JPH04143057A - Method for oscillating mold for vertical type continuous casting - Google Patents

Abstract

PURPOSE:To lighten upper part of a mold, to improve controllability of oscillation and to enable stable high velocity casting by dividing the mold face into two parts of the upper part and lower part in casting direction and oscillating only the upper part in contact with meniscus part in lateral direction. CONSTITUTION:The long side mold faces in the mold for vertical type continuous casting are divided into two parts of the upper part and the lower part in the casting direction and only one pair of the upper part mold faces 1a in contact with the meniscus part are relatively advanced/retreated while synchronizing with vertical oscillating period of the mold to adjust flowing condition of mold powder. Therefore, by dividing the mold into two parts and lightening the side oscillating part in weight, the stable mold horizontal oscillation can be executed and the operation is stabilized. As a result, the stable high velocity casting can be executed, and further, segregation of oscillation mark part on the cast slab surface is reduced and conditioning labor of the surface is reduced.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a continuous metal casting method, particularly a method of vibrating a casting mold in vertical continuous casting, which does not cause breakout even in high-speed casting. be.

<Prior Art> In Japanese Patent Application No. 1-313424, the present inventors proposed a method of positive vibration determined from the relationship between longitudinal vibration speed of a mold and slab withdrawal speed in order to prevent breakout during high-speed continuous casting of steel. A method of increasing the distance between at least one pair of mold surfaces of the mold and the slab during the trinope time to reduce the frictional force between the mold and the slab, and also increasing the distance between the mold and the slab during the negative strip time to reduce oscillation marks This paper proposes a method of increasing the distance between the mold and the slab by moving the mold to reduce the pressure within the molten mold powder film existing therebetween, thereby reducing the depth of the oscillation marks on the surface of the slab.

Figure 3 shows a configuration diagram of the transverse vibration of the mold in that case, and Figure 4 (a) shows the pattern of opening the mold in the positive strip period, and (b) shows the pattern of opening the mold in the negative strip period. These are graphs shown respectively. Moreover, FIG. 5 is a graph showing the change in the distance between the mold and the slab at that time.

However, although this method can be effective to a certain extent, in the case of a casting machine with a very large and heavy mold in the future, when the vibration frequency becomes high, the mold surface will be moved forward in synchronization with the longitudinal vibration. When performing reverse (opening/closing) control,
It is difficult to uniformly control the opening and closing distance of the mold surface on the left and right (width direction) and up and down (casting direction), so it is necessary to reduce ossion marks, prevent breakouts, and maintain stable operation for a long time. was no longer possible.

<Problems to be Solved by the Invention> The object of the present invention is to provide a method for vibrating a mold for vertical continuous casting, which makes it possible to reduce ossion marks even in a continuous casting machine having a large mold, and prevents the occurrence of breakouts. This is what we propose.

<Means for Solving the Problems> The present inventors conducted various experiments based on Japanese Patent Application No. 1-31.3424, and found that the effect of such a mold vibration method is that the mold, l ! : It was found that this can be achieved without controlling the distance between the slab and the slab. In other words, it was found that the same effect can be achieved by opening and closing only the upper part of the mold including the meniscus part.

That is, the present invention vertically vibrates a vertical continuous casting mold that creates a casting space with two pairs of mold surfaces, and moves the pair of mold surfaces relatively forward (closer) at the same frequency as the vibration.・In the vibration method of a vertical continuous casting mold that is moved back (separated), the mold surface is divided into upper and lower parts in the casting direction, and only the upper and paired mold surfaces that contact the meniscus are synchronized with the vertical vibration period of the mold. This is a method of vibrating a vertical continuous casting mold, which is characterized by adjusting the inflow conditions of mold powder by moving the mold powder relatively forward (approaching) or retreating (separating).

<Function> In the present invention, the mold surface is divided into two parts in the casting direction, and only the upper part in contact with the meniscus is vibrated to open and close in the lateral direction.
Due to its reduced weight, controllability of its vibrations can be improved. As a result, specifically, the lateral amplitude can be stably maintained almost constant in the width direction of the mold and in the casting direction.

