Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to a composition for the lining of a h~ndishl
said composition being intended to be applied against the permanent refractory
lining of said tundish.
The invention is also directed to a method for lining the interior
of a tundish and to the lining which is thus obtained.
Compositions consisting of mixtuTes of refractory particles embedded
in an organic or inorganic binder are already known. Compositions of this type
are employed especially for the fabrication of molds in ~oundry practice. The
natuTe of the constituents of these compositions is chosen so as to ensure that
the mold has a high degree of dimensional stability and so as to prevent any
dange~ o adhesion bet~een the mold and the metal which has solidified within
this latter. Such adhesion takes place in particular when the refractory
particles of the mold composition are sintered or in other words welded to-
gether under the action of heat of the metal.
This sintering process i5 prevented by means of refractory particles
having a high melting point such as grains of sand and it is a customary
practice to employ either a very small quantity of flux or no flux at all.
FurthermoreJ in order to limit the potential danger of sintering of particles,
the particle dimensions are selected from relatively coarse values correspond-
2Q ing to fineness indices within the range of 40 to 80 in accordance with the
AFS standard.
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Sintering of the particles is also avoided in
order -to permit re-use of the composition aEter a simple
grinding of the mold residues.
Another known practice involves the use of water-
molded refractory cements or clays of the type consistingof a magnesium or chromium magnesium coating compound or
having a chamotte base which is spread in a layer of more
or less substantial thickness over the surfaces of the
vessels employed for transferring liquid metals.
Coating compounds of this type result in the
formation of a hard layer which is comparable with cement.
However, these coatings have a poor heat-insulating
capacity, with the result that the slag and the metal have
a tendency to adhere thereto. Vessels lined with compounds
of this type can consequently be cleaned after use only
with very great difficulty. In the majority of instances,
the cleaning process in fact entails the need for burning-
off with a torch and this is a time-consuming and costly
operation. Moreover, said coating compounds or clays are
mixed with water and consequently call for preheating
prior to casting of the metal, thus immobilizing the cast-
ing vessels over long periods of time. The operations
which consist of cleaning with a torch and preheating
consequently set a considerable limitation on the effi-
ciency of casting operations.
Another known method consists in covering thepermanent refractory lining of the transfer vessels with
prefabricated plates of lightweight insulating refractory
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material. This solution already represents an appreciable improvement over
the use of the ~oating compounds mentioned above. However, by reason of the
fact that the casting vessels generally have dif~erent shapes and sizes, it is
found necessary to prefabricate a large series of plates having different
shapes and dimensions. This requixement results in relatively high costs,
relatively long periods of time devoted to the positioning of plates as well
as risks of errors in positioning of these latter. It should further be
mentioned that said plates must then be jointed with a refractory cement once
they have been placed in position. This refractory cement has the disadvantage
of adhering to the permanent refractory lining, thus gi~ing rise to difficul-
ties in regard to cleaning of the casting vessel after use.
The aim of the pTesent invention is to provide a composi~ion for
lining a tundish, which is very convenient to use, which does not call for any
preheating and which considerably facilitates cleaning of the lining of the
tundish after use.
Generally, in accordance with the invention, the aforesaid com-
position for a tundish lining is characterized in that it contains particles
and/or fibers of refractory material embedded in an inorganic and/or organic
binder, the nature and effective size chosen for the particles of refractory
material being such as to cause said particles to be sintered together as
they come into contact with the liquid metal which is introduced into the
tundish.
In particular, the present invention provides a composition for a
sinterable lining of a tundish to be applied against the permanent refractory lin~
in~ of the said tundish" comprising by weight:
50-90% of particles of a refractory material having an AFS fineness
between 100 and 220 and adapted to sinter in contact with the lten metal,
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0~2-15go of a carbonaceous material,
2-18% of a binder selected from the group consisting
of synthetic resin, animal, vegetable or synthetic glue,
refractory cement, silicate and phosphate binder~ and
0.2-20% of a sintering promoter selected from the group
eonsisting of ealcium borate, sodium carbonate, feldspar, blast
furnace slag, ferroehromium and glass powder.
