Continuous casting machine

A continuous casting machine has a flow through mold and a flexible starting bar composed of a plurality of short sections coupled by hinges which permit the sections to pivot inwardly to a slight degree but prevent outward pivotal movement beyond the machine's arcuate casting path. A storage assembly for the starter bar includes a pair of support stands each having spaced drive rolls disposed along the arcuate casting path through which the starter bar passes as it is moved into and out of its stored position. One roll of each stand is fixed and the other is mounted on a pivotal arm engaged by a hydraulic cylinder to provide a pinching effect on the starter bar as it is moved between its operative and stored positions.

BACKGROUND OF THE INVENTION 
This invention relates to continuous casting machines of the type designed 
to cast billets, blooms and slabs, for example, and more particularly to a 
continuous casting machine starting bar and starting bar storage system. 
Continuous strands of cast metal, such as steel, are produced by pouring 
molten metal into the open upper end of a flow-through casting mold and 
withdrawing the metal in a continuous strand from the opening in the 
bottom of the mold. The molten metal is delivered to the upper end of the 
mold by a tundish, which in turn, receives metal from the ladle used to 
transport the metal from the melting furnace. 
Initially, the lower end of the mold is closed by a starting bar which 
extends downwardly from the mold and through an arcuate guide assembly. 
When the end of the starting bar emerges from the open lower end of the 
mold, it is followed by the cast strand. As the joined ends of the cast 
product and starting bar move beyond the position of the withdrawal 
straightener mechanism rollers the two are disconnected by means of a 
separate mechanical device, so that the strand can pass to a runout table 
where it is cut into suitable lengths while the starting bar continues its 
movement along a separate path into its storage position. 
Some prior art continuous casting machines employ in arcuate guiding 
system, located between the mold and withdrawal straightener mechanism, 
for the purpose of guiding the cast strand as it exits the mold in a 
generally downward direction along with providing support for the starting 
bar chain during commencement of the casting sequence along with providing 
support during insertion of the starting bar into position prior to the 
start of the casting process. 
Two types of starting bars which satisfy this requirement are in common 
use. These include a rigid bar having a curvature which conforms to the 
arc described by the radius of the casting machine, and a flexible bar 
formed of a plurality of links which assume the contour of the support 
assembly through which it passes. 
Examples of rigid curved starting bars are shown in U.S. Pat. Nos. 
3,344,844; 3,370,641; 3,433,287; 3,628,595; 3,658,120; 3,930,533; 
4,286,649; and 4,412,579. These bars may be fabricated as a unitary member 
or may be composed of a number or rigidly secured segments as shown in 
U.S. Pat. No. 4,043,383. Examples of flexible starting bars are shown in 
U.S. Pat. Nos. 3,426,835; 3,495,651; 4,291,748; 4,382,462; 4,425,960; and 
4,457,353. Some prior art flexible starting bars are semi-rigid; that is, 
they are constructed and arranged to provide only a limited degree of 
flexibility as shown in U.S. Pats. Nos. 2,920,359; 3,608,619, and 
4,383,571. 
Each of the prior art casting machines discussed above requries a 
complicated and costly assembly for moving the starting bar away from the 
withdrawal rolls and for supporting the starting bar in its storage 
position. In addition, prior art starting bars are relatively complicated 
and expensive to manufacture. Further, prior art flexible starting bars 
require a curved guiding and supporting mechanism between the bottom of 
the mold and the entrance end of the withdrawal straightener unit, are 
expensive, and require costly and time consuming maintenance procedures 
int he event of a hot metal spill or a break out of a newly cast metal 
strand. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a new and improved starting bar 
system for continuous casting machines. 
A further object of the invention is to provide a starting bar system which 
can be readily adapted for use in continuous casting machines of the type 
which utilize either a curved or a straight mold. 
A still further object of the invention is to provide a starting bar system 
for continuous casting machines which does not require elaborate guiding 
and support mechanisms between the mold and the withdrawal straightener 
unit. 
