US3344844A

US3344844A - Apparatus for handling a curved continuous casting starting bar

Info

Publication number: US3344844A
Application number: US388562A
Authority: US
Inventors: Reinfeld Kurt; Rokop Joseph
Original assignee: Koppers Co Inc
Current assignee: Raymond Kaiser Engineers Inc
Priority date: 1964-08-10
Filing date: 1964-08-10
Publication date: 1967-10-03
Anticipated expiration: 1984-10-03
Also published as: GB1047669A

Description

1967 K. REINFELD ETAL 3,344,844

APPARATUS FOR HANDLING A CURVED CONTINUOUS CASTING STARTING BAR Filed Aug. 10, 1964 2 Sheets-Sheet l FIG. "1

INVENTOR5 KURT REINFELD 6 JOSEPH ROKOP BY v f/zezr Z Oct. 3, 1967 K. REINFELD ETAL 3,344,844

'APPARATUS FOR HANDLING A CURVED CONTINUOUS CASTING STARTING BAR Filed Aug. 10, 1964 2 Sheets-Sheet 2 i 7 5'9 9 7.9 INVENTORS Kl/E'T RE/NFELD 6 B JOS'EPH EO/(OP Meir Z a:

United States Patent 3,344,844 APPARATUS FOR HANDLING A CURVED CON- TINUOUS CASTING STARTING BAR Kurt Reinfeld and Joseph Rokop, Pittsburgh, Pa., as-

signors to Koppers Company, Inc., a corporation of Delaware Filed Aug. 10, 1964, Ser. No. 388,562 9 Claims. (Cl. 164-274) The present invention relates to the art of continuous metal casting and, more particularly, to improved apparatus and method for producing continuous metal castrngs.

The casting of a continuous strand of metal involves pouring molten metal into a flow-through type of casting mold, which confines the molten metal and partially shapes it to a desired cross section, and withdrawing the metal from the mold as an elongate continuous strand or billet. The casting mold is usually established at a convenient fixed level above a working area, and a ladle of molten metal is transported by a vehicle or crane to a position above the casting mold and machine.

Before teeming the ladle and starting the strand, it is first necessary to temporarily close the bottom of the mold to prevent the molten metal from simply running through the open bottom end of the mold. The open bottom end of the mold is usually closed by means of a dummy bar or starting bar, which is threaded through a customary set of pinch rolls located below the mold for the purpose of driving the dummy bar or starting bar up into the bottom of the mold and later withdrawing it. After the starting bar has been driven into the bottom of the mold, the clearance gap between the head end of the starting bar and the walls of the mold is then sealed with a suitable refractory material. The mold is now ready to receive molten metal from the ladle and a preheated tundish.

Once the mold is prepared to receive the molten metal, the ladle is teemed or discharged into a rectangular trough called a tundish located between the ladle and the mold and from which the metal flows directly into the casting mold. The molten metal first entering the mold is allowed to solidify and become fastened to the head end portion of the starting bar. After the molten metal has risen to some predetermined level in the mold, the mold may be oscillated or reciprocated to prevent sticking of the casting to the mold walls, and the pinch rolls may be actuated to start withdrawing the starting bar and casting from the mold.

The steel continues to solidify as the strand is withdrawn, and a thin skin, which forms on the surfaces of the strand adjacent the inner walls of the mold, thickens as the metal is pulled through the mold. To hasten cooling and to increase the thickness of the skin, the strand is usually passed through a cooling chamber located below the mold where it is sprayed with water from an array of nozzles. The solidifying strand, still at red heat, is pulled by the pinch rollers from the mold in synchronism with the rate of pouring metal into the mold so that the level of the liquid metal in the mold is maintained at a substantially constant level and the strand is formed in a steady continuous manner. At a convenient level below the mold the starting bar is disconnected from the strand and the strand is cut into convenient lengths for subsequent reduction in size.

Two general types of continuous casting machines are employed. One type of machine is known as a vertical cut-off casting machine wherein the casting is withdrawn in a vertical position and is cut to desired lengths at some point below the mold. In such machines, a straight rigid starting bar is used, and after the casting has descended and passed through the pinch rolls, the starting bar is disconnected from the strand and is stored in a convenient position until it is needed for the next casting. The other type of machine is called a horizontal cut-off casting machine wherein the casting is bent from the vertical and is guided by a chute toward a horizontal attitude.

