US3760867A

US3760867A - Apparatus for altering the cross-sections of continuously cast metal pieces

Info

Publication number: US3760867A
Application number: US00301248A
Authority: US
Inventors: T Murakami; T Hiromoto; Z Soejima; S Shibamoto; T Hamano; S Hashimoto
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 1970-12-21
Filing date: 1972-10-26
Publication date: 1973-09-25
Anticipated expiration: 1990-09-25

Abstract

An apparatus for altering the width dimension of a continuously cast piece in the continuous production of the cast piece by continuous casting. The apparatus has a water-cooled casting mold comprised of a first water-cooled front wall having an upper and a lower section, a second fixed water-cooled front wall spaced from the first water-cooled front wall, the sections of the first front wall being slidable on each other toward and away from the fixed front wall. Two spaced opposed side walls each having an upper and a lower section are positioned between the front walls, the corresponding sections of the side walls being slidable on each other toward and away from each other. Means is associated with the front walls for moving the front wall sections and releasably press fixing the sections of the first front wall to each other and for releasably press fixing the side walls between the front walls. Means is associated with the side walls for moving corresponding side wall sections toward and away from each other and for releasably press fixing the side wall sections to each other.

Description

United States Patent [191 Murakami et al.

[ Sept. 25, 1973 1 APPARATUS FOR ALTERING THE CROSS-SECTIONS OF CONTINUOUSLY CAST METAL PIECES [75] Inventors: Tadashi Murakami; Takeshi Hiromoto, both of Hirohata-ku, Himeji; Zenzo Soejima, Otsu-ku, Himeji; Toyosaburo Hamano, Takasago; Shinsuke Hashimoto; Shingo Shibamoto, both of Otsu-ku, Himeji, all of Japan [73] Assignee: Nippon Steel Corporation, Tokyo,

Japan [22] Filed: Oct. 26, 1972 [2]] Appl. No.: 301,248

Related US. Application Data [62] Division of Ser. No. 99,809, Dec. 21, 1970, Pat. No.

[52] US. Cl. 164/283 [51] Int. Cl. B22d 11/02 [58] Field of Search 164/82, 273 R, 280, 164/283 [56] References Cited UNITED STATES PATENTS 3,049,769 8/1962 Schultz 164/283 X 3,292,216 12/1966 Colombo 164/273 R 3,583,473 8/1971 Strohschein et al. 164/273 R FOREIGN PATENTS OR APPLICATIONS 1,125,594 3/1962 Germany 164/283 Primary ExaminerR. Spencer Annear Att0rneyE. F. Wenderoth et al.

[ 5 7 ABSTRACT An apparatus for altering the width dimension of a continuously cast piece in the continuous production of the cast piece by continuous casting. The apparatus has a water-cooled casting mold comprised of a first watercooled front wall having an upper and a lower section, a second fixed water-cooled front wall spaced from the first water-cooled front wall, the sections of the first front wall being slidable on each other toward and away from the fixed front wall. Two spaced opposed side walls each having an upper and a lower section are positioned between the front walls, the corresponding sections of the side walls being slidable on each other toward and away from each other. Means is associated with the front walls for moving the front wall sections and releasably press fixing the sections of the first front wall to each other and for releasably press fixing the side walls between the front walls. Means is associated with the side walls for moving corresponding side wall sections toward and away from each other and for releasably press fixing the side wall sections to each other.

5 Claims, 14 Drawing Figures SBEH 1 0F 5 PATENTEDSEPZSISH FIG;

FIG. 2 56 H36 52254559 mmgnserzsms saw u of 5 F C C Fl G. IO Fl 6. I l 69 57 57 69 PATENTED SEP 2 5 I975 snmsors FIG.|2

APPARATUS FOR ALTERING THE CROSS-SECTIONS F CONTINUOUSLY CAST METAL PIECES This application is a division of Ser. No. 99,809, filed Dec. 21, 1970, now US. Pat. No. 3,710,843.

The present invention relates to a method for altering the cross-sections and particularly the width dimensions of cast pieces without replacing the mold during the continuous casting of a molten metal.

The continuous casting of molten metals as a means of manufacturing such crudely shaped materials as slabs, billets and blooms is much superior to conventional blooming methods both with respect to the equipment and productivity and therefore has been extensively adopted.

Recently, as is generally known, in the field of casting steels serious studies are also being carried out and efforts are being exerted in practicing the results of the studies with great effect.

