Note: Descriptions are shown in the official language in which they were submitted.
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CONTINUOUS CASTING MOULD
This invention relates to continuous casting moulds and in particular to
continuous casting moulds in which at least a part of the mould which includes
means defining the mould passage can be oscillated in a direction which is
substantially in the direction of casting.
A continuous casting mould for casting a metal strand, such as for
example a slab, bloom, billet or a strand of round or more complex cross-
section, can be a structure of considerable size, weight and complexity. In
order
to reduce the weight of the mould which has to be oscillated, it is known from
EP-A-0325931 to form a movable mould part which includes means defining the
mould passage and to arrange for this movable mould part to be oscillated with
respect to a fixed part of the mould structure. The oscillated movable part
has to
be accurately guided for movement with respect to the fixed part of the mould
structure.
According to the present invention a mould for use in the continuous
casting of a metal strand comprises:
a fixed mould part;
a movable mould part which includes means defining the mould passage;
means for displacing the movable mould part relative to the fixed mould
part in a direction which is substantially in the direction of casting;
characterised by the provision of:
a plurality of guidance elements for guiding the movable mould part
relative to the fixed mould part, each element having a pair of opposite faces
which are of arcuate convex form; and
means for urging said faces of each element into abutting relation with
co-operating surfaces on the fixed and movable mould parts respectively, to
allow rocking of the element relative to the surfaces.
It is convenient for the movable part of the mould and that includes the
means defining the mould passage to be within the fixed part of the mould.
However, the means which define the mould passage may be outside of the
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fixed part and secured to a structure which is within the fixed part. The
guidance
elements are then in abutting relation with surfaces on the fixed part of the
mould and on the structure respectively.
The guidance elements have their faces urged into abutting relation with
parallel surfaces on the fixed and movable parts and the urging means
conveniently comprises at least one device which acts between the fixed and
movable parts to urge the movable part towards the fixed part so that each
guidance element is in contact with its co-operating surfaces. The device may
take the form of a further guidance element comprising a plate having a pair
of
opposite faces which are of arcuate convex form and one of the faces abuts
against a surface on the movable part and an adjustable-width spacer is
positioned in abutting relation with the other of said faces and a surface on
the
fixed part. By adjusting the width of the spacer, the movable part can be
urged in
the direction or directions to remove clearances and/or apply compressive
forces to the opposite faces of the other guidance elements.
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Alternatively the device could be a spring or the like
secured to the fixed and movable parts to urge the movable
part towards the fixed part to remove clearances.
Each of the guidance elements must be free to rock on
the surfaces against which the faces abut but it is
important that the guidance elements are not allowed to
slide or skew relative to the surfaces. To prevent sliding
or skewing of the elements, each of the elements may be
provided with two locating elements such as cylindrical
pins, one at each end of the face. At each face of the
element the two pins have.a common longitudinal axis which
is coincident with the line of contact between the element
and the surface at the mid displacement position of the
movable part of the mould. The two pins extend from
opposite edges of the face of the plate. Each pin is
mounted on a block which is bolted to one of the parts of
the mould and the arcuate edges of the plate and the co-
operating surfaces are partially cut-away to capture the
pins with the axis of the pins being co-incident with the
surf ace .
In order that the invention may be more readily
understood it will now be described, by way of example only,
with reference to the accompanying drawings in which:-
Fig. 1 is a plan view of a mould in accordance with the
invention;
Fig. 2 is section on the line II-II of- Fig. 1;
Fig. 3A is an enlargement of the detail A shown in Fig.
2;
Fig. 3B is an enlargement of the detail B shown in Fig.
2;
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Fig. 3C is a perspective view of a guidance element;
Figs. 4, 5, 6 and 16 are diagrammatic side elevations
of alternative forms of mould in accordance with the
invention;
Figs. 7, 8 and 9 are sectioned plan views of '
alternative forms of mould in accordance with the invention;
Figs. 10 to 14 are diagrammatic side elevations of a
mould showing alternative forms of construction; and
Fig. 15 is a diagrammatic side elevation of a mould for
use in the continuous casting of a metal strand such as a
bloom.
A mould for use in the continuous casting of a metal
strand such as a steel slab has provision for oscillating
a displacement part of the mould passage in the general
direction of casting during the casting operation.
