JPS6238742A - Continuous casting method for thin sheet - Google Patents

Abstract

PURPOSE:To prevent the wear of water cooling rolls and to improve the accuracy of a sheet thickness by rotating a pair of the water cooling rolls in synchronization to allow respective solidified shells to form and pressing and uniting both shells with the other rolling down rolls provided above said rolls. CONSTITUTION:A pair of the water cooling rolls 11 are disposed parallel and horizontally at a prescribed space and are immersed into a molten metal 13 in a molten metal vessel 12. Two sheets of the solidified shells 14, 14 cooled by contacting with the lower surfaces of the rolls 1 are pulled up as the rolls 11, 11 rotate synchronously. These shells are pressed and united by the separated provided small-diameter rolling-down rolls 15, 15. The shells 14 are rolled down in a high temp. state in the stage. Since the rolling force does not act on the rolls 15, the surface wear of the rolls 11 is prevented. Since the shells are pressed by the rolls 15 to be exclusively used, the accuracy of the sheet thickness is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for stably manufacturing a thin plate with good thickness accuracy by continuous casting.

(Prior Art) Conventionally, thin plates have been manufactured by hot rolling slabs, but if it is possible to continuously cast thin plates several cranes thick directly from molten metal, then the hot rolling process is possible. Since the process can be omitted, it is possible to significantly reduce the manufacturing cost of thin plates.

Therefore, recently, various continuous casting methods for thin plates have been proposed.

g'4'''''1'1'''''''1''''>K, -f to 7
filLl'L (lower portions of a pair of water-cooled rolls 1 and 1 are immersed in molten metal 2, and 2 solidified shells 3 formed on the surfaces of these water-cooled rolls are rolled by the pair of water-cooled rolls -11j). There is a method (Japanese Unexamined Patent Publication No. 159949/1983) in which the metal is made into a single thin plate.

Further, as shown in FIG. 3, the pair of water-cooled rolls l,
1 is made up of a large-diameter water-cooled roll 1' and a small-diameter water-cooled roll 1'', and these water-cooled rolls 1', 1'' are arranged with a gap corresponding to the thickness of the thin plate to be cast to form a thin plate. Continuous casting method (Unexamined Japanese Patent Application 5°9-3585
89″*b, ia, .

(Problems to be solved by the invention) ・1 All of the above-mentioned methods are excellent in that high productivity can be obtained. Since the method of rolling two solidified shells to form one thin plate is adopted, there are the following drawbacks: ■ Rolls for forming the solidified shell and rolling of the formed solidified shell Since the rolls used to form a single thin plate are the same roll, the structure of the roll becomes complicated and wear and tear on the roll surface is extremely large.

In other words, in general, when a roll is immersed in molten metal to form a solidified shell on its surface, in order to prevent the roll surface from deforming or cracking due to temperature rise, the part very close to the surface of the roll is water-cooled from inside. Because it is necessary,
Many cooling channels are provided just below the surface of the roll. On the other hand, in order to combine two solidified shells into one,
-C is required to be pressed with a large pressure, and therefore a large rolling blade acts on the roll surface. For this reason,
Cracks tend to occur from the cooling channel toward the roll surface, and if the roll surface is made of copper or the like, it lacks strength and is likely to be deformed or cracked. ■Difficulty achieving product thickness accuracy.

In other words, the roll is easily deformed as mentioned in item (2) above, and the axis of the roll used to form the solidified shell also serves as a water supply and drainage pipe for cooling the roll surface. As a result, the bearing structure becomes complicated, and the control of the distance between the roll axes for controlling the sheet thickness becomes extremely complicated, resulting in poor sheet thickness accuracy of the thin sheet formed by these rolls.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for stably and continuously casting thin plates with good thickness accuracy without wear and tear on equipment.

(Means for Solving the Problems) The present invention comprises a pair of rolls installed parallel and horizontally with a predetermined interval, and a water-cooled roll whose lower surface is immersed in molten metal. By synchronously rotating the water-cooled rolls so that the surfaces face upward from the bottom, each water-cooled roll forms a solidified shell and pulls these solidified shells upwards.Then, while the temperature of the solidified shell is sufficiently high, the other rolling rolls The gist is to press and integrate the pulled-up resolidified shells.

