JPH04322849A - Twin drum type strip continuous casting method - Google Patents

Abstract

PURPOSE:To stably obtain good sealing of a side weir by bringing press-contact surface at upper side of the side weir into contact with end faces of drums after bringing lower side of the side weir into contact with the end faces in the case the side weir press-contacts with the end faces of cooling drums. CONSTITUTION:Position for reducing speed in hydraulic cylinders 7-1-7-3 is set at position, where the lower side cylinder 7-3 approaches to the end face sides of cooling drums in some degree. In this result, raising of reaction to the lower side part of side weir, when the lower side part of side weir press- contacts, is quicker than that at the upper side part in some degree. After that, pressing starts and the lower side part starts to contact with the press- contacting face in some earlier and successively, the upper side part of side weir starts to contact, and then, all hydraulic cylinders are made under condition of receiving the reaction of about 100-150kg. At the time of detecting the reactions in all hydraulic cylinder with load cells 9-1-9-3, the detecting signal is transmitted to press-driving control devices 10-1-10-3, and pressing speed of each cylinder is made to further slower with the control device and pressed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin-drum casting technique for continuously casting thin slabs from molten metal, and more particularly to a side weir pressing technique.

0002

2. Description of the Related Art In general, a twin-drum continuous casting machine (hereinafter referred to as a continuous casting machine) has cooling drums 1, 1 arranged so as to rotate in parallel and in opposite directions, as shown in FIG.
, 1 are provided with side weirs 2, 2 on both end faces to form a pool 4, and the molten metal 5 in the pool is cooled by the rotation of the cooling drums 1, 1, and a thin slab S is cast. It has become. In addition, the side weirs 2, 2 are pressed against both end surfaces 1-1, 1-1 of the cooling drums 1, 1 by a presser, and are kept in a sealed state by wear due to rotation of the cooling drums to prevent hot water from leaking. .

Various proposals have been made in the past regarding techniques for pressing such side weirs. For example, in order to prevent the lower part of the side weir from receding outward due to rolling of the solidified shell during casting, the
Publication No. 4 etc. have been disclosed.

0004

[Problem to be Solved by the Invention] However, all of these methods detect the opening amount of the side weir and return it to a predetermined value, and the technology involves controlling the timing of pressure contact of the side weir in order to prevent seal failure. Until now, it had not received any attention at all. The present invention solves the problem of sealing side weirs from a completely new perspective.

[0005]

[Means for Solving the Problems] When the side weir is pressed against both end surfaces of a pair of cooling drums, the lower pressure contact surface of the side weir (the pressure contact surface due to the operation of the lower cylinder) comes into contact with the both end surfaces. After that, the upper pressure contact surface of the side weir (
The contacting means includes a method of decelerating the lower cylinder after the upper cylinder starts decelerating when pressing at the same pushing speed, or a method of decelerating the lower cylinder after the upper cylinder starts decelerating when pressing at the same pushing speed. The deceleration speed of the upper cylinder is set higher than that of the upper cylinder, and pressure is applied.

[0006]

[Operation] Conventionally, when pressing the side weir against the end face of the cooling drum, the contact timing of the side weir was not controlled.
It was being implemented. In other words, due to friction in the pressing cylinder and the pushing force transmission system, or variations in the distance between the pressing cylinder and the ceramic plate of the side weir,
The contact timing of the side weirs between the upper cylinder (2 points) and the lower cylinder (1 point) was inconsistent and not reproducible. The present inventors focused on the contact timing of the side weir and investigated the phenomenon, and found the following facts.

For example, if the lower part of the side weir moved by the lower cylinder is delayed and lands in contact with the lower part of the side weir, the adhesion between the ceramic plate of the lower part of the side weir and the end surface of the cooling drum deteriorates, and the cooling drum is further activated. Immediately after this, the lower part of the side weir opened by more than 0.1 mm due to the frictional force between the ceramic plate and the end face (downward opening phenomenon), and sealing failures such as hot water leakage or entrainment of cast burrs occurred, causing casting to be interrupted. Forced.

[0008] A similar problem also occurs in the case of landing deviation on the upper side of the side weir (single-opening phenomenon). Furthermore, even if the above-mentioned seal failure does not occur immediately after the cooling drum is started, uneven wear of the ceramic plates occurs due to variations in the adhesion of the side weirs, and the ceramic plates in the areas with the most wear are missing, resulting in seal failure. This led to the suspension of casting.

The present inventors used a cylinder that can adjust the position and moving speed of the rod, and moved the lower part of the side weir slightly faster than the upper part of the side weir by the lower cylinder, and also moved the upper part of the side weir corresponding to the upper cylinder. At the same time, when we made contact landing, the above-mentioned downward opening phenomenon and one-sided opening phenomenon were eliminated, and uneven wear of the ceramic plate was also significantly improved. Embodiments of the present invention will be described below based on the drawings.

