JPH0230359A - Method and apparatus for continuously casting metal tube - Google Patents

Abstract

PURPOSE:To suitably change thickness of metal tube without changing mold device by optimizing solidified time and solidified completing point fixing to the setting thickness of the cast tube drawing from tubular passage spreading toward outer part with a learning control based on actual casting results. CONSTITUTION:In the fixed solidified completing point at the tube forming passage 25 forming with a mold 19 and a core 20 in the mold device 13, the molten metal is controlled to draw so as to complete the solidification after reaching to the necessary and sufficient solidified time. As the above passage 25 is made to reverse tapered shape spreading toward outlet side of the mold in accordance with changing the solidified completing point of the molten metal along the passage 25, the thickness of the solidified casting tube 14 can be set to change. Further, the solidified time and solidified completing point fixing to the setting thickness of the tube 14 are optimized with the learning control based on the actual casting result. Therefore, the thickness of the tube 14 can be suitably changed without changing the device 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for continuous casting of metal tubes.

[Prior art] Regarding the continuous casting method of metal tubes, Japanese Patent Application Laid-Open No.
As described in Japanese Patent Application No. 55, a mold apparatus is used which includes a mold having an inner diameter portion for forming the outer surface of the tube, and a core disposed within the mold and having an outer diameter portion for forming the inner surface of the tube. That is, the above-mentioned mold device is disposed at the pouring port of a molten metal holding furnace, the molten metal is cooled in this mold device to form a cast tube, and this cast tube is pulled out horizontally by a drawing device.

[Problems to be Solved by the Invention] By the way, the wall thickness of a cast pipe manufactured in continuous casting of metal pipes is determined by the gap between the inner diameter portion formed on the outer surface of the tube of the mold and the outer diameter portion formed on the inner surface of the tube of the core.

Therefore, in continuous casting of metal tubes, it is necessary to prepare mold equipment for each product wall thickness, and when trying to obtain wall thicknesses of multiple sizes, mold equipment must be prepared according to those wall thicknesses. There is a need.

An object of the present invention is to appropriately change the wall thickness of a metal tube without changing the molding device.

[Means for Solving the Problem] The present invention according to claim 1 includes a mold having an inner diameter portion for forming the outer surface of the tube, and a core disposed within the mold and having an outer diameter portion for forming the inner surface of the tube. , the molten metal contained in the molten metal holding furnace is solidified into a tubular shape using a mold device installed at the pouring port of the molten metal holding furnace to form a cast pipe, and this cast tube is drawn out by a drawing device to form a metal tube. In the continuous casting method, a tapered tube forming passage that expands toward the exit side of the mold is provided by the inner diameter part of the mold for forming the outer tube surface and the outer diameter part for forming the tube inner surface of the core. ) is the mold pro-solidification time (L
), and further determine the position of the solidification completion point on the tube forming passage corresponding to the realization of the set wall thickness (T),
The optimum drawing speed of the cast pipe by the drawing device is calculated from the solidification time in the mold (t) and the position of the solidification completion point, the drawing device is optimally controlled at the calculated optimum drawing speed, and the set wall thickness (T The solidification time (t) in the mold determined for ) and the position of the solidification completion point on the tube forming path are controlled by learning based on casting results.

The present invention according to claim 2 has a mold having an inner diameter portion for forming the outer surface of the tube, and a core disposed in the mold and having an outer diameter portion for forming the inner surface of the tube, and the core is disposed in the mold and has an outer diameter portion for forming the inner surface of the tube. In a continuous casting machine for metal tubes, the molten metal contained in a molten metal holding furnace is solidified into a tubular shape using a mold device installed to form a cast tube, and the cast tube is pulled out by a drawing device. A tapered tube forming passage that expands toward the mold exit side is provided by the molding inner diameter part and the inner pipe molding outer diameter part of the core. A wall thickness detector measures the wall thickness of the cast pipe on the side, a drawing speed detector measures the drawing speed of the cast pipe by the drawing device, and the set wall thickness (T) of the currently cast pipe set by the wall thickness setting device. In addition to determining the in-mold solidification time (t) necessary to achieve the set wall thickness (T), the position of the solidification completion point on the tube forming passage corresponding to the realization of the set wall thickness (T) is determined, and the in-mold solidification time (t) is determined. t) and the position of the solidification completion point, calculate the optimum drawing speed of the cast pipe by the drawing device, optimally control the drawing device based on the calculation result and the measurement result of the drawing speed detector, and and a control device that learns and controls the solidification time (t) in the mold determined for the set wall thickness (T) and the position of the solidification completion point on the tube forming passage based on the measurement results. This is what I did.

