JPH0636971B2 - Twin belt type continuous casting machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a twin belt type continuous casting apparatus for producing a thin metal body while accurately maintaining a reference surface of a short side mold.

[Conventional technology]

Recently, from molten metal such as molten steel, several mm to several tens, which is close to the final shape
A continuous casting method for directly producing a metal ribbon having a thickness of about mm has attracted attention. According to this method, the rolling process in multiple stages as in the prior art can be omitted, so that the process and equipment can be simplified. In addition, since the step of heating the material to the processing temperature between each step is essentially unnecessary, an energy saving effect can be expected.
One of such continuous castings is a twin belt system.

FIG. 3 is a diagram showing an outline of this twin belt type continuous casting machine. In this continuous casting machine, the molten metal in the tundish 1 is supplied from the nozzle 2 to the casting space. This casting space is formed by partitioning opposite sides of a pair of belts 4 made of a heat-resistant material such as steel running around the pulley 3 with a short side casting die (not shown). ing. The molten metal poured into this casting space is
It is cooled and solidified by the cooling box 6 to be carried out as a thin metal strip 7.

[Problems to be solved by the invention]

The molten metal injected into the casting space is cooled and solidified by heat removal via the belt 4, and shrinks in the process of being carried out as the metal ribbon 7. This contraction also occurs in the width direction of the belt 4. Therefore, the short-side mold 5 that was in contact with both ends of the molten metal at the upper part of the molten metal pool forms a gap between the both ends of the solidified shell or the metal ribbon 7 as it goes downward.

As a result, when viewed from the metal thin body 7 which is a cast piece, the contact with the short side mold becomes insufficient, and heat removal is insufficient, so that the required shell thickness cannot be obtained. Such a shell easily breaks in the mold or on the exit side of the mold, and unmelted molten metal blows off, which causes double skin on the metal ribbon 7. Further, when the blowout of the molten metal is extreme, a breakout occurs and the operation becomes impossible.

On the other hand, in the movable short-side mold, as shown in FIG. 4, the cooling block 5a is connected by the link 5b, and the roll 9 provided at the tip of the link 5b along the guide rail 8 and on the wide surface side. The belt 4 is rotated substantially synchronously while being sandwiched between the belts. The relationship between the guide rail 8 and the roll 9 is to prevent a lock phenomenon from occurring when a small amount of dust or the like enters between them, as shown in FIG. It is provided or only one side receives the force as shown in FIG. Therefore, as described above, when the solidified shell contracts or the surface of the block 5a thermally expands and rises, an appropriate contact state with the solidified shell cannot be obtained, and the manufactured metal ribbon 7 is not obtained. Appears as defects such as poor surface quality and breakout.

Therefore, the present invention, by inclining the short-side mold to be fed into the casting space, cancels the gap caused by the shrinkage of the solidified shell or the metal ribbon, and further, the short-side mold is always operated by the thrust force acting from the belt in the width expansion direction. By pressing on the guide rail, while securing the reference surface of the short side mold,
The aim is to produce metal ribbons under stable conditions.

[Means for solving problems]

The twin-belt type continuous casting apparatus of the present invention, in order to achieve the object, in a continuous casting apparatus for cooling and solidifying the molten metal injected into the molten metal pool between the pair of belts to produce a metal ribbon, A short-sided mold partitioning both ends of the hot water pool portion is arranged so as to be able to travel along a conveyance path in which a mutual gap becomes narrower downward, and the short-sided mold running on the rear side of the short-sided mold. It is characterized in that a guide rail for supporting is provided.

〔Example〕

Hereinafter, the features of the present invention will be specifically described by way of examples with reference to the drawings.

1 and 2 show the running state of the short side mold in the embodiment of the present invention. Since the entire apparatus is an improvement of the twin-belt type continuous casting machine shown in FIGS. 3 and 4, the reference numerals of FIGS. 3 and 4 are appropriately used in the following description. There is.

In this embodiment, the conveying path of the short-side mold 5 that partitions the both ends of the molten metal pool is inclined toward the center of the belt 4. That is, the short side molds 5 arranged at both ends of the belt 4 have a narrower mutual gap toward the lower part. A guide rail 8 is arranged on the rear side of the short-side mold 5, and a roll 9 provided on the short-side mold 5 rolls on the guide rail 8.