0010

Embodiment FIG. 1 is a plan view of an apparatus for carrying out the present invention, and FIG. 2 is a cross-sectional side view taken along the line A-A of FIG.
Surface 2-2 of side weir 2 in contact with the end surfaces of cooling drums 1, 1
A pressing device 6 is installed on the opposite surface 2-1. The pressing device is a rod 8 fixed at two locations on the upper side of the side dam surface 2-1.
-1, 8-2, and a rod 8- fixed at one location on the bottom
3, and a hydraulic cylinder 7-1 into which each rod is fitted.
, 7-2, and 7-3. As such a hydraulic cylinder, it is preferable to use a high-precision stepping cylinder with a resolution of about 10 μm or more. Further, the ends of the hydraulic cylinders 7-1 to 7-3 are each fixed to the base 12, and load cells 9-1, 9-2, and 9-3 for detecting reaction force are attached to the ends. There is.

[0011] Pressing force drive control devices 10-1, 10-2, 10-3 are connected to the hydraulic cylinders 7-1 to 7-3, and the control devices 10-1 to 10-3 are connected to the load cell 9. -1 to 9-3 are connected. Reference numeral 11 denotes a side weir support that maintains the side weir 2 on the base 12.

The apparatus of the present invention has the above-mentioned structure, and is operated according to the procedure shown in FIG. 3. First, the side weir 2 is set in the open state of the side weir corresponding to both end surfaces 1-1, 1-1 of the cooling drums 1, 1, and the cooling drum pressure contact surface 2-2 of the side weir and the cooling drum end surface are The pressing force drive control devices 10-1 to 10- control the cylinder backward movement stop position of each hydraulic cylinder 7-1 to 7-3 so that the interval (stroke) of 1-1 becomes a predetermined distance (for example, about 40 cm).
Fine tune by step 3.

Next, the pushing speed of the hydraulic cylinder is set to a predetermined speed (for example, 10 mm/sec) up to the deceleration position, and the deceleration speed is adjusted to a predetermined speed (for example, 1 mm/sec).

The deceleration position is set at a position where the lower cylinder is slightly closer to the end surface of the cooling drum, for example, approximately 8 mm for the upper cylinders 7-1 and 7-2, and approximately 7.5 mm for the lower cylinder 7-3. Set to . As a result, the reaction force at the lower part of the side weir increases slightly faster than the upper part. In other words, when the upper part starts contacting, the reaction force of the lower part is 100~ compared to the upper part.
It is adjusted to show a value 150 kg higher.

[0015] The side weir deceleration position before pressing the side weir is set to the same position for both the upper and lower parts, and the hydraulic cylinder pushing speed of the lower part is slightly lower than that of the lower part (for example, 0.5 mm/sec). Even if the pressure is adjusted to be faster, the same result as above can be obtained.

After the pressure contact adjustment of the side weir is performed in this way, pressing is started, and the lower part of the side weir starts contacting the pressure contact surface a little earlier, and then the upper part of the side weir starts contacting each hydraulic cylinder. Both 100~150kg
It is in a state where it is subjected to a reaction force.

When the reaction force of the above value is detected in each cylinder by the load cells 9-1 to 9-3, this detection signal is sent to the pressing drive control devices 10-1 to 10-3, and the control device The pushing speed of each cylinder is further reduced (for example, 0.2 mm/sec), and at this speed the side weir reaction force is reduced.
Press until it reaches 500 kg (moves about 2 mm with cylinder stroke). The position where this reaction force is obtained is the cylinder advance stop position (pressing state).

[0018] When the side weir was pressed under the above-mentioned pressure welding conditions and cast, there was no seal failure and the variation in the amount of wear was less than 500μ, making it possible to cast for a long time. On the other hand, when the above-mentioned pressure welding adjustment was not performed, the amount of wear varied by 1 to 3 mm, the sealing performance was poor, and the casting could not withstand long-term casting.

[0019]

As described above, according to the present invention, poor sealing of the side weir and uneven wear of the ceramic plate of the side weir are eliminated in twin-drum continuous thin plate casting, and stable sealing for a long time is made possible. The edge shape of the pieces was improved and the yield was significantly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a diagram showing the relationship between the hydraulic cylinder operation state and the hydraulic cylinder pushing speed of the present invention.

FIG. 4 is a perspective view of a conventional twin-drum continuous casting machine.

[Explanation of symbols]

1... Cooling drum 2... Side weir 3... Molten metal discharge nozzle 4... Pool portion 5... Molten metal 6... Pressing device S... Thin slab 7-1 to 7-3... Hydraulic cylinder 8-1 to 8-3... Rod 9 -1 to 9-3...Load cells 10-1 to 10-3...Pushing force drive control device 11...Side weir support tool

Claims (3)

[Claims] Claim 1: A pool is formed by a pair of rotating cooling drums and side weirs placed in pressure contact with both end surfaces of the cooling drum, and after pouring molten metal into the pool, the molten metal is rapidly solidified. In the method for manufacturing a thin slab by pressing a side weir on both end surfaces of the cooling drum, after the lower press contact surface of the side weir contacts the both end surfaces, the upper press contact surface of the side weir is brought into contact with the both end surfaces. A twin-drum continuous thin plate casting method characterized by contacting with. 2. The method according to claim 1, wherein when the side weirs are pressed against both end surfaces of the cooling drum at the same pushing speed, the lower cylinder is decelerated after the upper cylinder of the side weir pressing device starts decelerating. 3. The method according to claim 1, wherein when the side weirs are pressed against both end surfaces of the cooling drum, the deceleration speed of the lower cylinder of the side weir pressing device is made faster than the deceleration speed of the upper cylinder.