[Operation] According to the present invention, the drawing control is performed so that the molten metal reaches a necessary and sufficient solidification time and completes solidification at the solidification completion point determined on the tube forming path formed by the mold and the core of the molding device. I am forced to do it.

Here, since the above-mentioned pipe forming passage has a tapered shape that widens toward the exit side of the mold, as the solidification completion point of the molten metal is changed along this tapered pipe forming passage, the solidification casting pipe is You can change the wall thickness.

The solidification time and solidification completion point determined for the set wall thickness of the cast pipe are optimized by learning control based on casting results.

Therefore, the wall thickness of the metal tube can be changed as appropriate without changing the molding device.

[Example] FIG. 1 is a control system diagram showing one embodiment of the present invention.

FIG. 2 is a sectional view showing the mold device, FIG. 3 is an end view showing the mold device, FIG. 4 is a schematic diagram showing a first embodiment of the shape of the mold device in which the present invention is implemented, and FIG. 5 is a mold The second part of the device shape
FIG. 6 is a schematic diagram showing a third embodiment of the mold device shape.

As shown in FIG. 1, the continuous casting apparatus IO includes a molten metal holding furnace 1.
A mold device 13 is attached to a casting hole 12 formed at the lower side of the mold. The continuous casting device 10 includes a mold device 1
3, the molten metal is cooled to form a casting tube 14, which is horizontally drawn and cast.

The continuous casting device 10 is configured to cast a casting tube 1 at the exit side of the mold device 13.
4 and a drawing roller device 16 for drawing out the cast pipe 14. The pulling roller device 16 consists of a pinch roller 17 and a press roller 18. In addition, the pulling roller device 16
is a hydraulic motor 16 driven by a hydraulic pump 16A.
B, and this hydraulic motor 16B operates a pinch roller.
17 to apply a pulling force to the cast tube 14 as a result.

As shown in FIGS. 2 and 3, the mold device 13 includes a mold 19 made of graphite and a core 20 also made of graphite.

The mold 19 has a hollow shape and includes a core holding inner diameter part 21 at the end on the molten metal inflow side, and a tube outer surface forming inner diameter part 22 around the mold center axis extending substantially over the entire length excluding the core holding inner diameter part 21.

The core 20 is inserted into the mold 19, and the flange portion 2 is fitted into the core holding inner diameter portion 21 of the mold 19 at the end on the molten metal inflow side.
3, and a pipe inner molding outer diameter part 24 that is provided around the mold center axis over substantially the entire length excluding the flange part 23 and forming a pipe molding passage 25 between the pipe outer molding inner diameter part 22 of the mold 19. . The core 20 also includes molten metal injection passages 26 that communicate with the tube forming passage 25 at each of a plurality of positions (four positions in this embodiment) around the mold center axis in the flange portion 23 . Each molten metal injection passage 26 has a cross-sectional shape of an arc. It is preferable that the thickness g of the joint portion 27 sandwiched between adjacent molten metal injection passages 26 be as small as possible to ensure strength, and that the passage area of each molten metal injection passage 26 be made larger.

That is, in the mold device 13, the flange portion 23 of the core 20 is fitted and fixed to the core holding inner diameter portion 21 of the mold 19, and the molten metal injection passage 26 and the tube forming passage 25 are communicated in a straight manner. Reference numeral 28 in FIG. 2 is a fixing pin between the mold 19 and the core 20.

Furthermore, the mold device 13 includes a portion of the tube inner surface molding outer diameter portion 24 of the core 20 extending from the intermediate portion to the mold outlet end.
It has a tapered shape that tapers toward the exit side of the mold.

Thereby, the mold device 13 expands the tube forming passage 25 formed by the tube outer surface forming inner diameter portion 22 of the mold 19 and the tube inner surface forming outer diameter portion 24 of the core 20 from the intermediate portion toward the mold exit side. It has a tapered shape that opens. Therefore, when using this molding device 13, as shown in FIG. 14 is given a wall thickness T1, and (i) If the solidification completion point is set within the range of the tapered tube forming passage (for example, point B or point 0), the inner diameter of the cast tube 14 is reduced and the thickness is increased. A different wall thickness (for example, T2 or T3) will be applied.

Specifically, the mold device 13 is configured to fit a water cooling jacket body 30 made of copper to the end of the mold 19 on the outflow side of the molten metal via a copper liner 29, and to fit a water cooling jacket body 30 made of copper to the end of the mold 19 on the inflow side of the molten metal from a brick. The insert rings 31 and 32 are fitted, and the water cooling jacket body 30 and the insert ring 31 are fitted.
An iron plate 33 is fitted in between. As a result, the mold device 13 has a cooling section for solidifying the molten metal in the water-cooled jacket body 30, and an insert ring 31.
A portion of the insert ring 32 is a non-cooled portion, and a portion of the insert ring 32 is a portion that is attached to the furnace wall 11A of the holding furnace 11.

