US3319699A

US3319699A - Apparatus for withdrawing and advancing the casting in a continuous casting machine

Info

Publication number: US3319699A
Application number: US432442A
Authority: US
Inventors: Olsson Erik Allan
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-02-04
Filing date: 1965-02-04
Publication date: 1967-05-16
Anticipated expiration: 1984-05-16

Description

May 16, 1967 E. A. oLssoN APPARATUS FOR WITHDRAWING AND ADVANCING THE CASTING IN A CONTINUOUS CASTING MACHINE Filed Feb. 4, 1965 3 Sheets-Sheet 1 V fivyf.

INVENTOR.

IIIIA May 16, 1967 E. A. OLSSON 3,319,699 APPARATUS FOR WITHDRAWING AND ADVANCING THE CASTING IN A CONTINUOUS CASTING MACHINE Filed Feb. 4, 1965 3 Sheets-Sheet 2 INVENTOR.

ERIK ALLAN OLSSON May 16, 1967 E. A. OLSSON 3,319,699

APPARATUS FOR WITHDRAWING AND ADVANCING THE CASTING Filed Feb. 4, 1965 INVENTOR.

ERIK ALLAN OLSSON a I a ATTO United States Patent APPARATUS FOR WITIIDRAWING AND ADVANC- ING THE CASTING IN A CONTINUOUS CASTING MACHINE Erik Allan Olsson, Tagerhalde 6, 8700 Kusnacht, Zurich, Switzerland Filed Feb. 4-, 1965, Ser. No. 432,442 16 Claims. (Cl. 164-282) This application is a continuation-in-part of my application Serial No. 152,259, filed November 14, 1961, now abandoned.

The invention relates to an apparatus for withdrawing and advancing and guiding the casting in a continuous casting machine in which the casting leaving an openended mold is engaged by rolls which are adapted to withdraw and advance the casting without subjecting it to a deforming mechanical working.

The degree of solidification of the casting when it leaves the mold is the deciding factor as regards how far from its mouth the withdrawing rolls must be placed in order not to damage the casting by deformation thereof. The rolls must engage the casting with a pressure so great that the friction between the casting and the rolls is sufiicient to Withdraw the casting from the mold and to support the weight of the casting so that the casting does not move downwards in an uncontrollable manner. The weight of the casting depends on the sump depth, and the length of casting required below the sump point, i.e., the height of the rolls and the cutting means and/or the bending means.

As disclosed inter alia in the Swedish Patent No. 164,526 internal defects in the form of fissures extending at an angle to the rolls may occur as a result of a too high roll pressure. Naturally, the material withstands little or no deformation associated with tension stresses as long as the temperature has not fallen sutliciently to result in an appreciable cohesion between the crystals. Some grades of steel have their ranges of red shortness which is well known from the rolling plant technology. Since an equalization of temperature occurs very slowly in iron and steel, it is readily seen that a deformation, e.g. a widening of the casting between the rolls, may result in cracks in some zones of the cross-section. Therefore, it is necessary that the cooling space, i.e., the distance between the mold and the rolls, is chosen so long that the casting is solidified substantially through or at least has obtained such a rigidity that the roll pressure necessary to provide the required friction does not deform the casting to a detrimental extent.

To obviate this disadvantage the practice has been to reduce the stresses exerted by the rolls on the casting, this being usually achieved by making the rolls with as large diameters as possible.

It is also indisputable that at the same pressure the depth of indentation or the linear pressure is reduced with an increasing roll diameter, but on the other hand the widening increases. Since breaks in the material at the temperature involved must depend on the material flow and the distribution of the various stresses (shearing, compression and tension stresses), it has been found in some cases that the widening is more dangerous than the elongation and therefore a smaller roll diameter is to be preferred.

The object of the present invention is to avoid the disadvantages of known machines and to provide a continuous casting machine in which the rolls for withdrawing and advancing the casting can act upon the casting while a great portion of the cross-section is still fluid without deforming the casting, whereby the rolls can be positioned closer to the outlet of the mold so that the 3,319,599 Patented May 16, 1967 overall height of the continuous casting machine can be considerably reduced, and also further reduce the height by deflecting the casting from a vertical to a substantially horizontal direction of travel.

In accordance with the present invention this and other objects are achieved by a continuous casting machine, in which the roll assembly for withdrawing and advancing the casting includes such a number of roll pairs, not less than three, arranged one behind the other in the direction of movement of the casting that the contacting pressure of each roll pair on the casting can be kept low while the total friction between the rolls of the roll assembly and the casting is sufiicient for withdrawing and advancing the casting, even while a great portion of the cross-section of the metal is still fluid.

In a preferred embodiment of the invention the roll pairs in the roll assembly are adjustable relatively to each other in such a manner that the roll assembly simultaneously with its withdrawing and advancing action, can bend the casting from a vertical to a horizontal or substantially horizontal direction of movement.