Two main types of horizontal machines exist; one employs a vertical roller apron above a set of pinch rolls and the other employs a curved roller apron and no pinch rolls. A horizontal cut-off casting machine also employs a set of straightener rolls between which the casting passes and from which it emerges as a straightened horizontal casting.

Vertical cut-off casting machines require an installation which are generally too large to be practical or economical. Horizontal cut-oif casting machines, on the other hand, obviously do not require as large an installation as the vertical cut-off machines and for that reason they are more practical and economical. On some horizontal machines, a straight rigid starting bar is used wherein the bar is bent and straightened on each cast. However, repeatedly bending, straightening, and bending the rigid starting bar deforms it to such an extent that it is no longer useful.

It has been proposed heretofore to use articulated starting bars which readily bend and conform to the geometry of the curved roller apron structure, without the attendant difiiculties of the straight rigid bar which must be continually bent and straightened. One form of articulated starting bar, of the sort mentioned, is described in US Patent No. 2,920,359. Such starting bars, however, after being disconnected from the strand, must still be removed and stored in some location near the casting machine until they are to be used again. In the overall operating time to make a casting, the time lost in picking up the stored starting bar, threading it back into the machine, and the time to disconnect it and place it back in storage, can become a serious economic factor.

The present invention relates to apparatus and method for handling curved rigid starting bars of a type useful in horizontal cut-oif casting machine. In accordance with the present invention, there is provided a curved starting bar supporting structure, which adjacently is positioned opposite the discharge end of a horizontal cutolf continuous casting machine, and on which a curved rigid starting bar may be conveniently stored when not in use. In a further aspect of the present invention, straightener rolls engage the curved rigid starting bar and drive it upward into operative engagement with the mold and withdraw it and the casting from the mold; the straightener rolls incorporating a novel mechanism for disconnecting the head end of the starting bar from the casting.

For a further understanding of the present invention and for advantages and features thereof, reference may be made to the following description taken in conjunction with the accompanying drawings forming a part of this application in which:

FIG. 1 is a schematic elevational view of a horizontal cut-01f continuous casting machine incorporating an embodiment of the present invention;

FIG. 2 is a schematic view, partly in section, showing the head end of the starting bar in mated relationship to a casting mold;

FIG. 3 is a schematic view, partly in section, showing the head end of the starting bar and the casting in relation to the disconnect apparatus; and

FIG. 4 is a schematic view, partly in section, showing the starting bar disconnected from the casting.

Referring to the drawings, FIG. 1 illustrates a portion of a continuous casting machine including a plurality of vertical columnar members '11, which are fixed to and rise above a working floor or ground level 13, and which support a plurality of horizontal girders 15 and 17 forming working support levels above the floor or ground level 13. The upper horizontal girders 17 support a conventional movable tundish 19, which is supported by or suspended from a suitable support carriage 21 that is rollable on the horizontal girders 17.

A conventional ladle 23 is shown in an operative position directly above the tundish 19. The ladle 23 is supported in a conventional manner by an arrangement of cables 25. A conventional spill-over box 26 is also suspended from the upper horizontal girder 1'7 and below the tundish 19.

Below the tundish'19 and ladle 23, there is a continuous type of vertical flow-through casting mold 27, which is established and fixed on the lower horizontal girders 15. Beneath the mold 27, there is positioned a conventional type of curved roller apron structure 29, having a typical water cooling spray section enshrouded by an enclosure 30. a a

It is generally desirable to support the roller apron structure 29 on a suitable framework 31, which includes a plurality of wheels 33 that bear and roll upon suitable rails (not shown) fastened to the working floor or ground level ISIThfl apron structure 29 and framework 31, may be readily maintained in an operative position, about where shown in FIG. 1, by means of latch arms 35, which are pivotally connected to the upright columnar members 11, and which engage suitable latch pins 37 fixed t the framework 31.