Another object of the invention is to provide a starting bar storage system 
relatively simplified and positioned in such a manner as to be free and 
clear of that of other mechanisms associated with continuous casting 
machines, thereby reducing congestion and the possibilities of damage 
resulting from congestion. 
Still another object of the invention is to provide a continuous casting 
machine starter bar system which is simplified in design, thereby 
expensive to manufacture. 
In general terms, the invention comprises a continuous casting machine 
having a mold oriented generally vertically and a starting bar comprising 
a plurality of pivotally interconnected links. The pivot axes of pivotally 
connected adjacent link pairs extends perpendicular to the axis of the 
casting path, and each of the links has first and second abutment surfaces 
at each end. Support means are disposed generally below the mold for 
supporting spaced apart points on the starting bar along the casting path 
with one end oriented generally vertically below the open lower end of the 
mold and the opposite end extending in generally horizontal direction. The 
first abutment surface on one link engages the first abutment surface on 
the adjacent link to limit pivotal movement of the links in an outward 
direction so that the unsupported portions of the starting bar will have a 
free form that lies along the casting radius. The second abutment surface 
at the end of each link engages the second abutment surface on the 
adjacent link when the links pivot inwardly from the casting path and are 
out of engagement when the first abutment surface is engaged, whereby 
slight pivotal movement of the links out of alignment with the casting 
path is permitted but outward pivotal movement of the links is arrested 
when the curvature of the casting path is reached.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A casting machine 10 which includes a starting bar 11 and a storage 
apparatus 12 in accordance with the invention, is shown schematically in 
FIG. 1. In general terms, the casting machine 10 includes a vertically 
oriented flow-through mold 13 which is disposed below a tundish 14. A pair 
of support strands 15A and 15B are disposed below the mold 13 and each is 
positioned for supporting the starting bar 11 and the cast strand 16 as 
they exit the mold 13 and are delivered to the storage assembly 12 or the 
run out and cutting table 17. Disposed between the supports 15A, 15B and 
the run out and cutting table 17 is a withdrawal and straightener assembly 
18 which includes opposed rolls 19A, 19B and 20A, 20B. The lower rolls 19B 
and 20B may for example be mounted for rotation about fixed axes while the 
upper rolls 19A and 20A are mounted on frames (not shown) which are urged 
by pressure exerting means, such as hydraulic cylinders 22A, 22B, into 
engagement with the strand 16. The rolls may also be driven for exerting a 
withdrawal force on the strand 16 or the starting bar 11 to withdraw the 
same from mold 13 and for feeding the same to the runout table 17 or the 
storage assembly 12. Roll 20A is also mounted on a pivot arm 21 for 
movement under the influence of cylinder 22B between its full and broken 
line positions shown in FIGS. 1 and 13. 
As those skilled in the art will appreciate, the mold 13 may be mounted on 
a vibrator assembly (not shown) which moves the mold 13 relative to the 
strand 16 to prevent adherence therebetween. A ladle 23 is supported in 
any suitable manner, such as by a crane, so that molten metal may be 
transported between the melting furnace (not shown) and the tundish 14. A 
second ladle (not shown) may be in transit between the melting furnace and 
the continuous casting machine 10 to provide a continuous delivery of 
molten metal. 
The support strands 15A and 15B respectively include pedestals 24A and 24B, 
each of which has a post 26 extending vertically upward from its upper 
end. Each post 26 is secured to a base plate 25 mounted atop the pedestals 
24A and 24B and each is reinforced by vertical side ribs 27. Rollers 29A 
and 29B are respectively mounted at the upper ends of the posts 26 of 
strands 15A and 15B. As seen in FIG. 1, the pedestal 24A has a greater 
height than pedestal 24B so that the rollers 29A and 29B of support stands 
15A and 15B define two points on a vertically curved path. 
The mold 13 has an arcuate passage 29 with openings at its upper and lower 
ends. The curvature of the mold passage defines an arcuate casting path 
comprising points equidistant from the mold passage center of curvature 
34. The rollers 29A and 29B define two points on this path and the rollers 
19A and 20A two additional points. 