Further, the continuous casting apparatus IO of this embodiment has a mold apparatus 13.
To prevent the molten metal flowing into the core from being supercooled,
A thank-you note 20A is provided at the molten metal inflow side end of the mold 1, and the end of the mold device 13 protrudes into the furnace.

Note that the continuous casting apparatus 10 includes a control device 41. The control device i41 controls the casting tube 14 according to ■drawing time (t
The hydraulic pump drive control unit of the drawing roller device 16 repeats as one cycle the process of pulling out by the drawing length P at a constant drawing speed (We) during e), and opening and stopping during the waiting time (tw) after drawing. 42. The drawing speed of the cast pipe 14 is fed back to the control device 41 via a drawing speed detector 43 connected to the output shaft of the hydraulic motor 16B.

Further, the continuous molding device 10 includes a wall thickness setting device 44 and a wall thickness detector 45 (ultrasonic wall thickness meter). The wall thickness setting device 44 sets the manufacturing wall thickness of the currently cast pipe 14. Thickness detector 4
5 measures the wall thickness of the casting tube 14 on the outlet side of the molding device 13.

Therefore, the control unit M41 controls the casting pipe 1 as follows.
The wall thickness of 4 can be adjusted.

■The control device 41 calculates the mold pro-solidification time (t) (■in) necessary to achieve the set wall thickness (T) (mW) of the currently cast tube 14 set by the wall thickness setting device 44 using the formula (1). Find it by

This is a constant determined by the metal and continuous casting equipment, and is determined in advance through actual measurements.

■The control device 41 also determines the position (L) (1 m) of the solidification completion point on the tube forming passage corresponding to the realization of the set wall thickness (T).
seek. The position of the solidification completion point is the length of the mold required for the slab to complete solidification after the start of solidification, and is determined according to the set wall thickness (T).

In FIG. 4, the set wall thickness is T1. If it is T2 or T3, the solidification completion point is A (or the straight part before A), B, or C, respectively.

■Next, the control device 41 controls the in-mold solidification time (t) of the above
and the position (L) of the solidification completion point in the above (2), and the optimum drawing speed (V c
) (am/win) is calculated using equation (2).

Vc=L/l...(2
) ■ The control device 41 controls the pulling roller device 16 based on the calculation result of the above (■) and the measurement result of the pulling speed detector 43.
The hydraulic pump drive control unit 42 is optimally controlled.

(2) Furthermore, the control device 41 determines the solidification time (t) in the mold determined for the set wall thickness (T) and the position (L) of the solidification completion point on the tube forming path based on the measurement results of the wall thickness detector 45. ) and control the learning.

Next, the operation of the above embodiment will be explained.

According to the above embodiment, the mold 19 of the mold device 13 and the core 2
At the solidification completion point defined in the tube-forming passage 25 formed by 0 and 0, the molten metal is pulled out and controlled so as to reach a necessary and sufficient solidification time and complete solidification.

Here, since the tube-forming passage 25 has a tapered shape that widens toward the exit side of the mold, as the solidification completion point of the molten metal is changed along this tapered tube-forming passage, solidification casting' You can change the wall thickness of 1F14.

Note that the solidification time and solidification completion point determined for the set wall thickness of the cast pipe 14 are optimized by learning control based on casting results.

Therefore, the wall thickness of the metal tube can be changed as appropriate without changing the mold device 13.

In carrying out the present invention, the tube forming passage 25 of the molding device 13 can be modified as shown in FIG. 5 or 6.

The mold device 13 in FIG.
It has a tapered shape that widens towards the exit side of the mold. Thereby, the mold device 13 expands the tube forming passage 25 formed by the tube outer surface forming inner diameter portion 22 of the mold 19 and the tube inner surface forming outer diameter portion 24 of the core 20 from the intermediate portion toward the mold exit side. It has a tapered shape that opens. Therefore, when the solidification completion point in the mold device 13 is selected to be, for example, point B or point 0, the outer diameter of the cast tube 14 is increased and an increased wall thickness (for example, T2 or T3) is provided.

