JPH0694059B2 - Cooling mold for continuous casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of immersing a lower portion of a cooling mold having a vertically passing mold hole in a molten metal to allow the molten metal to penetrate from a lower opening of the mold hole. The present invention relates to a cooling mold used for pulling and continuous casting in which a pipe is formed by cooling from the periphery of a die hole and solidifying to continuously form a tubular body.

(Prior Art) The conventional cooling mold used in the pulling continuous casting apparatus is the third type.
As shown in the figure, a tubular liner (2) made of a material with high thermal conductivity and excellent heat resistance is attached to the center of the annular cooling jacket (11), and the outer periphery of the jacket (11) is fire-resistant. It is protected by a material layer (14).

The inner surface of the liner (2) is a mold cavity corresponding to the outer diameter of the tubular body (51) to be manufactured.

The cooling mold (1) has its upper part exposed from the molten metal surface and its lower part immersed in the molten metal (5) so that the molten metal enters from the lower opening of the mold cavity.

While cooling and solidifying the molten metal (5) along the mold cavity with the cooling water in the cooling jacket (11) surrounding the mold cavity, the solidified layer is successively pulled up by a pulling device (6) such as a pinch roller, The body (51) is continuously cast.

(Problems to be Solved by the Invention) As described above, the pipe body (51) solidifies the molten metal (5) to a strength sufficient to withstand the pulling force and pulls it up. The position of the starting point was not constant, which caused a problem that the wall thickness of the casting pipe body (51) became uneven.

The present invention has the same height position of the freezing point in the liner,
It is intended to clarify a casting continuous casting mold that can solve the above problems.

(Means for Solving the Problem) A cooling mold for pulling casting according to the present invention includes a tubular liner (2) formed of a material having high heat conductivity and excellent heat resistance inside an annular cooling jacket (11). In a cooling casting mold for pulling up continuous casting, in which the cooling jacket (11) is protected by the refractory layer (14), the lower end of the liner (2) has excellent heat resistance and a higher thermal conductivity than the liner. A nozzle (3) made of a small material is projected below the cooling jacket (11), and a liner (2) is provided on the outer periphery of the upper end of the nozzle (3).
The lower part of is fitted.

(Operation and effect) The molten metal (5) that has penetrated into the liner (2) through the lower opening of the nozzle (3) contacts the liner and is cooled and solidified, and the solidified layer is successively pulled up by a pulling device to form a pipe ( 51) is formed.

Since the nozzle (3) is made of a material having low thermal conductivity and is located below the cooling jacket (11), it is hardly affected by the cooling action of the cooling jacket (11) and the molten metal (5) ) Is kept at about the same temperature. Therefore, the molten metal (5) does not solidify in the nozzle (3), and the molten metal (5) is rapidly cooled in contact with the liner (2) in the vicinity of the boundary between the nozzle (3) and the liner (2) to start solidification. As a result, the heights of the freezing points of the molten metal (5) in the cooling mold (1) are aligned, and a casting pipe body (51) having a uniform and constant thickness can be manufactured.

Further, since the lower end of the liner (2) is fitted on the outer periphery of the upper surface of the nozzle (3), the so-called molten metal (5) is inserted into the fine fitting gap between the nozzle (3) and the liner (2). Even if a crack occurs, the gap is formed along the axis, so that the pulling up of the casting pipe (51) does not become a great resistance, and the pulling up of the pipe (51) can be achieved smoothly. Can be prevented from hanging or cracking.

(Example) FIG. 1 shows a cooling mold (1) of the present invention. The cooling mold (1) encloses a copper cylindrical mold (12) with an annular cooling jacket (11), and a jacket. The outer periphery of (11) is protected by a refractory layer (14).

A water chamber (13) filled with cooling water is formed inside the cooling jacket (11).

A cylindrical liner (2) made of a material having excellent heat conductivity and heat resistance such as copper and graphite in the mold (12)
And the upper and lower ends of the liner (2) penetrate the refractory layer (14) to reach the upper and lower surfaces of the mold (1).

A step portion (21) having a small diameter is formed on the outer circumference of the lower end of the liner (2), and the step portion (21) is provided with a screw surface (22).