As those skilled in the art will appreciate, when the casting operation is 
commenced, the head 31 of starting bar 11 is disposed in the open lower 
end of the mold 13. The bar 11 extends downwardly from the mold 13 and 
along the casting path where it engages the rollers 29A and 29B and with 
its opposite end disposed between the rollers 19A, 19B and 20A, 20B. The 
molten metal to be cast is discharged from ladle 23 into tundish 14 from 
which it is fed into the open upper end of mold 13. As the metal begins to 
solidify from its outer surface inwardly, the withdrawal rollers 19A, 19B 
and 20A, 20B are actuated to withdraw the starting bar head 31 from the 
lower end of mold 13. As the head 31 exits the mold 13, it is followed by 
the partially solidified strand 16. A vibrator assembly (not shown) 
vibrates the mold to prevent the strand 16 from adhering thereto. The 
metal is fed into the upper end of the mold 13 from the tundish 14 at the 
same rate as it is withdrawn as a strand 16 from the lower end to insure 
continuous operation. 
As the starting bar 11 is withdrawn, it will follow the arcuate path 
defined by the support assembly 12 and into the storage position as shown 
by full lines in FIG. 1. To permit the starting bar to travel in this 
path, the roller 20A is initially in an elevated position. As will be 
discussed more fully below, when the head 31 of the starting bar passes 
the roller 20A, the latter is pivoted from its position shown by broken 
lines in FIG. 1 to its full line position so as to separate the starting 
bar 11 from the strand 16. With the roller 20A in this position the strand 
16 is straightened and passes to the runout table 17. 
The starting bar 11 is shown in FIG. 1 to comprise the head section 31, a 
first rigid arcuate section 34 pivotally coupled at one end to the head 
section 31. At its opposite end, the section 34 is coupled to a hinged 
section 35, the other end of which is coupled to one end of a second 
arcuate rigid section 36. 
The hinged section 35 comprises a plurality of short members 37 which may 
have any convenient shape, such as for example, short I-beam sections as 
seen in FIG. 3. Each member 37 has a center webb 38 which interconnect 
flanges 39. In addition, a first end piece 40 is disposed at one end of 
each section 37 and a second end piece 42 is located at the other end, as 
seen in FIGS. 2 and 4-6. End piece 40 has a pair of forwardly projecting 
portions 44 which define a groove 46 therebetween for receiving a tongue 
45 projecting from the end piece 42 of the next adjacent member 37. The 
end pieces 40 and 42 are configured so that pivotal movement will be 
limited whereby the bar will be self-supporting at the machine casting 
path with limited pivotal movement inwardly therefrom. In particular, each 
of the forwardly projecting portions 44 has a front face 48 which slopes 
upwardly and rearwardly from a laterally extending abutment surface 50 
located at about the mid-height of end piece 40. Extending downwardly and 
rearwardly from abutment surface 50 is an arcuate surface 52. The inner 
end of goove 46 terminates in a surface 54 which is generally 
perpendicular to a plane containing surface 50. Extending rearwardly from 
surface 54 is a third abutment surface 55 which defines a recess 57 
communicating with the lower portion of groove 46. The tongue 45 is formed 
similarly to projecting portions 44 in that it includes a sloping front 
face 62, a laterally extending abutment surface 63 and an arcuate surface 
65. At the rear of the tongue 45 there are a pair of abutment surfaes 67 
in an opposed relation to surfaces 48 of projecting portions 44 and a 
recess 68 is formed below each surface 67 to define an abutment surface 70 
perpendicular to surface 67 and disposed in an opposed relation to 
abutment surfaces 50. A pin 72 extends through aligned openings 73 and 74 
in the projecting portions 44 and the tongue 45 for pivotally connecting 
the end pieces 40 and 42. Spring pins lock the pin 72 in position. 
As seen in FIGS. 7 and 8, the head 31 is coupled to the arcuate section 34 
by a pivotal coupling 72 similar to the pivotal couplings 72 which 
interconnects the members 40 and 42. Accordingly, the connection 72 will 
not be discussed in detail. The head 31 includes a main body 78 having a 
longitudinal slot 80 which extends upwardly from its lower and front 
surfaces 82 and 83, respectively. A pin 85 is disposed within slot 80 and 
projects beyond the front surface 83 and in a generally axial direction. 
