JPS6049835A - Twin roll type continuous casting method - Google Patents

Abstract

PURPOSE:To prevent fluctuation in plate thickness owing to a change in the temp. of a molten metal and to cast a steel plate having a uniform thickness by detecting the temp. of the molten steel in the well on the two rolls of a twin roll type continuous casting device and controlling the rotating speed of the twin rolls according to the detected temp. CONSTITUTION:A standard rotating speed in the case of obtaining a prescribed plate thickness and a standard temp. of a molten steel 5 are preliminarily inputted to a device for controlling rotation. If the temp. detected with a temp. detecting meter 8 is higher than the standard temp., the rotating speed of rolls 1 is made lower than the standard rotating speed and if the temp. is lower than the standard temp., the rotating speed of the roll 1 is made higher than the standard rotating speed. If the temp. is the same as the standard temp., the rotating speed of the rolls 1 is controlled so as to be maintained always adequately according to the temp. of the molten steel 5, by which the fluctuation in the plate thickness owing to a change in temp. is prevented and the growth of a mush phase is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a twin-roll type continuous VI in which molten steel is poured into a pool on two IC rolls arranged parallel to each other and appropriately spaced, and a steel plate is cast from between the rolls while the molten steel is cooled by the rolls.
This is related to the 8th law.

As shown in Fig. 1, the twin-roll continuous casting method involves installing two cooling rolls 1 parallel to each other at an appropriate interval, and placing a barrel seal on the twin rolls 1.1 along the axial direction of the rolls 1. Zide seal plates 3 are provided on both end faces of the plate 2 and the twin rolls 1 and 10 to form a pool 4, and molten steel 5 is poured into the pool 4, and the twin rolls 1.1 are rotated in directions facing each other. While driving and cooling the molten steel 5, the roll gear 1
The steel plate 7 is discharged from the tube 6 to reach tR.

By the way, the thickness of the steel plate 7 that is cleaned and discharged from between the rolls 1 is mainly determined by the distance of the roll gap 6, but it also changes depending on the temperature of the molten steel 5 in the lagoon 4.

That is, in the lake pool 4, the molten steel 5 is cooled by the roll 1 and forms a solidified shell on the surface of the roll 1, and the solidified shells formed on both rolls 1 intersect and form the roll gap 6.
It is discharged as a cast steel plate 7, but temporarily the molten steel 5
If the temperature of molten steel is high, the thickness of the solidified shell formed on the surface of roll 1 will be thin, and the steel plate to be cast will also be thin. Conversely, if the temperature of molten steel is low, the solidified shell formed on the surface of roll 1 will be thin. The thickness of the hardened vA shell becomes thicker, and the steel plate also becomes thicker than U.
j will be built.

Therefore, there is a problem that the thickness of the cast steel plate changes depending on the temperature of the molten steel in the pool.

An object of the present invention is to provide a twin-roll continuous casting method that can always produce a steel plate with a constant thickness even when the temperature of molten steel in the pool changes.

The present invention relates to a method in which molten steel is poured into a pool on twin rolls that are rotatably installed parallel to each other while being appropriately spaced apart, and the molten steel is cooled to cast a steel plate from between the rolls. The system detects the temperature of the molten steel and controls the rotation speed of the twin rolls according to the temperature of the molten steel. When the temperature is low, the rotational speed of the rolls is increased to ensure that the thickness of the steel plate cast and discharged from between the rolls is always uniform.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the twin-roll continuous casting method according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, reference numerals 1 denote cooling rolls arranged parallel to each other and appropriately spaced from the tops 6, which are connected to a rotary drive device (not shown) and rotated in directions facing each other as indicated by arrows Iζ. . Rotary drive! The 1iIl device is constructed so that the rotational speed of the roll 1 can be adjusted freely. A cooling device (not shown) is provided inside the cooling roll 1 to cool the surface of the cooling roll 1, and is configured to keep the surface temperature of the roll 1 constant.

A barrel seal plate 2 is provided on the twin rolls 1.1 along the axial direction of the roll 1, and side seal plates 3 are provided on both end surfaces of the twin rolls 1.1 to form a newsletter 4. Ru.

A temperature detector 8 for detecting the temperature of the molten steel 5 in the sump 4 is installed in the sump 4.

Although not shown, the temperature detector 8 is connected to the rotation control device, the output of the temperature detector 8 is input to the rotation control device, the output of the rotation control device is input to the rotation drive device of the roll 1, and the output of the temperature detection meter 8 is input to the rotation control device of the roll 1. Grooves are provided so that the rotational speed of the molten steel 5 can be adjusted according to the temperature of the molten steel 5.

In the above process, molten steel 5 is poured into the lagoon 4 from a tundish (not shown) or the like, is cooled by the cooling roll 1, forms a solidified shell 9 on the surface of the roll 1, and both The solidified shells 9 formed on the rolls 1 are joined and discharged from the roll gear 17 as a steel plate 7.

