JPH0796353A - Horizontal continuous casting method for metal - Google Patents

Abstract

PURPOSE:To prevent the flapping generated at the time of casting a thin metal sheet by giving the optimum pass line angle according to the distance between a pass line roll and a mold and executing uniform heat conduction from the upper and the lower surface of the inner surface of the mold. CONSTITUTION:Molten metal 1a is cooled in the mold 2 to continuously draw out a cast slab 7. In the case of being 100mm <=L1<=1000 mm in the relation of the distance L1 between the pass line roll 3 and the mold 2, the cast slab is drawn out under condition of 0<tan theta1<=A1XL1 in the relation between the angle theta1 fromby the straight line connecting the contacting point of the cast slab 7 with the pass line roll 3, and the outlet of the lower surface 11 of the mold to the horizontal line and the distance L1 of the pass line roll 3 and the mold. Wherein, A1 is the constant decided with the metal in the range of 2.5X1/10<5=A1<=5.5X1/10<5>. By this method, as the uniform heat conduction from the upper and the lower surfaces in the inner surface of the mold can be executed, the flapping generated at the time of horizontally and continuously casting the metal thin sheet can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal continuous casting method for a metal, in which a molten metal is cooled by a mold attached to a holding furnace to continuously draw out a slab, and more particularly to a horizontal continuous casting method for thin metal plates. The present invention relates to a horizontal continuous casting method suitable for casting.

[0002]

2. Description of the Related Art An outline of a conventional horizontal continuous casting method for metal will be described with reference to FIG. The molten metal is cooled in a mold 2 attached to a holding furnace 1, and pinch rolls 5, 5a
, A relatively small thickness (about 15 to 20 mm) of the slab 7 is continuously drawn out in the horizontal direction, and a slab of the required length is shredded.
And cut it with an up coiler-8.

A secondary cooling device 4 is provided between the mold 2 and the pinch rolls 5 and 5a for cooling the high temperature cast slab 7 discharged from the mold 2 to room temperature. Therefore, the distance between the mold 2 and the pinch rolls 5, 5a is usually 2000 mm or more, and one or a plurality of pass line rolls 3 are installed to maintain the pass line of the slab.

Passline roll 3 closest to mode 2
When the distance between the mold and the mold is L ₃ , L ₃ is usually 1000 mm or more because it is necessary to keep a distance that does not hinder work such as tilting the holding furnace when replacing the mold 2. Has become. Conventional thickness is 15 ~ 20mm, width is 3
In casting a slab of 50 to 800 mm, the above-mentioned method did not cause any particular problem.

[0005]

However, in recent years, in order to improve the productivity and the yield, it has been desired to make the slab thinner and wider than before. However, the slab is made thinner. Or if the width is increased, as shown in FIG.
At the time of drawing, the phenomenon that the slab is wavy in the drawing direction appears. When the slab 7 undulates in this manner, the slab 7 also contacts the parts of the casting device where the slab does not originally come into contact, other than the rolls such as the pass line roll 3 and the pinch roll 5, etc. There is a problem of scratches. Further, when the slab 7 is cut, the holding furnace side end of the slab bumps into the shear 6,
A serious problem occurs that the cast piece cannot be pulled out. Further, in the up coiler 8, in order to detect the tip of the cast slab, the side surface of the cast slab 7 is detected by a sensor because of its structure, but this also has a drawback that it cannot be detected accurately.

[0006] In horizontal continuous casting of metal, in order to form a stable solidified shell in the mold, drawing is carried out by repeating forward and backward movements, but the slab is bent at the time of backward movement and a certain backward movement occurs. There is also a problem that the amount cannot be secured. Furthermore, since the slab comes into strong contact with the upper and lower inner surfaces of the mold during drawing, there is a problem that the life of the mold is significantly shortened.

The present invention has been made in view of the above circumstances. In horizontal continuous casting of metal, the slab is thinned,
Alternatively, it is an object of the present invention to provide a horizontal continuous casting method for a metal, which can prevent a corrugation phenomenon in a drawing direction of a slab that occurs when the width is widened.