The principle of continuous casting of such molten metal as molten steel and the like is that the molten metal is continuously fed into a bottomless watercooled mold, in which a dummy bar is positioned, and cast pieces are continuously pulled out of the bottom part of the water-cooled mold, while the molten metal is cooled at a velocity corresponding to' the molten metal pouring velocity.

ln carrying out a continuous casting method, it is nec- 'essary to produce cast pieces with cross-sectional dimensions which are optimum for the cross-sectional dimensions of the products to be produced from the cast pieces in order to obtain cast pieces which can be easily worked and produce a high yield in the processing step, such as rolling, subsequent to the continuous casting step for producing-theiproducts. However, it has not been possible to alter the 'cross-sectionof the cast piece for a product to be finally produced while still using the same mold during the continuous casting. Consequently, usually in continuous casting the mold must be rearranged or modified to the desired cross-section or replaced by a prepared mold of other desired dimensions so that the cross-section of the cast piece to-be produced can be altered. As a result thereof,"continuous casting must be interrupted for a long time, because ittakes, for instance,-at least one hour to rearrange or modify the mold or to replace the same.

In a conventional continuous casting operation it is customary to use a water-cooled mold of fixed dimensions having an integral wall body. A few proposals have been made for using a water-cooled continuous casting mold having walls divided into several sections. However, the arrangement of mold walls in several sections is for the purpose of increasing the cooling effect, to improve the quality of cast pieces or to make the production of cast pieces of large size possible, as it disclosed, for instance, in the Japanese patents published in the Patent Office Bulletins Nos. 1461/1954 and 12301/1963.

The present invention has as its object to provide a 'method for continuously altering the cross-sections and particularly the width dimensions of cast pieces during the casting, in a manner which heretofore has not been possible in a continuous casting method.

" More concretely, the present invention has as its ob constructed by a water-cooled front wall and watercooled sidewalls, each of which walls is formed by two sections movable independently of each other.

The terms used in the disclosure of the present invention water-cooled front wall" and water-cooled side wall" are to be understood as follows: the former designates a mold wall having a surface forming the front or back surface of a cast piece to be produced and the latter designates a mold wall having a surface forming each side surface of the above-mentioned case piece.

Thus, the present invention has several novel features, as will be described hereinafter:

The primary feature of the present invention is to provide a method which utilizes a mold constructed by positioning respective water-cooled side walls on both the right and left sides between two water-cooled front walls, each of the side walls and one of the front walls having two sections, which are positioned one over the other, forming upper and lower stages, the remaining water-cooled front wall being an integral body.

A second feature of the present invention is to provide a method which utilizes a water-cooled mold, wherein a water-cooled front wall and two watercooled side walls are formed by upper and lower sections each of said sections of each wall being movable horizontally independent of the other.

The horizontal movement of each wall section of the water-cooled front wall is in the thickness direction of a cast piece to be made. This is for the purpose of enabling the water-cooled side walls, or more exactly, the side wall sections to move horizontally as will be explained later. The water-cooled front wall which is not divided into two sections, can not move, but is fixed.

The horizontal movement of the water-cooled side wall sections is in the width direction of the casting being made. It is for the purpose of altering the width dimension of the above-mentioned casting.

The third feature of the present invention is to provide a method which utilizes a mold having a watercooled front wall and water-cooled side walls, each of which has upper and lower sections horizontally movable independently of the other, wherein the upper and lower sections of each of the water-cooled front wall and the water-cooled side walls pressed tightly together so that they are fixed to each other respectively. This condition will hereinafter be referred to as press fixing, or being press-fixed.

In the case of the water-cooled front wall the pressfixing can be of two kinds; that is, one is where the upper and lower sections of the water-cooled front wall ject to provide a methodwhich, employs a continuous itself are vertically press-fixed to each other and the other is where the water-cooled side walls lying between two water-cooled front walls, that is, the fixed front wall and the water-cooled front wall formed by two sections are press-fixed to the fixed water-cooled front wall by the horizontal pressure of the other front wall formed by two sections.

In the case of the water cooled side walls the press fixing is the state wherein the upper and lower sections of each of the water-cooled side walls are vertically press-fixed to each other.

The fourth feature of the present invention is to provide a method which utilizes a mold having a watercooled front wall and water-cooled side walls, each of which walls are formed by two sections horizontally movable independently of the other and press-fixable,

wherein the respective upper and lower sections of the water-cooled side walls are L-shaped,

By using the bshaped water-cooled side wall sections the width dimensions of cast pieces can be altered over a wider range, as will be later explained, because the contact surface between the upper and lower sections of the water-cooled side wall can be made large.

The fifth feature of the present invention is to provide a method of obtaining cast pieces of required dimensions, as the occasion demands, by altering the positions of the water-cooled side wall sections during the continuous casting of a molten metal by using the above-mentioned mold having the water-cooled front wall and water-cooled side walls, each of which walls are formed by the upper and lower sections horizontally movable independently of the other and which are press-fixable.

In the following the substance of the present invention will be explained in greater detail with reference to the attached drawings so that it can be more clearly understood.

In the attached drawings:

FIG. 1 is an exploded perspective view of a continuous casting water-cooled mold according to the present invention.

FIG. 2 is an explanatory view showing a mechanism for supporting and fixing the continuous casting watercooled mold and a mechanism for press-fixing the said mold.

FIG. 3 is an explanatory view, partially in crosssection, showing a press-fixing mechanism for the water-cooled front wallfor horizontally press-fixing the water-cooled side walls.

F IG. 4 is an explanatory view showing a cotter driving mechanism for operating the press-fixing mechanism of the water-cooled front wall shown in FIG. 3.

FIG. 5 is an explanatory view showing a mechanism for supporting and fixing the water-cooled side walls and vertically press-fixing the said water-cooled side wall sections with respect to each other.

FIG. 6 is a sectional explanatory view showing a mechanism for horizontally moving the water-cooled side wall sections. 1

FIG. 7 is a magnified explanatory view of the part A in FIG. 2.

FIG. 8 is a vertical sectional explanatory view showing the cooling structure of the water-cooled side wall section.

FIG. 9 is a sectional explanatory view taken on line 8-8 in FIG. 8.

FIGS. 10 and 11 are sectional views taken on line C-C in FIG. 9 showing a modification of the cooling water circulating system.

FIG. 12 is a block diagram of a control circuit, showing schematically the continuous casting according to the present invention.

FIGS. 13a-13e are explanatory views showing the steps of altering the cross-section of a cast piece to a smaller size; and

FIGS. Ma -14a, are explanatory views showing the steps of altering the cross-section of a cast piece to a larger size.

In FIG. 1 the mold 1 comprises a first water-cooled side wall having two

sections

6 and 7, which are positioned one over the other, forming upper and lower portions, and another water-cooled side wall also formed by upper and lower sections 6 and 7'. These side walls are positioned opposite each other between a fixed water-cooled front wall 2 formed in one piece and a water-cooled front wall opposed thereto and formed by upper and

lower sections

3 and 4, which are positioned one over the other. The fixed water-cooled front wall 2 can have the same construction as the water-cooled front wall formed by the upper and

lower sections

3 and 4.

The mold of the present invention having the construction as described above is used during the continuous casting operation with the above-mentioned four walls being pressed tightly against and fixed to each other and with the upper and lower sections of each wall being vertically press-fixed to each other. When it is required to alter the width dimension of a cast piece, the space between the water-cooled

side wall sections

6 and 6' and 7 and 7 must be altered, that is, widened or narrowed (see FIGS. 13 and 14). For this purpose they must be, of course, at first released from the front walls.

The mechanisms for press-fixing the water-cooled front walls and side walls and their sections to each other and for releasing them from each other will be described hereinafter.

The fixed water-cooled front wall 2 is fixed to a fixing device 8 by means of a supporting arm 9, as shown in FIG. 2. This water-cooled front wall 2 determines the location of the center of a cast piece E passing between pull-off rolls (see FIG. 12) used to pull the cast piece out of the mold l.

The water-cooled

front wall sections

3 and 4 can move forwardly and backwardly independently of each other and are connected to a press-fixing mechanism 10 for the

side wall sections

3 and 4 for press-fixing the water-cooled side walls.

FIG. 3 shows an example of the press-fixing mechanism 10 for one of the water-cooled

front wall sections

3 and 4.

In the drawing, 13 is a frame of the press-fixing mechanism 10. Within said frame there are provided four hollow shafts 14 for supporting the water-cooled front wall section 3, upper and lower pairs with corresponding shafts in the upper and lower pairs being vertically aligned. The hollow shafts themselves are supported by means of

bearings

15 and 16 in frame 13.

The water-cooled front wall section 3 is supported on the ends of the above-mentioned hollow shafts by means of a notched part 17 at the end of each of said hollow shafts held between supporting metal pieces 18 provided in the water-cooled front wall section 3.

In the middle part of the outer periphery of each of the above-mentioned hollow shafts a threaded portion 19 is provided extending along the length of said hollow shaft a distance sufficient to move the shaft rightwards and leftwards a desired distance and meshing with the said screw is an interiorly threaded portion 20 of a worm wheel 21. Said worm wheel 21 is rotatably supported at a fixed position by the above-mentioned bearings l5 and 16.

The worm wheel 21 is engaged with a worm 23 on a rotary shaft 22 on the frame 13. Said rotary shaft 22 can be rotated manually with a handle (not illustrated) or can be rotated by using a motor (not illustrated).

A shaft 25 is slidably positioned in the interior of each hollow shaft 14 and the shaft 25 is provided with a plate spring 26 at the front end thereof. The front end surface of said plate spring 26 is in contact with a metal piece 27 on the back of the water-cooled front wall section 3. At the rear end of the above-mentioned shaft 25 there is mounted a cotter 28 vertically movable through slots in the rear ends of shafts 14 and having wedge portions for pushing the shafts 25 forwards.

Frames 13 having the equipment as above described are provided for both the upper and

lower wall sections

3 and 4 and together they constitute the press-fixing mechanism 10. i

In press-fixing the water-cooled

side wall sections

6 and 6' and 7 and 7' between the fixed water-cooled front wall 2 and the water-cooled front wall formed by

sections

3 and 4 by pushing the water-cooled front wall formed by

sections

3 and 4 towards the fixed watercooled front wall 2, the abovementioned cotter 28 for pushing the shafts 25 is an important element. The cotter 28 is driven vertically by a driving mechanism shown in FIG. 4.

FIG. 4 is a general view of a cotter driving mechanism for pushing the rear ends'of the respective shafts 25 of the water-cooled

front wall sections

3 and 4 forwards, wherein 29 and 30 are arms, which are rotatably mounted on the frame 13 on

shafts

31 and 32.

Each of the above-mentioned

arms

29 and 30 is provided with a hole 33, through which extends a metal piece 34 projecting from the cotter 28. The

abovementioned arms

29 and 30 are rotatably connected with each other at one end by an arm 35.

The other end of the arm 30 is pivotally connected with a rod 37 of a piston-cylinder mechanism 36 mounted on theframe 13.

When operating the thus constructed press-fixing mechanism to assemble the water-cooled mold walls, the rotary shaft 22 in the mechanism 10 is rotated at first in a certaindirection to advance the hollow shafts 14 through worm gears 23 and 21, whereby the surfaces of the water-cooled

front wall sections

3 and 4 and the water-cooled

side wall sections

6 and 7 and 6' and 7' are brought into contact with each other and with the surface of the fixed front wall 2 such that the

wall sections

6 and 6' or 7 and 7' can be moved by a slidingdevice 38, which will be described hereinafter. At this point rotation of the rotary shafts 22 is stopped.

Then, in order to press and fix all the mold walls to each other, the shafts 25 must be pushed in the forward direction. For this purpose the cotters 28 are moved by the operation of the

arms

29 and 30 by driving the piston-cylinder mechanisms 36, whereby the shafts 25 are pushed in the forward direction and the water-cooled

front wall parts

3 and 4 are pushed by the plate spring 26 so that the water-cooled

side wall parts

6 and 6 and 7 and 7 are pressed against and fixed to the watercooled front wall 2.

On the contrary, when the water-cooled side wall sections 6 and 6' are to be moved to alter the distance between them, the press-fixing action of the watercooled

front wall sections

3 and 4 must be eliminated by releasing the

watepcooled wall sections

3 and 4 from the pressing action of the shafts 25. This is done by driving the cotters 28 in the opposite direction. N Further, when disassembling the mold for the purpose of repair of the mold, the cotters 28 are operated to release the shafts 25 and thereafter the rotary shafts 22 are caused to rotate in the direction opposite to the abovementioned direction. Then, the hollow shafts 14 are caused to withdraw to a determined position through the worm gears 23 and 21.

In the foregoing description there has been described the manner in which two water-cooled side walls are pressed and fixed between the fixed water-cooled front wall 2 and the water-cooled front wall formed by the

sections

3 and 4 by advancing the hollow shafts l4 and the shafts 25. However, it is also possible to use a piston and cylinder instead of the hollow shafts l4 and the shafts 25. Further, an eccentric cam can be used instead of the cotter 28 for pushing each of the shafts 25.

The horizontal movement of the water-cooled side wall sections is carried out by means of the sliding devices 38, on which the water-cooled

side wall sections

6 and 7 are supported and fixed by arms 39, as is shown in FIG. 5.

As shown in FIG. 6, the above-mentioned sliding devices 38 rotate threaded shafts 41 through speed change gears consisting of worm gears by the rotation of a motor (not illustrated), whereby the arms 39 meshing with said threaded shafts are advanced and withdrawn in the horizontal direction. 42 is a sliding surface supporting the arm 39 and bearings 43 are provided to support threaded shaft 41.

In order to be able to move the water-cooled

side wall sections

6 and 6'. or 7 and 7 horizontally in opposite directions by using the above-mentioned sliding device 38, it is, of course, necessary to release the watercooled

side wall sections

6 and 6' or 7 and 7' by operating the press-fixing device 10.

When the horizontal movement of the water-cooled

side wall sections

6 and 6 or 7 and 7' is finished, however, it is important to press-fix them again by pressing the water-cooled

front wall sections

3 or 4 toward the fixed wall 2.

Next, a mechanism for fixing the water-cooled

front wall sections

3 and 4 to each other and water-cooled

side wall sections

6 and 7 and 6' and 7' to each other will be described.

In order to fix the water-cooled

front wall sections

3 and 4 to each other, it is necessary at first to support the lower section 4. For this purpose projections 44 are provided on both the lower parts of both ends of the water-cooled wall 2 and the section 4, and a hole 44' is provided in each projection 44. A bar member 45 is passed through said holes 44' and 44 and is fixed at the ends thereof to the fixing device 8 and the press-fixing mechanism 10 respectively, as shown in FIGS. 1, 2 and 5.

On the other hand, a projection 46 is provided on the lower part of each end of the water-cooled front wall section 3.

Further, a bar member 47 is rotatably pivoted at one end on a pin 48 on the mold side of the press-fixing mechanism 10, and is positioned on the abovementioned projection 46. At the other end the bar member 47 is engaged with a fixed metal piece 49 provided on the fixing device 8.

As shown in FIG. 7, a tapered cotter 50 is inserted between said fixed metal piece 49 and bar member 47 so as to push the bar member 47 downwards and push down the projection 46.

Thus, the water-cooled

front wall sections

3 and 4 are vertically pressfixed by means of the bar member 47 in collaboration with the bar member 45.

The advance and retreat of the above-mentioned cotter 50 is accomplished by means of a piston cylinder mechanism 51, as is shown in FIG. 7. Alternatively, a driving mechanism (not illustrated) consisting of a screw and gear may be adopted instead of the piston cylinder mechanism 51.

The devices for fixing the water-cooled

front sections

3 and 4 to each other are provided on both right and left end parts of the water-cooled

front wall sections

3 and 4.

Devices for fixing the water-cooled

side wall sections

6 and 7 and 6 and 7' to each other will be described with reference to FIGS. 1, 2 and 5.

Supporting

metal pieces

52 and 53 are securely mounted on the water-cooled

side wall sections

6 and 6 and 7 and 7 respectively. The lower end of the supporting metal pieces 53 for each of said water-cooled

side wall sections

7 and 7 is in contact with the abovementioned bar member 45.

Further, a bar member 54 is rotatably pivoted at one end on a pin 55 on the mold side of the fixing device 8, engages the supporting metal piece 52 of the watercooled

side wall sections

6 and 6, and is engaged at the other end with a fixed metal piece 56 provided on the press-fixing mechanism 10. By inserting a cotter 50' provided with a taper, like the cotter described in connection with FIG. 7, between said fixing metal piece 56 and bar member 54, the bar member 54 can be pushed downwards and the supporting metal piece 52 is pushed down. Thus, the water-cooled

side wall sections

6 and 6 and 7 and 7' are vertically press-fixed to each other respectively by means of the bar member 54 in collaboration with the bar member 45.

As described above, in the present invention cast pieces are produced by using the continuous casting mold, wherein the above-mentioned water-cooled

front wall sections

3 and 4 and water-cooled

side wall sections

6 and 7 and 6' and 7' are respectively vertically press'fixed by means of the press fixing devices, by an ordinary continuous casting method comprising continuously feeding a fixed amount of molten metal, for instance, molten steel, while vertically vibrating the mold up and down.

In the foregoing there has been described the use of the

cotters

50 and 50 as a means of pushing down the

bar members

47 and 54 by inserting them, when pressfixing the water-cooled

front wall sections

3 and 4 and water-cooled

side wall sections

6 and 7 and 6' and 7' between the

bar members

47 and 54 and the fixed

metal pieces

49 and 56 respectively. However, it is also possible to replace the fixed

metal pieces

49 and 56 by piston cylinder mechanisms or eccentric cams (not illustrated) so that the

bar members

47 and 54 may be directly pushed down thereby to vertically press-fix the water-cooled

front wall sections

3 and 4 and watercooled

side wall sections

6 and 7 and 6' and 7' respectively.

Further, the water-cooled

front wall sections

3 and 4 and water-cooled

side wall sections

6 and 7 and 6' and 7' may be vertically press-fixed directly by means of a cotter or an eccentric cam respectively by inserting the cotter or positioning the eccentric cam between the projections provided on the water-cooled

front wall sections

3 and 4 or water-cooled

side wall sections

6 and 6' or 7 and 7' and projections (not illustrated) corresponding to the above-mentioned fixed metal pieces, on the press-fixing mechanism 10 for the water-cooled

front wall sections

3 and 4 or on the sliding device 38 for the water-cooled

side wall sections

6 and 6 or 7 and 7 on the side of the mold.

In the mold of the present invention, that is, in the mold composed of the water-cooled front wall and water-cooled side walls having two sections respectively, which sections are positioned one above the other, forming the upper and lower stages, and separately movable in the horizontal direction and capable of being press-fixed to each other, it is preferable to shape each of the water-cooled

wall sections

6 and 6' and 7 and 7 in the form of an L. Making the respective water-cooled

side wall sections

6 and 6' and 7 and 7' L- shaped makes it possible to move the wall sections 6 and 6' relative to the wall sections 7 and 7' to a large extent, whereby the object of the present invention can be advantageously achieved, as will be later described.

FIG. 1 shows the embodiment in which the abovementioned L-shaped water-cooled side walls are used. As shown in FIG. 8 each of the water-cooled side wall sections, for instance,

sections

6 and 6, consists of a side surface 57 and a sliding surface 58. As regards the cooling system for each of the L-shaped side wall sections it is preferable to provide the side surface and sliding surface with separate cooling systems respectively, as shown in FIGS. 8 and 9. In the cooling system for the side surface 57 there are provided water feeding and discharging

ports

59 and 60 on the back side of the side surface 57 and a plurality of rows of flow paths running parallel with the side surface 57 and communicating with said

ports

59 and 60.

The port 60 for the water discharge is provided with a water discharging jacket 62 and the port 59 for the water feed is provided with a water feeding jacket 63. 64 is a water supply pipe and 65 is a water discharging pipe.

On the other hand, the cooling system for the sliding surface 58 has water feed and

discharge ports

67 and 68 on the end surface 66 of the sliding surface 58 and is provided with a plurality of side by side flow paths running parallel with the sliding surface 58, as shown in FIGS. 10 and 11.

The ports 68 for the water discharge are provided with water discharging jackets 70 and the ports 67 for the water feed are provided with water feeding jackets 71. The arrangement of the inlets and outlets of the above-mentioned flow paths can be in the order of the inlet side outlet side outlet side inlet side, as shown in FIG. 10 or the flow paths can be concentrically arranged so that a plurality of inlets are connected to a single feeding jacket and a plurality of outlets are connected to a single discharging jacket, as shown in FIG. 11. In the drawings, 72 is a water feed pipe and 73 is a water discharge pipe. I

With the cooling systems arranged as described the cooling capacity of the boundry part of the side surface 57 and the sliding surface 58 can be greatly increased.

Now, the operation of the continuous casting according to the method of the present invention and using the described apparatus will be explained with reference to FIG. 12. First of all, the water-cooled front wall 2 and each of the

front wall sections

3 and 4 and the water-cooled

side wall sections

6 and 6 and 7 and 7', from which the mold 1 is constructed, must have sufficient cooling capacity for performing an ordinary continuous casting. The water-cooled mold 1 is so compactly constructed that all wall sections may be jointly vertically vibrated in the conventional manner, and the water-cooled

side wall sections

6 and 6 and 7 and 7 are so arranged that they may be separately moved independently of each other in the width direction of a cast piece E, as described hereinbefore.

On the side of the water-cooled mold I there is provided a radioactive ray position detecting device 77 to detect the level of the molten steel D poured-in through a pouring pipe 75 of a tundish 74, and a position detecting measuring signal from the said position detecting device 77 is impressed on a control device 78.

A stopper operating device 79 driven by an instruction from the said control device 78 moves a stopper 80 vertically to control the volume of the molten steel D poured into the mold.

The molten steel D poured into the water-cooled mold 1 through the pouring pipe 75 is cooled in the water-cooled mold 1 and is pulled as a cast piece E out of the bottom part of said water-cooled mold 1. Th control the velocity with which the piece E is pulled out, the rotating velocity of the pull-out roll or guide roll 81 is detected by a pulse transmitter. 82. Said pull-out velocity signal is impressed on the controlling device 78. 83 is a driving device for the pull-out roll or guide roll 81. Said driving device 83 is controlled by the control device 78. 84 is a device for lifting of the tundish 74.

On the basis of the cooling capacity of the watercooled mold l, the driving device 83 is operated at an appropriate velocity by the instruction from the control device 78 and the cast piece E is pulled out. At the same time, the stopper operating device 79 operates to control the volume of flow of the molten steel in response to the pull-out velocity of the cast piece E and the molten steel D is poured into the water-cooled mold 1 through the pouring pipe 25. The cast piece E cooled in the water-cooled mold l is pulled out at a controlled velocity.

During such continuous casting, the width dimension of the cast piece can be altered by the steps shown in FIGS. 13 or 14. FIGS. 13a to 132 show steps of altering the cross-section of the cast piece E from a fixed width dimension to a smaller width dimension. First of all, the configuration of the mold set for continuous casting as shown in FIG. 13a is changed to reduce the width dimension by changing the positions of the water-cooled side wall sections 6 and 6' in the upper stage, as shown in FIG. 13b. The horizontal movements of the side wall sections 6 and 6' for changing the distance between them to that shown in FIG. 13b are performedby carrying out steps as follows:

At first, the press-fixed condition of the

sections

6 and 7 and 6' and 7' is released by releasing the bar member 54 engaging the above-mentioned sections by withdrawing the cotter 50'. Then, the press-fixed condition of the

front wall sections

3 and 4 is released by releasing the bar member 47 from engagement with the said sections by withdrawing the cotter 50. Thereafter, the press-fixed condition of the

side wall sections

6 and 7 and 6' and 7' and the front wallsections 3 and 4 is released by withdrawing the shaft 25 by appropriately moving the cotter 25.

With the mold parts in the thus released state the sliding device 38 can operate to horizontally move the sections 6 and 6' in the direction toward each other, to the positions as shown in FIG. 13b. Then, the vertical vibrating movement of the water-cooled mold 1 is stopped and the pull-out of the cast piece E is stopped. Then, as shown in FIG. 13c, the amount of the molten steel D poured-in is increased by increasing the opening of the stopper 80 until the pouring level 76 along the water-cooled

side walls

6 and 6 is reached. At the same time, the tundish 74 is elevated in response to the change in the molten steel level in the mold. When the surface of the molten steel approaches the pouring level 76 for the watercooled

side wall sections

6 and 6, the amount of the molten steel poured-in is reduced by controlling the stopper 80. Meanwhile, a shell (hatched part of the cast piece E) which allows the cast piece to be pulled out is formed on the outer periphery of the molten steel D in the mold over a period of time, for example, of 20 to 50 seconds, although the time is different depending on the cross-section of the cast piece, and then the pull-out of the cast piece E is started again.

At the moment, when the stepped part F of the casting, which is formed by the alteration of the width dimension of the cast piece E, has been shifted downwardly due to the pull-out of the cast piece E a distance greater than the stroke of the vertical vibratory movement of the water-cooled mold 1, the vertical vibratory movement of the water-cooled mold 1 is started.

Then, when the stepped part F of the cast piece E has moved below the water-cooled side wall sections 7 and 7' as shown in FIG. 13d, the positions of the watercooled side wall sections 7 and 7' are shifted toward each other so that they coincide with the positions of the water-cooled side wall sections 6 and 6'.

Then, the molten steel pouring level is lowered to the pouring level 76 of the water-cooled side walls sections 7 and 7' if desired by controlling the stopper 80 to continue the continuous casting.

FIGS. 14a, to 142, show steps of altering the crosssection of the cast piece E from a fixed width dimension to a larger width dimension. The configuration of the mold set for continuous casting as shown in FIG. 14a, is changed to increase the width dimension by changing the positions of the water-cooled side wall sections 6 and 6' as shown in FIG. 14b Then, the vertical vibrating movement of the water-cooled mold 1 is stopped, the pull-out of the cast piece E is stopped and, as shown in FIG. 14c the amount of the molten steel D poured-in is increased by increasing the opening of the stopper 80 until the pouring level 76 along the water-cooled

side wall sections

6 and 6 is reached. At the same time, the tundish 74 is elevated in response to the change in the molten steel level in the mold. When the surface of the molten steel approaches the pouring level 76 along the water-cooled side wall sections 6 and 6', the amount of the molten steel poured-in is reduced by controlling the stopper 80. Meanwhile, a shell (hatched part of the cast piece E) which allows the cast piece to be pulled out is formed on the outer periphery of the molten stee'l D in the mold over a period of time of 20 to 50 seconds; although the time is different depending on the cross-section of the cast piece.

Then, as shown in FIG. 14d the positions of the water-cooled side wall sections 7 and 7' are changed so that they coincide with the positions of the watercooled

side wall sections

6 and 6.

As the upper end parts of the water-cooled side wall sections 7 and 7' are separated from the stepped part F formed by the alteration of the width dimension of the cast piece E, the vertical vibrating movement of the water-cooled mold l and the pull-out of the cast piece cooled side wall sections 7 and 7' if desired by controlling the stopper 80 to continue the continuous casting.

In the foregoing there has been described a method of altering the width dimension of a cast piece so that it is smaller or larger, wherein the stopping of the vertical vibrating movement of the water-cooled casting mold has been carried out after the positions of the upper sections of the water-cooled side walls have been changed to give the casting the desired dimension. However, the time of stopping the vertical vibrating movement of the said casting mold may be before the alteration of the width dimension of the cast piece.

When altering the width dimension of the cast piece E according to the method of the present invention, as is explained above, the vertical vibrating movement of the water-cooled casting mold is temporarily suspended, and therefore it is necessary to carry out quick and accurate alteration of the molten steel pouring level in the water-cooled mold. For that purpose, the tundish 74 may be provided with a plurality of pouring pipes 75.

When a plurality of pouring pipes 75 are provided, the poured amount per unit time can be varied widely and the control of the poured amount can be performed easily.

What is claimed is:

1. An apparatus for altering the width dimension of a continuously cast piece in the continuous production of the cast piece by continuous casting, comprising a water-cooled casting mold comprised of a first watercooled front wall having an upper and a lower section, a second fixed water-cooled front wall spaced from said first water-cooled front wall, said sections of said first front wall being slidable on each other toward and away from said fixed front wall, and two spaced opposite side walls each having an upper and a lower section and positioned between said front walls, the corresponding sections of said side walls being slidable on each other toward and away from each other, and means associated with said front walls for moving said front wall sections and releasably press fixing the sections of said first front wall to each other and for releasably press fixing said side walls between said front walls, and means associated with said side walls for moving corresponding side wall sections toward and away from each other and for releasably press fixing said side wall sections to each other.

2. An apparatus as claimed in claim 1 in which said means for moving said front wall sections and press fixing them to each other comprises a mechanism connected to said first front wall and having a shaft connected to each front wall section and means for moving said shafts toward and away from said fixed front wall for moving said front wall sections, and a fixing rod engaged with each section of said first front wall and wedge means engaging said rods for moving them simultaneously against said front wall sections for press fixing said front wall sections against said side walls and said side walls against said fixed front wall.

3. An apparatus as claimed in claim 2 in which said shafts are hollow and said rods are slidable within said hollow shafts.

4. An apparatus as claimed in claim 1 in which said side wall sections have laterally extending flanges thereon with the opposed faces of the flanges on the respective upper and lower sections in sliding contact with each other so that the upper and lower sections of the respective side walls slide on each other on the opposed faces of the flanges.

5. An apparatus as claimed in claim 4 in which the flange of each side wall portion has cooling water passages therethrough and the remaining portion of each side wall portion has cooling water passages therethrough separate from the cooling water passages in said flanges.

Claims

1. An apparatus for altering the width dimension of a continuously cast piece in the continuous production of the cast piece by continuous casting, comprising a water-cooled casting mold comprised of a first water-cooled front wall having an upper and a lower section, a second fixed water-cooled front wall spaced from said first water-cooled front wall, said sections of said first front wall being slidable on each other toward and away from said fixed front wall, and two spaced opposite side walls each having an upper and a lower section and positioned between said front walls, the corresponding sections of said side walls being slidable on each other toward and away from each other, and means associated with said front walls for moving said front wall sections and releasably press fixing the sections of said first front wall to each other and for releasably press fixing said side walls between said front walls, and means associated with said side walls for moving corresponding side wall sections toward and away from each other and for releasably press fixing said side wall sections to each other.