JPS6064753A - Method and device for casting with twin roll type casting machine - Google Patents

Abstract

PURPOSE:To eliminate leakage of a molten metal even in casting of a broad material by providing twin rolls in such a way that the one roll can move in the radial direction of the other roll and controlling the compression rate of the thickness of the solidified shell of the molten metal during casting so as to attain a reguired positive value. CONSTITUTION:One cooling roll 64 of a twin roll type continuous casting machine is supported to a frame 50 via a load cell 52 and the other roll 63 is provided in such a way that the roll gap is adjusted by a worm reduction gear unit 58. The compression rate of th thickness of the solidified shell 24 of the molten metal 70 formed by the rolls 63, 64 is so controlled as to attain a required positive value. The gap (d) in the narrowest part A between the rolls 63 and 64 is made small in the stage of starting pouring and casting is performed while the gap (d) is opened to a required size as time passes by until the stationary state is attained. Leakage of the molten metal is thus prevented even in casting of a broad material by which the execution of the safe operation is made possible and the thickness of the billet during casting is made changeable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a casting method and apparatus for improving operability when manufacturing thin plate materials using a twin-roll casting machine.

[Background of the invention]

As a conventional technology, casting machines using twin rolls are It is known as the Sebu type continuous caster.

As shown in FIG. 1, this casting machine consists of two cooling rolls 1 and 2, in which molten metal 5 is poured between the rolls by a nozzle 4, and the pooled molten metal is cooled by a roll 1.2. In the narrowest gap between the rolls, the solidified shell formed on both roll sides is compressed into a single plate to obtain a cast product 6.

Incidentally, the molten metal pool 7 between the rolls in FIG. 1 is prevented from flowing out by the flanges 3 on both sides.

Since such a conventional casting apparatus can manufacture thin plates from molten metal all at once, it has the advantage of being able to manufacture products at a much lower cost than those using conventional large steel equipment.

However, since the roll diameter cannot be made extremely large with this casting machine, there is a limit to the thickness of the product that can be manufactured.Those with a roll diameter of φ500 to 1000 mm are usually made with a thickness of about 1 to 6 yuan. is being produced.

In addition, thin plate products are required to have a wide plate width of 600 to 1600 rran, but conventionally only widths of 150 m or less could be manufactured.

The reason for this is that when the casting machine starts pouring, a large amount of molten metal flows out from the gap in section A in Figure 1 when the casting machine is wide, which is a dangerous operation. This is because it was only practical.

That is, at the start of casting, the molten metal inevitably flows out from the gap shown in part A in Figure 1, but if the width is narrow, a pool 7 of the molten metal is easily formed, and the cooling time in the rolls is secured. After a few seconds, the sum of the thicknesses of the solidified shells formed by the rolls on both sides at part A will be crimped at this part (the gap in part A), and the outflow of the molten metal will end. However, with a wide width one, it is not possible to prevent the molten metal from flowing out from the gap in the part A, and it is impossible to form a molten metal pool, so there is a problem that a wide thin strip cannot be manufactured.

In addition, if it becomes possible to manufacture wide materials, a continuous mass production system will be adopted, but in this case, it is desirable to establish a technology that can change the thickness to any desired thickness during casting. was.

[Purpose of the invention]

The purpose of the present invention is to prevent leakage of molten metal even when casting wide materials, so that casting can be carried out safely.
It is an object of the present invention to provide a casting method using a twin-roll type casting machine and an apparatus therefor, which can easily change the thickness to a required thickness during casting.

[Summary of the invention]

In the present invention, at least one of the two cooling rolls is moved so that the gap in section A can be adjusted.

[Embodiments of the invention]

First, before entering into a detailed explanation of the invention, the basic idea that forms the basis of the present invention will be explained.

That is, at the start of casting, the gap in section A shown in Figure 2 is set to 0 to 0.
, 5■. As described above, if the gap in the section A is small, the amount of molten metal flowing out from the gap between the rolls will not occur, but even if it does, it will be very small, and the pool 7 of the molten metal can be easily formed.

Once the gurua is shaped, the molten metal is cooled on the surfaces of the rolls 63 and 64 on both sides, and a solidified shell is formed.
The gap between the rolls is increased to a predetermined value as the rolls are formed.

The solidification thickness S produced when the molten metal is cooled on the surface of one roll can be determined by the following formula.

s = k v'〒n7 ・・・・・・・・・・・・(
1) is a constant, usually = 20 to 26 mm/body. The value in equation (1) is the contact length of the molten metal with the roll as shown in FIG. This contact length increases with the pool depth H of the molten metal 70. The relationship between L and H is expressed by the following equation.

L=πDsin-' (H/R)/360 ・-・(2
) In order to prevent the molten metal from leaking from part A in FIG. 2, the following formula must be satisfied for the roll gap d in part A.

2S = 2kV'〒7〉d... (3) When formula (3) is obtained, if the amount of (2S-d) can be crimped at part A as the roll rotates, it is safe work without leakage of molten metal. becomes possible.

