Note: Descriptions are shown in the official language in which they were submitted.
1068469
The invention relates to a cap for a method of
retaining a hot-top lining within the head portion of a casting
mould. The invention is especially suitable for making ingots.
Molten metal cast in the mould tends to contract
on cooling and, unless a hot-top lining is located in the head
portion of the mould, the metal located there will tend to cool
more quickly than the metal located in the mould body and this
can result in castings of poor quality or considerable wastage.
Where the head portion is of rectangular cross-sectional shape
the lining is usually formed o~ four individual lining slabs.
The slabs are held against the inner surface of the head portion
by wedges driven into the corners. The lining must be held
tight since as the level of molten metal rises in the mould
on pouring, there is a tendency for the metal to lift the
lining away from the head portion. In one known version, the
wedges are suitably shaped metal plates. To accept such wedges,
it has been proposed in Canadian Patent 852,654 issued
September 24, 1970 to Koch ~ Rocher to cut inclined grooves in
the face of the slabs. This system has disadvantages in that
any cutting weakens the strength of the slab and so it is
necessary to reinforce it in some way, e.g., by locating a
chicken wire reinforcement within the slab body, and there is
a tendency for the wedging plate to cause portions of the slab
to break away from the wire reinforcement. This tendency is
especially irritating in that workmen may be required to replace
individual slabs thus holding up the relining operation in a
plant. If the structural weakness resulting from such grooves
is compensated for by the use of slabs of increased thickness
then an undesirable shoulder may be created in the ingot.
Another disadvantage is that the choice of structural materials
for the slabs is limited in the case of a grooved structure to
those of high compressive strength. It may be desirable to use
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1068469
a material which is lower in compressive strength but which
is flexible to conform with the surfaces of the mould.
This invention is based upon the realization that
a cap may be attached to the outside of a preformed slab in
such a way as to reinforce its strength and yet be designed
to accept the wedge plate to ensure a satisfactory securement
of the lining within the ingot mould head portion.
According to this invention there is provided a
cap for use with a hot-top slab, an edge portion of the cap
being bent upon itself to form a passageway to receive an
edge portion of à wedging plate, the cap including means by
which it may be held to a wall of the slab.
Most preferably the cap has a generally flat plate
of trapezoidal shape, to be abutted against a wall of the slab,
the longest side of the trapezoidal plate being shaped to
provide the wedge-receiving passàgeway.
The plate may be secured to the slab by any con-
venient-means, for example by being anchored to the slab by
bolts, pins and the like. It is however preferred according
to the invention to cause the cap resiliently to grip opposite
sides of the slab without penetrating the body of the slab.
To achieve this, the cap may be generally U-shaped in plan,
one arm of the U being the plate referred to above, and the
other being an extension of such plate shaped for engagement
with the opposite face of the slab. As an alternative the
plate may be L-shaped so as to include an extension engaging
the end edge of the slab.
The cap may be made of metal in sheet or strip form,
such as mild steel or spring steel.
The cap may have suspending means for suspending
the slab to which it is attached within the mould head portion
from the top. The suspending means may be permanently attached
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I I
10684b9
to the cap, for example by welding, or in an adjustable or
releaseable manner. The suspending means may alternatively
be directly connected to the slabs.
The invention includes an assembly comprising a
mould, the mould having a head portion of generally rectangular
cross-sectional shape, a hot-top lining being present in the
head portion, the lining being formed of slabs, each slab
having at each end a cap as defined above with the passageway
facing inwardly of the mould head portion so that a pair of
caps is present in each corner of the mould head portion, the
passageways of the caps in each corner facing each other, a
wedge plate being present in each corner, opposite sides of
the wedge plate being in engagement with the opposite passage-
ways, the wedge plate tending to urge the slabs towards the
respective mould head portion walls.
Referring now to the drawings which illustrate a
preferred embodiment of this invention:
Figure 1 is a perspective view illustrating the head
portion of a mould having hot top slabs wedged in position by
caps in accordance with this invention;
Figure 2 is a detailed plan view illustrating a
corner of the mould shown in Figure l;
Figure 3 is a detail perspective view of a cap in
position on a hot top slab;
Figure 4 is an elevation view of a wedge plate;
Figure 5 is an elevation view of another cap of
this invention;
Figure 6 is a perspective view of another cap of
this invention.