Furthermore, the composition may also comprise
10-25% of an oxidizable material selected from the group
consisting of aluminum-magnesium, silicon-aluminum alloy and
silicon-aluminum-magnesium alloy, and
5-20% of an oxidizer seleeted from the group consisting
of FeO, Fe2O3, Fe3O4 and MnO2,
said partieles of a refraetory material being present in the
amount of 50-80~ by weight.
The principal original feature of this composition ::
eonsequently lies in the faet that this latter is sinterable in
eontaet with the metal, whieh is not the ease with the eompositions
employed up to the present time for the fabrieation of foundry
molds.
Surprisingly, it has been found that this sintering
proeess endows the lining with outstanding meehanical strength
and heat-insulating power and adheres neither to the east metal
within the tundish nor to the subjaeent permanent refraetory lining.
On eompletion of the easting operation, the residual
sintered lining ean eonsequently be detaehed ~rom the tundish as a
single unit simply by turning said tundish upside-down. The
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problem of cleaning of the permanent lining of the tundish is thus
effectively solved.
The present invention thus provides a lining comprising
as a coating on the inside walls of a tundish, a composition as
defined above, said particles of a refractory material being
sintered together so as to ensure cohesion of the lining, said
lining being detachable from the walls of the tundish simply by
inverting the tundish.
The invention is also directed to a method for lining the
interior of a tundish.
In one advantageous embodiment of said method, a com-
position in accordance with the invention is directly applied in
contact with the permanent refractory lining and said lining is
allowed to harden prior to
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introduction of the li~uid metal into the tundish.
The application of the composition in accordance with the invention
can be caTried out by means of a trowel, by spraying, tamping, molding or the
like.
After hardening o the compo~ition, there is thus obtained a con-
tinuous lining uhich sinters in contact with the liquid me~al without adhering to
the subjacent refractory lining.
In another embodiment of the method in accordance with the invention,
prefabricated heat-insulating plates are first placed against thc lateral walls
of the tundish and maintained in position by means of suitable packing elements
and a composition in accordance with the invention is applied against the
bottom wall of the tundish in oIder to coat the base of said heat-insulating
plates with said composition and the lining obtained is allowed to harden
prior to intxoduction of the liquid metal into the tundish.
In a preferred embodiment of the invention, prefabricated heat-
insulating plates having identical dimensions are applied against the lateral
walls and the bottom wall of the tundish and the spaces ~ormed between the
different plates are filled with a composition in accordance with the inven-
tion.
The combined use of identical insulating plates with a composition
in accordance with the invention permits an appreciable reduction in the cost
of the lining, especially when the tundish has a relatively complex shape.
Preferably, the insulating plates e~ployed are obtained after
hardening of a composition which is similar to the composition in accordance
with the invention.
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~ xperience has sh~wn in this case that a perect welded joint is
formed betw~en the plates and the composition in accordance witll tlle in-
vention. This welded joint results from sintering of the refracto~y particles
contained in said plates and in said composition. There is thus obtained on
completion of the casting operation a continuous lining which can be detached
from the tundish walls in a single unit.
Further distinctive features and aldvantages of the invention will
become apparent from the following description~ reference being made to the
accompanying drawings which are given by way of example without any limit-
ation being implied, and in which:
- Figure 1 is a half-sectional plan view of the lateral walls of a
continuous-casting tundish placed above two ingot-mOlds and provided with an
internal lining obtained from a composition in accordance with the invention,
in a first embodiment of the method;
- Figure 2 is a sectional view taken along the plane II-II of
Figure l;
^ Pigure 3 is a view which is similar to Figure 1, the tundish
being provided with a lining obtained in accordance with a second embodiment
of the method acco~ding to the invention;
2a - FiguTe 4 is a sectional view taken along the plane I~-IV of
Figure 3;
- Figure 5 is a sectional view taken along the
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plane V-V of Figure 3;
- Figure 6 is a sectional view talcen along the plane VI-VI of
Figure 3;
- Pigure 7 is a vi.ew which is sim:ilar to Figure 1, the tundish
being provided with an internal lining obta:Lned in accordance with a third
embodiment of the method according to the invention;
- Figure 8 is a sectional view taken along the plane VIII-VIII of
FiguTe 7;
- Figure 9 is a sectional view taken a.long the plane IX-IX of
Figure 7.
