JPH0716765B2 - Pull-up casting equipment and method of adjusting molten metal height in pull-up casting - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pull-up casting apparatus and a method for adjusting a molten metal level with respect to a cooling mold of the apparatus.

(Prior Art) In the conventional pull-up casting, as shown in FIG. 7, the upper part of the cooling mold (2) is exposed from the surface of the molten metal, and the lower part of the mold is immersed in the molten metal (9) to form the mold. The molten metal (9) is introduced into the die hole (21) through the lower opening of the hole (21).

The starting rod (90) is inserted into the mold hole (2) from above the cooling mold (2), and the shaft (91) protruding from the lower end of the rod is made to adhere to the molten metal (9) to form the mold hole (21). ) Wait for solidification of the outer circumference, and pull up the starting rod (90).

When the solidified layer (92) is pulled up to a certain height, the pulling up is interrupted and the next solidified layer is formed in the mold cavity.

By intermittently repeating the pulling up of the solidified layer in this manner, a tubular body in which the tubular solidified layer is connected can be continuously formed.

In the above-mentioned pull-up casting, in order that the solidified layer (92) can be stably formed, the mold cavity (21) and the molten metal (9) in contact with the mold cavity should be secured for a relatively stationary time. Therefore, the cast pipe is pulled up intermittently for this reason.

Further, when manufacturing a tubular body having a uniform wall thickness by pulling casting, it is important to keep the height of the molten metal surface with respect to the mold cavity (21) constant.

The wall thickness of the solidification layer (92) increases as the time during which the molten metal is in contact with the mold cavity (21) is longer, that is, the higher the level of the molten metal in the mold cavity (21). Further, the shorter the time of contact with the die cavity (21), that is, the lower the level of the molten metal in the die cavity (21), the smaller.

Since the amount of molten metal gradually decreases as the casting progresses, there are the following four means and their applications in order to keep the height of the molten metal surface to the mold cavity (21) constant. Correspondingly done.

First means As shown in FIG. 3, a molten metal supply furnace (11) is connected to the molten metal storage furnace (1), and the molten metal supply furnace (11) moves from the molten metal storage furnace (11) in accordance with the decrease of the molten metal (9). Supply molten metal (9) to 1),
The height of the molten metal in the supply furnace (1) is kept constant.

Second means As shown in FIG. 4, the height position of the cooling mold (2) is fixed, and the molten metal containing furnace (1) is raised in accordance with the decrease of the molten metal (9). Keep the surface level constant.

Third Means As shown in FIG. 5, an auxiliary holding furnace (12) is provided in communication with the molten metal holding furnace (1), and a refractory mass (13) is hung up and down in the auxiliary holding furnace (12) to raise and lower the refractory mass. By adjusting the amount of immersion of (13) in the auxiliary storage furnace (12), the height of the molten metal in the storage furnace (1) is kept constant.

Fourth Means As shown in FIG. 6, a pressurizing chamber (14) is provided in communication with the molten metal storage furnace (1), and the pressure in the pressurizing chamber is adjusted by the pressurizing pump (15), so that the storage furnace (1 ) Keep the surface level constant.

(Problems to be Solved by the Invention) All of the above-mentioned four means require large-scale equipment,
Further, a device for detecting the level of the molten metal is required, and the device for detecting the level of the molten metal is extremely expensive and there is a problem that equipment cost rises.

INDUSTRIAL APPLICABILITY The present invention maintains a constant relative height of the molten metal surface with respect to the cooling mold and a pull-up casting device capable of detecting the molten metal surface height of the molten metal (9) with respect to the mold cavity (21) of the cooling mold (2). This is to clarify the method of adjusting the height of the molten metal surface.