Therefore, in the present invention, when starting pouring when the pool height H of the molten metal is small, the roll gap in the section A must be made small, and the operation must be performed so that the condition satisfying the formula (3) is satisfied.

Let the solid shell thickness and 2S be as shown below.

2S=d+ΔS ・・・・・・・・・・・・(4)(4
), ΔS represents the amount of pressure applied to the solidified object in the narrow gap between the twin rolls.

Therefore, α in the formula below is the isthmus-solid pressure Ha due to the twin rolls.
rate.

α=(2S-d)/28-ΔS/28...(5)(
If we substitute equations 1) and (2) into equation (5), equation (5) becomes...
・・・・・・・・・・・・(6) It becomes.

In equation (6), if α>0, unsolidified molten metal will remain below the twin roll narrow gap. That is,
When pouring starts, the molten metal will flow out, and even after the plate has been shaped, if the α value is negative, the molten metal will remain below the gap, and a thin solidified shell will swell due to the static pressure of the molten metal. , you can't get a good quality product.

At the start of pouring, since the depth of the molten metal pool in Fig. 2 is small, if the gap d in the narrow roll gap is a dog, (6
) In the equation, α must be negative, and the molten metal will flow out.

Therefore, when starting pouring, set the gap d small,
This is to start casting.

However, the pool depth H in equation (6) increases rapidly when the gap d is small, creating a pool.

On the other hand, it is necessary to keep α in equation (6) positive as described above, but it is desirable that this positive value α be as constant as possible. That is, as α becomes large, the amount ΔS to be compressed becomes large, requiring a large load to compress between the rolls, and furthermore, as α becomes large, a slipping accident may occur.

In order to control the α value in equation (6) to be almost constant as the pool depth H changes, it is necessary to change the roll opening degree d while appropriately controlling the change in the pool depth H, or to The speed V can also be adjusted and controlled together with d so that the α value is a constant positive value.

In any case, at the start of pouring, while controlling α in equation (6) to a positive desired value, the roll opening dl
It expands to a predetermined opening degree.

Next, when manufacturing a thin plate of a predetermined thickness in a steady state,
We will describe a method for changing to manufacturing a thin plate with a different thickness midway through production.

In the steady state, the pool depth H in equation (6) is controlled to be maintained at a constant upper limit value in order to use the full capacity of the twin roll forming machine. Therefore, in order to move the rolls so that the roll gap d corresponds to the desired plate thickness, it is necessary to control the roll circumferential speed V so that the α value in equation (6) becomes the desired positive value. There is.

This is because if the α value becomes negative, as described above, the molten metal will remain below the narrow gap between the rolls, and a plate will be manufactured that swells due to the static pressure of the molten metal.

Of course, in special cases, the roll gap d may be adjusted by moving the rolls while controlling the pool depth H.

In any case, the roll is moved during casting while controlling the α value in equation (6) to a desired positive value.

In order to prevent the molten metal from remaining below the narrow roll gap A in FIG. 2, the α value in equation (6) is selected as follows depending on various purposes.

For the purpose of simply preventing the molten metal from flowing out or remaining on the plate below part A in Figure 2, the following α1 value is selected: αl = Q, 95
~0.1. That is, the value is selected to match the error rate of the solidified shell thickness formed by twin rolls. If the plate thickness is approximately equal to the roll gap d, then the following equations (4) and (5) can be obtained, and the compression amount ΔS can be determined.

ΔS=α・d/(1-α) ・・・・・・(7) If d = 0.5 M, then a = 0.1 and ΔS; 0 to start pouring.
．． Regarding 028, if d=3 questions in steady state, α=0.1 and ΔS
= about 0.33 kaku.

For other purposes, i.e., to perform strong compression processing in the narrow gap between the twin rolls,
If you want to change the cast structure to the rolled structure, α,=Q,
A suitable value between l and 0.6 is taken.

In this case as well, in order to keep the rolling structure constant, it is necessary to control α2 so that the α value remains constant.

Next, one embodiment of the present invention will be described using FIGS. 3 and 4. FIG. 3 is a front view, and FIG. 4 is a plan view of FIG. 3.

The molten metal is poured from the nozzle 4 between two cooling rolls 63 and 64 to form a pool 7.

The two rolls 63 and 64 are each provided with flanges 62 and 68 to prevent the molten metal from flowing out from both width ends.
The position of this flange 62.68 is the ring nut 61.7.
N is adjusted by 2. This roll 63,64 is the bearing box 5
3.54, one roll 64 is fixedly supported in the frame 50 via the load cell 52.
Supported by The other roll 64 is moved by a worm reduction device 58 provided within the frame 50 so as to adjust the gap between the rolls.

That is, although the spring 55 is provided between the bearings of the two rolls 63 and 64, the motor 66 resists this force.
By rotating the worm wheel 56 using the coupling 65 and shaft 60 and moving the screw 57, the bearing box 54 is moved via the pin 56.