The mold device 13 in FIG. 6 includes a portion of the inner diameter portion 22 of the mold 19 extending from the intermediate portion to the mold outlet end.
A tapered shape that widens toward the exit side of the mold, and a taper that tapers toward the exit side of the mold from the intermediate portion to the end of the mold exit side in the outer diameter portion 24 of the tube inner surface molding of the core 20. The situation is as follows. As a result, the mold device 13 connects the tube outer surface forming inner diameter portion 22 of the mold 19 and the core 20.
The tube forming passage 25 formed by the tube inner surface forming outer diameter portion 24 is formed into a tapered shape that widens from the intermediate portion toward the exit side of the mold. Therefore, when the solidification completion point in the mold device 13 is selected to be, for example, point B or point 0, the outer diameter of the casting tube 14 is increased and the inner diameter is decreased to increase the wall thickness (for example, T2 or T3). ) is granted.

[Effects of the Invention] As described above, according to the present invention, the wall thickness of the metal tube can be changed as appropriate without changing the molding device.

[Brief explanation of the drawing]

Fig. 1 is a control system diagram showing one embodiment of the present invention, Fig. 2 is a sectional view showing a molding device, Fig. 3 is an end view showing the molding device, and Fig. 4 is a molding device in which the present invention is implemented. FIG. 5 is a schematic diagram showing a first example of the shape of the molding device, FIG. 5 is a schematic diagram showing a second example of the molding device shape, and FIG. 6 is a schematic diagram showing a third example of the molding device shape. DESCRIPTION OF SYMBOLS 10... Continuous casting device, 11... Molten metal holding furnace, 12... Casting port, 13... Mold device, 14... Casting pipe, 16... Drawing roller device, 19... template. 20... Core, 22... Tube outer surface molded inner diameter part, 24... Tube inner surface molded outer diameter part, 41... Control device, 43... Pulling speed detector, 44... Wall thickness Setting device, 45... Thickness detector. Agent: Patent Attorney Osamu Kawa: Fig. 1, Fig. 2, Fig. 4, J Fig. 5, Fig.

Claims (2)

[Claims] (1) A mold device that has a mold having an inner diameter portion for forming the outer surface of the tube, and a core disposed in the mold and having an outer diameter portion for forming the inner surface of the tube, and is disposed at the pouring port of a molten metal holding furnace. The molten metal contained in the molten metal holding furnace is solidified into a tubular shape to form a cast pipe.
In this continuous casting method for metal tubes, in which the cast tube is drawn by a drawing device, a tapered tube-forming passage expands toward the exit side of the mold by an inner diameter portion formed on the outer surface of the tube of the mold and an outer diameter portion formed on the inner surface of the tube of the core. In addition to determining the mold pro-solidification time (t) necessary to achieve the set wall thickness (T) of the cast pipe,
Furthermore, the position of the solidification completion point on the tube forming passage corresponding to the realization of the set wall thickness (T) is determined, and the mold pro-solidification time (
t) and the position of the solidification completion point, calculate the optimum drawing speed of the cast pipe by the drawing device, optimally control the drawing device at the calculated optimum drawing speed, and create a mold that is determined for the set wall thickness (T). A continuous casting method for metal tubes, characterized in that the pro-solidification time (t) and the position of the solidification completion point on the tube forming path are controlled by learning based on casting results. (2) A mold device that has a mold having an inner diameter portion for forming the outer surface of the tube, and a core disposed in the mold and having an outer diameter portion for forming the inner surface of the tube, and is disposed at the pouring port of a molten metal holding furnace. The molten metal contained in the molten metal holding furnace is solidified into a tubular shape to form a cast pipe.
In a continuous casting device for metal tubes in which the cast tube is drawn by a drawing device, the tapered tube expands toward the exit side of the mold due to the outside of the mold, the inner diameter portion formed on the surface, and the outer diameter portion formed on the inner surface of the tube of the core. A forming passage is installed, and a wall thickness setting device is used to set the manufacturing wall thickness of the cast pipe, a wall thickness detector is used to measure the wall thickness of the cast pipe at the exit side of the mold, and a drawing device measures the drawing speed of the cast pipe. The mold pro-solidification time (t) required to achieve the set wall thickness (T) of the currently cast pipe set by the drawing speed detector and wall thickness setting device.
), and further determine the position of the solidification completion point on the tube forming passage corresponding to the realization of the set wall thickness (T),
The optimal drawing speed of the cast pipe by the drawing device is calculated from the mold solidification time (t) and the position of the solidification completion point, and the drawing device is optimally controlled based on the calculation result and the measurement result of the drawing speed detector. , and the in-mold solidification time (t) determined for the set wall thickness (T) based on the measurement results of the wall thickness detector.
and a control device that learns and controls the position of the solidification completion point on the tube forming path.