Therefore, stable casting operation is possible, oscillation marks are reduced, and breakage (breakage) is prevented from occurring.

<Example> FIG. 6(a) is an example in which the conventional method and FIG. 6(b) are examples in which the movement of the opening and closing amplitude in the lateral direction was measured using an eddy current displacement meter when the mold was used in the method of the present invention. The casting conditions are: steel type: 5pcC1 slab cross-sectional size: 260 x 2000mm, casting speed:
1.67m/Pongee, mold navy blue, transverse frequency: 140cpm,
Vertical vibration amplitude: 1.8tmv, set horizontal vibration amplitude:
It was set to 0.4 mm.

The mold to which transverse vibration is applied has a pair of long side surfaces, and in the case of the present invention, as shown in Figs. 1 and 2, the long side mold is divided into an upper and a lower half, with a length of 350 mm for the upper part and 550 mm for the lower part. did. The vibration pattern is a pattern in which the mold is opened in the positive period, as shown in FIG. 4(a).

Further, in the conventional method, as shown in FIG. 3, the long-side mold is one in which the upper and lower sides are integrated, and the size is the same as that of the mold in the present invention method except that hydraulic nolinders are arranged at the four corners.

As can be seen from Figure 6, in the case of conventional method (a), the lateral vibration ψM of the long side of the mold at fixed points on each side is not uniform and unstable, and the control sometimes exceeds the set value of 0.4 mm. A disturbance is occurring. After 15 minutes of casting, a restraint breakout occurred due to the insertion of FJt4 into the corner of the mold.

On the other hand, in the case of the present invention, as shown in FIG. 6(b), the transverse amplitude changed almost as set, and casting was successfully completed. Furthermore, onration marks were also reduced compared to conventional products.

<Effects of the Invention> By dividing the mold into two and reducing the weight of the lateral vibration part, stable lateral vibration of the mold becomes possible, making the operation more stable than before. As a result, stable high-speed casting is possible, and the segregation of oscillation marks on the surface of the slab is reduced, which has the great effect of reducing surface care.

[Brief explanation of drawings]

Part 1 is a block diagram of equipment such as molds used in the implementation of the present invention, Figure 2 is a tour of the molds used in the implementation of the present invention, and Part 3
The figure is a configuration diagram of the transverse vibration of the mold according to the conventional method, and Figure 4 is a graph showing the opening/closing timing of the longitudinal vibration and transverse vibration of the mold.
a) is a pattern in which the template opens during the positive strip phase;
(b) is a pattern of opening the template in the negative strip phase. FIG. 5 is a schematic diagram showing changes in the distance between the mold and slab, and FIG. 6 is a graph showing changes over time in the transverse amplitude when casting is performed by transversely vibrating the mold using the method of the present invention and the conventional method. 1... Mold, 1a... Upper mold, lb
... lower mold, 2 ... short side mold, 3 ...
Slab, 4...Hydraulic cylinder 5...Solenoid valve for opening and closing the upper clamp, 6...Solenoid valve for opening and closing the lower clamp, 7...Hydraulic motor, 8...Hydraulic tank, 9...Water cooling template,
10: Mold powder, 11: Contains steel, 12: Solidified shell, Y: Slab drawing direction, T: Positive strip time, TH: Negative strip time, xo ...Expanded distance between mold and solidified shell, ...Distance between normal mold and solidified nonyl, ■. ...Velocity of contraction direction vibration of the mold, ■. ...The drawing speed of slab.

Claims (1)

[Claims] A vertical continuous casting mold that creates a casting space with two pairs of mold surfaces is vertically vibrated integrally, and the pair of mold surfaces are relatively advanced (approached) and retreated (separated) at the same frequency as the vibration. In the method of vibration of a mold for vertical continuous casting, the mold surface is divided into upper and lower parts in the casting direction, and only the upper pair of mold surfaces in contact with the meniscus are moved relatively forward (approaching each other) in synchronization with the vertical vibration period of the mold. )・A method for vibrating a vertical continuous casting mold, which is characterized by adjusting the inflow conditions of mold powder by retreating (separating) it.