Referring particularly to Figs. 1 to 3, a continuous
casting mould for casting a steel slab comprises a part 1
which is movable with respect to a fixed part 2. The part 1
includes a pair of "long" copper plates and a pair of
"narrow" copper plates [neither plates being shown]. The
narrow plates are within the long plates and rams (not
shown) are provided for displacing the narrow plates within
the long plates and for holding them in the required
position. The long and narrow plates together define a
mould passage 3 of generally rectangular cross-section and
with the casting axis substantially vertical.
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The longitudinal axis of the mould passage may be
curved so that the.casting axis curves away from the
vertical but the general direction of the casting axis
is vertical.
The copper plates are backed-up with water jackets and
water is supplied to the rear of the copper plates for
cooling purposes. The water jackets, the copper plates and
the means for adjusting the position of the narrow copper
plates are the major parts of the movable part of the mould
and they may be designed as a cassette which can readily be
replaced with an alternative cassette having different sizes
of long and narrow copper plates.
The movable part 1 of the mould is located within and
supported from the fixed part 2 which more or less surrounds
the movable part. At each end of the mould there are at
least two pairs of guidance elements 4 arranged at
substantially 90° to the directlonS Of casting. Each
guidance element comprises an elongate flat metal plate 5
having a pair of opposite faces 6. These faces are of
arcuate convex form and conveniently these faces comprise
parts of a cylindrical surface. The respective edges are in
rolling contact with a flat surface 7 on the movable part
and with a flat surface 8, parallel to the surface 7, and
located on the fixed part of the mould. the plates 5 are
compressed to eliminate any clearances in the system. The
guidance elements are arranged parallel to each other such
that the movable inner part can be moved in a straight line
normal to lines through the guidance element contact points
when the system is at mid-stroke as shown in Fig. 2. The
movable part 2 is oscillated by one or more oscillation
imparting devices [not
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shown] such as controlled hydraulic cylinders, mechanical
eccentric cams, electromagnetic devices or the like. A
k
controlled hydraulic cylinder may be located at each end of
the movable part of the mould, the cylinders acting between
the movable and fixed parts. When the cylinders are
energised, the movable part can be oscillated vertically in
either a sinusoidal or non-sinusoidal manner to provide an
amplitude of up to about l2mm.
As indicated above, the movable part has to be
accurately located with respect to the fixed part and the
guidance elements should be compressed so that the arcuate
faces are in abutting relation with the respective surfaces.
As shown in Fig. 3B, a device for urging the faces 6 into
abutting relation with the surfaces 7 and 8 comprises an
adjustable width spacer 9. The spacer has a pair of tapered
wedges 10 and 11 which are located between a surface of the
fixed part of the mould and the surface 8 against which the
guidance element abuts. A bolt 12 associated with one of
the wedges permits the wedge to be moved relative to the
other wedge to vary the separation between the surfaces and
eliminate clearances. Each guidance element may have a
separate adjustable width spacer associated with it but
alternatively, only those guidance elements on one side of
the movable part of the mould may be provided with
adjustable width spacers.
a
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The clamping of the long faces of the mould is
maintained by means. such as disc springs and the clamping
force can be relieved for width adjustment using hydraulic
cylinders. The slab width can be changed during casting
using a drive arrangement mounted in the narrow plates of
the mould so that square or rectangular slabs can be cast.
Each of the guidance elements must be free to rock on
the vertical surfaces against which the faces of the plate 5
abut and it can be seen from Fig. 3 that the guidance
elements will be inclined as the inner part of the mould is
displaced relative to the outer part. It is important
however that the guidance elements are not allowed to skew
or slip relative to the vertical surfaces. To avoid skewing
or slipping of the elements, each of said faces of each
element is provided with two cylindrical pins 13, one at
each end of the face. At each face of the element the two
pins 13 have a common longitudinal axis which is coincident
with the line of contact between the element and the
vertical surface in the mid stroke position. The two pins
extend from opposite ends of the face of the plate. Each
pin is mounted in a block 14 which is bolted to the inner or
outer part of the mould and the arcuate edges of the plate
are partially cut-away to capture the pins with the axis of
the pins being coincident with the vertical surface. In
this way the pins are located relative to the inner or outer
part of the mould and the plate forming the guidance member
is rockable about the pins.
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It is not essential for -the part of the mould which
defines the mould passage to be within the fixed part of the
mould. In the arrangement shown in Fig. 4 the part of the
mould which defines the mould passage 3 is located above the
fixed part of the mould. This part is mounted vertically
above a structure 15 and the structure is guided within the
fixed part 2 of the mould. In the arrangements shown in
Figs. 5 & 6, the mould passage 3 is defined by a part which
is offset from the fixed part of the mould. In both of
these arrangements this part is secured to a structure 16
which is guided within the fixed part of the mould, whereas
in the Fig. 16 arrangement the structure is guided around
the fixed part. Oscillation of the structure in the
vertical direction will cause vertical oscillation to be
applied to the part defining the mould passage.