[0008]

In order to achieve the above object, the present invention provides a horizontal continuous casting method for a metal, in which a molten metal is cooled by a mold provided in a holding furnace to continuously draw out a slab. In the case where the distance L ₁ between the pass line roll and the mold is 100 mm ≦ L ₁ ≦ 1000 mm, the angle θ ₁ formed by the straight line connecting the slab and the contact of the pass line roll and the outlet on the lower surface of the mold with And the distance L ₁ between the pass line roll and the mold is 0 <tan θ ₁ ≦ A ₁
The feature is that the slab is pulled out under the condition of × L _1, and the position of the pass line roll closest to the mold (distance L ₁ from the mold) and the cross-sectional size of the slab (width W, thickness T) However, 350mm ≦ W ≦ 1200mm, 8mm ≦
When T ≦ 20 mm, the slab is characterized in that the slab is pulled out under the condition that the relationship between the distance L ₁ from the mold and the cross-sectional size of the slab is L ₁ ≦ A ₂ × T / W. Is horizontal, the relationship between the inclination angle θ of the lower surface of the inner surface of the mold, the length L ₂ in the drawing direction of the mold, the opening width t ₂ on the melt side and the opening width t ₁ on the drawing side is
0.8 × 1/10 ³ ≦ tan θ = (t ₁ −t ₂ ) / L ₂ ≦
This is a horizontal continuous casting method for metal, characterized in that a mold satisfying the condition of 1.8 × 1/10 ³ is used.

The feature of the present invention is that it is optimal depending on the distance between the mold and the pass line roll in order to prevent uneven heat removal from the upper and lower surfaces of the mold, which is the cause of corrugation of the slab. pass line angle theta ₁ by providing (and pass line roll cast slab contacts, the straight line connecting the outlet of the mold lower face angle theta ₁ which forms between the horizontal line) thin, upon withdrawal of the wide slab This is a horizontal continuous casting method for metal that can prevent the corrugation phenomenon.

[0010]

Next, the operation of the present invention will be explained. The cause of the corrugation phenomenon that occurs during drawing in the horizontal continuous casting method is that the upper and lower surfaces of the slab are ununiformly removed in the mold. Immediately after the start of casting, the molten metal is removed from heat by the upper surface of the mold, the lower surface of the mold and the leading damber, and solidifies. Due to gravity, the solidified and shrunk slab comes into contact with the lower surface of the mold more widely than the upper surface of the mold. Therefore, the heat removal from the lower surface of the slab becomes larger than the heat removal from the upper surface of the slab. As a result, upwardly convex thermal stress is generated in the slab. Then, as the casting progresses and the time elapses, the slab pulled out of the mold loses the constraint from the mold, and the thermal stress is released, so that upward convex strain occurs. Due to this strain, the upper surface of the mold contacts more widely than the lower surface of the mold.
The heat removal from the upper surface of the slab becomes larger than that from the lower surface of the slab. As a result, downwardly convex thermal stress is generated in the slab.

Further, the corrugation phenomenon generated by the above mechanism is such that when casting progresses with the passage of time and a convex portion on the slab reaches the pass line roll, the slab will be moored.
Wider contact with the bottom surface of the field, which in turn causes upward thermal stress. Further, the slab is released from thermal stress outside the mold as time passes, and progresses while generating upward convex strain.This time, the lower convex portion of the slab reaches the pass line roll. Then, the slab comes into wider contact with the upper surface of the mold, and conversely, a downward convex thermal stress is generated. The slab is released from thermal stress outside the mold as time passes, and progresses with a downward convex strain, and when the convex part on the slab reaches the pass line roll, Has a wider contact with the lower surface of the mold, and on the contrary, an upwardly convex thermal stress is generated to return to the initial situation. After that, this cycle is repeated and a sine-curve-like undulation occurs.

In order to prevent the occurrence of the above wavy phenomenon,
Due to the mechanism of this waving phenomenon, it is necessary to make the ingots evenly contact the upper and lower surfaces of the mold, and therefore, in order to prevent this waving, the top of the pass line roll is placed above the horizontal line. Position to raise the slab and make the area of contact of the slab with the lower surface of the mold approximately the same as the area of contact with the upper surface of the mold, so that uniform heat removal from the upper and lower surfaces of the mold is performed. I can go and solve it. Moreover, the pass line angle θ that can prevent waviness
₁ is related to the distance L ₁ between the pass line and the mold, and there is a relational expression of 0 <tan θ ₁ ≦ A ₁ × L ₁ ... (1). That is, this equation holds true for the distance L ₁ between the pass line and the mold in the range of 100 mm to 1000 mm. In the equation (1), A is a constant determined by the metal and is in the range of 2.5 × 1/10 ⁵ to 5.5 × 1/10 ⁵ . Therefore, by determining the optimum pass line angle θ ₁ corresponding to the distance L ₁ between the pass line and the mold, it is possible to uniformly remove heat from the upper and lower surfaces of the inner surface of the mold and prevent undulation. .