The arcuate roller apron structure 29 includes a plurality of spaced apart guide rollers 39, upon which the casting is supported as it is withdrawn from the mold. The apron structure is positioned, preferably, so that the upper end is substantially vertical and adjacent the bottom of the fixed mold 27. The lower end of the apron structure extends generally horizontally and at a convenient level above the working floor or ground level 13. Moreover, the curvilinear axis of the apron structure is generally coplanar with the vertical axis of the mold, the tundish, and the ladle.

Preferably, the axis of the apron structure, at the lower horizontal end, is at substantially the same level as a first entrance set of straightener rolls 41, in a straightener apparatus 43, which is fixed to the working floor or ground level 13. The straightener apparatus 43 also includes a second exit set of straightener rolls 45, which are adjustable and movable vertically by means of a suitable ram cylinder 47 and link mechanism 49, mounted conveniently on the straightener apparatus, about as shown in FIG. 1. a

Adjacent to and just beyond the vertically movable straightener exit rolls .45, there is a triangular shaped stop bar 51 (see FIG. 3), which is mounted rigidly to the frame of the straightener apparatus 43 in a manner such that the stop bar 51 is generally perpendicular to the plane of the casting machine. Also, there is mounted near the upper straightener exit rolls 45, a conventional roller type limit switch 53, which is for a purpose to be described hereinafter.

To the right of the straightener apparatus .43, as viewed in FIG. 1, there is a conventional casting take-off apparatus 55, on which the straightened casting is supported as it moves toward a conventional cut-off mechanism, not shown.

Just above the casting take-off apparatus 55, there is provided an arcuate starting bar rack structure 56, the

.axis of which is substantially coplanar with the axis of the roller apron structure 29 and the casting mold 27. The starting bar rack structure 56 includes a pair of arcuate spaced apart parallel plates 57,- 59, which may be maintained in such relation by being fixed to the horizontal girders 15, 17, and to a plurality of vertical support columnar members 61, 63, or in any other appropriate manner.

Between the spaced apart

plates

57, 59, there may be mounted, in any suitable manner, a plurality of guide rollers and support rollers 67, which are conveniently disposed oppositely and in spaced apart relation, about as shown in FIG. 1. The

rollers

65, 67 are spaced apart a distance sufiicient to accommodate a curved starting bar 77, when the same is disposed therebetween in a manner to be described hereinafter.

Above the upper horizontal girder 17, there is provided a conventional type sheave 69, which may be mounted in a vertical position, about as shown in FIG. 1, in a suitable bearing support 71 which may be fixed to the columnar members 11. Below the sheave 69, there is provided a suitable hoisting mechanism 73, which may be conveniently powered by an electric motor 75; both of which are fixedly mounted on the lower horizontal girders 15. The hoisting mechanism 73 is positioned, preferably, so that a hoisting cable 75, that is wound on the hoisting drum, passes over the sheave 69, and is connectable to a suitable joining eye 74, fixed in one end of the curved starting bar 77. The curved startting bar 77 is shown in its stowed position in FIG. -l, from which position it is readily removable at the commencement of a casting, as will be described hereinafter.

Referring to FIG. 3, the lower end, or what is actually the head end of the starting bar 77, includes first and

second body portions

79, 81 that are detachably connected together. The first body portion 79 has a cross section that is generally rectangular or square and, a length which is substantially equal to the width of the casting. The first body portion 79, moreover, has a plurality of slots 83, which have a generally Y-shape configuration, similar to that shown in FIG. 3. There is provided in the right hand wall forming the vertical leg of the Y, another rectangular slot 85. A bolt-like member 87 is fixed to and projects outwardly from the body portion81 in such a manner that the shank of the bolt 87 is received in the slot 85, and the head of the bolt is received in the slot 83. A similar bolt-like member 89 is fixed to and projects from the first body portion 79.

As may be seen in FIG. 2, when the head end portion of the starting bar is positioned in mated relationship with the casting mold, the bolt-like member 89 projects into the bottom portion of the mold and becomes fixed to the solidified initial portion of the casting, when it'is poured. Each of the bolt-

like members

87, 89 may be readily maintained in its

respective body portion

81, 79, by means of suitable keeper pins 91, or in any other appropriate manner. To facilitate disconnecting the first body portion 79 from the second body portion 81, the upper part of the surface of the body portion 79, which abuts the body portion 81, is curved, about as shownin FIGS. 3 and 4.