Pairs of aligned openings 86 are formed through the head 78 and each pair 
is coaxial with an opening 87 in pin 85. Extending through each group of 
aligned openings 86 and 87 is a dowel pin 89 for retaining the pin 85 in 
the position shown. 
It can be seen that outward pivotal movement past the machine casting path 
curvature is prevented by the engagement of surfaces 50 and 70 on one side 
of pin 72 and surfaces 55 and 63 on the other. Similarly, inward pivotal 
movement is limited by the engagement of surfaces 48 and 67 on one side of 
pin 72 and 54 and 62 on the other. This minimizes stresses on the pin. 
Also, the tongue-in-groove connection of the links 37 provides a 
substantially continuous contact surface for the rollers of the withdrawal 
assembly 18 and the storage assembly 12. 
The storage assembly 12 inlcudes a frame 90 for supporting a pair of drive 
units 90A and 90B along the casting path defined by the mold, passage 29 
and the rollers 29A and 29B. The drive units 90A and 9B are identical 
accordingly only unit 90A will be described in detail for the sake of 
brevity. 
Drive unit 90A is shown in FIGS. 9-11 to include a frame 91 having pairs of 
opposed bearings 92 and 93 which rotatably support a pair of flanged 
rollers 94 and 95 on shafts 96 and 97. Also mounted on shafts 96 and 97, 
respectively, are pulleys 98 and 99. 
The bearings 93 are fixed but bearings 92 are mounted on pivot arms 100 
which pivot about a shaft 101 rotatably mounted on frame 91 in parallel 
spaced relation with respect to shafts 96 and 97. This permits the 
application of pressure to the upper and lower flanges 39 so that the 
starting bar 11 can be controlled during the time that it is within the 
confines of the drive units 90A and 90B. Also mounted on shaft 101 is a 
second pulley 102 which is coupled to pulley 98 by a belt or chain 103. A 
fourth shaft 104 is also mounted on frame 91 parallel to shaft 101 and has 
a pulley 105 mounted thereon which is coupled by a belt or chain 106 to 
pulley 99. The shaft 101 is also coupled to a drive motor (not shown) by a 
second pulley 107 and a belt or chain (not shown). Finally, meshing gears 
109 and 110 mounted on the shafts 101 and 104, respectively, interconnect 
the two so that both may be rotated by the drive motor (not shown). 
Driving pressure is applied to the member 37 by means of a hydraulic 
cylinder 112 pivotally mounted by means of trunnion pins 114 pivotally 
mounted on the frame 84. Extending from cylinder 112 is a piston rod 115, 
the other end of which is coupled to a bracket 117 fixed to the arm 100. 
Also mounted on frame 91 and in alignment with the gap between the rollers 
94 and 95 are a pair of inlet guides 120 each having an obliquely 
extending guide plate 122. The inner ends of the plates 122 and the 
rollers 94 and 95 lie along the opposite sides of the casting radius of 
the machine 10 and the path movement of bar 11. 
Prior to the commencement of the casting operation, the starting bar is 
held in the position shown in FIG. 1 by cylinders 112. When the operating 
sequence is commenced, the cylinders 22A and 22B are actuated to move the 
rollers 19A and 20A to their positions shown by broken lines in FIG. 1. 