Fig. 7 shows a mould where a mould cavity of generally
square cross-section is defined by a movable part 17 of the
mould and this part is located within the fixed part. The
fixed part has a vertical surface 18 which acts as a datum
surface and a pair of guidance elements 4 of the form
described above act one above the other between this datum
surface and a parallel vertical surface on the moving part.
At the opposite side of the movable part 17 of the mould a
pair of elements 19 act one above the other between the
movable part and the fixed part and serve to urge the
movable part towards the datum surface 13 thereby removing
clearances between the faces & surfaces.
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Similarly, in the arrangement shown in Fig. 8, the
movable part 20 of the mould is of generally square cross-
section and it is located within a fixed mould part 2 of
generally square cross-section. At each of a pair of
adjacent corners of the fixed mould part there is a vertical
datum surface 21 which is at 45° to the side walls of the
mould part. At the corresponding corners of the inner mould
part there are also vertical surfaces and a pair of guidance
elements 4 one above the other act between the datum surface
and the corresponding surfaces on the movable part of the
mould. At the other pair. of corresponding corners of the
inner and outer mould parts there are guidance devices 19
which urge the movable part of the mould towards the datum
surfaces to remove clearances between the faces & surfaces.
A similar arrangement is shown in Fig. 9 where there are two
guidance elements 4 at a pair of adjacent corners and one
device 19 for urging the movable part of the mould towards
the datum surfaces 21 on the fixed mould part.
Figs. 10 to 14 illustrate various embodiments where
different devices are used to urge the movable part towards
the datum surfaces 18 on the fixed part. In each of these
figures, the fixed part of the mould provides a vertical
flat datum surface 13. At least two guidance elements 4 are
associated with this datum surface. Each element'has one
arcuate face abutting against the datum surface and the
opposite arcuate face abutting against a vertical surface on
the movable part of the mould. In Fig. 10 there are shown
two further guidance elements 4' which also have provision
[not shown] for urging the movable part towards the datum
surface. In the Fig. 11 arrangement there is only one
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guidance element which has provision for urging the movable
part towards the datum surface. A simpler arrangement is
shown in Fig. 12 where one or more tension members 22, such
as leaf springs, are connected to the fixed and movable part
to urge the movable part towards the datum surface.
In the Fig. 13 arrangement the means for urging the
movable part towards the datum surface comprise a pair of
elements 23 including spring loaded rollers 24 which are in
contact with the movable part on the side thereof opposite
the datum surface. These spring loaded devices may also
have adjusting devices in series with them, the adjusting
devices may take the form of tapered wedges 9 as shown in
Fig. 14.
Fig. 15 illustrates a typical construction for the
continuous casting of a steel bloom. The mould passage 34 is
generally vertical but it is slightly curved out of the
vertical plane. This is well known in the continuous
casting art. The part of the mould 26 which defines the
mould passage is positioned on a substantially horizontal
bracket 27 which in turn is secured to a vertical structure
28 which is guided by means similar to that shown in Fig. 10
but any of the means described above could be employed. An
oscillator device 29 is mounted on the fixed part of the
mould and has a vertically extending rod 30 which is secured
to the structure 28. When the oscillator is energised, the
rod is caused to oscillate in the vertical direction and
this movement is applied to the structure which is caused to
oscillate, whilst guided, within the fixed part of the
mould. The vertical oscillation of the structure causes the
mould part 26 and the mould passage to be oscillated along
substantially the same
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path as the direction of casting.
Below the bracket there are sets of rollers 31 for guiding
the casting 32 emerging from the mould passage and passing
through the bracket. To achieve the required path of
oscillation of the mould passage each guidance element 4 is
so arranged that a straight line connecting the line of
contact of each of its faces G with the co-operating
surfac-es 7 and 8 also intersects the centre of curvature 35
of the mould passage 34 when the movable part is at its mid
displacement position relative to the fixed part. Ideally
the surfaces on the fixed and moving parts would be curved
with a centre of curvature coincident with the centre of
curvature of the mould passage 34. However, in practice,
flat surfaces may be used which are tangential to the ideal
curved surfaces at the mid displacement position with only a
small inconsequential geometric inaccuracy.