In addition to the above relationship, it is also possible to arrange the pass line rolls at a fixed distance close to the mold. Moreover, the optimum distance between the pass line roll and the mold that can prevent this waviness is related to the thickness and width of the slab, and the relational expression L ₁ ≦ A × T / W (2) Exists. That is, assuming that the distance between the pass line roll 4 and the mold 2 is L ₁ , the limit distance L that does not cause waviness is L.
_{No. 1} is proportional to the thickness T of the cast slab in the range of 8 mm to 20 mm and inversely proportional to the width W of the width W in the range of 350 mm to 1200 mm. In the above equation, A is a constant determined by the metal and is in the range of 1 × 10 ⁴ to 5 × 10 ⁴ . Therefore, by determining the optimum distance L ₁ from the mold of the pass line roll corresponding to the drawn cross-section size (width W × thickness T) of the slab, the upper and lower surfaces of the inner surface of the mold can be determined. Uniform heat removal can be performed and waving can be prevented.

In addition to the above relationships, the optimum inclination angle θ of the lower surface of the inner surface of the mold is as follows: length L ₂ in the drawing direction of the mold, opening width t ₂ on the melt side, opening width t ₁ on the drawing side.
, And 0.8 × 1/10 ³ ≦ tan θ = (t ₁ −
There is a relation of t ₂ ) / L ₂ ≦ 1.8 × 1/10 ³ , and a mold having an inclination angle θ of the lower surface of the inner surface of the mold which meets this condition.
By using the rudder, without causing more wavy phenomenon,
It is possible to stably cast a thin slab.

[0015]

[Examples] As a result of various experiments and studies conducted by the inventors to prevent corrugation of a slab, the cause of corrugation was found to be
It was found that the upper and lower surfaces of the slab were ununiformly heat-exhausted in the mold, the mechanism of its occurrence was clarified by experiments, and a horizontal continuous casting method capable of preventing the waving phenomenon was invented. An experiment conducted on horizontal continuous casting for a thin plate of phosphor bronze alloy used as a spring material or the like in electric / electronic equipment parts by the horizontal continuous casting method according to the present invention will be described below with reference to the drawings. FIG. 1 shows a horizontal continuous casting apparatus used in this experiment, in which a molten metal is cooled in a mold 2 attached to a holding furnace 1 and a pinch roll 5 or 5a is used to make a particularly thin thickness ( (Approximately 8 to 15 mm)
The slab 7 is continuously drawn out in the horizontal direction, the slab having a required length is cut by the shear 6, and is coiled by the up coiler 8. A secondary cooling device 4 is provided between the mold 2 and the pinch rolls 5 and 5a for cooling the high temperature slab 7 that has come out of the mold 2 to room temperature. And
In FIG. 1, the distance between the mold 2 and the first pass line roll 3 is indicated as L ₁ .

Next, the mechanism of the generation of waviness clarified by this experiment will be described with reference to FIGS. 2, 3 and 4. Figure 2 shows the state immediately after the start of casting,
The casting time has passed from (a) to (d). (A)
In the above, the molten metal 1a is removed from the heat by the mold upper surface 10, the mold lower surface 11 and the damber 9 and solidifies. The slab 7 that has solidified and contracted is molded on the lower surface 11 of the mold by gravity.
The contact is wider than that of the upper surface 10. The heat removal from the bottom surface 7b of the slab becomes larger than the heat removal from the top surface 7a of the slab. As a result, an upward convex thermal stress is generated as shown by the arrow P in (b). The cast piece 7 pulled out of the mold 2 with the elapse of the casting time loses the constraint from the mold 2, the thermal stress is released, and the upward convex strain occurs. Due to this strain, the upper surface of the mold 1
It contacts 0 more widely than the lower surface 11 of the mold. The heat removal from the slab upper surface 7a becomes larger than that from the slab lower surface 7b. As a result, a downward convex thermal stress is generated as shown by the arrow Q in (c). (D) shows a state in which the convex portion on the slab 7 reaches the first pass line roll 3.