This allows sufficient clearance to permit the free passage of the 
starting bar 11. After the rollers 19A and 20A have been elevated, the 
hydraulic pressure exerted by the cylinders 112 in both of the drive units 
90A and 90B is reduced to convert the clamping forces into a force 
sufficient to permit full control of the starting bar 11 during insertion 
by balancing out the over running load due to the mass of the starting bar 
itself. At this point, air cylinders (not shown) are activated to retract 
locking pins (not shown) so that the starting bar 11 is permitted to move 
downwardly under the influence of gravity. A D.C. drive motor which is 
coupled to each of the pulleys 107 of units 90A and 90B are operated to 
begin rotating each of the rollers 94 and 95. As a result, the head 31 of 
the starting bar moves downwardly through the withdrawal and straightener 
mechanism 18 and toward the lower end of the mold 13. As the head 31 moves 
through the withdrawal and straightener mechanism 18 in a direction 
opposite from that of the casting direction and passes beyond the plane 
described by the vertical center line of roll 19B, the cylinder 22A is 
actuated to move the roller 19A downwardly until it engages the upper 
surface of the bar 11. A sufficient force is applied to balance out the 
overrunning load due to the mass of the starter bar assembly. The starter 
bar 11 is then propelled until the head 31 reaches the lower end of the 
mold 13. At this point, the bar 11 is jogged into position where the head 
31 is at the proper elevation inside the mold by operation of the rolls 
19A and 19B. 
When the casting operation is commenced, the end 31 of the starting bar 11 
is disposed within the open lower end of the mold 13. The opposite end 36 
of bar 11 is disposed between the drive rollers 19A, 19B and 20A, 20B. 
Additionally, the roller 20A is in its elevated position. Molten metal may 
then be discharged from the ladle 23 into the tundish 14 from which it 
flows into the open upper end of mold 13. 
As the molten metal within the mold 13 begins to solidify around the pin 85 
extending from the head 31 of bar 11, the rollers 19A and 19B are operated 
so that the bar is withdrawn followed by the partially solidified strand. 
While the bar is positioned between the mold 13 and the rollers 19A, 19B 
each of the segments 37 will be in their full outwardly rotated position 
relative to each other so that the abuting surfaces 50 of end pieces 40 
will engage the surfaces 70 and the abuting surfaces 63 of each end piece 
42 will engage the surface 55. Each of the segments will then be in its 
position shown in FIG. 4 in which case, the bar 11 will be self supporting 
between support points and conform to the arcuate casting path. As the 
result, only minimum support is required by the rollers 29A and 29B. 
As the bar 11 is moved toward the first drive assembly 90A, it will follow 
the arc described by the radius of the casting machine and move between 
the guide plates 122 of the first drive 90A. This will continue as the 
starting bar head 31 moves toward the drive rolls 19A and 19B. 
Just prior to the time when the head 31 is between the rollers 19A and 19B 
the cylinders 112 are each actuated to provide contact between rolls 94 
and 95 and the starter bar 11 so that the weight of the bar will now be 
controlled by the drive assemblies 90A, 90B. Meanwhile the juncture 
between the head 31 and the newly cast strand 16 will proceed through the 
withdrawal straightener assembly 18 until the head 31 passes the elevated 
roller 20A. A limit switch (not shown) is then activated by the starter 
bar 11 and in turn causes the hydraulic cylinder 22B from its broken line 
position in FIG. 13 downwardly to the point where roller 20A contacts the 
newly cast strand 16. When the roller 20A descends it shears the dowel 
pins 89 whereby the pin 85 separates from the head 31 and simultaneously, 
the strand 16 is straightened about the center line of roll 19B. The 
forward end of the strand passes on to the run out table 17 while the bar 
11 proceeds up through the drive assemblies 90A and 90B. Meanwhile, the 
drive assemblies 90A, 90B propel the starting bar 11 to its storage 
position shown in FIG. 1. Because the pivotal movement of the members 37 
are limited as shown in FIG. 6 by the engagement of the surfaces 48 and 54 
on end member 40 with the surfaces 67 and 62 on the end member 42 as shown 
in FIG. 6, the result is that the starting bar 11 is substantially self 
supporting in the stored position. 
When the starting bar 11 reaches the fully retracted position shown in FIG. 
1 a limit switch (not shown) is actuated by the starting bar 11 whereby 
hydraulic pressure of the cylinders 112 in both drive units 90A, 90B is 
increased to create a clamping force sufficient to hold a starting bar 
assembly in this stored position. When this preset pressure is reached, 
air cylinders (not shown) are activated to push locking pins (not shown) 
in place to hold the starting bar in this position.