JP2990554B2 - Contact limiting plate for twin roll continuous casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact limiting plate for making a temperature of an injected molten metal uniform in a twin-roll continuous caster for producing a thin plate slab.

[0002]

2. Description of the Related Art A twin-roll continuous casting method in which molten steel is poured between two rolls rotating inward to cast a thin metal plate is known as the Bessemer method.

In this method, two rolls are arranged at an appropriate interval, and when the molten metal is rotated inward while pouring the molten metal from above, the injected molten metal comes into contact with the rolls and loses heat. As a result, a solidified shell is formed on the roll surface,
With the rotation of the roll, the two solidified shells are joined, and further reduced to form a slab having a predetermined thickness, which is then sent out below the roll to produce a thin slab.

In this case, the solidified shell starts solidification from the point where the molten metal comes into contact with the roll, continues to grow, and becomes a solidified shell having a predetermined thickness at the roll kiss point. In order to maintain the accuracy of the thickness of the slab to be manufactured, the distance from the solidification start point to the roll kiss point must be constantly controlled.

On the other hand, in the pool of the molten metal injected,
For example, if there is a difference in the temperature of the molten metal in the slab width direction at the level of the solidification starting point, a difference occurs in the shell temperature in the solidification process, making it impossible to form a uniform solidified shell, and maintaining the surface properties and accuracy of the slab Will also be difficult. Therefore, the temperature of the injected molten metal must be kept uniform at any point in the width direction.

[0006]

As a technique for keeping the distance from the solidification start point to the roll kiss point constant in order to maintain the accuracy of the slab thickness, for example, Japanese Patent Publication No. Sho 62-588
There is a technique of a twin-roll type casting and rolling mill disclosed in Japanese Patent Application Publication No. 11 and a control method thereof.

In this technique, a contact restricting plate for adjusting a contact area between a roll and molten steel is provided in a pool of molten steel formed by two rolls, and a contact restricting plate sliding on the roll surface is provided. This is a control method for a twin-roll type casting and rolling mill that sets a position to a desired value, controls a contact area between molten steel and a roll in a pool, and controls a thickness of a formed solidified shell.

However, in this technique, a contact limiting plate for adjusting a contact area between a roll and molten steel is provided in a pool of molten steel, and a thickness of a solidified shell formed by adjusting a position of a solidification starting point is controlled. However, it does not mention the temperature difference in the width direction of the roll or the imbalance of the solidified shell.

In the continuous casting method for a solidified sheet under the molten metal disclosed in Japanese Patent Application Laid-Open No. 61-186153, the lower part of the intermediate vessel is closely attached to a quenching device by continuous sheet casting between a cooling roll and / or a water-cooling belt. This is a technology that heats the vicinity of the supply nozzle to make the thin plate uniform in the width direction without air oxidation and enables maintenance-free rolling.

However, this method is extremely effective in improving the surface properties in the width direction of the slab, but also mentions the temperature difference in the width direction of the roll and the imbalance of the solidified shell as described above. is not.

The present invention has been made in view of the above problems, and
In a twin-roll continuous casting machine, there is provided a contact limiting plate for producing a uniform slab even in the width direction by equalizing the temperature of the poured molten metal.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a contact limiting plate for a twin-roll continuous casting machine, which is charged into a molten metal pool formed between two rolls to fix a solidification start point of molten metal. A contact limiting plate for a twin-roll continuous casting machine, characterized in that a groove is formed in the surface of the contact limiting plate in the casting direction.

[0013]

FIG. 2 is a diagram for explaining the operation of the present invention.
(A) shows the case where the conventional contact limiting plate 14 is attached,
(B) shows a case where the contact limiting plate 4 according to an example of the present invention is attached.

In the conventional contact limiting plate 14, the injection nozzle 9
The molten metal that has flowed into the basin 3 from the squirt gushes toward the contact limiting plate 14 and then splits right and left into the corners 3 of the basin 3.
Collide with a. Therefore, the temperature of the corner 3a rises abnormally. Therefore, a temperature imbalance occurs in the molten metal in the basin 3.

In the present invention, a groove 4a is formed in the surface of the contact limiting plate 4 in the casting direction, and the molten metal flowing from the injection nozzle 9 into the pool 3 collides with the contact limiting plate 4 and then collides. It is decelerated by 4a and flows to the corner 3a while being stirred. Accordingly, the temperature of the molten metal is made uniform in the pool 3.