In the embodiment of Figures 1 and 2, the continuous-casting
tundish 1 is made up of a central portion 2 having two end extensions 3 and
4 which are inclined at a certain angle with respect to said central
portion. Said two end extensions 3 and 4 each have a casting outlet 5
placed above an ingot-mold 6. In comparison with a conventional tundish
of rectangular cross-section, the tundish 1 permits of better visibility
in the ingot-molds 6.
The tundish 1 comprises an outer casing 7, a peTmanent intermedia~e
lining 8 of Tefractory cement or of refracto~y bricks and an internal lining
9 of consu~able heat-insulating material.
In accordance with the invention, the heat-insulating internal
lininR 9 is obtained from a composition containing particles and/or fibers
of refractory material which are embedded in an inorganic and/o~ organic
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binder, the na-ture and effec-tive size of -the particles of
refractory material being chosen in such a manner as to
weld the particles together by sintering as these latter
come into con-tact with the liquid me-tal which is intro-
S duced into the casting distributor 1.
Two non-limita-tive e~amples of sinterc~ble compo-
sitions for the fabrication of the consumable heat-
insulating lining 9 are given hereunder.
EXAMPLE 1
10 Oxidizable Aluminum and/or magnesium and/or 10 to
silico-aluminum and/or silico-
material aluminum magnesium 25 %
Oxidizer FeO and/or Fe203 and/or Fe304 5 to
and/or MnO2 20 %
15 sintering prolr~ters such as: .
Derivatives of boron, calcium
borate, sodium, boric acid, blast 0.2 to
furnace slag, ferrochromium, glass 20
powder, feldspar, etc
20 Carbona- Paper pulp, and/or sawdust, and/or
ceous vegetable fibers, and/or vegetable 0.2 to
material ashes, and/or synthetic fibers and 15
some other carbonaceous compound such
as : graphite, coke, anthracite, etc
25 Refract- Silica and/or alumina and/or magnesia
ory charge and their compounds, 50 to
the refractory aluminous and silico- 80
aluminous products such as bauxite,
and/or dolomite and/or rice ashes and/
or silicon carbide~
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sinder Liquid and/or solid binders.
Syn-the-tic resin with catalyst and
hardening agen-t such as polyisocyana-te
and/or hardening eatalyst such as a
mixture of silieate and aluminate of
alkaline-earth metals or basic salts
and solvents such as :
tarolene, linseed oil, anthracene oil, 2 to
or furfuryl aleohol, and/or animal 18
glue and/or vegetable glue and/or
synthetic glue or refractory eement
and/or mineral adhesives sueh as
silieates or phosphate binders.
The effective size of the refractory particles
of this eomposition is preferably within the range of the
fineness indices 100 to 220 in accordance with the AFS
standard.
By reason of the presence both of oxidizable
materials and of oxidizers, this eomposition has the
property of being exothermic.
