Plate mould for continuously casting steel strands

A plate mould for continuously casting steel has a carrying frame, and side and end walls with cooling devices. At least one side wall is movable transversely relative to the mould by separate apparatus. The end walls are each comprised of a holding plate, a supporting plate and a cooled copper plate and can be clamped between the side walls by spring clamping elements. Wedge-shaped noses are provided on the upper and lower edges of the supporting plate for engagement with a wedge-shaped groove in the pertaining holding plate and with a clamping piece, respectively.

BACKGROUND OF THE INVENTION 
The invention relates to a plate mould for continuously casting steel, 
which mould has a carrying frame and walls supported therein that are 
provided with cooling means and delimit the mould cavity at least one side 
wall is movable transversely relative to the mould axis and the end walls 
are comprised of a holding plate, a supporting plate and a cooled copper 
plate that can be clamped between the side walls. 
In continuous casting plants it is necessary to be able to quickly change 
or exchange the end walls for changing the dimensions, in particular the 
thickness, of continuously cast slabs. 
Plate moulds have been known which allow for an exchange of the end walls, 
but their removal and installation requires a lot of work and time and 
thus for substantial periods of time the plant is at a standstill. In a 
known plate mould, hydraulic cylinders are used for clamping the end walls 
between the side walls, the hydraulic cylinders being supported against 
the carrying frame. This design has the disadvantage that the clamping 
force is dependent upon pressure fluctuations in the hydraulic system; if 
the mould is turned off for a long period of time, the cylinders become 
unpressurized. When the hydraulic system fails, there is an immediate 
danger of a breakthrough of the molten core of the slab, since the side 
walls are pressed apart. 
In the known plate mould the end walls are fixed on the carrying frame by a 
hang-in and bracing means, wherein the hang-in means for an end wall has a 
T-shaped guide in the supporting plate and a sliding block that is 
resiliently fixed on the carrying frame via a bolt. With such a hang-in 
means a quick exchange of the end walls is not possible. A further 
disadvantage which has to be stressed is the fact that the resilient 
fastening of the end walls on the frame permits position changes when the 
casting conditions change. Such position changes of the end walls have an 
extremely detrimental influence upon the quality of the slab. 
SUMMARY OF THE INVENTION 
The invention aims at preventing the above-described disadvantages and 
difficulties and has as its object, on the one hand, to increase the 
safety of the clamping means and thus the operational safety of the plant 
and, on the other hand, to enable a quick exchange of the end walls of the 
plate mould. 
According to the invention, this object is achieved in that the end walls, 
whose pertaining supporting plate is provided with wedge-shaped noses at 
its upper and lower edges, has the lower nose engaged in a wedge-shaped 
groove of the holding plate and the upper nose secured on the holding 
plate with a clamping piece backing up the nose. The end walls can be 
clamped between the side walls by a spring clamping means and the 
loose-side side wall is moved by a separate hydraulically or mechanically 
acting means which is supported on the carrying frame. 
Advantageously, telescopically retractable and extendible pipes are 
provided between the water box of the mould and bores in the holding and 
supporting plates, respectively, which pipes supply and drain cooling 
water to and from the copper plate, which is provided with cooling 
channels. 
Suitably, the spring clamping means comprises a drawing anchor penetrating 
the side walls, clamping nuts fixing the drawing anchor on the fixed-side 
wall, a spacer block adapted to the respective slab thickness, and a 
laminated spring. The pre-stress of the spring is adjustable by adjusting 
nuts. 
According to a preferred embodiment, the end wall can be actuated by a 
drive that is displaceable in the direction perpendicular to the side 
walls of the mould and is mounted on the water box. By means of this drive 
the dimensions of the mould and the inclination of the end wall are 
adjustable. Because of the displaceability of the drive it is possible to 
adjust the drive to the new mould center plane when an end wall has been 
exchanged for another end wall of a different width. Thus jamming of the 
end wall between the side walls is avoided when the lengths of the side 
walls change during casting due to temperature fluctuations, since the 
frictional forces that occur between the side walls and the end walls 
occur symmetrically to the drive. Suitably, the drive, having an 
adjustment spindle and a gear, is secured to a guide plate which is 
displaceable in guides secured to the water box, is adjustable to the 
center plane of the mould by means of a pressure medium cylinder and is 
fixable relative to the water box by a clamping means.