Furthermore the shape of the groove 4 a, by the immersion depth of the injection nozzle 9 variously selected, it is possible to control the flow rate of the molten metal in the basin part 3, in a more basin part 3 It becomes easy to control the flow speed of the molten metal and make the temperature uniform.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a side view showing an example of a twin-roll type continuous casting machine for a thin plate, and FIG. 1 (b) is a perspective view showing a main part of FIG. 1 (a). Indicates only one side. Reference numerals 1a and 1b denote a pair of casting rolls. Side weirs 2 are attached to both side surfaces of the upper portions of the opposing rolls.
A pool portion 3 of the molten metal is formed between the roll and the roll.

A contact limiting plate 4 is inserted into the roll surface of the pool 3 from above, and a groove 4a is formed in the contact limiting plate 4 in a casting direction 8 (longitudinal direction). The solidified shell 5 grows almost in proportion to the arc length from the solidification start point 6 where the contact limiting plate 4 contacts the rolls 1a and 1b to the roll kiss point 7.

Here, the molten metal flows from the injection nozzle 9 toward the left and right contact restricting plates 4 into the pool 3 and collides with the contact restricting plate 4, and is then decelerated and agitated by the groove 4a while being stirred. It flows to the part 3a . During this time, the molten metal decelerates,
During the stirring process, the temperature in the pool 3 is made uniform.

FIG. 3 is a view showing a contact limiting plate 4 according to another embodiment. FIG. 3A shows a trapezoidal groove 4b, FIG. 3B shows a semicircular groove 4c, and FIG. When the flow speed of the molten metal is changed depending on the type of the molten metal, the width of the cast slab, the thickness of the slab, etc., the grooves having these shapes are selected together with the immersion depth of the contact limiting plate. The flow rate of the molten metal in the basin can be controlled.

The groove 4a formed in the contact limiting plate 4 as described above.
, The temperature of the molten metal in the pool 3 is made uniform, and there is no temperature difference or imbalance in the width direction of the roll of the solidified shell 5 to be formed. Thickness accuracy is maintained, and a homogeneous slab can be manufactured.

Further, according to the present invention, by making the temperature in the pool 3 uniform, the contact limiting plate 4 is not damaged by local overheating and the service life of the refractory can be increased. The cost can be reduced while maintaining the accuracy of the contact limiting plate.

[0024]

As described above, according to the present invention, the temperature of the molten metal in the pool is made uniform by forming grooves in the contact limiting plate, so that the temperature difference and imbalance in the width direction of the roll are eliminated. The solidification proceeds uniformly, the accuracy of the slab thickness is maintained, the surface properties are improved, and a homogeneous slab can be manufactured.

Further, by equalizing the temperature in the pool, the contact limiting plate is not damaged by local overheating, and the service life of the refractory can be increased, and the accuracy of the contact limiting plate can be maintained. Thus, the cost of the refractory can be reduced .

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and FIG. 1 (a) is a side view showing an example of a twin-roll thin-sheet continuous casting machine, and FIG. 1 (b) is a perspective view showing a main part of FIG. 1 (a). It is.

FIG. 2 is an explanatory view of an operation of a contact limiting plate, and FIG.
FIG. 2B is a drawing showing a case where a conventional contact limiting plate is attached, and FIG.

3 (a) is a drawing showing a trapezoidal groove, FIG. 3 (b) is a semicircular groove, and FIG. 3 (c) is a saw-tooth groove. .

[Explanation of symbols]

 1a, 1b Casting Roll 2 Side Weir 3 Pool Pool 3a Corner of Pool Pool 4,14 Contact Limiting Plate 4a, 4b, 4c, 4d, Contact Limiting Plate Groove 5 Solidification Shell 6 Solidification Starting Point 7 Roll Kiss Point 8 Casting direction 9 Injection nozzle

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Moroboshi 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (56) References JP-A-62-252645 (JP, A) JP-A-1-99752 (JP, A) JP-A-62-38745 (JP, A) JP-A-58-144806 (JP, A) JP-B-62-58811 (JP, B2) (58) Int.Cl. ⁶ , DB name) B22D 11/06 330 B22D 11/18

Claims (1)

(57) [Claims] 1. A contact limiting plate of a twin-roll continuous casting machine for fixing a solidification start point of a molten metal charged in a molten metal pool formed between two rolls. A contact limiting plate for a twin-roll continuous casting machine, characterized in that grooves are formed in the direction.