JP3091067B2 - Horizontal continuous casting method for metal - Google Patents

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, and a slab is continuously drawn. 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 is then pinch rolls 5, 5a.
The slab 7 having a relatively small thickness (about 15 to 20 mm) is continuously drawn out in the horizontal direction, and the slab 7 having a required length is
And coiled with an up coiler-8.

[0003] A secondary cooling device 4 is provided between the mold 2 and the pinch rolls 5 and 5a to cool the high-temperature slab 7 coming out of 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 provided to maintain the pass line of the slab.

The pass line roll 3 closest to the mold 2
A motor - and the distance between the field and L _3, L ₃ is mode - usually 1000mm above the need to keep a distance of only does not disturb the work such as tilting the holding furnace when replacing the shield 2 and Has become. Conventional thickness is 15-20mm and width is 3
In the casting of a slab having a diameter of 50 to 800 mm, no particular problem was caused by the method described above.

[0005]

However, in recent years, in order to improve productivity and yield, it has become more desirable than ever to reduce the thickness and width of cast slabs. Or widening, as shown in FIG.
At the time of drawing, a phenomenon in which the slab undulates in the drawing direction appears. As described above, when the slab 7 is wavy, the slab 7 also comes into contact with a part of the casting apparatus other than the rolls such as the pass line roll 3 and the pinch roll 5 where the slab does not originally come into contact with the slab. There is a problem of scratching. Moreover, when the slab 7 was cut, the holding furnace side end of the slab hit the shear 6,
There is a serious problem that the slab cannot be pulled out. Further, in the upcoiler 8, in order to detect the tip of the slab, the side surface of the slab 7 is structurally detected by a sensor. However, there is a disadvantage that this cannot be detected accurately.

In the horizontal continuous casting of metal, the metal is drawn while repeating forward and backward in order to form a stable solidified shell in the mold. There is also a problem that the amount cannot be secured. Furthermore, since the slab makes strong contact with the upper and lower surfaces of the inner surface 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, and in a horizontal continuous casting of metal, a slab is reduced in thickness.
Alternatively, it is an object of the present invention to provide a horizontal continuous casting method for metal capable of preventing a waving phenomenon in a drawing direction of a slab which occurs when the width is increased.

[0008]

SUMMARY OF THE INVENTION 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 and a slab is continuously drawn. 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 between the horizontal line and the straight line connecting the slab, the contact point of the pass line roll and the outlet of the lower surface of the mold. And the distance L ₁ between the pass line roll and the mold is 0 <tan θ ₁ ≦ A ₁
It is characterized in 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) But 350mm ≦ W ≦ 1200mm, 8mm ≦
When T ≦ 20 mm, 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 molten metal 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 ≦
A horizontal continuous casting method for metal, characterized by using a mold satisfying a condition of 1.8 × 1/10 ³ .

A feature of the present invention is that, in order to prevent uneven heat removal from the upper and lower surfaces of the inner surface of the mold, which is a factor of the waving of the slab, the optimum distance is determined by the distance between the mold and the pass line roll. 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 waving phenomenon.

[0010]

Next, the function of the present invention will be described. The cause of the waving phenomenon that occurs during drawing in the horizontal continuous casting method is that the upper and lower surfaces of the slab are non-uniformly removed in the mold. Immediately after casting is started, the molten metal is removed by the upper mold surface, the lower mold surface, and the top dummy bar, and solidifies. The solidified and contracted slab contacts the lower mold surface more widely than the upper mold surface due to gravity. 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, an upwardly convex thermal stress is generated in the slab. Then, as the casting progresses, the slab drawn out of the mold as time elapses loses the restraint from the mold, and the thermal stress is released, so that a convex distortion occurs. Due to this strain, the upper surface of the mold is now in wider contact than the lower surface of the mold.
And the heat removal from the slab upper surface becomes larger than the heat removal from the slab lower surface. As a result, a downwardly convex thermal stress is generated in the slab.