DESCRIPTION OF EXEMPLARY EMBODIMENTS 
In FIG. 1 a carrying frame of a mould designed as a water box is denoted by 
1. In this frame loose side wall 2 and fixed side wall 3 of the mould are 
inserted. Each one of the two side walls is connected with copper plates 
denoted by 4 and 5. The end wall in the end wall region illustrated 
comprises a copper plate 6 and the supporting plate 7, which are connected 
to each other by screws 8 (FIG. 2). For moving the loose side wall in the 
direction of the arrows 9 and 10 (FIG. 1), a hydraulic cylinder 11 is 
provided, which cylinder is supported on the water box or carrying frame 1 
and whose piston is connected to the loose-side wall 2. 
As can be seen from FIG. 2, the supporting plate 7 is provided with 
wedge-shaped noses 12 and 13 at its upper and lower edges, the lower nose 
being hung on a wedge-shaped receiving groove 14 of a holding plate 15. At 
the upper edge the supporting plate 7 is connected with the holding plate 
15 by a clamping piece 16 which has a flange 17 backing the nose 12 and a 
flange 19 engaged in a groove 18 of the holding plate. The clamping piece 
is braced on the nose 12 of the supporting plate and on the upper end of 
the holding plate 15 by means of a screw connection 20. Between the copper 
plate 6 provided with cooling channels 21 and the supporting plate 7 
O-rings 22 are inserted, and between the supporting plate 7 and the 
holding plate 15 O-rings 23 are inserted. The water is supplied via 
telescopically retractable and extendible pipes 24 and 25, with the pipe 
24 running into a bore 26 of the holding plate and sealed relative thereto 
by O-ring 27. The water is drained in the same manner via the telescoping 
pipes 24' and 25' in the upper part of the mould. As can be seen from FIG. 
1, the end wall is clamped between the side walls 2 and 3, that is between 
their copper plates 4 and 5. The clamping means is comprised of a drawing 
anchor 30 penetrating the protruding plate-shaped parts 28 and 29 of the 
side walls 2 and 3, which drawing anchor is fastened on the fixed-side 
plate 29 by clamping nuts 31. On the other side there are provided a 
laminated spring 33 in a housing 32 as well as adjusting nuts 34 and 35 on 
the drawing anchor. Moreover, there is provided a spacer block 36 between 
the plate 28 and a nut 34 on the drawing anchor. The spacer block is 
adapted to the respective thickness of the slab. The play 37 between the 
lower edge of the housing and the adjusting nut 34 is the displacement 
path, which path is dimensioned in such a manner that the springs are not 
compressed to form a block. By 38 the displacement spindles and by 39 the 
displacement gears of the end wall are denoted. 
From FIG. 3 it becomes apparent that for assuring the lateral position of 
the copper plate, the noses 13 are kept in their position by lateral 
holding pieces 40. 
The detachment or installation of the end wall takes place in the following 
manner: The cylinders 11 are actuated, wherein the loose side wall 2 is 
moved in the direction of the arrow 9 and the play 37 is overcome. If the 
end wall only is exchanged, without a change of dimensions, the structural 
unit 6, 7 is exchanged for one of similar size. If the dimensions are also 
to be changed, the structural unit 6, 7 is exchanged for another one 
having the new desired dimensions. The screw connection 20 or other 
pressure means, such as a wedge or a bayonet catch which may be provided, 
are detached, the clamping piece 16 is lifted off and the unit 6, 7 is 
removed. In such a change to different dimensions the spacer block 36 also 
has to be exchanged in order to obtain the same pre-stress of the spring 
for clamping the end wall. 
Altogether the procedure is the following: the loose-side side wall is 
detached in the direction of the arrow 9, the end wall is lifted out, the 
loose-side side wall is moved in the direction of the arrow 10, the new 
spacer blocks are inserted, the loose-side side wall is moved in the 
direction of the arrow 9 until play 37 has been overcome, the new end wall 
is inserted and the cylinder 11 is relieved. 
The adjustment gears 39 are secured to a guide plate 41. The guide plate is 
displaceable along guide columns 42, mounted on the water box, by means of 
a piston rod 44 that can be actuated by a pressure medium cylinder 43. 
Clamping screws 45 serve for fixing the guide plate on the guide columns. 
By means of inserts 46, which can be pushed over the guide columns, the 
displacement path can be limited depending on the respective width of the 
end wall, so that the guide plate need only be displaed until it contacts 
the inserts. This results in an especially quick adjustment of the guide 
plate to the respective end wall. If the adjustment spindles 38 are in the 
mould center plane, they remain free from any bending moment strain such 
as can occur when the end wall jams due to frictional forces between the 
end walls and the side walls that are unsymmetrical with respect to the 
adjustment spindles. 
The water supply and drain pipes 25 and 25' run into bores 47 of the guide 
plate 41 (FIG. 2). At the back of the guide plates the coolant conduits 
each continue with a pipe piece 48 rigidly secured to the guide plate and 
slidably guided on the water box. Sealing is effected by means of O-rings 
49. In order to keep the water supply and drain openings 50 of the water 
box from being covered by a displacement of the guide plate 41, the pipe 
pieces 48 have diameters that are enlarged to the maximum displacement 
path relative to the openings 50. Covers, not shown, on the pipe pieces 48 
are provided to keep the sliding faces on the water box free from dirt. 
FIGS. 4 and 5 show an embodiment, which differs from the embodiment 
illustrated in FIGS. 1 to 3 in that the spring clamping means is supported 
on the water box on one side and on the loose side wall 2 on the other 
side. A further difference comprises the configuration of the guides of 
the guiding plate 41. The guiding plate 41 is guided without play with its 
lower end in a groove 51 having wedge-like arranged side faces. On the 
water box the guide plate can be fixed by a clamping piece 52 which 
embraces in a bracket-like manner the wall 53 of the water box as well as 
the upper end of the guide plate 41 and which can be secured to the wall 
of the water box by a wedge connection 54. 
In this embodiment, the clamping piece 16 is also secured by a wedge 
connection 55 at the upper end of the holding plate 15. 
The bores 47 of the guide plate provided for the water supply and drainage 
are arranged opposite the bores of the water box and are so dimensioned 
that when the guide plate is displaced, the free cross-section necessary 
for a sufficient supply of water to the mould always remains. 
In this embodiment it is also possible to exchange the structural unit 6, 7 
along with the displacement spindles 38, the displacement gears 39 with 
which it is connected and the guide plate 41, for a structural unit of 
different dimensions having fully assembled displacement spindles 38, 
displacement gears 39 and guide plate 41. This allows an especially quick 
exchange of the end walls to be carried out, since the drives need no 
longer be displaced. If time is available for the exchange of the end 
wall, suitably only the structural unit 6, 7 is exchanged and the guide 
plate is displaced together with the displacement drives and spindles to 
the new center of the mould.