Referring now to Figure 1, the head portion of an
ingot mould is shown including side walls 10 and 11 and end
walls 12 and 13. Hot top slabs 15 are held against end walls 13
10684~9
and hot top slabs 16 are held against sides 10.
The manner in which such top slabs are held in
position is apparent from Figures 1 to 4, which illustrate a
cap 18 in engagement with each side edge 17 of a slab 15 or 16.
The cap 18 is generally U-shaped in plan and has
one branch 19 in contact with the inwardly facing surface 20
of slab 15 and another branch 21 in contact with the ou~er
sur~ace 22 of slab 15. The bight 18a of the U-shaped cap is
dimensioned such that the contact of the cap with the slab is
a frictional engagement with the outer surfaces of the slab
which is thus free o holes or apertures which will tend to
weaken the hot top slab. However, in some cases the cap may
be held to the slab by pins, dowels or gripping serrations.
Even where pins or dowels axe used the structure of the slab
will not be weakened to the same extent as will result from
grooves. Bight 18a also provides an abutment against edge 17.
A hanger wire 23 has a portion 24 welded or otherwise secured
to bight 18a of the cap 18 and a top portion 25 which extends
horizontally for engaging the upper edges of the walls 10, 11,
12 or 13 of the mould.
As shown best in Figure 3, the branch 19 is generally
trapezoidal in shape and the edge of the longest wall (the right
hand edge as shown in Figure 3) is bent back up on itself in
any convenient way to form a passageway 26 having an outer
wall 27. It will be noted that the passageway 26 is generally
V shape in cross-section. The passageway 26 is inclined with
respect to the vertical to receive an edge 31 of a metal wedge
plate 30 when assembled as shown in Figure 1.
In use, the caps are force fitted on to the end
of the slabs in the position shown in Figure 3. The slabs are
then suspended in the mould head portion such that in each
corner there are two capped slab ends. A wedge plate is then
10684~j9
urged into the corner to be received in and between the
passageways 26 of the two caps. As the wedge is driven
downwardly it tends to urge the caps apart thus improving
the wedging action, the V-shaped passageways acting as guides
for the wedge. In all instances the wedge contacts the
metal of the passageways, not the slabs themselves.
In the embodiment illustrated in Figure S, a cap 32
has a sleeve 33 and securing nut 34 to engage a hanger 36
at any position thereon. This may be used to vary the height
at which the hot top lining slabs are suspended, within the
ingot-mould, which may be desirable when casting small ingots
in larger capacity moulds.
In the embodiment illustrated in Figure 6,
trapezoidal plate 37 has at one end a lip 38 bent to define
sloping passageway 39. The other end of plate 37 is bent to
an L-shape to provide an extension 40 to engage end 41 of
slab 42. Extension 40 is desirable even if a U-shape as
illustrated in Figure 3 is not to be used to provide an abutment,
in view of the pressure resulting from the wedging action.
With this embodiment it will generally be desirable to include
auxiliary fastening means such as pins 43. Figure 6 also
illustrates the fact that suspending means need not necessarily
be secured to the cap. The slab may be provided with other
suspending means connected directly to it (not shown).
It has been found in practice that a hot top lining
having slabs with caps of the invention can easily and quickly
be assembled within a mould head portion. Molten steel at
1650C. was teemed into the mould until the mould was
completely filled; there was no incidence of any movement
of the lining slabs and no tendency for the slabs to float on
the surface of the molten metal.
~ 1068469
In the embodiment discussed, the cap was of U-
shape having one branch for engaging the wedge plate and the
other to assist in holding the cap to the slab. It will be
appreciated however that other means may be used to secure
the plate passageway to the slabs in a position for receiving
the wedge plate without departing from the scope of the
invention.
Advantages flowing from the use of this invention
include:
the avoidance of weakening the slabs or providing
a reinforcement therefor when engaging the wedge
plate;
the improvement of t~e wedging action flowing rom
the contact of the metal wedge plate with the
metal cap;
improved ease and reliability of holding of the
lining of the mould in the plant;
the avoidance of a shoulder on the casting where
the weakness of the slab is compensated for by
increased thickness of the slab;
materials may be used in forming the slab which
would not be strong enough to provide a satisfactory
grooved slab. Thus, the material used in forming
the slab may have some flexibility to conform
with the mould, the provision of such flexibility
may involve, however, some loss of the strength
in compression necessary for a grooved slab.
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