FIG. 3 shows the situation during the subsequent casting,
The casting time has passed from (a) to (d). The waviness generated by the mechanism described with reference to FIG. 2 is such that, with the passage of time, the upward convex portion is the first pass line roll 3.
When reaching the upper side, the slab comes into wider contact with the lower surface 11 of the mold as shown in (a), and a thermal stress P convex upward is generated. The slab 7 is released from the thermal stress outside the mold 2 as the casting time elapses, causing upward convex strain (b).
After this, the downwardly convex portion reaches the pass line roll 3, and the slab 7 makes wider contact with the mold upper surface 10 as shown in (c), and a downwardly convex thermal stress Q is generated. To do.
As the casting time elapses, thermal stress is released outside the mold 2 as the casting time elapses, and a downward convex distortion is generated, and the situation returns to the situation of (a) through the situation of (d). After that, this cycle is repeated and a sine-curve-like undulation occurs.

Further, as shown in FIG. 4, when a plurality of pass line rolls are installed, when the pass line roll R closer to the mold is removed, the slab is bent downward by its own weight. . Due to this deflection, the cast slab 7 makes wider contact with the lower surface 11 of the mold, and an upwardly convex thermal stress P is generated. This deflection also occurs immediately after the start of casting shown in FIG. That is, immediately after the start of casting, waviness is caused by both the phenomenon that the slab 7 solidified and shrunk in the mold 2 makes wider contact with the lower surface 11 of the mold and the slab 7 makes wider contact with the lower surface 11 of the mold. Occur.

Considering the mechanism of undulation described above, it can be understood that in order to prevent undulation, it is sufficient to evenly contact the slab on the upper and lower surfaces of the mold. As a result of various studies on the method, the inventors have raised the slab 7 by positioning the top of the pass line roll 3 above the horizontal line H, as shown in FIG. 5, as one of the methods. It has been found that the area where the slab comes into contact with the lower surface 11 of the mold is set to be approximately the same as the area where it comes into contact with the upper surface 10 of the mold. Moreover, the pass line angle theta ₁ which can prevent undulation, was found to exist with respect to the distance _{L 1 0 <tanθ 1 ≦ A} 1 × L 1 ··· (1) the relationship between the pass line contact and the mold 2 . As a result of an experiment, this relationship holds in the range of L ₁ from 100 mm to 1000 mm, and L ₁
It was found that the relation of the equation (1) does not always hold when is not within this range. A is a constant determined by the metal,
The range was from 2.5 × 1/10 ⁵ to 5.5 × 1/10 ⁵ .

Furthermore, in addition to the above method, it has been found that the first pass line roll may be arranged close to the mold. It was found that the distance L ₁ between the first pass line roll and the mold capable of preventing waviness has a relationship of L ₁ ≦ A × T / W (2) with respect to the thickness and width of the slab. It was This relationship will be described with reference to FIG. The distance between the first pass line roll 3 and the mold 2 is L ₁
Then, the limit distance L ₁ that does not cause waviness is proportional to the thickness T of the slab 7 and inversely proportional to the width W. As a result of experiments, it has been found that this relationship is established in the range of the width W from 350 mm to 1200 mm, and the relationship of the equation (2) is not necessarily established when the width W is not within this range. Further, the thickness T is established in the range of 8 mm to 20 mm, and if it is not within this range, (2)
It turns out that the relations of the formulas do not always hold. In addition,
A is a constant determined by the metal and is 1 × 10 ⁴ to 5 × 10 ⁴
Was in the range.

In addition to the above method, as shown in FIG. 7, the optimum inclination angle θ of the lower surface of the mode inner surface is the length L ₂ in the drawing direction of the mold, the opening width t ₂ on the molten metal side and the opening on the drawing side. 0.8 × 1/10 ³ ≦ tan θ between width t ₁
= So _{(t 1 -t 2) / L} 2 ≦ 1.8 × 1/10 that there are ^three relationships were found the results of the experiment, more waviness by using a mold to form the lower surface inclination angle of the θ It is possible to cast more stable cast pieces. At this time, it is desirable that the upper surface 10 of the mold be horizontal, but the upper surface 10 may be defined at a constant angle.