(Means for Solving the Problem) The pulling-up casting apparatus of the present invention has a mold hole (21) that penetrates vertically.
The cooling mold (2) having the above is suspended and supported by the suspension frame (4), the lower part of the cooling mold is immersed in the molten metal (9) in the molten metal storage furnace (1), and the lower part of the mold cavity (21). In a pull-up casting apparatus for injecting a molten metal (9) through an opening and cooling and solidifying the molten metal (9) to pull up a solidified layer to form a tubular body, a portion of a frame (4) on which a load of a mold acts is applied. A load detector (8) for converting a change in load into an electric signal is provided and configured.

Further, in the method of adjusting the height of the molten metal surface in the pulling casting, the cooling mold (2) having the mold hole (21) penetrating up and down is supported on the lifting / lowering stand (5), and the lower part of the cooling mold is held in the molten metal storage furnace. The molten metal (9) in (1) is immersed in the molten metal (9) through the lower opening of the mold cavity (21), and the molten metal (9) is cooled and solidified while the solidified layer is pulled up to form a tubular body. In pull-up casting, a load detector (8) for converting a load change into an electric signal is provided at a portion of the frame (4) on which the load of the mold is applied, and the molten metal (9 ) Corresponding to the decrease of the buoyancy against the cooling mold (2) and the change of the electric signal of the load detector (8) due to the decrease of the buoyancy.
4) is operated and the cooling mold (2) is lowered to maintain a constant molten metal level relative to the cooling mold (2).

[Action and effect]

As the molten metal (9) decreases, the molten metal surface lowers, the buoyancy with respect to the cooling mold (2) decreases, and the electric signal output from the load detector (8) changes. Therefore, the change in the electric signal causes the molten metal surface to change. The height can be detected.

In addition, the elevating drive device (44) is activated in response to the lowering of the molten metal surface to lower the cooling mold (2), so that the mold cavity (2
It is possible to maintain a constant bath level for 1).

By intermittently lowering the mold in synchronization with the pulling operation and stopping of the molten metal solidification layer (91), the relative stationary time of the solidification layer (91) and the cooling mold (2) can be secured, and casting with a substantially uniform thickness is achieved. Can form a tube.

(Example) As shown in FIG. 1, a molten metal storage furnace (1) is provided on a base (3), and a cooling mold (2) is suspended and supported in the furnace.
The lower part of the mold is immersed in the molten metal, and the upper part is exposed.

The frame (4) for suspending the cooling mold (2) is provided with vertical columns (41) on the base (3) at four symmetrical positions around the cooling mold (2), and a rectangular shape is provided between the upper ends of the columns. It is formed by connecting with the frame body (42).

Inside each pillar, a rotary screw shaft (43) is arranged vertically, and across the rotary screw shafts (43), a hanging stand (5) is arranged so that it can be raised and lowered. A through hole (53) is formed in the central portion to allow passage of the cast pipe.

The cooling mold (2) is a suspension table in which the axial center of the through hole (53) and the axial center of the mold hole of the mold are aligned with each other via four load detectors (8) for converting a change in load into an electric signal. It is suspended and supported by (5).

The load detector (8) is a known one such as a load cell and a strain gauge that converts a load change into a voltage change, and the screw shaft (81) protruding above and below the detector (8) is cooled by a mold. The cooling mold (2) is suspended and supported on the suspension base (5) by being screwed onto the (2) and the elevating suspension base (5).

Each load detector (8) is connected to a control device (82), and the control device (82) is connected to a lifting platform elevating drive device (44) described later.

The lifting / lowering stand (5) has screw holes (51) at the four corners,
The rotary screw shaft (43) is screwed into the screw hole (51).

The four rotary screw shafts (43) are connected to one motor (44) at the upper part of the frame (4) via a rotation transmission means (45), and the forward rotation of the motors causes the lifting / lowering stand. (5) is rotated all at once in the direction of raising it, and by the reverse rotation of the motor, it is rotated all at once in the direction of lowering the lifting / lowering platform (5).