Further, the waving phenomenon generated by the above mechanism is such that when the casting progresses with the passage of time and the convex portion on the slab reaches the pass line roll, the slab is deformed.
The lower surface of the solder comes into wide contact, and a thermal stress that is convex upward is generated. Further, as the time elapses, the thermal stress is released outside the mold, and the slab progresses while generating an upward convex strain. This time, the convex portion below the slab reaches the pass line roll. Then, the slab contacts the mold upper surface more widely, and conversely, a downwardly convex thermal stress is generated. As time elapses, the slab is released from the outside of the mold under thermal stress, and the slab proceeds while generating a downwardly convex strain. Comes in wider contact with the lower surface of the mold, and on the other hand, an upwardly convex thermal stress is generated, returning to the initial state. Thereafter, this cycle is repeated, and a sine curve wave is generated.

In order to prevent the occurrence of the waving phenomenon,
From the mechanism of occurrence of this waving phenomenon, it is necessary to equalize the contact of the slab to the upper and lower surfaces of the mold. Therefore, in order to prevent this waving, the top of the pass line roll must be placed above the horizontal line. , The area where the slab contacts the lower surface of the mold is approximately equal to the area where the slab contacts the upper surface of the mold, so that uniform heat removal from the upper and lower surfaces of the mold inner surface is achieved. Can solve it. In addition, the pass line angle θ that can prevent waving
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, the distance L ₁ between the pass line and the mold, the formula is satisfied in the range of 1000mm from 100 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, motor by determining the optimum path line angle theta ₁ which corresponds to the distance L ₁ between the pass line and the mold - on the field inside surface, it is possible to perform uniform heat extraction from the lower surface, the waviness can be prevented .

In addition to the above relationship, it is also possible to arrange the pass line roll at a fixed distance close to the mold. Moreover, the best distance between the pass line roll and the mold that can prevent the waving is related to the thickness and width of the slab, and the relational expression of L ₁ ≦ A × T / W (2) Exists. That is, Pasurainro - Le 4 and motor - and the distance between the shield 2 and L _1, the distance of the limit which does not cause waving L
₁ is proportional to the thickness T when the thickness T of the slab is in the range of 8 mm to 20 mm, and is inversely proportional to the width W when the width W is 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, the optimal Pasurainro corresponding to withdrawal cross-sectional size of the cast strip (width W × thickness T) - by determining the distance L ₁ of the limitations of the field mode - - Le of Mo on the field inside surface, from the lower surface Uniform heat removal can be performed, and waving can be prevented.

Further, in addition to the above relationship, the best inclination angle θ of the lower surface of the inner surface of the mold is the length L _{2 of} the mold in the drawing direction, the opening width t ₂ on the molten metal side, and the opening width t ₁ on the drawing side.
And 0.8 × 1/10 ³ ≦ tan θ = (t ₁ −
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 meeting this condition.
By using the field, the wave phenomenon does not occur further,
A thin cast piece can be cast stably.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventors have conducted various experiments and studies to prevent the slab from waving, and as a result,
It has been found that the upper and lower surfaces of the slab are unevenly removed in the mold, the mechanism of the occurrence is clarified by experiments, and a horizontal continuous casting method capable of preventing the waving phenomenon has been invented. Hereinafter, an experiment conducted on a horizontal continuous casting for a thin plate of a phosphor bronze alloy used as a spring material or the like for electric / electronic device parts by the horizontal continuous casting method according to the present invention will be described with reference to the drawings. FIG. 1 shows a horizontal continuous casting apparatus used in this experiment, in which a molten metal is cooled by a mold 2 attached to a holding furnace 1, and is particularly thinned by pinch rolls 5, 5a ( About 8-15mm)
The slab 7 is continuously pulled out in the horizontal direction, the slab having a required length is cut by a shear 6 and coiled by an upcoiler 8. A secondary cooling device 4 is provided between the mold 2 and the pinch rolls 5 and 5a to cool the high-temperature slab 7 coming out of the mold 2 to room temperature. And
1 mode - field 2 and the first Pasurainro - distance between Le 3 is displayed as L _1.

