JPH07164110A - Production of nonuniform thickness pipe by draw-up continuous casting method and cooling mold therefor - Google Patents

Abstract

PURPOSE:To form a nonuniform thickness pipe having uniform outer diameter by using a draw-up continuous casting. CONSTITUTION:A cooling mold surrounding the outer periphery of a heat resistant sleeve 2 forming a mold hole 20 vertically penetrated with a cooling jacket 3 is exposed from molten metal surface at the upper part and dipped into the molten metal at the lower part to invade the molten metal into the mold hole 20, and a molten metal solidified layer 61 solidified by contacting with the mold hole 20 is drawn up to continuously cast the pipe 6. The cooling jacket 3 is divided into plural water chambers 32, 33, 34, 35 in the peripheral direction with partition plates 30 and the cooling mold arranging a water supplying hole 37 and a water draining hole 38 in each water chamber 32, 33, 34, 35, is used. Further, the cooling mold having the high part and the low part of cooling capacity so as to interpose the mold hole 20 by varying the flow speed of the cooling water in each water chamber 32-35 therein, is used. The high cooling capacity part is formed to the thick thickness and the low cooling capacity part to the thin thickness in the mold and thus, the nonuniform thickness pipe having uniform outer diameter can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an uneven wall thickness tube which has a uniform outer diameter and can be made thick or thin at a required portion by pulling and continuous casting and is optimal as a material for a bend tube, and a cooling mold therefor. It is a thing.

[0002]

2. Description of the Related Art Heretofore, it has been proposed to manufacture a pipe by a pulling continuous casting method. Pull-up continuous casting method, a cooling mold having a mold hole penetrating vertically,
The upper part is exposed from the surface of the molten metal, the lower part is immersed in the molten metal to enter the molten metal into the mold cavity, and the molten metal solidified layer that is in contact with the mold cavity is pulled up to continuously cast a pipe. The cooling mold is formed by surrounding the outer circumference of the heat resistant sleeve with a cooling jacket.

In the above conventional cooling mold, the cooling capacity is the same over the entire circumference of the mold cavity, and therefore, the wall thickness of the cast tube is uniform. However, as shown in FIG. 4, when producing a bend pipe by high-frequency bending of a pipe that is continuously cast by pulling,
As shown in Fig. 4, the tensile side part during bending is thinned,
The compression side is thickened. Therefore, a bend pipe manufactured by high-frequency bending a pipe having a uniform wall thickness may be out of the standard with respect to the specified wall thickness dimension.

Therefore, the pipe as a material of the bend pipe must be formed such that the wall thickness of the pipe is thick on the tensile side of the portion to be bent and thin on the compression side.
It was not possible to form the tube with uneven thickness. INDUSTRIAL APPLICABILITY The present invention clarifies a continuous pull-up continuous casting method for a true pipe and a cooling mold thereof, which can form a thick or thin wall portion at any portion of the pipe and is suitable as a material for a bend pipe.

[0005]

The cooling mold (1) of the present invention is a continuous pull-up casting in which a cooling jacket (3) surrounds the outer circumference of a heat-resistant sleeve (2) having a mold hole (20) penetrating vertically. In the cooling mold (1) for cooling, the cooling jacket (3) is a partition plate.
It is divided into a plurality of water chambers in the circumferential direction by (30), and each water chamber is provided with a water supply port (37) and a drain port (38).

Further, in the continuous casting method of the present invention, the cooling mold (1) is allowed to come out from the surface of the molten metal at the upper part, and the lower part is immersed in the molten metal so that the molten metal enters the mold cavity (20) to cool it. Cooling mold (1) where the high cooling capacity and the low cooling capacity are opposed to each other across the mold cavity by changing the flow velocity of the cooling water in each water chamber (32) (33) (34) (35) of the mold ) Is used to form a thick portion in the cooling mold (1) having a high cooling capacity and a thin portion in the cooling mold (1) to manufacture an uneven thickness pipe.

[0007]

FUNCTION AND EFFECT The solidification rate is high and the solidified layer is thick in the high cooling capacity of the cooling mold (1). On the other hand, the solidification layer becomes thin in the portion having low cooling ability and the solidification layer becomes thin.

The portion where the solidification rate is high and the solidification layer is thick becomes the thick portion of the pipe (6), and the portion where the solidification rate is slow and the solidification layer is thin becomes the thin portion of the pipe (6). . Mold hole (2
(0) is sandwiched between the low cooling part and the high cooling part, so the thick part (6a) and the thin part (6b) are located at opposite positions on the diameter line.
It is possible to form an uneven thickness pipe in which and face each other.

The water chambers (32) (33) (34) (3) of the cooling mold (1)
If the flow velocity of the cooling water in 5) is the same, the cooling capacity will be the same over the entire circumference of the mold cavity (20), and a tube of uniform wall thickness can be formed. Therefore, by controlling the amount of water supplied to each of the water chambers (32) (33) (34) (35), when casting the pipe as the material of the bend pipe, the compression side of the bend target part of the bend pipe is thin. In addition, it is possible to easily and continuously manufacture a pipe having a thick wall on the pulling side, and a part other than the bending target portion having an intermediate thickness between the wall thickness on the compression side and the wall thickness on the pulling side. By cutting this pipe at a portion other than the portion to be bent, using this material as a material, and bending it as shown in FIG. 3, it is possible to form a bend pipe having a uniform wall thickness over the entire length.

[0010]

EXAMPLE FIG. 1 shows the state of implementation of continuous pull-up casting. The cooling mold for continuous casting (1) is a cylindrical sleeve.
Surrounding (2) with cooling jacket (3), cooling jacket
(3) is protected by a refractory layer (4).

