US3524494A

US3524494A - Tundish dumping and skewing device for continuous casting

Info

Publication number: US3524494A
Application number: US716763A
Authority: US
Inventors: Wilbur R Smith
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1968-03-28
Filing date: 1968-03-28
Publication date: 1970-08-18
Anticipated expiration: 1987-08-18

Description

Aug. 18, 1970 w. R. SMITH 3,524,494

' TUNDISH DUMPINGI AND SKEWING DEVICE FOR CONTINUOUS CASTING Filed March 28, 1968 2 SheetS -Sheet 1 v INVENTOR v M760! 1?- Smifh Aug. 18, 1970 w. R. SMITH 3,524,494

TUNDI SH DUMPING AND SKEWING DEVICE FOR CONTINUOUS CASTING Filed March 28, 1968 2. Sheets-Sheet 2 dh/a i 55 6 1331 60 Q I| I l I *1 a l r INVENTOR g 8 mm A. sm/m United States Patent "ice 3,524,494 TUNDISH DUMPING AND SKEWING DEVICE FOR CONTINUOUS CASTING Wilbur R. Smith, Allentown, Pa., assignor to Bethlehem Steel Corporation, a corporation of Delaware Filed Mar. 28, 1968, Ser. No. 716,763 Int. Cl. B22d 11/10, 41/04 US. Cl. 164-281 4 Claims ABSTRACT OF THE DISCLOSURE A tundish, adapted to be rotated about its trunnions, is disposed above a vertical mold. The trunnion seats are pivotally mounted and independently movable whereby the tundish may be skewed about a vertical axis. A hydraulic cylinder controls the rotation of the tundish about its trunnions whereby the tundish can be leveled prior to casting and dumped following casting. The cylinder is connected to the trunnion seat and the tundish whereby skewing of the tundish results in substantially no rotation of the tundish about its trunnions.

BACKGROUND OF THE INVENTION This invention relates to continuous casting apparatus, and more particularly to apparatus for centering the streams of molten metal pouring from a tundish into a vertical continuous casting mold without affecting the level position of the tundish.

In the continuous casting of slabs of molten metal, e.g. steel, the molten metal is generally poured from a ladle into a tundish and thence into a vertical mold. The tundish is a hollow vessel, lined with a refractory material, and generally has a plurality, e.g. two or more, of nozzles, also lined with a refractory material, in the bottom thereof.

It is vitally important that the streams of molten metal leaving the nozzles enter the mold as symmetrically as possible in order to ensure uniform solidification. Thus, the nozzles should be centered with respect to the geometric center lines of the cross section of the mold.

Frequently, the nozzles of a tundish are disposed along a line which is not centered with respect to the mold cross section. It is therefore essential to skew the tundish, i.e. rotate it about a vertical axis, to center it above the mold. However, the skewing of the tundish must not result in tilting of the tundish, as tilting of the tundish will cause the metal to leave the nozzles at an angle, and the metal falling into the mold will build up along one side thereof with consequent nonuniform cooling.

In addition to the foregoing, the tundish should be provided with means for controlling the rotation of the tundish about its trunnions. That is, this means should be capable of initially leveling the tundish prior to the casting operation, and capable of dumping the metal out of the tundish after the casting operation is completed.

This means should further be capable of rotating the tundish through a relatively large angle, e.g. 109, whereby no metal is left therein after dumping. This means must, however, be connected to the tundish in such a manner that skewing of the tundish does not appreciably affect the level position of the tundish.

It is an object of this invention to provide improved means for skewing and dumping a tundish, the skewing and dumping motions being substantially independent of each other.

SUMMARY OF THE INVENTION I have discovered that the foregoing object can be attained by providing a support frame, comprising two horizontal members disposed above a vertical continuous 3,524l,4194 Patented Aug. 18, 1970 casting mold, pivotally mounted trunnion seats disposed on said support frame, a tundish provided with trunnions rotatably mounted in said trunnion seats, extensible and retractile means linking each of said trunnion seats and said support frame, slidable means mounted on each of said horizontal members, means pivotally connecting said tundish and said slida-ble means for controlling the rotation of said tundish about its trunnions, and means connecting said trunnion seats and said slidable means whereby any change in the horizontal position of said tundish trunnions as a result of skewing results in substantially no rotation of said tundish about its trunnions.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. la and 1b are diagrammatic plan views of a tundish having nozzles disposed above the mold of a continuous slab casting machine.

FIG. 2 is a side elevation showing the tundish in a level position.

FIG. 3 is a side elevation showing the tundish in a dumping position.

FIG. 4 is a plan view, partly in section, showing details of the skewing and dumping mechanism.

FIG. 5 is an enlarged sectional view showing details of the skewing and dumping mechanisms.

FIG. 6 is a sectional view taken along the lines 6-6 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1a shows a tundish 10 disposed above the mold 12 of a continuous slab casting machine. In the bottom of said tundish are three nozzles 14 through which molten metal leaves the tundish 10 and falls into the mold 12. As can be seen, the nozzles 14 are not centered above the longitudinal center line 16 of the mold 12. It is therefore necessary to skew the tundish 10, in the direction of the arrows, until it assumes the position shown in FIG. 1b. (The amount of misalignment ShOWn in FIG. 10 has been greatly exaggerated for the sake of clarity. In general, the tundish need not be skewed more than about one-half nch on each side thereof.) The angle of skew 18, which is herein defined as the angle between the center line 20 of the tundish 10 before skewing and the center line 22 of the tundish 10 after skewing, is usually less than one degree, e.g. i051'.