Next, a description will be given of the mechanism of the generation of the undulations clarified by this experiment with reference to FIGS. 2, 3 and 4. FIG. FIG. 2 shows a state immediately after the start of casting.
The casting time has elapsed from (a) to (d). (A)
, The molten metal 1a is removed by the mold upper surface 10, the mold lower surface 11 and the dummy bar 9, and solidifies. The solidified and shrunk slab 7 is molded on the mold lower surface 11 by gravity.
The contact area is wider than that of the upper surface 10 of the shield. And the heat removal from the slab lower surface 7b becomes larger than the heat removal from the slab upper surface 7a. As a result, as shown by the arrow P in FIG. As the casting time elapses, the slab 7 drawn out of the mold 2 is released from the restraint from the mold 2, the thermal stress is released, and an upwardly convex strain is generated. Due to this distortion, the mold upper surface 1
0 comes in wider contact than the lower surface 11 of the mold. The heat removal from the slab upper surface 7a is larger than the heat removal from the slab lower surface 7b. As a result, a downwardly protruding thermal stress is generated as shown by the arrow Q in (c). (D) shows a state in which the portion projecting above the slab 7 has reached the first pass line roll 3.

FIG. 3 shows the situation during the subsequent casting.
The casting time has elapsed from (a) to (d). As the time elapses, the wavy generated by the mechanism described with reference to FIG.
When the slab reaches the upper side, the cast slab contacts the mold lower surface 11 more widely, as shown in FIG. As the casting time elapses, the thermal stress is released outside the mold 2 with the elapse of the casting time, and an upward convex distortion is caused (b).
Then, the downwardly convex portion reaches the pass line roll 3, and the slab 7 comes into wide contact with the mold upper surface 10 as shown in FIG. 3C, and a downwardly convex thermal stress Q is generated. I do.
As the casting time elapses, the thermal stress is released outside the mold 2 with the elapse of the casting time, and the state returns to the state of FIG. Thereafter, this cycle is repeated, and a sine curve wave is generated.

Further, as shown in FIG. 4, when a plurality of pass line rolls are installed, if the pass line roll R closer to the mold is removed, the cast slab is bent downward by its own weight. . Due to this deflection, the slab 7 comes into wide 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, the slab 7 solidified and contracted in the mold 2 comes into wide contact with the lower surface 11 of the mold, and the slab 7 comes into wide contact with the lower surface 11 of the mold due to bending. Occur.

Considering the above-described mechanism of the generation of the waving, it can be understood that the occurrence of the waving can be prevented by making the contact of the slab to the upper and lower surfaces of the mold uniform. As a result of various studies of the method, the inventors raised the slab 7 by positioning the top of the pass line roll 3 above the horizontal line H as shown in FIG. It has been found that the area in which the slab contacts the lower surface 11 of the mold should be approximately equal to the area in 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 . This relationship is satisfied in the range result of the experiment, L ₁ from 100mm to 1000 mm, L ₁
Is outside this range, it has been found that the relationship of equation (1) does not always hold. 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-described method, it has been found that the first pass line roll should be disposed close to the mold. It has been found that the distance L ₁ between the first pass line roll and the mold that can prevent waving has a relationship of L ₁ ≦ A × T / W (2) with respect to the thickness and width of the slab. 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 at which no waving occurs is proportional to the thickness T of the slab 7 and inversely proportional to the width W. As a result of an experiment, it was found that this relationship was established when the width W was in the range of 350 mm to 1200 mm, and when the width W was not in this range, the relationship of the expression (2) was not necessarily established. In addition, the thickness T is established in the range of 8 mm to 20 mm.
It turns out that the relationship of the formulas does not always hold. In addition,
A is a constant determined by the metal, from 1 × 10 ⁴ to 5 × 10 ⁴
Was in the range.

Further, in addition to the above method, as shown in FIG. 7, the best inclination angle θ of the lower surface of the inner surface of the mode is the length L ₂ of the mold in the drawing direction, the opening width t ₂ on the molten metal side, and the opening width on the drawing side. 0.8 × 1/10 ³ ≦ tan θ between width t ₁
= (T ₁ −t ₂ ) / L ₂ ≦ 1.8 × 1/10 ³ As a result of experiments, it was found that the use of a mold having a lower surface with an inclination angle of θ made it possible to further undulate. Cast slab can be cast more stably. In this case, it is desirable that the upper surface 10 of the mold is horizontal, but it may be defined at a fixed angle.