EXAMPLE 2
Carbonaeeous Paper pulp and/or sawdust and/or
material vegetable fibers and/or vegetable 0.2 to
ashes and/or synthetie fibers 15 %
and some other earbonaeeous
eompound sueh as : graphite, coke,
anthraeite
Refraetory Siliea and/or alumina and/or magnesia
eharge and their eompounds,
the refraetory aluminous and silieo- 60 to
aluminous produets sueh as bauxite, 90 %
and/or dolomite and/or riee ashes
and/or silieon earbide
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Binders Liquid and/or solid binders : synthetic
resins + catalyst -~ hardening agent such
as polyisocyana-te and/or hardening
catalys-t such as a mi~ture of silicate
and aluminate of alkaline-earth metals 2 to
or of basic salts and solvents such as : 18 %
tarolene, linseed oil, anthracene oil,
or furfuryl alcohol,and/or animal ~lue
and/or vegetable g]ue and/or synthetic
glue and/or mineral glue such as silicate
or phosphate binder
Flux sintering promot~rs sucl~ ~s :
derivatives of boron, calci.um borate,
sodium, boric acidr blast furnace slag, 0.2
ferrochromium, glass powder, feldspar, to 20
etc
The effective size of the refrac-tory particles is
preferably within the range of the fineness indices 100 to
220 in accordance with the AFS standard.
One e~ample of particle-size analysis of the
refractory charge which satisfies the fineness indices
aforesaid is given hereinafter :
Retained on a test sieve having a mesh size of 0.210mm: 1
- " " " " " " "" 0.177mm: 1
" " " " " " "" 0.149mm: 1
" " " " " " ", " 0.125mm: ~ %
" " " " " " " " 0.083mm: 10~
'~ ". " " " " " " 0.075mm: 13%
" " " " " " " " 0.053mm: 21%
30 Particles of higher fineness : 47%
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In the two compositions mentioned above, -the
composition of the binder can be given by way of example
as follows :
Binder furane resin, phenolic resin 3 to 12 % (with
(of the Resol and/or Novolak respect to the
type) or polyvinyl ace-tate total weight of
the composition)
Catalysts cobalt salt in relatively
heavy organic solvents such as 2 to 6 %
paraffin or turpen-tine
Hardening phosphoric acid or sulphonic
agents parato:luene 0.1 to 5 %
Two detailed examples of preferred compositions
are given hereunder :
EXAMPLE 3 (exothermic composition)
aluminum yranules 10 %
iron oxide (Fe203) 5 %
sodium carbonate 5 %
coke dust 10 %
20 quartz sand (IF150) 64 %
phenol-formol resin 6 %
EXAMPLE_4 ~inert composition)
sawdust 10 %
quartz sand (IF150) 82 %
25 phenol-formol resin 5 %
fluorspar 3 %
The compositions in accordance with Examples 1 and
2 given above are advantageously prepared in two separate
packages, one package being intended to contain a pre-
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mixture of ~he binder with the other constituents whils-t
the other package contains a premixture of -the constitu-
ents as formed with the hardening agen-t alone. This
accordingly prevents any possible reaction between the
constituents of the compositions prior to use.
AEter mixing the different constituen-ts and
compositions in accordance with Examples 1 or 2, there is
obtained an oily material of clay consistency which ean
be readily laid and hardens on exposure to the surrounding
air.
The mean setting time of the compositions in
aeeordanee with Examples 1 or 2 is of the order of 30
minutes.
The bending strength of a rod having a length of
17 cm and a diameter of 1.5 em obtained after hardening
or the eomposition is within the range of 40 to 53 kg/em2.
In order to Eorm the heat-insula-ting lining 9, it
is only neeessary to apply the mixture of the different
eonstituents of the eomposition directly against the
permanent refractory lining 8. This application can be per-
formed by means of a trowel, by spraying, by tamping or
the like. `
It can be advantageous in some cases to mold the
lining 9 against the permanent lining 8 by means of a
mold. The introduction of the composi-tion into a mold of
this type ean be carried out by blowing or by suction.
The thickness of the heat-insulating lining 9 ean
vary over a wide range sueh as, for example, between 1 and
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20 cm and preferably betl~een 1.5 and 6 cm~ depending Oll the dimensions of
the casting tundish.