The inter-roll gap d75 shown in Fig. 4 is 0 to 0 before starting pouring.
．． It is set to about 5m.

At the start of pouring, the gap d is closed by rotating the motor 66.
Gradually expand and adjust to the desired position.

The method for automatically adjusting the gap d over time is preferably carried out as follows.

As a first method, the rolls 63 on both sides in FIG.
．． When the solidified shell 24 formed at 64 begins to be compressed at point A, a compressive load is generated due to this compression. As compression loads, a compression force P that tries to separate the rolls and a torque T that drives the rolls are generated.

This compressive force P and torque T are determined by the crimping length t of the solidified shell 24.
Then, the following relationship holds true.

T"=koPt -----nee C'i?)ko is a constant Moreover, the compressive force P can be determined by the following formula.

p = Niyu BLQp -----C9) k is the deformation resistance, and Qp is the coefficient. Therefore, these quantities can be known from both P and T\
If so, the crimp length t can be calculated backwards.

Therefore, if the compressive force P from the load cell 52 in FIG. 3 is known, the crimping state of the solidified shell 24 at section A in FIG. 2 can be predicted. Of course, the crimping condition can also be known by measuring the driving torque of the rolls 63 and 64.

In this way, the gap between the rolls can be adjusted while measuring the compression load and predicting the presence or absence of crimping.

In this case, it is of course possible to simultaneously adjust and control the roll circumferential speed. Thereby, the α value in the above-mentioned equation (6) can be controlled to a desired positive value.

The second method is to measure the height H of the pool 70 in Figure 2 and adjust the opening while predicting the solidified shell according to equations (1) and (2) above. It is. FIG. 5 shows a control system which is an embodiment of the invention described above.

Detection amount is pool 70 depth H85, compressive force between rolls P8
4. The driving torque of the rolls 63 and 64 is 86T. These detected values are input to the control device 80, and the inter-roll gap d is
The speed n of the motor ML81 that should adjust d of and and the rotational speed N of the main motor Ml that drives the twin rolls 63 and 64 are adjusted, and the α value in the above equation (6) is changed to a positive desired value α8. This is to adjust the roll gap d while maintaining the same.

Adjustment of the gap d between the rolls is carried out at the start of pouring and during pouring.
This is carried out when changing the plate thickness.

〔Effect of the invention〕

According to the present invention, by being able to adjust the gap between the rolls during casting, it is possible to perform safe work with less leakage of molten metal at the start of pouring, and it is possible to perform safe work with a thickness of 1 to 60 mm, which is relatively thick.
It has become possible to cast wide materials of 0 to 1600 rran. Furthermore, since the thickness of the plate can be changed freely during the casting process, operability can be greatly improved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the Bethsema 7 type casting machine, which is a conventional twin roll casting machine, Fig. 2 is an explanatory diagram showing the state of solidified shell formation in the twin roll casting machine which is the basis of the present invention, and Fig. 3
The figure is a schematic structural diagram showing a twin roll casting machine which is an embodiment of the present invention, Figure 4 is a plan view of Figure 3, and Figure 5 is a control system diagram applied to the casting machine shown in Figure 3. It is. 4... Nostle, 7... Pool, 52... Load cell, 63.64... Cooling roll, 58... Worm reduction gear Figure 1''$ 2 Figure 3

Claims (1)

[Claims] 1. In a twin-roll type casting machine in which a pair of rolls are arranged in parallel in the axial direction, the compressibility of the thickness of the solidified shell of the molten metal formed by the twin rolls is adjusted to a required positive value. 1. A method for casting using a twin-roll casting machine, characterized in that at least one roll is moved in a radial direction toward the other roll during casting so that the casting value can be controlled so as to maintain a constant value. 2. In claim 1, the molten metal is poured between a pair of rolls from above, and when pouring starts, the gap between the narrowest gap between the pair of rolls is made small. 1. A method for casting using a twin-roll type casting machine, characterized in that casting is carried out while the gap at the narrowest gap portion is opened to a predetermined size over time until reaching a steady state. 3. In a twin-roll casting machine that has two pairs of cooling rolls and a nozzle for pouring molten metal between the cooling rolls, and solidifies the molten metal with the cooling rolls to continuously cast thin strips. , at least one of the cooling rolls is provided with a moving device capable of moving the axial end of the roll in the radial direction of the other cooling roll, and the solidified shell of the molten metal formed by both of the cooling rolls is 1. A casting device for a twin-roll casting machine, comprising a detection device for detecting a compression load, and a control device for controlling the moving device based on an output from the detection device. 4. A casting device for a twin roll casting machine according to claim 3, wherein the detection device is a load detector that detects compressive force acting on the cooling roll. 5. A casting device in a twin-roll casting machine according to claim 3, wherein the detection device is a torque detection device of a drive device that drives a cooling roll.