[0022]

According to the present invention described above, the slab is lifted by positioning the top of the pass line roll above the horizontal line, and the area where the slab contacts the lower surface of the mold is brought into contact with the upper surface of the mold. In this case, the heat can be uniformly removed from the upper and lower surfaces of the inner surface of the mold, and the optimum pass line roll mold corresponding to the cross-sectional size of the thin cast slab can be obtained. mode by pulling the cast strip at a distance L ₁ of the limitations of the - above the field inside surface, it is possible to perform uniform heat extraction from the lower surface,
It is possible to completely prevent waving that occurs during horizontal continuous casting of a thin metal plate. In addition, by using a mold having an optimum inclination angle of the lower surface of the mold corresponding to the drawing cross-sectional size of the slab, casting a more stable thin-walled and wider slab without causing a waving phenomenon. Can be.

[Brief description of the drawings]

FIG. 1 is a process explanatory view of an embodiment of the present invention.

FIG. 2 is an explanatory view of a process in the present experiment.

FIG. 3 is an explanatory view of a process in this experiment.

FIG. 4 is an explanatory view of a process in this experiment.

FIG. 5 is a process cross-sectional view of this embodiment.

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

FIG. 7 is an explanatory view of a mold section of the present embodiment.

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

[Description of Signs] 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 face 7b Cast piece lower face 8 Up coiler 9 Dummy bar 10 Mold upper face 11 Mold lower face

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-320236 (JP, A) JP-A-5-169195 (JP, A) JP-A-5-69091 (JP, A) JP-A-4- 319058 (JP, A) JP-A-4-284946 (JP, A) JP-A-62-61758 (JP, A) JP-A-61-219445 (JP, A) JP-A-62-57740 (JP, A) JP-A-59-174257 (JP, A) JP-A-57-91846 (JP, A) JP-A-57-22853 (JP, A) JP-A-53-95828 (JP, A) (58) (Int.Cl. ⁷ , DB name) B22D 11/045 B22D 11/128

Claims (3)

(57) [Claims] 1. A horizontal continuous casting method for metal in which a molten metal is cooled by a mold provided in a holding furnace and a slab is continuously drawn, wherein a distance L ₁ between a pass line roll and the mold is 100 mm ≦ L. _In the case of ₁ ≦ 1000 mm, the relationship between the angle θ ₁ formed between the horizontal line and the straight line connecting the contact point of the slab and the pass line roll and the outlet of the lower surface of the mold and the distance L ₁ between the pass line roll and the mold is 0 <tan θ ₁ ≦ A ₁ ×
Horizontal continuous casting method of the metal, characterized in that withdrawing the cast piece by L ₁ and becomes conditions. However, A ₁ is 2.5 × 1/10 ⁵
Within the range of ≦ A ₁ ≦ 5.5 × 1/10 ⁵ , the constant is determined by the metal. 2. In a horizontal continuous casting method for a metal in which a molten metal is cooled by a mold provided in a holding furnace and a slab is continuously drawn, a position of a pass line roll closest to the mold (a distance from the mold). L ₁ ) and the section size (width W, thickness T) of the slab are 350 mm ≦ W ≦ 1200 mm,
In the case of 8mm ≦ T ≦ 20mm, claim 1 relationship between the distance L ₁ and the cross-sectional size of the slab from the mold, characterized in that pull the piece cast under the condition that the _{L 1 ≦ A 2 × T /} W A horizontal continuous casting method for a metal as described above. However, the above A ₂ is 1 × 10 ⁴
Within the range of ≦ A ₂ ≦ 5 × 10 ⁴ , the constant is determined by the metal. 3. A horizontal continuous casting method for a metal in which a molten metal is cooled by a mold provided in a holding furnace and a slab is continuously drawn out, wherein 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 of the mold in the drawing direction, the opening width t ₂ on the molten metal side, and the opening width t ₁ on the drawing side is 0.8 × 1/10 ³ ≦ ta.
^3. The horizontal continuity of a metal according to claim 1, wherein a mold that satisfies a condition of nθ = (t ₁ −t ₂ ) / L ₂ ≦ 1.8 × 1/10 ³ is used. Casting method.