After hardening of the composition, the heat-insulating lining 9
has a density within the range of approximately 1 to l.S. Experience has
shown that this heat-insulating lining 9 can readily withstand the pressure
exerted by the molten metal. As they come into contact with this latter,
the organic constituents of the heat-insulating lining 9 undergo decom-
position but do not result in destruction of the lining by virtue of the
sintering of the refractory particles. This sintering process occurs
between temperatures within the range of 800C to 1450C, depending on the
nature of the refractory particles and of the fluxes employed.
It is also noted that, on completion of the casting operation,
the sintered residual heat-insulating linlng 9 is detached from the
permanent lining 8 in a single unit simply after turnîng the tundish 1
upside-down, thus removing all the impurities which may have settled on
the bottom of the tundish. The subjacent permanent lining ~ is thus free
of any impurity and is ready to receive directly a fresh insulating lining
9 for a ~urther casting operation. The successive casting operations can
accordingly take place with minimum idle periods between operations.
The fact that the lining does not adhere to the subjacent re-
fractory lining can be explained as follows: the duration of con~act
between the liquid metal and the
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lining in accordance with -the invention is limited -to
appro~imately two hours and thirty minu-tes. ~nder these
conditions and by virtue of the heat insulation provided
by the lining in accordance with the invention, -the inter-
face between refractory lininc~ and lining in accordancewith the invention is maintained at a temperature below
the temperature of sintering of the inorganic particles
contained in the lining in accordance with the invention.
Adhesion of the two coatings as a result of sintering is
thus prevented.
In order to prevent said sintering process, the
thickness of the lining in accordance with the invention
must usually be greater than 30 mm.
Moreover, the temperature of the interface afore-
said is nevertheless sufficient to suppress as a result ofthermal decomposition any possible adhesion between the
organic constituents of the lining in accordance with the
invention and the permanent refractory lining.
In the embodiment shown in Figs. 3 to 6, the
inner hea-t-insulating lining of the continuous-casting
tundish 1 comprises prefabricated plates 10 placed
against the inner lateral face 8a of the permanent re-
fractory lining 8. The plates 10 are fabricated from a
refractory insulating material which is preferably
obtained by hardening of a composition in accordance with
the invention.
The base lOa of the plates 10 (as shown in Figs.
4 and 6) is embedded in a lining 11 which covers the
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bottom wall of the t~mdish. Said lining 11 is obtained by direct applicationof a composition in accordance with the inv~ention.
It is further appa~ent that the plates 10 are maintained applied
against the pexmanent lining 8 by means of packing elements 10b and lOc
placed respectively at the t~o corners of each end portion 3 and 4 and at
the angles which form a junction between said two end portions and the
centTal portion 2 of the tundish.
Said packing elements lOb and 10c can be constituted by rigid
prefabricated elements of material which is identical with the material
used for the plates. However, said packing elements ran be replaced by
a filling produced by direct application of a composition in accordance
with the invention in the unhardened state.
It is further apparent from Figures 3 and 4 that the bottom wall
of the tundish is provided substantially at the mid-point of the central
portion 2 with a plate 12 of refractory material which is capable of
affording resistance to the orce of impact of the jet of metal which is
pou~ed into the tundish. Said plate 12 is embedded in the lining 11.
Othe~ plates 13 of this type are also placed against the lateral wall 8a
of the tundish in order to protect the permanent lining 8 against splashing
2Q caused by the jet of molten metal.
It can also be seen that pTOYiSion is made on each side of said
impact plates 12 and 13 for barrier plates 14 and lS which are maintained
in position by insertion of the lining 11 and/o~ in the plates 10 of
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insulating material. The barrier plates 14 and 15 can be formed o re-
fractory material or by a metallic grid embedded in a composition in
accordance with the invention. Said barrier plates 14 and 15 constitute a
casting impact container and perform the function of filter for re~aining
impurities such as scoria and alumina contained in the lten metal.