In this way, when the conveyance path of the short-side mold 5 is inclined, it is possible to follow the contraction of the metal ribbon 7 in the width direction and obtain good contact of the short-side mold 5. Then, as the belt 4 and the short side mold 5 move downward as indicated by the arrow X, slippage occurs between the belt 4 and the short side mold 5. Therefore, as shown in FIG.
From the short side mold 5. Since this force F pushes the short side mold 5 outward, the roll 9 is pressed against the guide rail 8.

That is, the conventional short-sided mold 5 is premised on that the short-sided mold 5 is cooled by being brought into contact with the short-sided mold 5 by bulging by the pressure of the molten metal or the solidified shell inside.
The position was decided so that they would run in parallel. Therefore, when the solidified shell or the metal ribbon 7 contracts, the internal pressure is not applied to the short-side mold 5, the running state of the short-side mold 5 becomes unstable, and the contact heat removal becomes unstable. . On the other hand, in the present embodiment, the force F due to the slip between the belt 4 and the short side mold 5
Since the short-side mold 5 is pressed against the guide rails 8, the short-side mold 5 is always maintained under stable conditions regardless of contraction and pressure of the solidified shell or the metal ribbon 7. it can.

Therefore, the reference surface of the short-sided mold 5 can be kept constant with an appropriate gradient, and the short-sided mold 5 is compressed by the bulging force without excessively compressing the solidified shell against the contraction of the slab. The heat can be removed by contacting the block 5a of.

The inclination angle θ of the conveying path of the short side mold 5 with respect to the conveying direction X of the belt 4 is determined as follows. That is, in FIG. 2, when the inlet width between the pair of short side molds 5 is W _i and the outlet width is W ₀ , the outlet width W ₀ is represented by the following equation.

W ₀ = W _i × {1-λ (T _si .T _s0 )} where λ: thermal expansion coefficient T _si : solidification temperature T _s0 : outlet surface temperature Therefore, the width reduction amount ΔW (W _i −W ₀ ) is , ΔW = W _i λ (T _si −T _s0 ). Therefore, the inclination angle θ of the conveying path of the short side mold 5
Is expressed by the following equation, where l is the length of the casting region.

0 <θ ≦ tan ⁻¹ {W _i λ (T _si −T _s0 ) / 2l} This inclination angle θ is maintained in the range of 0.05 to 0.2 degrees when steel is continuously cast by a belt type continuous casting machine. It is preferable.

〔The invention's effect〕

As described above, in the present invention, the outward force is exerted on the short side mold by inclining the conveyance path of the short side mold with respect to the belt conveying direction. Therefore, the short side mold always travels in a state of being pressed by the guide rail regardless of the gap between the short side mold and the solidified shell or the metal ribbon contracted in the casting space. Therefore, the reference surface of the short side mold is kept constant, and the casting operation can be performed under stable conditions.

[Brief description of drawings]

FIG. 1 shows the state of conveyance of the short-side mold in the embodiment of the present invention, and FIG. 2 is a diagram for explaining the force applied to the short-side mold at that time. On the other hand, FIG. 3 shows a conventional twin belt type continuous casting machine, and FIG. 4 is an explanatory view of a conventional countermeasure method against a locking phenomenon in a movable short side mold.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuhiro Maeda 1 Nishinosu, Oita-shi, Oita Pref.Nippon Steel Co., Ltd. Oita Works (72) Noriyuki Kanai 1 Nishinosu, Oita-shi, Oita Pref. Oita Steel Works, Steel Works Co., Ltd.

Claims (1)

[Claims] 1. A continuous casting apparatus for producing a thin metal strip by cooling and solidifying a molten metal injected into a basin between a pair of belts, and a short side mold partitioning both ends of the basin is downwardly moved. Twin belts, which are arranged so as to be able to travel along a conveyance path in which a mutual gap becomes narrower toward each other, and a guide rail for supporting the traveling short-side mold is provided behind the short-side mold. Type continuous casting equipment.