The tundish 10 is supported above the mold 12 by means of a framework 24 comprising beams 26 and columns 28. The framework 24, which is provided with suitable trusses (not shown), is adapted to be raised, lowered, and moved horizontally by well known means (also not shown).

Each beam 26 is provided with a bracket 30 on which a trunnion seat 32 is pivotally mounted by means of a pm 34. Each column 28 is provided with a bracket 36 on which one end of a turnbuckle-like device 38 is pivotally mounted, the other end of the device 38 being pivotally mounted on the trunnion seat 32. The device 38 comprises a shaft 40 having a wheel 42 mounted thereon. One end of the shaft 40 is free to rotate within shaft housing 44, said housing being pivotally mounted on bracket 36 by means of pin 46. The other end of shaft 40 threadedly engages shaft housing 48, housing 48 being pivotally mounted on trunnion seat 32 by means of pin 50.

Each trunnion seat 32 is provided with a slot bearing 52 in which one trunnion 54 of the tundish 10* rests. A lock plate 56 is bolted across the top of the slot bearing. Each trunnion 54 is provided with a spherical bearing surface to permit skewing of the tundish 10 without binding the trunnions. Each trunnion is disposed in substantial vertical alignment with its respective trunnion seat pivot whereby small rotary movements of said trunnion 3 seat result in substantially entirely horizontal motion of said trunnion,

A connecting rod 58 is provided which links the trunnion seat 32 to a block 60 slidably mounted on the beam 26. As is shown in detail in FIGS. 4, and 6, each connecting rod 58 comprises plates 62 which are pivotally connected to trunnion seat 32 by pin 64 and spacer blocks 65. The other end of the connecting rod 58 is pivotally connected to block 60 by pin 66 and spacer blocks 68.

Interposed between the spacer block 68 is a selfaligning bushing assembly 70 which is connected to one end 72 of a hydraulic cylinder 74. The bushing assembly 70 is mounted within the block 60 by the pin 66 and com prises a spherical bearing 76. The block 60 is adapted to slide along a bearing surface of plate 78 disposed on the beam 26.

The hydraulic cylinder 74 has a shaft 80 connected to the piston thereof. The end of the shaft 80 is connected to a tongue 82 pivotally conected to the pin 84 of a clevis block 86. The tongue 82 is provided with a self-aligning bushing assembly 88 similar to the bushing assembly 70. The clevis block 86 is rigidly affixed to a bracket 90 mounted on the side of the tundish 10.

The hydraulic cylinder 74 is utilized for both initially leveling the tundish and for dumping same. The center of gravity 91 of the tundish is so disposed that, referring to FIG. 2, the tundish 10 has a clockwise moment which is balanced by the cylinder 74.

Mounted on the beam 26 is a heat shield 92 adapted to protect the above-described skewing and dumping mechanisms from the intense heat of the molten metal in the tundish 10.

The subject apparatus operates substantially as follows:

Assuming the nozzles of the tundish 10 are misaligned with respect to the mold 12, the tundish is skewed by rotating one or both of the wheels 42, depending upon the degree of misalignment. Rotation of the wheel 42 results in either extending or retracting the shaft housing 48 and imparts a rotary motion to the trunnion seat 32.

By reason of the arrangement of the connecting rod 58 and the block 60, any change in the horizontal position of the trunnion as a result of the extension or retraction of the shaft 40 is transformed into a substantially equal change in the horizontal position of the block 60. has much as the block 60 is also connected to the tundish 10 at bracket 90, by means of hydraulic cylinder 74, bracket 90 will change its horizontal position by an amount substantially equal to the change in horizontal position of block 60. Thus, skewing of the tundish 10 results in substantially no rotation of the tundish about its trunnions, and the tundish remains level.

To dump the tundish 10, all that is required is to retract the shaft 80 of the hydraulic cylinder 74, as is shown in FIG. 3. As can be seen, the motion of the dumping mechanism is substantially independent of the motion of the skewing mechanism.

While the subject invention has been described with reference to a tundish having a plurality of nozzles, which generally requires a skewing motion to center said nozzles with respect to the mold, the invention may also be used for centering a tundish having but one nozzle therein. In this case, no skewing is necessary, and the tundish nozzle may be centered by rotating both of the wheels 42 in the same direction.

I claim:

1. In a vertical continuous casting machine,

(a) a support frame including two horizontal members,

spaced apart, disposed above a vertical mold,

(b) a trunnion seat pivotally mounted on each of said horizontal members,

(c) a tundish, comprising a hollow vessel having a nozzle in the bottom thereof and provided with trunnions at the sides thereof, said trunnions being rotatably mounted in said trunnion seats,

(d) means slidably mounted on each of said horizontal members,

(e) means for separately rotating each of said trunnion seats about its pivot,

(f) means linking each of said trunnion seats and means ((1) whereby any change in the horizontal position of said trunnion as a result of the rotation of its trunnion seat is transformed into a substantially equal change in the horizontal position of means (d), and

(g) means, pivotally mounted on said tundish and means (d), having a retracted and an extended position for controlling the rotation of the tundish about said trunnions.

2. Apparatus as recited in claim 1, in which each of said trunnions is in substantial vertical alignment with its respective trunnion seat pivot.

3. Apparatus as recited in claim 2, in which:

(i) said trunnions are provided with a spherical bearing surface, and

(ii) the means pivotally mounting means (g) to said tundish and said means (d) comprises self-aligning bearings.

4. Apparatus as recited in claim 1, in which said tundish has a plurality of nozzles in the bottom thereof.

References Cited UNITED STATES PATENTS 3,459,312 8/1969 Britcher et al. 164335 X J. SPENCER OVERHOLSER, Primary Examiner I. E. ROETHEL, Assistant Examiner US Cl. X.R.