Referring to FIG. 1, it is convenient to assume-thata continuous casting has just been completed and that another is to be commenced. The starting bar 77 at this time is in its stowed position in the'starting bar rack structure 56, and it is held in this stowed position bythe hoisting cable 75 and hoisting mechanism 73. The casting machine may be conveniently operated from a control console or panel 99 located on the lower horizontal girders 15, at which location, an operator regulates and controls the power output from a power unit 101, conveniently located nearby, to operate the casting machine.

The exit straightener rolls 45 are first raised to the position shown in FIG. 3, and then opened or separated a distance great enough to admit the starting bar 77, which, at the same time, is being lowered from the rack structure until the head end of it passes between the exit straightener rolls 45 and between the entrance straightener rolls 41. The entrance straightener rolls 41 may then be actuated to drive the starting bar 77 upward toward the mold 27.

It will be noted that the hoisting cable 75, as it pays out to lower the starting bar, may be guided by a suitable guide roller 103, fixed to the starting bar rack structure, and by the other guide rollers 65. The starting bar 77 is driven upward by the straightener rolls 41 until the head end abuts the mold in mating relationship, about as shown in FIG. 2. The joint between the mold and the head end may now be suitably sealed with a suitable refractory material to prepare the mold to receive molten metal. The ladle, with molten metal therein, may thereuponbe teemed, and the metal flows into the tundish and into the mold to initiate the casting.

After the casting has become inseparably connected to the bolt-like member 89, the straightener rolls 41 may be reversed to withdraw the starting bar and the casting from the mold. The starting bar will follow the curvature of the apron structure to which it is conformable, and the lower end of the starting bar again passes between the spaced apart vertically movable exit straightener rolls 45. The starting bar will then enter between the

rollers

65, 67 in the starting bar rack structure 56. The curved roller apron structure and the starting bar rack support structure have, peferably, the same curvature so that there will be no bending forces exerted on the starting bar. The entrance straightener rolls 41 continue to withdraw the starting bar and casting from the mold at substantially the same rate of speed as the casting is being formed in the mold. It will be appreciated by those skilled in the art, that in the present invention there is no need to employ the usual set of pinch rolls which ordinarily engage the starting bar and drive it into the mold, and later withdraw it and the casting from the mold. In the present invention, the starting bar, being a curved rigid member, may be readily moved forward and backward by the straightener rolls. One purpose of the straighteners rolls is to advance and retract the curved starting bar without deforming it. So, too, the straightener rolls later engage the casting when it has grown sufiiciently in length and passes through the straightener rolls. By the time the straightener rolls engage the casting, it is solid throughout and there is little or no danger of inducing cracks, flaws and other defects.

After the head end of the starting bar and casting have passed through the exit straightener rolls 45, and are in 'a position about as shown in FIG. 3, a limit switch, not shown, is actuated by the roller contact member 53 falling into one of the Y-shaped slots 81. The downward movement of the roller contact member causes the ram cylinder 47 to move the pivotal link member 49 so that the straightener rolls 45 move rapidly downward. In doing so, they exert a downward force on the end of the casting and the starting bar to which it is connected. However the tapered end portion of the starting bar bears against the stop bar 51 and is restrained from downward movement. Consequently, the bolt-like member 87 becomes disengaged from the

slots

83, 85 and the first body portion 79 is separated downwardly from the second body portion 81.

' During the downward motion of the rolls 45 to disconnect the casting from the starting bar, the hoisting mechanism 73 is actuated to exert a pulling and restraining force on the starting bar which is sufficient to hold it, and to advance it upwardly further into the storage rack. After the casting has been disconnected, it will be straightened in the usual manner and directed horizontally, about as shown in FIG. 4. The casting moves toward the casting takeoff apparatus, mentioned previously; the driving force. being exerted by the entrance set of straightener rolls 41.