These and other features characteristic of this invention will be explained more in detail below with reference to the embodiment illustrated on the accompanying drawings.

FIGURE 1 shows diagrammatically and in elevation a continuous casting machine including a withdrawing and advancing apparatus in accordance with this invention.

FIGURES 2 and 3 show the same machine in elevation and in end view, respectively, and with some parts broken away.

The continuous casting machine shown on the drawings comprises a supporting frame 1 which carries the pouring box 3 for supplying the casting metal to a mold 9 provided on the frame, a device 2 provided directly below the mold 9 for cooling the casting and finally the apparatus for withdrawing and advancing the casting according to this invention. The latter apparatus comprises a plurality of

roll pairs

4, 5 arranged one behind the other and engaging the casting with a suitable pressure. Each roll pair is carried on a yoke-like supporting arm 7. The arm 7 which is closest to the mouth of the mold is rigidly attached to the frame while the other arms 7 are hingedly connected to each other in such a way that the rolls, as seen in FIGURES 1 and 2, can either discharge the casting vertically downward or also serve as means to bend and guide the casting from a vertical to a more or less horizontal direction to facilitate its advancement to a straightening apparatus 8. In the embodiment illustrated, hydraulic or pneumatic cylinder-piston devices 19 (FIG. 2) are utilized to adjust the supporting arms 7 in accordance with the desired bending of the casting, and these devices are capable of positioning the arms and their associated roll pairs to bend the casting either in a circular are or in a multiple radius curve, for example a curve whose radius decreases between successive roll pairs. This apparatus may be used to carry out the method disclosed in my copending application Ser. No. 152,161, also filed Nov. 14, 1961.

The cooling zone which according to FIGURE 1 is rather long, can be reduced, depending on the casting speed, the size of the casting and the grade of cast metal, sometimes even to a minimum where the withdrawing and advancing apparatus is situated more or less immediately below the mold. Cooling of the casting can be provided, as needed, between the rolls. Similarly supporting rollers or other means for supporting the casting laterally can also be provided between the rolls to counteract its swelling due to the hydrostatic pressure which acts from the interior of the casting.

On account of the bending of the casting by means of the rolls, these must of course be driven at different speeds on opposite sides of the casting. This can be achieved in a variety of ways, but in a suitable embodiment the drive of each roll is achieved by hydraulic motors, whereby it will also be possible to vary the rotational speeds of the rolls as desired, which is of particular importance if the bending radius is to be changed, in which case it is also necessary to change the rotational speed of the rolls at the same side of the casting.

By the'roll assembly of this invention which enables the casting to be bent already in the cooling zone, a considerable reduction of the height of the total machine is achieved, as compared to known machines where the entire bending apparatus follows the drawing apparatus.

Due to the fact that the roll carrying arms 7 can be adjusted inter alia so that the casting can pass through without bending, the advantage is gained that if for some reason a casting operation must be interrupted with the casting still in the straight path, where it cools entirely, the cooled straight casting part can be removed from the machine without bending, since the rolls can be adjusted for straight vertical movement. Thus, the apparatus need not be constructed and dimensioned for bending a cold rod, as would be necessary if the bending means could not be so adjusted. Similarly, the apparatus permits the use of a rigid starting bar which, when operation is to be started, is passed up through the apparatus to the bottom of the mold or a short distance thereabove to form a bottom closure therefor when pouring starts, and to serve as a connecting piece between the casting formed in the mold and the apparatus of this invention before the casting itself is engaged by the rolls. Of course, when the casting opeartion is interrupted a sufficient length of the casting can be left in the machine to serve as a starting bar in the next operation.

When thin or narrow sections are cast, it may be suitable to build the advancing and bending apparatus so long that the casting can be straightened by the last pair or pairs of rolls so that a special straightening means need not be provided.

The invention is not restricted to the embodiment shown and described, which can be varied in many ways without departing from the spirit and scope of the invention. For example, the bending can be achieved by one or more cylinders supported in a manner different from that shown on the drawings. The use of spindles would also be possible. Embodiments in which some only of the rolls in the apparatus are driven are also within the scope of the invention.

I claim:

1. Apparatus for withdrawing and advancing the casting in a continuous casting machine wherein the casting leaving an open-ended mold may have a molten interior comprising:

(a) at least three pair of opposed driven roll means positioned successively in the direction of movement of the casting for frictionally advancing and guiding the casting without altering the cross-sectional shape thereof,

(b) means for:

(1) independently adjusting the alignment of said pairs of rolls relative to one another and relative to the direction in which the casting leaves the mold and (2) successively bending the casting away from the direction in which it leaves the mold to a direction at an angle thereto,

() each of said pairs of rolls being positioned along a non-circular arcuate path.