[0022]

According to the present invention described above, by positioning the top of the pass line roll above the horizontal line, the cast piece is lifted, and the area where the cast piece contacts the lower surface of the mold is brought into contact with the upper surface of the mold. By making the area approximately the same as that of the mold, uniform heat removal from the upper and lower surfaces of the inner surface of the mold can be performed, and the optimum pass line roll mold corresponding to the drawing cross-sectional size of the thin cast piece. Since it is possible to uniformly remove heat from the upper and lower surfaces of the inside of the mold by pulling out the slab at the limit distance L ₁ from
It is possible to completely prevent waviness that occurs during horizontal continuous casting of a thin metal plate. In addition, it is possible to cast a more stable thin-walled and wide slab without causing a corrugation phenomenon by using a mold having an optimum mold bottom surface inclination angle corresponding to the drawing cross-sectional size of the slab. You can

[Brief description of drawings]

FIG. 1 is a process explanatory diagram of an example of the present invention.

FIG. 2 is a drawing explaining the steps of this experiment.

FIG. 3 is a drawing explaining the steps of this experiment.

FIG. 4 is a drawing explaining the steps of this experiment.

5A to 5C are cross-sectional explanatory views of the steps of the present embodiment.

FIG. 6 is a perspective view of the present embodiment.

FIG. 7 is a cross-sectional explanatory view of a mold of this embodiment.

FIG. 8 is a process explanatory diagram of a conventional example.

[Explanation of symbols]

 1 Holding furnace 1a Molten metal 2 Mold 3 Pass line roll 4 Secondary cooling device 5,5a Pinch roll 6 Shear 7 Cast piece 7a Cast piece upper surface 7b Cast piece lower surface 8 Up coiler 9 Dummy bar 10 Mold upper surface 11 Mold lower surface

Claims (3)

[Claims] 1. In a horizontal horizontal continuous casting method for a metal, in which a molten metal is cooled in a mold provided in a holding furnace to continuously draw out a slab, a distance L ₁ between a pass line roll and the mold is 100 mm ≦ L. _{When 1} ≦ 1000 mm, the relationship between the angle θ ₁ formed by the straight line connecting the contact point between the slab and the pass line roll and the outlet on the lower surface of the mold with the horizontal line, and the distance L ₁ between the pass line roll and the mold 0 <tan θ ₁ ≦ A ₁ ×
A horizontal continuous casting method for a metal, which comprises drawing a slab under the condition of L ₁ . However, A ₁ is 2.5 × 1/10 ⁵
It is a constant determined by the metal within the range of ≦ A ₁ ≦ 5.5 × 1/10 ⁵ . 2. In the horizontal horizontal continuous casting method for a metal, in which a molten metal is cooled in a mold provided in a holding furnace and a cast piece is continuously drawn out, the position of a pass line roll closest to the mold (distance from the mold L ₁ ) and the cross-sectional size of the slab (width W, thickness T) are 350 mm ≦ W ≦ 1200 mm,
When 8 mm ≦ T ≦ 20 mm, the distance from the mold L ₁
The horizontal continuous casting method for a metal according to claim 1, wherein the slab is drawn out under the condition that the relation between the slab and the cross-sectional size of the slab is L ₁ ≦ A ₂ × T / W. However, the above A ₂ is 1 × 1
The constant is determined by the metal within the range of 0 ⁴ ≦ A ₂ ≦ 5 × 10 ⁴ . 3. In a horizontal horizontal continuous casting method for a metal, in which a molten metal is cooled in a mold provided in a holding furnace and a cast piece is continuously drawn out, when the upper surface of the inner surface of the mold is horizontal, The relationship between the inclination angle θ of the lower surface, the length L ₂ in the drawing direction of the mold, the opening width t ₂ on the melt side and the opening width t ₁ on the drawing side is 0.8 × 1/10 ³ ≦ ta
A horizontal metal continuous die according to claim 1 or 2, wherein a mold satisfying the condition of nθ = (t ₁ -t ₂ ) / L ₂ ≦ 1.8 × 1/10 ³ is used. Casting method.