' After a'casting'has been completed, the same curved starting bar is readily available and may be quickly positioned, as described hereinbefore, to commence another casting.

We claim:

1. A starting system for a continuous metal casting machine having an arcuate. roller apron structure with 6 an entrance end adjacent the bottom of a fixed vertical flow-through casting mold and a discharge end oriented in a substantially horizontal direction, comprising:

(a) an arcuate rigid starting bar conformable to the curvature of said arcuate roller apron structure;

(b) staightener apparatus adjacent the discharge end of said apron structure and having a set of first roller members for advancing said arcuate starting bar into mating relation with said casting mold and for controllably withdrawing said bar and casting from said mold, said straightener apparatus having a set of second movable vertically opposed rollers capable of operating upon said bar and casting;

(c) a starting bar support adjacent said straightener apparatus and substantially coplanar with said roller apron structure for receiving and supporting said starting bar;

(d) a limit switch actuatable at a predetermined moment after the end portion of said casting has passed between said vertically opposed rollers to move said rollers downward rapidly and disconnect said starting bar from said casting; and

(e) a hoisting mechanism fixed to said starting bar support and having a cable connected to said arcuate starting bar whereby said starting bar engages said starting bar support and said bar is maintained in said support.

2. A starting arrangement for a continuous metal casting machine having an arcuate roller apron structure with an entrance end adjacent the bottom of a fixed vertical flow-through casting mold and a discharge end oriented in a substantiallyhorizontal direction, comprising:

' (a) an arcuate rigid starting bar conform-able to the curvature of said apron structure; and

(b) straightener rolls positioned adjacent the discharge end of said apron structure and adapted to operate upon said arcuate starting bar for advancing the same into mating relation with said casting mold and controllably withdrawing said bar and casting from said mold.

3. A starting arrangement for a continuous metal casting machine having an arcuate roller apron structure positioned with its entrance end adjacent the bottom of a vertical flow-through casting mold, and its discharge end oriented in a substantially horizontal direction, compnsmg:

(a) an arcuate rigid starting bar conformable to the curvature of said arcuate roller apron structure; (b) straightener apparatus positioned adjacent the discharge end of said apron structure and having a set of first roller members for advancing said starting bar toward said casting mold and controllably withdrawing said bar and casting from said mold, said straightener apparatus having a set of second Vertically movable roller members capable of operating upon said bar and casting;

(c) a stop bar fixed in relation to said vertically movable roller members and downstream therefrom; (d) an arcuate structure positioned adjacent said straightener apparatu and substantially coplanar therewith, said arcuate structure being conformable to the curvature of said arcuate rigid starting bar and adaptable to support the same;

(e) means actuatable at a predetermined moment after an end portion of said casting has passed between said vertically movable roller members and said starting bar bears against said stop bar whereby said vertically movable roller members descend rapidly and disconnect said starting bar from said casting; and

(f) means for supporting and maintaining said starting bar in said arcuate structure.

4. A starting arrangement for a continuous metal casting machine having an arcuate roller apron structure. positioned with its entrance end adjacent the bottom of a vertical flow-through casting mold, and its discharge end oriented in a substantially horizontal direction, comprising:

(b) means for advancing said starting bar toward said casting mold and controllably withdrawing said bar and casting from said mold;

(c) an arcuate structure adjacent said starting bar ad vancing means and substantially coplanar with said apron structure, said arcuate structure being conformable to the curvature of said arcuate rigid starting bar and adaptable to support the same;

(d) means actuatable at a predetermined moment after said bar has been received by said arcuate structure to disconnect said casting from said starting bar; and

(e) means for maintaining said starting bar in said arcuate structure.

5. A continuous metal casting machine comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure positioned with its entrance end adjacent the bottom of said mold and its discharge end oriented in a substantially horizontal direction;

(c) an arcuate rigid starting bar conformable to the curvature of said arcuate roller apron structure; (d) means for advancing said starting bar toward said casting mold and controllably withdrawing said bar and casting from said mold;

(e) an arcuate structure adjacent said starting bar actuating means and substantially coplanar with said apron structure, said arcuate structure being conformable to the curvature of said arcuate rigid starting bar and adaptable to support the same;

(i) means actuatable at a predetermined moment after said bar has been received by said arcuate structure to disconnect said casting from said starting bar; and

(g) hoisting means to elevate and maintain said starting bar in said arcuate support structure.

