 incompletely. As a result,
The amplitude amount during high-speed vibrations is not much different from normal times, but the amplitude amount during low-speed vibrations is significantly smaller than during normal times, and the displacement rate of the above-mentioned amplitude amount is remarkable compared to the displacement rate during normal times. becomes large.

Therefore, if the displacement rate when the above-mentioned abnormality occurs in the link mechanism is set as a fixed value, that is, a threshold value, for example, 10%, when the displacement rate exceeds this value, it can be accurately detected as a vibration abnormality. can do.

Next, the present invention will be described by way of examples with reference to the drawings.

〔Example〕

The device shown in Fig. 2 is used to continuously cast steel slabs while moving the mold 1 up and down at a constant amplitude.The casting is stopped at regular intervals, and the vibrating frame 2 to which the mold 1 is attached is moved at a rate of 180 cp+n. The amplitude when vibrating at a high speed of 1100 Cp and the displacement rate of the amplitude when vibrating at a low speed of 1100 Cp were determined based on the formula. On the other hand, the constant value of the displacement rate when an abnormality occurs in the link mechanism, that is, the threshold value, was set to 10%.

Table 1 shows the displacement rates for a certain period of time determined in this manner. FIG. 1 is a graph showing the change in displacement rate based on Table 1.

As is clear from Table 1 and FIG. 1, the displacement rate suddenly increased to 1.90% during Na 5 measurement.

So, when we inspected the link mechanism, we found that the vibration frame 2
The connecting portion of the second linter 8 that connects the support frame 4 and the support frame 4 was worn and damaged. Therefore, when these parts were replaced and repaired, the displacement rate decreased to 3.21% at the next Nn6 measurement.

〔Effect of the invention〕

As described above, according to the present invention, vibration abnormalities in the vibration frame for supporting the mold and moving it up and down at a constant amplitude in the mold vibration device of a continuous casting machine can be detected early and accurately. ``industrial'' - useful effects that can be detected.

[Brief explanation of the drawing]

FIG. 1 is a graph showing changes in the displacement rate of the amplitude amount, and FIG. 2 is a schematic side view showing an example of a mold vibration device. In the drawings, 1. Mold, 2. Vibrating frame, 3. Base, 5. 6. Horizontal shaft, 8. Second link, 11. Connecting rod 13.1.4.15. Connecting shaft. 17...Sensor. 4. Support frame, 7. First link, 9. 10. Pin, 12 Drive rod, 16. Air spring,

Claims (1)

[Claims] 1. An amplitude amount obtained by measuring the amplitude amount during high-speed vibration and low-speed vibration of a vibration frame in a continuous casting mold vibration device for supporting a mold and moving it up and down at a constant amplitude. According to the formula, ((amplitude amount during high-speed vibration) - (
Amount of amplitude during low-speed vibration)) / (Amount of amplitude during low-speed vibration) x 1
Detection of vibration abnormality in a continuous casting mold vibration device, characterized in that a displacement rate is determined based on 00, and when the displacement rate thus determined exceeds a certain value, it is detected as a vibration abnormality of a vibration frame. Method. 2. Claim 1, wherein the constant value of the displacement rate is 10%.
Detection method described.