JPS6143143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic vibration mold for continuous casting.

An ultrasonic transducer (hereinafter referred to as
It has been conventional practice to install a vibrator (simply referred to as a vibrator) and perform casting while vibrating the mold to prevent molten steel from sticking to the inner surface of the mold and to cast good slabs.

However, in the past, among the vibration waves generated in the mold by the vibrator, the placement of the vibrator and the design of the mold focused only on longitudinal waves, which made it impossible to vibrate the mold efficiently. , and the antinode of the vibration wave is located at the end of the mold, restricting the fastening of the end of the mold to the mold frame. There was a problem in that it could lead to damage to the parts provided at the ends that promote shell formation and ensure good slab drawing.

As a result of intensive research to solve the above-mentioned problems, the inventors of the present application have discovered that the vibrator generates longitudinal and transverse vibration waves in the mold, and the mold combines these two vibration waves. Since the vibration is extremely complex, if both of these vibration waves are effectively used to vibrate the mold, it is possible to vibrate the mold efficiently.
Furthermore, by locating the nodes of the vibration waves at the ends of the mold, restrictions on fastening the ends of the mold to the mold frame will be relaxed, and damage to the break ring will not occur in horizontal continuous casting equipment. I gained a lot of knowledge.

This invention has been made based on the above findings, and includes a plurality of ultrasonic transducers attached to the outer surface of a continuous casting mold perpendicular to the outer surface of the mold,
The length of the mold in the slab drawing direction is set to such a length that the mold resonates in the slab pulling direction and a direction perpendicular to the slab pulling direction by the ultrasonic vibrator, and The vibrator is characterized in that it is attached to the mold so that nodes of vibration waves caused by the resonance are located at both ends of the mold.

The principle of this invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing the relationship between the mounting position of the vibrator 2 on the outer surface of the mold 1 and the vibration waves generated in the mold 1.

Figure 1A shows longitudinal waves (waves that vibrate in the same direction as the slab pulling direction) generated in the mold 1 by multiple vibrators 2 attached to the outer circumferential direction of the mold ₁ , and the propagation speed is slower than that of the longitudinal waves. FIG. 2 is an explanatory diagram showing the generation state of transverse waves (waves vibrating in a direction perpendicular to the slab drawing direction) B ₀ . Although a plurality of vibrators 2 are actually provided in the circumferential direction of the outer surface of the mold 1, as shown in FIG. 6 or FIG. 7, which will be described later, only one vibrator 2 is shown here. Here, λ _A indicates one wavelength of longitudinal wave A ₀ , and λ _B
indicates one wavelength of the transverse wave B ₀ . The length of mold 1 is 3λ _A
It is. The vibrator 2 is attached at a position λ _A /2 from the end of the mold 1.

Looking at the longitudinal wave _A0 , the mounting position of the vibrator 2 is a node. This is because for longitudinal waves, the vibration input portion becomes the vibration node. On the other hand, when looking at the transverse wave B _O , the mounting position of the vibrator 2 is at the antinode. This is because, as mentioned above, the propagation speed of transverse waves is higher than that of longitudinal waves, and the input portion of vibration becomes the antinode of vibration.

Next, the attachment positions A ₁ and B ₁ of the vibrators a and b to the mold are shown when focusing on the longitudinal wave A ₀ and the transverse wave B ₀ separately. The oscillators a and b are oscillators whose phases are different from each other by 1880° in order to excite vibrations.

In other words, in A ₁ and B ₁ , if the oscillators are installed at positions where the signs of oscillators a and b match, the longitudinal wave will be
It can be seen that A ₀ and transverse wave B ₀ can be effectively used to vibrate the mold. Furthermore, as is clear from A ₁ and B ₁ , the oscillator b installed to excite the longitudinal wave A ₀ caused by the oscillator a can conversely act to cancel the vibration of the transverse wave B ₀ . Recognize.

_{Therefore ,} as shown in FIG. 2, the node of vibration by the vibrator 2 is located at the end of the mold 1, and the mold 1 can be vibrated by effectively utilizing longitudinal waves and transverse waves generated in the mold 1.

2 to 4 show examples in which the length of the mold is increased based on the same principle as shown in FIG. 1.