In order to fabricate the internal heat-insulating lining of the
tundish shown in Figure 3, the operation is performed as follows:
The heat~insulating plates 10 and the packing elements lOb and lOc
are first placed against the lateral walls 8a of the tundish, whereupon the
impact plates 12, 13 and the barrier plates 14 and 15 are placed in positionO
A composition in accordance with the invention is then applied against the
bottom wall of the tundish.
After hardening of the lining 11 thu~ obtained, the complete
assembly of plates 10, of packing elements lOb and lOc and of plates 12 to
15 is perfectly maintained in position within the tundish without making
use of any fastening means such as nails, adhesive, cement, or p~ops.
The refracto~y particles of the lining 11 which come into
contact with the liquid metal are sintered togethe~ as in the case of the
lining 9 of the tundish shown in Fi~ure 1. Since the plates 10 and the
packing elements lOb and lOc are fabricated frDm material which
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is identical or very similar to that of the lining 11, said material also
sinters in contact with the molten metal. l'his sintering process produces a
remarkable result in that the lining 11 is weldPd to the plates 10 and to
the packing elements lOb and lOc as well as to the baIrier plates 14 and 15
if these latter are fabricated from sinterable material which is si~ilar ~o
that of the lining 11.
The lining 11 thus forms with the plates 10 a continuous and
coherent coating which has the same properties as the lining 9 of the
tundish shown in Figure 1. In particular, the heat-insulating lining thus
formed is detachable from the subjacent permanent refractory lining 8 as
a result of simple inversion of the tundish.
In the e~bodiment shown in Figures 7 to 9, the internal heat-
insulating lining of the tundish comprises a set of prefabricated plates
16 having identical dimensions and obtained from a composition in
accordance with the invention. The spaces formed between the different
plates 16 are filled with a packing 17 formed by means of a composition in
accordance with the invention.
The use o plates 16 having identical dimensions as mentioned
above considerably facilitates the fabIication of the heat-insulating
lining of the tundish, especially in the case of a tundish which has a
complex shape of the type illustrated in thP drawings. This is made
possible by the composition in accordance
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with the invention since the relatively large spaces
between the different identical plates 16 can be readily
filled-in. This solution consequently achieves a con-
siderable economy of -time and labor in comparison wi-th the
known solution which consis-ts in assembling to~ether a
large number of pla-tes having differen-t shapes and dimen-
sions. The invention also dispenses with the need to
employ a refractory cement for jointing said plates.
Moreover, in order to compensate for surface
irregularities of the permanent refractory lining 8, there
can be applied on this latter a thin layer of the composi-
tion in accordance with the invention or a layer of re-
fractory material in powdered form as indicated at 18 in
Fig. 8. It is also possible to cover the top edge 19 of
the tundish with a composition in accordance with the
invention which adheres to the adjacent edge of the plates
16 as shown at 20 in Fig. 8.
It also proves advantageous to cover the refract-
ory brick 21 (as shown in Fig. 9) in which is formed the
casting outlet 5, with a layer 22 obtained by application
of a composition in accordance with the invention. Said
layer 22 thus serves to achieve continuity with the
adjacent packing 17. In addition, said la~er 22 serves to
guard against abrasion of the refractory brick 21 as a
result of casting of the metal and to remove any potential
danger of solidification of the metal at the level of said
casting orifice 5.
As will be readily understood, the invention is
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not limited to the examples described in the foregoing and many modifications
can accordingly be contemplated without thereby departing from the scope or
the spirit of the invention.
~ lus the composition in accordance with the invention can be
employed f~r lining a tundish and like vessels of any shape for transferring
liquid metals.
It will also be Teadily appa~ent that the invention is not limited
to the examples of compositions hereinbefore described since the nature and
composition of the constituents can vary ovler a wide range. The essential
requirement to be met is that the composition in accordance with the
invention can be applied directly against the walls of the tundish and
that sinteTing is achieved under the conditions of temperature of the
molten metal which is intToduced into the casting vessel.
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