JPH0542344A - Method for adjusting molten metal surface height in drawing-up casting - Google Patents

Abstract

PURPOSE:To make molten metal surface level the constant to a mold hole in a cooling mold. CONSTITUTION:The cooling mold 2 is siftably set at the fixed position and a weight 23 is connected to this cooling mold, and by balance between wt. of the cooling mold 2 containing the weight 23 and buoyancy of the molten metal, the molten metal surface in the mold hole of cooling mold 2 is kept to the fixed height. Only by liftably setting the cooling mold 2 and connecting the weight 23 to this cooling mold, the molten metal surface to the mold hole 21 in the cooling mold is kept to the constant. Further, as the molten metal surface in the mold hole of cooling mold 2 is kept to the fixed height by balance between the wt. of cooling mold 2 containing the weight 23 and the buoyancy of molten metal, there is no fear of mechanical or electrical malfunction and the height of molten metal surface to the mold hole can be surely controlled and a casting pipe body having high uniformity to the thickness can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the height of a molten metal surface with respect to a cooling mold in pull casting.

[0002]

2. Description of the Related Art In the conventional pull-up casting, as shown in FIG. 6, the upper part of the cooling mold (2) is exposed from the molten metal surface, and the lower part of the mold is immersed in the molten metal (9). The molten metal (9) is introduced into the die hole (21) through the lower opening of the hole (21).

The starting rod (8) is inserted into the mold hole (21) from above the cooling mold (2), and the molten metal (9) is attached to the shaft body (81) projecting from the lower end of the rod to form the mold. After the outer peripheral portion of the hole (21) is solidified, the pulling device (7) pulls up the starting rod (8). Solidified layer at a certain height (91)
When is pulled up, 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.

When manufacturing a tubular body having a uniform wall thickness by the above-mentioned pulling casting, it is important to keep the height of the molten metal surface with respect to the die hole (21) constant.

The thickness of the solidified layer (91) increases as the molten metal is in contact with the die cavity (21) for a longer period of time, that is, the higher the level of the molten metal in the die cavity (21). Also, the shorter the time of contact with the mold cavity (21), that is, the lower the level of the molten metal in the mold cavity (21), the smaller.

Since the amount of molten metal gradually decreases as the casting progresses, in order to keep the height of the molten metal surface relative to the mold cavity (21) constant,
There are the following four means and their application variations, and all of them are performed in accordance with the progress of casting.

First means As shown in FIG. 2, a molten metal supply furnace (11) is connected to the molten metal storage furnace (1), and the molten metal is fed from the molten metal supply furnace (11) in accordance with the decrease of the molten metal (9). The molten metal (9) is supplied to the storage furnace (1) to keep the height of the molten metal surface of the supply furnace (1) constant.

Second means As shown in FIG. 3, the height of the cooling mold (2) is fixed and the molten metal is melted.
The molten metal holding furnace (1) is lowered in accordance with the decrease in (9) to keep the molten metal surface level of the holding furnace (1) constant.

Third means As shown in FIG. 4, an auxiliary furnace is provided in communication with the molten metal storage furnace (1),
The refractory mass (13) is hung up and down freely in the auxiliary storage furnace (12),
By adjusting the amount of the refractory mass (13) dipped in the auxiliary storage furnace (12), the molten metal level of the storage furnace (1) is kept constant.

Fourth Means As shown in FIG. 5, a pressurizing chamber (14) is provided in communication with the molten metal accommodating furnace (1), and the pressure in the pressurizing chamber is adjusted by the pressurizing pump (15) to accommodate it. Keep the height of the surface of the furnace (1) constant.

[0011]

All of the above-mentioned four means have a problem that large-scale equipment is required. Further, in each case, a sensor for detecting the height of the molten metal surface is required, but the function of the sensor is not fully exhibited in a high temperature environment, and there is a problem in reliability and accuracy.

According to the present invention, a cooling mold is provided by simple equipment.
The purpose of the present invention is to clarify the method for adjusting the height position of the molten metal surface in the pulling casting, which can keep the molten metal surface height of the molten metal (9) constant with respect to the die hole (21) of (2).

[0013]

According to the molten metal height adjusting method of the present invention, a lower portion of a cooling mold (2) having a vertically-passing mold hole (21) is used as a molten metal (9) in a molten metal storage furnace (1). In the pull-up casting in which the molten metal (9) is soaked and penetrated through the lower opening of the die hole (21), the molten metal (9) is cooled and solidified and the solidified layer (91) is pulled up to form a tubular body, The cooling mold (2) is arranged at a fixed position so that it can be moved up and down freely, and the weight (23) is connected to the cooling mold, and cooling is performed by balancing the weight of the cooling mold (2) including the weight (23) and the buoyancy of the molten metal. The molten metal surface in the mold cavity of the mold (2) is maintained at a constant height.

[0014]

[Operation and effect] The cooling mold (2) can be freely moved up and down, and the weight (23) can be connected to the cooling mold to maintain a constant molten metal surface relative to the mold cavity (21). Such a large-scale device is not required, and the device can be simplified.