To the lower end of the liner (2), a nozzle (3) made of a material having higher heat resistance and smaller thermal conductivity than the liner (2) is connected.

The inner diameter and outer diameter of the nozzle (3) are smaller than that of the liner (2).

A small-diameter step portion (31) is formed on the outer peripheral portion of the upper end of the nozzle (3), and a tapered surface (33) is formed on the inner peripheral portion of the upper end that gradually expands at an inclination of 30 to 60 °.

On the outer circumference of the nozzle (3), a screw surface (32) is provided on the lower outer circumference of the small diameter step (31).

The small diameter part of the nozzle (3) is fitted to the lower end of the liner (2), and the connection ring (is straddled over the thread surface (22) of the liner (2) and the thread surface (32) of the nozzle (3). 4) is screwed to connect both.

However, the cooling mold (1) is immersed in the molten metal (5) to such a depth that the molten metal surface reaches the upper part of the liner (2).

The molten metal (5) that has entered the liner (2) through the lower opening of the nozzle (3) is cooled by the contact with the liner (2) and solidifies, and the solidified layer is successively pulled up by a pulling device and the tubular body (51). Is formed.

Since the nozzle (3) is made of a material having low thermal conductivity and is located below the cooling jacket (11), the nozzle (3) hardly receives the cooling action of the cooling jacket (11) and the molten metal (5 ) Is kept at about the same temperature. Therefore, the molten metal (5) does not solidify inside the nozzle (3), and the molten metal (5) starts to solidify near the boundary between the nozzle (3) and the liner (2). Thereby, the molten metal (5) in the cooling mold (1)
The height position of the freezing point of the
1) can be manufactured.

Further, since the lower end of the liner (2) is fitted on the outer periphery of the upper surface of the nozzle (3), the so-called molten metal (5) is inserted into the fine fitting gap between the nozzle (3) and the liner (2). Even if occurs, since the gap is formed along the axis, there is not a large resistance to the pulling up of the casting pipe body (51), and the smooth pulling up of the pipe body (51) can be achieved. It can prevent the layers from hanging or cracking.

Further, the upper end of the inner surface of the nozzle (3) is formed into a taper surface (33) which is inclined outwardly, and the width of the annular flat surface at the upper end of the nozzle (3) is reduced, so that the nozzle (3) and the liner (2) are reduced. It is possible to prevent a so-called hot water boundary in which the flow of the hot water to the corner formed in the corner is smooth and the flow of the hot water to the corner becomes poor, so that a ring-shaped recess is formed on the outer circumference of the casting pipe body (51). .

In the above example, cooling mold liner (copper) inner diameter 62mm liner thickness 10mm liner effective length (excluding screw) 270mm nozzle (boron nitride) inner diameter 40mm nozzle outer diameter 70mm nozzle length 70mm Casting condition Molten metal composition (HK40) Molten metal temperature 1450 ℃ Pipe pulling speed 600mm / min. Produced pipe The outer diameter of the pipe was 60mm, and the wall thickness was 10mm.

FIG. 2 shows another embodiment of the cooling mold (1),
An inner screw surface (23) is formed at the lower end of the liner (2), and a nozzle (3) is directly screwed to the inner screw surface (23) to connect them.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a cooling mold of the present invention, FIG. 2 is a sectional view of a cooling mold of another embodiment, and FIG. 3 is a sectional view of a conventional cooling mold. (1) …… Cooling mold, (2) …… Liner (3) …… Nozzle

Claims (1)

[Claims] 1. A tubular liner (2) made of a material having high thermal conductivity and excellent heat resistance is mounted inside an annular water cooling jacket (11), and the cooling jacket (11) is provided with a refractory layer. In the cooling mold for pulling continuous casting protected by (14), a nozzle (3) made of a material having excellent heat resistance and a smaller thermal conductivity than the liner is provided at the lower end of the liner (2) as a cooling jacket. A cooling mold for pulling continuous casting, which is provided so as to project below the (11), and the lower portion of the liner (2) is fitted on the outer peripheral portion of the upper end of the nozzle (3).