The sleeve (2) is made of a ceramic heat-resistant material such as graphite or boron nitride, and has an inner surface serving as a die hole (20) vertically penetrating therethrough. The inner wall (31) of the cooling jacket (3), which is in contact with the outer surface of the sleeve (2), is made of copper having good thermal conductivity. The inside of the cooling jacket (3) is divided into a plurality of water chambers by the partition plate (30) in the circumferential direction, and in the embodiment, four water chambers (32) (33) (34) (35) of the same size. ing.

The water chambers (32), (33), (34) and (35) are provided with a baffle plate (36) hanging from the upper part to the lower part, and the water chambers (32) (33)
(34) and (35) are provided with a water supply port (37) below the upper end of the baffle plate (36) and a drainage port (38) above, and each water supply port (37) has a flow control valve (39). ) Is connected to the pump (8).

Each flow control valve (39) is connected to the control device (9). A pulling device (5) is arranged above the sleeve (2) of the cooling mold (1). Example of lifting device (5)
Is constructed by disposing a pair of pinch rollers (51) (51) with the pulling transition path of the pipe (6) interposed therebetween.

Then, the cooling mold (1) is immersed in the molten metal (7) to such a depth that the molten metal surface reaches near the upper half of the sleeve (2). Of the water chambers (32) (33) (34) (35) of the cooling mold (1), one set of water chambers (32) (34) facing each other has a unit time A large amount of cooling water is supplied to the other water chamber (34), and an intermediate amount of cooling water is supplied to the other two water chambers (33) and (35).

Water chamber with a large supply of cooling water per unit time
The amount of drainage of the (32) from the drainage port (38) increases accordingly, that is, the flow velocity increases and the cooling capacity increases. On the contrary, the water chamber (34) with a small amount of cooling water supplied per unit time
The flow velocity becomes slow and the cooling capacity becomes low. That is, the cooling mold
In (1), a portion having a high cooling ability, an intermediate portion, a low portion, and an intermediate portion are present in this order in the circumferential direction, and the high portion and the low portion face each other with the mold cavity (20) interposed therebetween.

A starting rod (not shown) is inserted into the mold cavity (20) from above the cooling mold (1), waits for the molten metal on the upper part of the mold cavity to solidify, and the pulling device (5) moves the starting rod. Pull up. The molten metal solidification layer (61) which is cooled and solidified in contact with the die hole (20) is pulled up together with the starting rod.

In the high cooling capacity portion of the cooling mold (1), the solidification rate is high and the solidification layer is thick. On the other hand, the solidification layer becomes thin in the portion having low cooling ability and the solidification layer becomes thin.

The portion where the solidification rate is fast and the thickened solidification layer is formed becomes the thick portion of the pipe (6), and the portion where the solidification rate is slow and along the solidification is thin becomes the thin portion of the pipe (6). . Mold cavity
Since the low cooling part and the high cooling part face each other across the (20), the thick part (6a) and the thin part (6a)
It is possible to form an eccentric wall tube that is opposed to b).

If the flow velocity of the cooling water in each of the water chambers (32), (33), (34) and (35) of the cooling mold (1) is made the same, the cooling capacity is maintained over the entire circumference of the mold cavity (20). It becomes the same and can form a tube with a uniform wall thickness.

Therefore, each flow rate adjusting valve is controlled by the controller (9).
By operating (37) to control the amount of water supplied to each water chamber (32) (33) (34) (35), when casting the pipe as the material of the bend pipe, The compression side is thin, the tension side is thick, and the part other than the part to be bent is an intermediate thickness between the compression side thickness and the tension side thickness. Can be manufactured.

By cutting this pipe at a portion other than the portion to be bent, using this as a material, and bending it, a bend pipe having a uniform wall thickness can be formed over the entire length. The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a continuous casting state.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view of an uneven thickness straight pipe and a bend pipe thereof manufactured according to the present invention.

FIG. 4 shows a normal straight pipe and its bend pipe.

[Explanation of symbols]

 (1) Cooling mold (2) Sleeve (3) Cooling jacket (32) Water chamber (34) Water chamber

Claims (2)

[Claims] 1. A cooling mold (1) for continuous casting in which a heat-resistant sleeve (2) having a mold hole (20) penetrating vertically is surrounded by a cooling jacket (3). (3) has a plurality of water chambers (3
2) A cooling mold which is divided into (33), (34) and (35), and each water chamber is provided with a water supply port (37) and a drainage port (38). 2. A cooling mold in which the outer circumference of a heat-resistant sleeve (2) having a vertically passing mold hole (20) is surrounded by a cooling jacket (3), the upper part is exposed from the molten metal surface, and the lower part is In a continuous pulling casting method in which the molten metal is immersed in the molten metal to enter the mold cavity (20) and the molten metal solidified layer (61) which is in contact with the mold cavity (20) is pulled up to continuously cast the pipe (6), Cooling jacket (3)
Is divided into a plurality of water chambers (32) (33) (34) (35) in the circumferential direction,
Using a cooling mold (1) in which a water inlet (37) and a drainage port (38) are provided in each water chamber (32) (33) (34) (35), the cooling water in each water chamber of the cooling mold is used. Using a cooling mold (1) in which a high cooling capacity portion and a low cooling capacity portion face each other across the mold hole (20) with different flow speeds, the cooling mold portion (1) having a high cooling capacity is thick, A method for manufacturing an uneven wall thickness tube with a uniform outer diameter by forming the part with low cooling capacity thin.