The thickness of the solidified shell 9 gradually increases from the triple point 10 at the point where the molten steel 5, the side seal plate 2, and the cooling roll 1 contact each other to the tight point 11 where both solidified shells 9 intersect.

The thickness of the solidified shell 9 formed on the surface of the roll 1 depends on the cooling speed of the cooling roll 1, the rotation speed, and the triple point 10 to the tight point 1.
It is determined by various factors such as the length of the solidified shell 9, but if these are kept constant, the thickness of the solidified shell 9 is
It changes depending on the temperature.

In particular, the molten steel 5 is once transferred from the ladle to the tongue tissue),
Hot water is poured into the hot water pool 4 from the tanditshu at
This pouring is not continuous, and the temperature of the molten steel 5 in the lagoon 4 just before the river and the lake changes considerably in the temperature of the molten steel 5 immediately after pouring. In other words, the molten steel 5 immediately before the river and lake is more likely to drop to near the solidification temperature than immediately after pouring, and therefore, the thickness of the solidified shell 9 on the surface of the roll 1 is thick and easy to splatter.
On the other hand, immediately after pouring the melt 1i15, the humidity is high, so the thickness of the solidified shell 9 tends to become thinner.

Therefore, if the temperature of the molten steel 5 in this lake newsletter 4 is detected by the humidity detector 8, and the rotational speed of the roll 1 is adjusted based on the output, controlling the thickness of the solidified shell 9 to be always constant, casting The steel plate 7 can always have a constant thickness regardless of the temperature change of the molten steel 5.

That is, the standard rotational speed N and the standard temperature Ts of the molten steel 5 for obtaining a predetermined plate thickness t are input into the rotation control device, and the temperature e-Th detected from the humidity detection fft8 is inputted into the rotation control device.
lfi mark (higher than the temperature Ts), the rotation speed of roll 1 is made slower than the standard rotation speed N according to the degree of the height, and if the temperature TA is lower than the standard temperature Ts, the degree of lowness is Accordingly, the rotation speed of roll 1 is made faster than the standard rotation speed N, and if the temperature TA is the same as the standard temperature Ts, the rotation speed becomes the standard rotation speed N.J: Output from the rotation control device to the rotation drive device of the roll 1 By controlling the rotational speed of the roll 1 to be always appropriate depending on the temperature of the melt 11115, it is possible to always cast a steel plate 7 of a constant thickness.

Moreover, on the hard point 11 where the solidified shell 9 formed on the surface of the cooling roll 1 intersects, a solidified body partially protruding from the solidified shell 9 is so-called a mass, which becomes a semi-solid body by receiving heat from the molten steel 5 above. As the II of &T hard shell 9 increases, the massi 11 becomes a giant, and it is bitten into the roll 11 whelk 6 and is ejected, and the cast steel plate 7 is just like a snake with an egg. A steel plate 7 is cast, which has an abnormally thick part of the sea urchin melt #4 as described above.
By controlling the rotational speed of the roll 1 according to the temperature of step 5, the growth of mushy layer 12 is suppressed, and the mashy layer 12 is suppressed.
It is possible to prevent the current spear from becoming abnormally thick in some parts due to 2 biting.

In addition, in the above-mentioned embodiment, the tip of the temperature detection old 8 is
Although an example is shown in which it is provided above the massification 12 formed on the kitsu point 11, the present invention is not limited to this, and the present invention is not limited to this. Any position is acceptable. In addition, since the molten steel 5 has a certain degree I'l a '' Even if the temperature is detected as the steel temperature TA, it is also included in the present invention.

As is clear from what has been described in detail above, the present invention provides a superior effect to the following.

(1) By controlling the rotational speed of the rolls according to the temperature of the molten steel, variations in plate thickness due to changes in the temperature of the molten steel can be prevented, and steel plates with uniform thickness can always be cast.

(2) Since the rotational speed of the rolls can be controlled, it is possible to suppress the growth of mashy on the joint of both solidified shells,
It is possible to prevent a part of the steel plate from becoming abnormally thick J7 due to the huge massing.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional twin-roll continuous casting machine;
The figure is a front cross-sectional view showing an embodiment of an apparatus for carrying out the double-ru continuous casting method according to the present invention. In the figure, 1 is a roll, 4 is a sump, 5 is molten steel, 7 is a steel plate, 8 is a temperature detector, and 9 is a solidified shell. Patent applicant Ishikawajima 1! ltl￥V Heavy Industries Co., Ltd. Representative Patent Attorney Nobuo Kinutani

Claims (1)

[Claims] In a method in which molten steel is poured into a pool on twin rolls that are freely rotatable in parallel with each other while being appropriately spaced apart, and the molten steel is cooled at - and a steel plate is cast from between the rolls, the molten steel in the pool is A twin roll continuous VJ manufacturing method characterized by detecting temperature and controlling the rotational speed of the twin rolls according to the temperature.