2. An apparatus as in claim 1, in which the casting leaves the mold in a generally vertical direction, the roll pairs being positioned in spaced succession one below the other, said means for independently adjusting the alignment being effective to shift the relativepositions of 4 the roll pairs laterally of the direction of travel of the casting so that the rolls in addition to withdrawing and advancing the casting, also selectively bend it from a generally vertical to a substantially horizontal direction of movement.

3. Apparatus as in claim 2, in which the rolls of each roll pair are driven by means of driving means such that the rotational speed of the rolls is individually controllable.

4. An apparatus as in claim 2, in which each roll pair is attache-d to a supporting arm, said arms being hingedly connected to each other to achieve the desired bending of the casting.

5. An apparatus as in claim 4 in which the arms are joined together by means of links including cylinder-piston devices.

6. A guide for deflecting a continuous casting from its initial path of travel to a path disposed at an angle thereto and then effecting a straightening thereof comprising a succession of opposed spaced elements between which the casting is moved, and means to adjustably position certain of said elements relatively to others along the curved path in advance of straightening to provide a curved path for the casting, which curved path is of successively different radii.

7. A guide for deflecting a continuous casting from its initial path to a path disposed at an angle thereto comprising a succession of opposed spaced elements between which the casting is moved, and means to adjustably position certain of said elements to provide a curved path for the casting, which path is of successively radii.

8. A guide as defined in claim'6 in which said opposed elements are rollers.

9. A guide as defined in claim 6 in which said opposed elements are rollers, at least some of said rollers being power-driven.

10. A guide as defined in claim 6 in which said 0p posed elements are rollers, at least some of said rollers being power-driven, each roll of each power-driven pair having an individual adjustable-speed drive through which the rolls of each pair may be driven at different speeds relative to each other and to the rolls of other pairs.

11. In a continuous casting machine having an open ended mold with upper and lower ends, means centered in line with the lower end for receiving a casting formed in the mold and guiding it and supporting it, said means comprising a fixed top frame with opposed rollers therein, a succession of progressively lower frames each pivotally hung from the one above and each supporting a pair of opposed rollers similar to the first and movable from a position where the pairs of rollers define a straight path to a position where they define a curved path, and means for selectively adjusting the frames angularly relative to one another and holding them in adjusted position.

12. In a continuous casting machine having an openended mold with upper and lower ends, means centered in line with the lower end for receiving a casting formed in the mold and guiding it and supporting it, said means comprising a series of supporting frames one below another, the uppermost frame being relatively fixed in a horizontal plane, means for adjustably supporting each succeeding frame selectively in a position parallel with the first or at a predetermined angle relatively thereto, each frame having a pair of confronting rolls therein spaced from each other and defining a guideway through which the casting emerging from the mold is supported.

13. A continuous casting apparatus as defined in claim 11 in which the said frames can be selectively adjusted to provide a straight passage for the casting or one in which at least some of the frames define a curve of decreasing radius away from the mold.

14. A continuous casting apparatus as defined in claim 12 in which at least some of the rollers of confronting pairs have means for driving them at relatively different peripheral speeds.

15. A guide for deflecting a continuous casting from its initial direction of travel to a direction disposed at an angle thereto along a curved path comprising a plurality of opposed spaced elements between which the casting is moved and means for adjustably positioning certain of said elements relative to each other for varying the radius of curvature of said path along successive portions thereof.

16. A guide for deflecting a continuous casting from its initial direction of travel to a direction disposed at an angle thereto along a curved path comprising a plurality of opposed spaced rolls between which the casting is moved means for adjustably positioning certain of said opposed rolls relative to each other for varying the radius of curvature of said path along successive portions thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,264,289 12/1941 Betterton et a1. 2257.2 2,284,503 5/ 1942 Williams 22-57.2 2,698,467 1/ 1955 Tarquinee et al 2257.2 2,947,075 8/ 1960 Schneckenburger et a1. 2257.2

J. SPENCER OVER'HOLSER, Primary Examiner. R. A. SANDLER, Assistant Examiner.

Claims

1. APPARATUS FOR WITHDRAWING AND ADVANCING THE CASTING IN A CONTINUOUS CASTING MACHINE WHEREIN THE CASTING LEAVING AN OPEN-ENDED MOLD MAY HAVE A MOLTEN INTERIOR COMPRISING: (A) AT LEAST THREE PAIR OF OPPOSED DRIVEN ROLL MEANS POSITIONED SUCCESSIVELY IN THE DIRECTION OF MOVEMENT OF THE CASTING WITHOUT ALTERING THE CROSS-SECTIONAL SHAPE THE CASTING WITHOUT ALTERING THE CROSS-SECTIONAL SHAPE THEREOF, (B) MEANS FOR: (1) INDEPENDENTLY ADJUSTING THE ALIGNMENT OF SAID PAIRS OF ROLLS RELATIVE TO ONE ANOTHER AND RELATIVE TO THE DIRECTION IN WHICH THE CASTING LEAVES THE MOLD AND