6'. A starting arrangement for a continuous metal casting machine, comprising:

(a) a rigid arcuate starting bar;

(b) an arcuate structure adjacent to and lying substantially in the vertical plane of said machine for receiving and supporting said arcuate starting bar; and

(c) means for maintaining said starting bar in an elevated position adjacent said machine and for lowering said starting bar from said arcuate structure to operatively coact with said machine.

7. A horizontal cut-oil continuous metal casting machine comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure for supporting said casting;

(c) a rigid arcuate starting bar conformable to and cooperative with said apron structure;

(d) means actuatable at a selected time to disconnect said starting bar from said casting; I

(e) an arcuate structure adjacent to and lying substantially in the vertical plane of said machine for supporting said arcuate starting bar in an elevated position after the same has been disconnected from said casting and maintaining said bar adjacent said machine in such a manner that said starting bar may be lowered from said support structure to operatively I coact with said machine; and

(f) powered means to elevate and maintain said starting bar in said support structure.

8. A horizontal cut-off continuous metal casting machine comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure capable of sup- (e) means actuatable by said starting bar for disconnecting said starting bar. from said casting;

(f) an arcuate structure adjacent to and lying substantially in the vertical plane of said machine for supporting said arcuate starting bar in an elevated position after the same has been disconnected from said casting and maintaining said bar adjacent said machine in such a manner that said starting bar may be lowered from said support structure to operatively coact with said machine; and

(g) means for elevating and maintaining said starting bar in said support structure.

9. A continuous metal casting machine of the horizontal cut-ofi type comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure positioned with one end adjacent the bottom of said mold and with the other end oriented in a substantially horizontal direction, said apron structure and said mold being substantially coplanar;

(c) a rigid arcuate starting bar conformable to and cooperative with said apron structure and said mold;

(d) straightener apparatus positioned adjacent the discharge end of said apron structure and having a set of first powered roller members engageable with said starting bar for driving said bar toward said casting;

mold and controllably withdrawing said bar and casting from said mold; V

(e) a set of vertically movable roller members adjacent said straightener apparatus and positioned downstream therefrom which are capable of operating upon said casting to exert a downward force thereon;

(f) an arcuate structure adjacent to and lying substantially in the vertical plane of said machine for supporting said arcuate starting bar in an elevated position after the same has been disconnected from said casting and maintaining said bar adjacent said machine in such a manner that said starting bar may be lowered from said support structure to operatively coact with said machine;

(g) means for restraining said starting bar from downward movement relative to said casting;

(h) means for moving said vertically movable roller members downward at a predetermined moment and disconnecting said casting from said starting bar; and

(i) hoisting means connected to said starting bar for elevating the same in said arcuate structure after said bar has been disconnected from said casting, and maintaining said bar in a selected position in said arcuate structure.

References Cited 1. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner.

Claims

2. A STARTING ARRANGEMENT FOR A CONTINUOUS METAL CASTING MACHINE HAVING AN ARCUATE ROLLER APRON STRUCTURE WITH AN ENTRANCE END ADJAENT THE BOTTOM OF A FIXED VERTICAL FLOW-THROUGH CASTING MOLD AND A DISCHARGE END ORIENTED IN A SUBSTANTIALLY HORIZONTAL DIRECTION, COMPRISING: (A) AN ARCUATE RIGID STARTING BAR CONFORMABLE TO THE CURVATURE OF SAID APRON STRUCTURE; AND (B) STRAIGHTENER ROLLS POSITINED ADJACENT THE DISCHARGE END OF SAID APRON STRUCTURE AND ADAPTED TO OPERATE UPON SAID ARCUATE STARTING BAR FOR ADVANCING THE SAME INTO MATING RELATION WITH SAID CASTING MOLD AND CONTROLLABLY WITHDRAWING SAID BAR AND CASTING FROM SAID MOLD.