JPS61222663A - Forging device for continuously cast strand - Google Patents

Abstract

PURPOSE:To annihilate the harmful unsolidified segregation at the center of a cast strand with a simple device by moving an anvil mechanism which grasps under pressure the surfaces of the strand emitted from a continuous casting mold to a prescribed thickness in follow up to the strand movement in the stage of grasping the same under pressure and resetting the mechanism to the home position in the stage of opening. CONSTITUTION:Surface-pressing anvils 2, 2' at the top ends of levers 4, 4' supported by pivotal shafts 7, 7' to a movable frame 8 which is imposed on a pair of mounting rollers 13, 14 and moves in the moving direction of the cast strand 1 grasp the surface of the strand 1 under the pressure by a liquid pressure device 5 and move in follow up the movement of the strand. The anvils 2, 2' are automatically reset to the home position by a hydraulic mechanism 15 in the stage of opening. The strand 1 is therefore successively grasped under the pressure down to the prescribed thickness of a stopper 1 by which the harmful central segregation is annihilated. The rollers 21 of the frame 8 are the guide rollers for the strand 1 and the rollers 20 of a base plate 12 are the guide rollers in common use as the rollers for positioning of the frame 8.

Description

[Detailed Description of the Invention] C) Industrial Application Fields So-called center segregation inevitably occurs in slab strands obtained by continuous steel casting, and in order to avoid its light range or adverse effects, it is necessary to In the thickness direction of the slab strand, which is being pulled out from the continuous casting mold through the secondary cooling zone or the cooling support and guide device, near the final solidification zone of the unsolidified molten steel surrounded by the solidified shell, It is effective to apply a pressure of This specification describes the results related to the research and development of a continuous casting strand forging device that can function suitably for such thickness reduction.

In order to prevent the above-mentioned center segregation, attempts have been made to force electromagnetic stirring into the unsolidified molten steel, for example, in a secondary cooling zone, but the effect cannot be said to be sufficient.

It is also known that C
(Japanese Patent Publication No. 59-16862), roll rolling causes a near linear local load on the slab strand, so it is difficult to prevent solidification shrinkage and bulging that occur in the middle of the pitch of the roll pair. In addition, due to the linear contact, the concentrated load causes strong bending stress on the solidified shell and there is a risk of internal cracking, so it is not possible to take a large rolling reduction, and it is relatively light. During rolling, most of the deformation remains near the surface of the slab strand and tends to penetrate into the solidification interface, which is necessary to prevent segregation.

(Prior art) JP-A No. 68-406118 proposes sequentially forging the vicinity of the final solidification region of a slab strand using a pair of casting dies having flat forging surfaces. In this case, 1. Because it is under surface pressure, a reduction that penetrates to the solidification interface is applied, which is more effective than roll reduction.

25 A forging surface that can suppress strain at the solidification interface can be set, and the frictional force between the slab strand and the slab strand that occurs during processing can be used to create compressive strain on the solidification interface, allowing for a larger rolling reduction compared to roll rolling. .

8. Since it is under surface pressure, center segregation due to bulging does not occur, and the center segregation is significantly improved compared to roll pressure. However, on the other hand, in the case of slab strands for C slabs, the reduction blade is significantly lower than roll reduction due to surface reduction.

It is difficult to compactly fit a forging device with such a large reduction blade into a continuous casting facility, and it is particularly difficult to fit the forging device with such a large reduction blade into a continuous casting facility. It is also difficult to continue the forging process sequentially.

(Problems to be Solved by the Invention) A method for solving the above-mentioned difficulties in the conventional technology, particularly advantageously preventing center segregation that is inevitable in continuous casting of steel, and stably ensuring a sound continuously cast slab. The purpose of this invention is to invite

(Means for Solving the Problems) The present invention provides for a cast slab and a land that are being pulled out from a continuous casting mold through a secondary cooling zone or a cooling support and guide device, to have a pair of It is equipped with an anvil, a lever-type hydraulic device that reciprocates these anvils toward and away from each other, and a movable frame that pivots and supports the lever mechanism.・This is a continuous casting strand forging device that is connected to a hydraulic device that accompanies and follows the drawing movement of the slab strand during the forging process by Chika, and restores it during the mutual IIFM process.

This forging device has a movable frame equipped with follower rollers that sandwich the slab strands vertically, and an anvil that has a flat forging surface, a relief slope facing toward the introduction side of the slab strand, and a forging surface. In practical terms, it is preferable to provide a stopper to set the minimum distance between the surfaces of the slab. Not only can a large reduction blade be easily obtained, but also this lever-mounted hydraulic device is incorporated into a movable frame that can follow the removal movement of the slab strand. The forging process of the slab strands can be smoothly performed successively without any hindrance to the drawing movement.

Now, FIG. 1 shows the overall configuration of the above-mentioned forging machine, in which 1 is the slab strand being pressed, 2゜2' is a pair of anvils sandwiching the top and bottom of the slab strand l, 8, 8'. is a forging head equipped with anvil 2.2';
'' is a lever mechanism that forms a pair between the forging head 8.8' on the left and right, and 5 is a lever mechanism. This is a lever-loaded hydraulic device that reciprocates the Tenbiru 21m' via the 4''.

The lever mechanism 4.4' is pivotally connected to the forging head 8 by a transverse shaft 6.6', and pivotally supported by the movable frame 8 by a pivot shaft 7.7', and is also provided with a connecting pin 9, 9' pivotally connects the hydraulic device 5 of the lever arrangement.

The movable frame 8 has a cavity 10 that guides the passage of the slab strand 1 by drawing it out, and on its exit side there is a lever mechanism of the anvil 2゜2'' that is attached to the forging head 8.
4" to approach and separate each other. During the separation movement, the thickness of the slab strand 1 is reduced by the reciprocating drive of the hydraulic device 5 equipped with a lever. In the figure, 11 indicates the forging surface of the anvil 2.2". This is a stopper that arbitrarily sets the minimum interval between the two parts according to the forging allowance.