A pulling device (7) for pulling up the casting pipe is arranged in the center of the frame (4), and the pulling device sandwiches the pulling transition path of the casting pipe and a pair of pinch rollers (71).
(71) are arranged opposite to each other, and the drive motor (7
2) are connected to each other, and an intermittent drive setting device (not shown) is connected to the drive motor (72) so that the stop time and the operation time can be arbitrarily set to repeat the motion stop.

However, the starting rod (90) is inserted into the mold hole (2) from above the cooling mold (2), the molten metal (9) is attached to the lower end of the rod, and the solidification of the outer peripheral portion in the mold hole (21) is performed. Wait, pull up the starting rod for a certain amount of time, then stop.

While pulling up the starten rod (90) is stopped,
There is no change in the height of the molten metal surface, the mold cavity (21) and the molten metal (9) are relatively stationary, and the molten metal (9) is absorbed in the mold cavity (21) by the heat taken by the cooling mold (2). Cools and solidifies along.

When the starting rod (90) is pulled up for a certain period of time after a certain period of time, the solidified layer (91) is pulled up together.

When the solidified layer (92) is pulled up, the molten metal surface is lowered corresponding to the thickness and the pulled length, but as the molten metal surface is lowered, the buoyancy against the cooling mold (2) becomes smaller and the load detector. The electric signal output from (8) changes. As a result, the control device (82) operates and the motor (4
4) operates, the cooling mold (2) descends, and the relative height of the molten metal surface relative to the mold cavity (21) can be kept constant.

By intermittently lowering the mold in synchronism with the pulling up and stopping of the molten metal solidification layer (92), the relative rest time of the solidification layer (92) and the cooling mold (2) can be secured, and casting with a substantially uniform thickness is achieved. Can form a tube.

In carrying out the present invention, for example, a stone gauge is attached to a portion of the cooling mold, such as the suspension table (5) and the rotary screw shaft (43), on which the load of the cooling mold acts, so as to reduce the buoyancy force against the cooling mold corresponding to the decrease in the molten metal. It is also possible to control the height of the molten metal surface by detecting the strain of the strain gauge.

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 perspective view of a pull-up casting apparatus used in the present invention, FIG. 2 is a sectional view of the same apparatus, FIG. 3, FIG. 4, FIG. 5, FIG. 6 and FIG. It is a figure. (1) ... Molten metal storage furnace, (2) ... Cooling mold (3) ... Base, (4) ... Frame (8) ... Load detector

Claims (2)

[Claims] A cooling mold (2) having a mold hole (21) penetrating up and down is hung and supported by a hanging frame (4), and the lower part of the cooling mold is melted in a molten metal storage furnace (1) ( 9) so that the molten metal (9) penetrates through the lower opening of the mold cavity (21),
In a pull-up casting apparatus for pulling up a solidified layer while cooling and solidifying the molten metal (9) to form a tubular body, a change in the load is converted into an electric signal in a portion on the frame (4) on which the load of the mold acts. A pulling casting machine equipped with a load detector (8). 2. A cooling mold (2) having a mold hole (21) penetrating up and down is supported on a lifting / lowering platform (5), and the lower part of the cooling mold is placed on the molten metal (9) in the molten metal storage furnace (1). A frame (4) in pull-up casting in which a molten metal (9) is dipped into the molten metal (9) through the lower opening of the mold hole (21) to solidify the molten metal (9) while pulling up a solidified layer to form a tubular body. A load detector (8) for converting a load change into an electric signal is provided in a portion of the upper mold where the load acts, and a cooling mold (2) corresponding to the decrease of the molten metal (9) accompanying the progress of casting of the pipe body (2). Relative to the cooling mold (2) by actuating the lifting drive device (44) of the lifting / lowering platform and lowering the cooling mold (2) by the change of the electric signal of the load detector (8) due to the decrease of the buoyancy force to the cooling mold (2). A method for adjusting the height of the molten metal surface in pull-up casting that maintains a constant molten metal surface height.