FIG. 2 shows a case where the length of the mold 1 is 2λ _A , and one vibrator 2 is attached to the center of the mold 1. FIG. 3 shows a case where the length of the mold 1 is 4λ _A , and one vibrator 2 is attached at a position λ _A from the end of the mold 1. Fig. 4 shows a case where the length of the mold 1 is 6λ _A , and a vibrator 2 is attached at a position λ _A from the end of the mold 1, and another vibrator 2 is attached at a distance of 4 λ _A from there. is installed. In both cases, as in the case shown in FIG. 1, longitudinal waves and transverse waves generated by a vibrator are used to vibrate the mold, and the mold is efficiently vibrated, and the nodes of vibration are located at the ends of the mold.

FIGS. 5 and 6 show a case in which the ultrasonic vibration mold of the present invention is used in horizontal continuous casting equipment, in a partially cutaway sectional view and a sectional view taken along the line A--A in FIG. 5.

In FIGS. 5 and 6, 3 is a tundish, and 4 is a presser foot 5 at the bottom of the tundish.
6 is a mold connected to the tip of the feed nozzle 4 via a break ring 7 and has a cooling water passage 8 formed therein; 9 is a vibrator attached to the outer surface of the mold 6; Further, 10 indicates a mold frame on which the mold 6 is fixed.

The relationship between the mold 6 and the vibrator 9 attached thereto is the same as that shown in FIG. That is, if the wavelength of the longitudinal wave generated by the vibrator 9 is λ _A , then the mold 6
The length of is 3λ _A , and the vibrator 9 is located at a position of λ _A /2 from the end of the mold 6 on the break ring 7 side.
As shown in FIG. 6, four are mounted facing each other.

The vibration frequency of the vibrator 9 is preferably about 20 KHz. This is because if the vibration frequency is increased too much, vibration damping will be large and the efficiency will be poor, while if the vibration frequency is decreased, it will approach the audible range and cause factory noise. If the vibration frequency of the vibrator 9 is 20KHz, the wavelength of vibration by the vibrator 9 at this time λ _A
is approximately 260mm. This means that the sound speed of longitudinal waves propagating in steel (slab) and copper (mold) is 5.81 Km/sec.
and 4.62Km/sec, the wavelength of vibration λ _A is 295
mm and 232 mm. From this, taking into consideration the material that constitutes the vibrator, we took the average of these values and determined λ _A to be approximately 260 mm.

Therefore, the length of the mold 6 is approximately 780 mm, and the length of the vibrator 9 is approximately 780 mm.
The installation position is approximately 130 mm from the end of the mold 6 on the break ring 7 side.

The mold 6 is used to cast a slab with a square cross section, but when casting a slab with a circular cross section, a mold 11 as shown in FIG. 7 is used, and a plurality of vibrators 9 are placed in the circumferential direction of the mold 11 be installed radially.

The ultrasonic vibration mold of the present invention may be installed in vertical continuous casting equipment as shown in FIG. In FIG. 8, 12 is a tundish, 13 is an immersion nozzle, and the others are the same as those shown in FIG. 5, and the same effects as described above can be obtained.

As explained above, according to the present invention, by effectively utilizing the longitudinal waves and transverse waves generated in the mold by the vibrator to vibrate the mold, it is possible to vibrate the mold efficiently. Since the knot is located at the end of the mold, it is easy to attach the mold to the mold frame, and in the case of horizontal continuous casting equipment, it can prevent damage to the break ring, etc.
Various useful effects are brought about.

[Brief explanation of the drawing]

1 to 4 are explanatory diagrams showing the principle of the present invention, FIG. 5 is a partially cutaway sectional view when the ultrasonic vibration mold of the present invention is used in horizontal continuous casting equipment, and FIG. Fig. 5 is a sectional view taken along line A-A, Fig. 7 is a sectional view when another mold is used, and Fig. 8 is a sectional view when the ultrasonic vibration mold of the present invention is used in vertical continuous casting equipment. FIG. 3 is a partially cutaway sectional view. In the drawings, 1... Mold, 2... Vibrator, 3... Tandate, 4... Feed nozzle, 5... Presser foot,
6... Mold, 7... Break ring, 8... Cooling water passage, 9... Vibrator, 10... Mold frame,
11...Mold, 12...Tandatetsu, 13...
...Immersion nozzle.

Claims (1)

[Claims] 1 A plurality of ultrasonic transducers are attached to the outer surface of a continuous casting mold at right angles to the outer surface of the mold, and the length of the mold in the slab drawing direction is determined by the ultrasonic transducers. is set to a length that resonates in the slab drawing direction and the direction orthogonal to the slab pulling direction, and the ultrasonic vibrator is set so that the vibration waves generated by the resonance are located at both ends of the mold. An ultrasonic vibration mold for continuous casting, characterized in that it is attached to.