The movable frame 8 is mounted on the base 12 under the guidance of a pair of front and rear mounting rollers 1a and 14 arranged on the base 12.
It is possible to move forward and backward by a hydraulic device 15 disposed in front of the. In the figure, 16 is a piston put of the hydraulic device 16, 17
is a bracket that pivotally connects the end piece 18 to the movable frame 8 with a pin 19.

A guide roller 2 is provided on the base 12 for guiding the drawing movement of the slab strand 1 inside the cavity 10 of the movable frame 8.
0 is disposed in the movable frame 8, and a following roller 2 is installed between the upper and lower sides of the slab strand 1 introduced into the cavity of the movable frame 8.
It is desirable to provide 1.

In Fig. 1, the relationship between the anvils 2 and 21 is shown after the forging process on the slab strand is completed by approaching each other, but Fig. 1g2, sv! In the forging process state at I, the side and plane of the forging device, as well as the M-A in Figure 8.
, BB and aa4 cross sections are illustrated. The numbers in the figure are the same as in Figure 1, but in Figure 2, 22 is a drawing pinch reeler, 28, and 24 is a guiding p-ra.Here is an example of the center segregation 25 that occurred in the slab strand l. As illustrated in FIG. 1, at the center of the thickness of the final solidification zone of the unsolidified molten steel 26, which is surrounded by a thickened solidified shell while passing through the secondary cooling zone or cooling support and guide device of the continuous casting equipment, the steel This occurs when the middle components such as c, s, and p become concentrated and become positively segregated.

In other words, as shown in FIG. 5, near the tip 3 of the final solidification zone 36, the molten steel with the segregated components concentrated due to the suction action that creates pores due to solidification shrinkage of the slab strand l, bulging of the solidified shell, etc. This causes positive segregation and remains at the center of the thickness, which causes non-uniformity in the mechanical properties in the thickness direction of thick plate products and lamination defects. When rolling reduction is applied by the pair of guide rollers 28° 29 shown, depending on the amount of reduction, internal cracks 80 may occur at the solidification interface, which is insufficient to prevent center segregation. , while upper and lower anvils 2. as shown in FIG.
Although the forging process using hydraulic pressure with 21 is effective, it has already been mentioned that it requires a large reduction blade.

C) In the forging device according to the present invention, as shown in FIGS. 1 to 8, the anvil 2.2" is connected to the lever 2.degree.・During the stretching process of the hydraulic device 5, the strands are brought close to each other to apply a reduction in the thickness direction of the slab strand 1, thereby performing a forging process.

At this time, as soon as the anvil 2.2' starts contacting the slab strand 17, the movable frame 8 moves the mounted roller 1a,
14, the slab strand 1 is moved along with the drawing movement of the slab strand 1, and is stabilized by the stopper 11 of the anvil 2.2', and the forging process is performed to reach an appropriate reduction amount.

Then, the reversing operation of the lever hydraulic device 5 causes the anvils 1, 1' to release the slab strand l, and the subsequent operation of the hydraulic device 15 causes the movable frame 8 to return to its original position in the opposite direction.

Thereafter, by repeating the above operations, the sequential forging process is continued as shown in FIG. 7.

Here, the anvil 2.2'' has a flat forging surface a extending over a length j□ and a relief slope surface extending over a length l toward the introduction side of the slab strand l, and the required reduction amount δ When the reduction amount δ is set within the range of the slope of the relief slope, the reduction is completed, and the slab soot land l is pulled out per 1# pressure cycle that started when the previous forging was completed (imaginary line). By setting the movement amount p to be 10 or less, which is the length of the forging surface a, the entry side thickness ho can be uniformly and sequentially reduced to a uniform exit side thickness.

By disposing a follower roller 81 on the movable frame 8, the slab strand l is moved to the forging surface a of the anvil 2, 2'.
-A, the cast slab strand can be stably and smoothly fed one after another regardless of the movement of the pass line.

C) Effect of the invention) During the forging process, the movable frame including the drive system of the anvil follows along with the movement of the slab strand glue, making it possible to operate smoothly and reliably in the continuous casting equipment line. In particular, since this forging process is driven by a lever mechanism, the overall structure of the device is simple and compact, which reduces equipment costs and is suitable for integration into existing continuous casting equipment with limited space. .

Brief explanation of the front screen Figure 1 is a perspective view, Figure 2 is a side view, Figure 8 is a plan view and sectional view, Figure 4 is an illustration of central segregation, and Figure 4 is an illustration of central segregation. J is an explanatory diagram of center segregation occurrence behavior, Fig. 8 is an explanatory diagram of forging process procedure, and Fig. 7 is an explanatory diagram of repeated operation.

1... Slab strand 2.2'... Anvil,
4.4'...Lever device 6...Lever device hydraulic device

Claims (1)

[Scope of Claims] 1. A pair of anvils that sandwich the strand above and below the strand that is being pulled out from the continuous casting mold through the secondary cooling zone or the cooling support guide device, and these anvils. It is equipped with a hydraulic device for a lever mechanism that reciprocates in the direction of approaching and separating from each other, and a movable frame that controls the pivoting support of this lever mechanism. A forging device for continuous casting strands, which is connected to a hydraulic device that follows the drawing movement of the slab strands and restores the original state during the mutual separation stroke. 2. The forging device according to 1, wherein the movable frame is provided with follower rollers that vertically sandwich the slab strand. 3. The anvil has a flat forging surface, a relief slope facing toward the introduction side of the slab strand, and a stopper that sets the minimum distance between the forging surfaces.
The forging device described.