Further, the balance between the weight of the cooling mold (2) including the weight (23) and the buoyancy of the molten metal keeps the molten metal surface in the mold cavity of the cooling mold (2) at a constant height. There is no fear of mechanical or electrical malfunction, and the height of the molten metal surface relative to the mold cavity can be reliably controlled, and a cast pipe body with a high wall thickness uniformity can be formed.

[0016]

EXAMPLE As shown in FIG. 1, a molten metal storage furnace is mounted on a base (3).
(1) is provided, and a cooling mold (2) is suspended and supported in the furnace.

The frame (4) for suspending the cooling mold (2) is
Vertical columns at four symmetrical positions around the cooling mold (2) on the base (3)
(41) is provided, and the upper ends of the columns are connected by a rectangular frame (42).

Inside each pillar, a screw shaft (43) is arranged vertically, and an elevating table (5) is arranged straddling between the screw shafts (43).

The lifting table (5) has screw holes (51) at four corners, and the screw shaft (43) is screwed into the screw holes (51). Four
The screw shaft (43) of the book is connected to one motor (44) at the upper part of the frame (4) through a rotation transmission means (45), and the forward rotation of the motor causes the elevator table (5) to move. Are simultaneously rotated in a direction of raising, and by the reverse rotation of the motor, the elevator (5) is simultaneously rotated in a direction of lowering.

The lift table (5) is not directly related to the vertical movement of the water-cooled mold (2).
When setting the movable range of (2), the height position of the lifting platform (5) is determined so that the water-cooled mold is at the upper and lower limit positions.

A suspension frame (52) is provided on the lower surface of the center of the lift table (5), and a plurality of slide shafts (22) projecting upwardly on the cooling mold (2) are provided with thrust bearings (53) through the above-mentioned slide shafts (22). Sliding through the suspension frame (52) and placing the weight on the slide shaft (22).
(23) is replaceably attached.

The lower part of the cooling mold (2) is the molten metal storage furnace (1)
Cooling mold containing weight (23) immersed in molten metal (9)
The weight of (2) and the buoyancy of the molten metal are balanced, and the cooling mold (2) floats on the molten metal.

A pulling device (7) for pulling up the casting pipe is provided at 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
The drive motor (72) is connected to an intermittent drive setting device (not shown), and the stop time and the operation time can be arbitrarily set to repeat the dynamic stop.

Then, the mold cavity (21) is introduced from above the cooling mold (2).
Insert the starting rod (8) into the mold, attach the molten metal (9) to the lower end of the rod, wait for the outer periphery of the mold cavity (21) to solidify, and pull up the starting rod for a certain period of time before stopping. Let

While the pulling of the starting rod (8) is stopped, there is no change in the height of the molten metal surface, and the mold cavity (21) and the molten metal (9)
Is relatively stationary, and the molten metal (9) is cooled and solidified along the mold cavity (21) by heat removal by the cooling mold (2).

After a certain period of time, the starting rod
When (8) is pulled up for a certain period of time, the solidified layer (91) is pulled up together.

When the solidification layer (91) is pulled up, the level of the molten metal falls according to the thickness and the length of the solidified layer (91), but the level of the cooling mold (2) floating in proportion to the buoyancy of the molten metal also falls. The molten metal lowers correspondingly, the relative position between the molten metal surface and the cooling mold does not change, and the molten metal surface with respect to the mold cavity (21) is kept constant.

By thus intermittently repeating the pulling up of the solidified layer (91), it is possible to continuously form a tubular body in which the tubular solidified layer is connected.

Since the weight of the water-cooled mold (2) can be adjusted by the weight (23), the level of the molten metal surface relative to the mold cavity can be easily adjusted.

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 of a pull-up casting apparatus used in the present invention.

FIG. 2 is an explanatory diagram of a level control of a conventional example.

FIG. 3 is an explanatory diagram of a molten metal level control of a conventional example.

FIG. 4 is an explanatory view of a molten metal level control of a conventional example.

FIG. 5 is an explanatory diagram of a molten metal level control of a conventional example.

FIG. 6 is a cross-sectional view of a main part of a conventional pull-up casting apparatus.

[Explanation of symbols]

 (1) Molten metal storage furnace (2) Cooling mold (23) Weight (5) Lift table

Claims (1)

[Claims] 1. A lower part of a cooling mold (2) having a vertically passing mold hole (21) is immersed in a molten metal (9) in a molten metal storage furnace (1),
The molten metal (9) is introduced from the lower opening of the die hole (21) to
In pull-up casting in which the solidified layer (91) is pulled up while cooling and solidifying (9) to form a tubular body, the cooling mold (2) is arranged at a fixed position so that it can be freely moved up and down, and the weight (23) is placed on the cooling mold. ) Are connected to each other, and the weight of the cooling mold (2) including the weight (23) and the buoyancy of the molten metal are balanced to maintain the molten metal surface in the mold cavity of the cooling mold (2) at a constant height. How to adjust the level of the molten metal.