(Function) In the method of the present invention, a pair of water-cooled rolls for forming a solidified shell and a reduction roll for pressing two solidified shells are separately disposed for continuous casting. No force is required to press the solidified shells, so there are almost no defects such as cracks on the roll surface. Further, since the shaft position of the water-cooled roll can be fixed, there is no need to control the shaft position during operation, and since no force is applied to press the shaft, the structure of the bearing part of the water-cooled roll can be simple.

(Example) The present invention will be described below based on an example shown in FIG.

In the drawings, a pair of water-cooled rolls 11 and 11 are installed parallel and horizontally with a predetermined interval, and these water-cooled rolls 11 and 11 have the same diameter and a large diameter. The lower surfaces of these water-cooled rolls 11,11 are immersed in the molten metal 13 in the molten metal bath 12, and are rotated at the same speed so that their respective opposing surfaces face upward from below.

Thus, two solidified shells 14.1 are formed by being cooled in contact with the lower surfaces of the pair of water-cooled rolls 1.11.
4 are pulled up as the water-cooled rolls 11.11 rotate, and are pressed and integrated by a pair of small-diameter reduction rolls 15.15.

Note that the reduction roll 15.15 has a solidified shell 14.1.
Of course, it is arranged at a position where the pressure can be reduced while the temperature of No. 4 is sufficiently high.

Although not shown, an electromagnetic stirring device may be provided on the side of the molten metal tank 12, an inert gas supply device may be provided at the bottom of the molten metal tank 12, or a downwardly open type container may be provided at the upper edge of the molten metal tank 12. The inner surface of the solidified shell 14.14 is washed with the molten metal 13 by installing the solidified shell 14.1 in an airtight manner, and by providing an inert gas supply device in the container.
4 to the surface of the water-cooled roll 11, 11, or reducing the unevenness of the solidified shell 14, 14 to make the thickness of the thin plate uniform, it is optional.

In the figure, 16 is a pouring nozzle.

(Experimental Results) A thin steel plate having a thickness of 3 fins and a width of 600 fins was manufactured by the method of the present invention.

The molten metal used was low carbon aluminum killed steel produced in a converter. Also, water-cooled rolls 11.11 for forming solidified shells.
A diameter of 1000 m was used, and the surface part was made of copper, and the inner surface was water-cooled.

Further, the distance between the axes of the water-cooled rolls 11 and 11 was 1010 mm, and a gap of 10 n was provided between the outer peripheral surfaces of the water-cooled rolls 11 and II.

When the water-cooled rolls 11.11 are rotated at a circumferential speed of 80 m/min, the solidified shells 14.1 each have a thickness of 1.6 mm.
4 was formed.

Then, the two solidified shells 14 and 14 are rolled onto the rolling roll 15.
．． 15 to form a steel plate with a thickness of 3 cranes. According to the method of the present invention, no defects such as cracks were generated on the surface of the water-cooled rolls 11 and 11 even after a total of 30 hours of casting.

(Effects of the Invention) As explained above, the method of the present invention enables continuous casting by separately disposing a water-cooled roll for forming a solidified shell and a reduction roll for pressing two solidified shells. ,
The structure of the water-cooled roll is simple, and wear and tear on the roll surface can be prevented.Furthermore, since the pressure is applied using a special reduction roll, the accuracy of the plate thickness is also improved.

That is, the method of the present invention has the great effect that thin plates with good thickness accuracy can be stably and continuously cast without wear and tear on equipment.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an apparatus for implementing the method of the present invention, and FIGS. 2 and 3 are schematic explanatory diagrams similar to FIG. 1 in the case of the conventional method. 11 is a water-cooled roll, 13 is a molten metal, 14 is a solidified shell, and 15 is a reduction roll.

Claims (1)

[Claims] (1) A pair of water-cooled rolls, which are installed parallel and horizontally at a predetermined distance and whose lower surfaces are immersed in molten metal, are rotated in synchrony so that their opposing surfaces face upward from below. As a result, solidified shells are formed on each of the water-cooled rolls, and these solidified shells are pulled upward, and then, while the temperature of the solidified shells is sufficiently high, the two pulled-up solidified shells are pressed together by another reduction roll. A continuous casting method for thin plates characterized by: