US3844333A

US3844333A - Continuous metal castings

Info

Publication number: US3844333A
Application number: US00282121A
Authority: US
Inventors: P Peytavin
Original assignee: CERTIFUGATION SOC CIV D ETUDES
Current assignee: CERTIFUGATION SOC CIV D ETUDES; SOC CIVILE D ETUDES DE CERTIFUGATION FR
Priority date: 1971-08-25
Filing date: 1972-08-21
Publication date: 1974-10-29
Anticipated expiration: 1991-10-29
Also published as: JPS4830629A; IT964046B; CA966973A; DE2241422A1; FR2150237B1; FR2150237A1; GB1406843A

Abstract

The continuous casting of metal blanks is effected by using a false blank to initiate the casting process, the blank being cast through a mould on to the upper end of the false blank. The false blank is formed of at least two sections screw-threaded together. These sections are of a length to conform with the length of the sections into which the cast blank will be cut.

Description

United States Patent [191 Fl w Peytavin Oct. 29, 1974 [54] CONTINUOUS METAL CASTINGS 3,239,894 3/1966 Masters [64/274 [75] I In entor: Pierre Peytav n Neumy upse ne, 3,565,157 2/l97l Peytavln 164/282 X France 73 Assignee: Societe Civile DEtudes De Primary Examiner-Andrew R. Juhasl Certifugation, Paris, France Assistant Examiner.lohn S. Brown Filed: g 1972 Attorney, Agent, or FirmBrisebois & Kruger [2]] Appl. No.: 282,121

[57] ABSTRACT [30] Foreign Application Priority Data Aug. 25, l97l France 71.30834 The ontinuous casting of metal blanks is effected by using a false blank to initiate the casting process, the [52] U.S. Cl. 164/82, 164/282 blank being cast through a mould on to the upper end [51] Int. Cl 322d 11/00 of the false blank, The false blank is formed of at least Fleld 0f Search two sections screw-threaded together. These sections v 85 are of a length to conform with the length of the sections into which the cast blank will be cut.

, [56] References Cited UNITED STATES PATENTS 5 Claims, 6 Drawing Figures 2,l7 6,990 lO/l939 Crampton 164/274 Pmmmnm 29 1914 smnurz .Qgya

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CONTINUOUS METAL CASTINGS The invention relates to a process and apparatus for initiating a continuous casting process for metals, such as steel, in order to obtain solid or hollow metallic bars or blanks (hereinafter for convenience simply called blanks).

It is at present known to make, by a continuous casting process, metallic blanks, for example of steel, by introducing molten metal into a cooled mould, the shape of which corresponds to that of the blank which it is desired to make, and by extracting the solid blank at the bottom of the mould.

Metallic blanks continuously produced in this way are then cut into suitable lengths.

This cutting is effected at the lower part of the continuous casting apparatus each blank length being received in a tipping device which turns them from a vertical to a horizontal altitude and discharges them into a removal device or conveyor.

In conventional continuous casting processes the blank, during production, is not rotated about its longitudinal axis but is merely urged downwards by an extraction device. ln this case, the blank may also be cut into lengths as indicated above.

The processes and apparatus used presently are satisfactory where blanks of relatively small cross-section are being produced. However, these processes and apparatus have serious drawbacks when it is desired to produce bars of substantial cross-section in large capacity apparatus.

In fact, considering the various factors which determine cooling of the metal, there exists in the blank during production a core of molten metal extending from the upper part of the apparatus where the mould, which serves to define the cross section of the blank, is located to the middle region of the blank up to distances which may amount to metres or tens of metres, when bars of substantial cross-section are being produced in large capacity apparatus.

Naturally, the blanks produced cannot be cut in the zone where the molten metal is located at the centre of the blank, and equally, for safety reasons, sectioning of the blank can only be effected beyond the point where the blank has become solidified.

This height of molten metal core is critical as regards the dimensions of the casting apparatus for a given section and rate of throughput since it is necessary to provide for such a height, a satisfactory guide and driving means for the bar in the course of solidification.

Moreover, it is also known to use, for initiating a continuous casting process as refered to above, a false blank which is introduced into the apparatus before the casting begins so as to occupy the place of the blank in the course of solidifying, while the apparatus is operating, and to retain the molten metal at the beginning of the casting.

The molten metal which is then introduced into the mould is fused to the upper part of the false blank which is also guided and moved by thedevice provided for the continuous operation, so that there is thus obtained, as soon as the continuous casting process has got under way, a functioning which is practically the tion, a false blank must be provided the length of which corresponds to the height of the apparatus which is (as has previously been explained) determined by the height of the blank in which there is a certain amount of molten metal at the centre.

Naturally the first cut which may be made during the continuous casting process may only be made above the false blank.

In consequence, the tipping device which is located below the known apparatus must have a sufficient length to receive and tilt the false blank.

This constitutes a serious drawback when a blank of large cross-section is formed in large capacity apparatus, since, in this case, the solidification height is very great, which necessitates a very long false blank. Now, as it happens, in this case it is not necessary to make metal sections of great length, precisely due to the large cross-section of these pieces.

Consequently, in the present state of the art, the tipping device, which is located at the lower part of the apparatus, must be dimensioned to pivot the false blank and this is found to be much bigger than would be necessary for pivoting the blank sections, since these sections are usually notably shorter than the false blank used for starting the process.

An object of the present invention is therefore a process and apparatus which make it possible to obviate or mitigate this drawback very simply.

According to the present invention a process for initiating a continuous casting process for metals, such as steel, by using a false blank intended to serve as the lower part of the blank during production, said flase blank and the blank sections produced being received and discharged by a device located at the lower part of the casting apparatus, and the false blank being obtained by interconnecting a plurality of sections each having a length corresponding to the length of the blank sections which it is desired to cast, the false blank sections being screwed together, and each false blank section which reaches the bottom the guide and extraction means of the apparatus being separated from its upper section by a relative rotary movement which effects the unscrewing and separation of the lower section which is then received in' the discharging device.

In a preferred embodiment of the invention, the process is applied to a continuous rotary casting process in which the blank being formed is rotated about a vertical axis.

In this case, the lower section of the false blank is unscrewed very simply by means of a gripper or locking device located at the lower part of the guiding and extracting means, for example substantially on a level with the device for cutting the blank into sections, the direction of the screw-threading allowing the unscrewing of the lower section when this section is held stationary while the upper sections continue to rotate.

In the case where the process according to the'invention is applied to a continuous static casting process the unscrewing of the lower false blank section may easily be effected by rotating the lower section of the false blank about its vertical axis. This rotation may be effected by any device which grips the lower part of the false blank and rotates it.

It will be seen that the process according to the invention makes, it possible to subdivide the false blank very easily into as many sections as are desired, each section of the false blank being detached, tipped and removed by means of the tipping device which is dimensioned .solely as a function of the cast metallic blank sections which it must handle during the continous casting process proper.

Moreover, the use of a sectioned false blank has the advantage of facilitating the introduction of the false blank into the apparatus by the tipping device at the instant when one prepares to initiate the continuous casting. if so desired, the false blank sections may also be introduced successively, since they are of reduced dimensions, at the upper part of the apparatus, i.e., through the casting mould, the sections being moved down progressively while the subsequent sections are introduced successively at the top.

The present invention is also apparatus for continuously casting metallic blanks, for example of steel, in which molten metal is introduced into a cooled mould, and the blank during solidification being held in guide and extraction means disposed vertically beneath the mould, the apparatus being characterised by the fact that a device, for receiving and discharging the blank sections, disposed at the lower part of the apparatus, is dimensioned as a function of the length of the blank sections which it is desired to case, and that a false blank located in the guide and extraction means at the beginning of the continuous casting process, is subdivided into sections, the length of each which is at the' most substantially equally to the length of the blank sections which it is desired to cast, the various flase blank sections being screwed together, means being located, preferably between the lower part of the guiding and extracting means and the discharge device, which is capable of imparting to the lower false blank section a relative movement with respect to the other upper false blank sections, so as to unscrew said lower section, which may then be discharged by the discharge device, or by reversing the direction of rotation, to assemble the secions of the false blank before the casting begins.

In a modification of the apparatus according to the invention, which is applied to continuous rotary casting processes, the means for imparting the relative movement to the lower section of the false blank is constituted by a holding device or similar means which prevents the lower section from rotating.

In the embodiment in which the invention is applied to a continuous non-rotary casting process, the means which impart the relative movement to the lower section is constituted by a gripping device, which engages the lower section and rotates it about a vertical axis.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIGS. 1, 2 and 3 are diagrammatic elevation views showing three stages of the process for removing the false blank sections, in the case of a continuous rotary casting process; and,

FIGS. 4, 5 and 6 are diagrammatic views showing three stages of the removal of the lower sections of the false blank in the case of a continuous non-rotary casting process.

There is diagrammatically shown in FIGS. 1, 2 and 3 a continuous rotary casting apparatus according to the invention.

The apparatus comprises at its upper part a cooled mould l rotating about its vertical axis, into which is directed a jet 2 of molten metal which serves to produce the blank.

Below the mould 1, guide rollers 3, which are diagrammatically shown, are located, the function of which is to hold the blank as it solidifies laterally, while it is moved down by extractor rollers 4 which are also arranged in a casing rotating about a vertical axis, in the direction of the arrows F of FIG. I.

In order to initiate the continuous casting process, a false blank 5 constituted by an assembly of two

sections

5a and 5b interconnected by screw threading 6, is disposed between the

rollers

3 and 4.

At the bottom of the apparatus a tipping device is diagrammatically shown, which device receives the blank sections and discharges them after having pivoted them about a horizontal axis 8.

At 9 there is shown, in a purely diagrammatic manner, a device for cutting the blank into convenient lengths. This device 9 may be of any convenient from. It may be constituted by a saw or a cutting flame, for example.

In addition to the cutting device 9, there is diagrammatically shown a gripper device 10.

This device 10 which may be of any convenient form is constituted in this instance, by two jaws, for example, disposed on either side of the axis of the blank being cast, said jaws allowing, in the open position, free passage of the false blank while in the closed position they engage the false blank and prevent it from rotating.

According to the invention, the sense of the screwthreading 6 and the direction of rotation of the blank as indicated by the arrow F is selected so that when the lower section of the false blank is held stationary an unscrewing of this section occurs with respect to the section immediately above it.

In the device which. has just been described and which is shown in FIGS. 1 to 3, the false blank is constituted by two sections. Naturally, the false blank may have any convenient number of sections dependent on each section corresponding in length to the length of each blank section being cast and the dimensions of the tipping device 7.

The total length of the false blank corresponds to the total height of the apparatus i.e., to the length of the apparatus between the mould l and the extraction or

guide rollers

3, 4.

The process for initiating the continuous casting will now be described.

FIG. 1 shows the two false blank sections positioned between the guide and

extraction rollers

3, 4 at the instant when casting begins.

The false blank is rotated in the direction of arrows F in the same manner as the blank being cast is rotated during the casting operation.

The molten metal firstly enters the mould at 2, where it becomes solid and adheres to the upper part of the upper section 5b of the false blank. Atlthe same time, the extractor rollers 4 slowly move the assembly constituted by the false blank and solidifying metal which is commencing to form a blank downwards.

This process continuing, the position shown in FIG. 2 is reached, in which the lower section 5a of the false blank lies entirely below the extractor rollers 4, while being received in the tipping device 7, whilst a corresponding length of the cast blank 11 is formed above the section 5b of the blank.

According to the invention, the section 5a of the false blank is gripped by the device which prevents the section 5a from rotating, while the section 5b continues to rotate at the same time as the bar 11 which is being cast.

There occurs very quickly an unscrewing of the section 50 of the false blank, which is thus released from the section 5b.

The gripper device 10 is then loosened, as shown in FIG. 3, and the section 5a falls into the tipping device 7 which, by pivoting about the axis 8 in the direction of the arrow F, dispose the section 5a in the horizontal position and discharges it so that the sequence can be repeated.

The gripper device 10, which prevents the lower section 5a from rotating, may preferably be moved slightly downwards so as to follow the downward movement of the section 5a, a movement which is necessary, on the one hand, for the vertical extraction speed of the blank and, on the other hand, for the axial component of the unscrewing movement of the section 5a with respect to the section 5b.

The process is continued until the section 5b of the false blank has arrived substantially in the position occupied by the section 5a in FIG. 1.

In this case, the section 5b is released by using the cutting device 9 for cutting the blank 11 into lengths just above the section 5b, which is then extracted by the tipping device 7.

Of course, if the false blank was constituted by a greater number of sections, there would be located between the section 5a and the section 512 shown in FIGS. 1 to 3, intermediate sections which would be released in same manner as the section 5a, from the upper sections by means of the locking device 10.

FIGS. 4 to 6 show the application of the invention in the case of a non-rotary continuous casting process.

FIGS. 4 to 6 show substantially the same components as FIGS. 1 to 3, with, however, the following differences.

The extraction and guide device comprises only rollers 4, only certain of which may be propulsive.

In fact, it is unnecessary to provide rollers having a vertical axis 3 since the blank does not rotate.

The main difference relates to the device 10, which effects unscrewing of the lower section 5a of the false blank.

In the embodiment of FIGS. 4 to 6, this device 10 is formed not only to engage the section 5a but also to rotate it in a direction such that the section 5a is unscrewed with respect to the section 5b.

The operation, in the case of the embodiment in FIGS. 4 to 6, is exactly the same as that which has been described with reference to FIGS. 1 to 3, with the exception that the part of the false blank, which is located between the cutting device 9 and the mould 2, is not subjected to any rotation about a vertical axis, but only to a downward extraction movement, while the lower section of the false blank is rotated instead of being blocked to ensure its unscrewing so that it can be introduced into the tipping device 7.

It is seen that the invention makes it possible to extract the false blank easily, by means of tipping devices of small dimensions, in the case of both continuous rotary casting operations and continuous non-rotary casting operations.

Naturally, the embodiments which have been described above are not limitative and any desirable modification may be made thereto without departing from the scope of the present invention.

In particular, it will be manifest that the invention is applicable both to the production of solid as well as hollow blanks, and that the cross-sectional shape of the blanks has no influence in the carrying out of the process.

Moreover, naturally one would not depart from the scope of the invention by removing the false blank sections, or blank sections by means of a device other than the tipping device which has been described.

In particular, for this purpose, a device could be used which receives the false blank sections. or cast blank sections vertically and moves them parallel to each other in order to extract them vertically after having disengaged them from the continuous casting line.

What is claimed is:

1. In a method of initiating the continuous casting of a metallic object which is to be cut into sections, which method comprises the steps of introducing a false blank beneath the metal being cast to form said object, and receiving said false blank and object successively in guide means and a tipping extractor beneath said guide means, which extractor is dimensioned to tip severed sections of said object having at most a predetermined maximum length out of alignment with said guide means,

the improvement which comprises the steps of employing a false blank comprising a plurality of sections which are screwed together, the length of each section being at most equal to said maximum length, and separating the lowermost section of said false blank from the remainder of said false blank during the descent of said false blank by unscrewing said lowermost section therefrom, and then tipping said lowermost section in said tipping extractor once it has passed below said guide means.

2. A process according to claim 1, in which the blank being cast is rotated about a vertical axis.

3. In a process for initiating the continuous rotary casting about a vertical axis of a metallic object which is to be cut into sections, which method comprises the steps of introducing a false blank beneath the metal being cast to form said object, and receiving said false blank and object successively in guide means'and a tipping extractor beneath said guide means, which extractor is dimensioned to tip severed sections of said object having at most a predetermined maximum length out of alignment with said guide means,

the improvement which comprises the steps of employing a false blank which rotates with said object and comprises a plurality of sections which are screwed together, the length of each section being at most equal to said maximum length and separating the lowermost section of said false blank from the remainder of said false blank by unscrewing said lowermost section therefrom by preventing rotation of said lowermost section and tipping said lowermost section in said tipping extractor once it has passed below said gudie means.

4. A process according to claim 1, in which the blank being cast is not rotated, the lower section of the false blank is rotated to unscrew said section.

5. A process as claimed in claim 1 comprising the step of employing a false blank having sections substantially equal in length to the severed sections of said object.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,8,333 Dated October 29 197 Inventor s) P IERRE PEY'IAVIN It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[73] Assignee: Societe Civile D'Et'udes De Centrifugation,

Paris France Signed and sealed this th day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. IMSGE-I Commissioner of Patents Attesting; Officer and Trademarks FORM PO-IOSO (10-69) USCOMM-DC 60376-P69 l 0.5. GOVERNMENT PRINTING OFFICE 2 ll, O-Ji-SM.

Claims

1. In a method of initiating the continuous casting of a metallic object which is to be cut into sections, which method comprises the steps of introducing a false blank beneath the metal being cast to form said object, and receiving said false blank and object successively in guide means and a tipping extractor beneath said guide means, which extractor is dimensioned to tip severed sections of said object having at most a predetermined maximum length out of alignment with said guide means, the improvement which comprises the steps of employing a false blank comprising a plurality of sections which are screwed together, the length of each section being at most equal to said maximum length, and separating the lowermost section of said false blank from the remainder of said false blank during the descent of said false blank by unscrewing said lowermost section therefrom, and then tipping said lowermost section in said tipping extractor once it has passed below said guide means.

3. In a process for initiating the continuous rotary casting about a vertical axis of a metallic object which is to be cut into sections, which method comprises the steps of introducing a false blank beneath the metal being cast to form said object, and receiving said false blank and object successively in guide means and a tipping extractor beneath said guide means, which extractor is diMensioned to tip severed sections of said object having at most a predetermined maximum length out of alignment with said guide means, the improvement which comprises the steps of employing a false blank which rotates with said object and comprises a plurality of sections which are screwed together, the length of each section being at most equal to said maximum length and separating the lowermost section of said false blank from the remainder of said false blank by unscrewing said lowermost section therefrom by preventing rotation of said lowermost section and tipping said lowermost section in said tipping extractor once it has passed below said gudie means.