A tundish has an entry location for receiving a molten alloy, such as steel, and bottom outlet openings for withdrawing the molten alloy. The tundish bottom comprises a sump located downstream of the inlet location and upstream of the outlet openings. Undissolved, molten alloying ingredient, denser than the molten alloy as whole, (e.g. lead or bismuth in the case of molten steel) accumulates in the sump. The sump has a floor and passageways which extend downwardly from the sump floor to a drain in the steel tundish shell underlying the sump. The passageways are permeable to undissolved, molten alloying ingredient but impermeable to the molten alloy. There are expedients for maintaining the passageways at a temperature which prevents undissolved alloying ingredient descending through the passageways from cooling to a temperature at which the undissolved alloying ingredient blocks the passageways against further passage by undissolved, molten alloying ingredient.

BACKGROUND OF THE INVENTION 
The present invention relates generally to tundishes used in the continuous 
casting of molten alloys, such as molten steel, and more particularly to a 
tundish constructed to control or direct the escape from the tundish of an 
undissolved, molten alloying ingredient denser than the molten alloy as a 
whole. 
The following discussion is in the context of molten steel containing 
undissolved, molten lead and/or bismuth as the denser alloying ingredient. 
However, that particular steel is merely an example of one type of molten 
alloy with which the present invention is intended to be employed; the 
present invention may also be employed with other molten alloys having 
similar characteristics, e.g. a molten copper-based alloy containing 
undissolved, molten lead. 
In the continuous casting of molten steel, a stream of molten steel is 
poured from a ladle into an intermediate vessel known as a tundish having 
a bottom containing outlet openings through which molten steel flows into 
a continuous casting mold. Molten steel is conventionally introduced into 
the tundish at an entry location spaced from each of the outlet openings, 
and the molten steel normally flows along the bottom of the tundish 
downstream from the entry location to an outlet opening. 
Certain steels, known as free-machining steels, contain lead and/or bismuth 
to improve the machinability of the steel. Typical contents for each are 
about 0.04-0.40 wt. % bismuth and 0.05-0.50 wt. % lead. Lead and/or 
bismuth my be added to the stream of molten steel entering the tundish. 
Lead and bismuth have a relatively low solubility in molten steel, compared 
to other alloying ingredients added to molten steel, and lead and bismuth 
are denser than molten steel. Because of these properties, substantial 
amounts of undissolved lead and bismuth tend to accumulate at the bottom 
of the tundish. If these accumulations of undissolved lead and bismuth are 
allowed to flow out through the outlet openings in the bottom of the 
tundish, they will do so as relatively large globules, and this will be 
manifest in the solidified steel as large, localized concentrations of 
lead or bismuth, which is undesirable. 
Various expedients have been employed to cope with the problems described 
in the preceding paragraph. Many of these expedients are described in 
Jackson, et al. U.S. Pat. No. 4,852,632, issued Aug. 1, 1989, and the 
disclosure thereof is incorporated herein by reference. One such expedient 
comprises interposing a refractory dam between the tundish entry location 
and the tundish outlet opening. This dam extends upwardly from the vessel 
bottom and prevents undissolved, molten alloying ingredient which settles 
on the tundish bottom from moving downstream past the darn. As used 
hereinafter, the term "undissolved, molten alloying ingredient" refers to 
undissolved molten lead or bismuth or other elements having like 
properties. 
Expedients which prevent undissolved, molten alloying ingredient from 
entering a tundish outlet opening result in the accumulation of large 
amounts of undissolved alloying ingredient on the vessel bottom at a 
location spaced upstream from the tundish outlet opening, and that too is 
undesirable. 
One proposal for preventing large accumulations of undissolved alloying 
ingredient on the vessel bottom comprises providing, at the bottom of the 
tundish, a sump located between the entry location and the tundish outlet 
opening. This sump has a floor which is lower than the tundish bottom 
surrounding the sump. The relatively dense, undissolved molten alloying 
ingredient collects in or about the sump as a result of the difference in 
density between the undissolved molten alloying ingredient and the molten 
steel. The sump floor is composed of a refractory material which is 
impermeable to molten steel but is permeable to the undissolved, molten 
alloying ingredient. A drain is provided in the metal shell of the tundish 
underlying the sump, and it is intended that the undissolved, molten 
alloying ingredient pass downwardly from the sump floor through the 
refractory material permeable to that alloying ingredient and then be 
removed through the drain in the underlying tundish steel shell. One 
embodiment of the sump described in the preceding part of this paragraph 
is disclosed in the aforementioned U.S. Pat. No. 4,852,632 
Problems have arisen in the employment of the sump described in the 
preceding paragraph. More particularly, the passageways in the refractory, 
through which the undissolved, molten alloying ingredient was supposed to 
pass in the course of being removed from the sump, have become plugged 
with solidified or cooled, viscous alloying ingredient. This prevents 
removal of the undissolved alloying ingredient from the tundish bottom, 
causing the accumulations of undissolved, molten alloying ingredient on 
the tundish bottom to grow larger and larger. Some of this unremoved, 
undissolved, molten alloying ingredient may work its way underneath the 
refractory dam, behind which the undissolved, molten alloying ingredient 
is supposed to be contained; the undissolved, molten alloying ingredient 
can also work its way through cracks at the bottom of the refractory dam. 
When those things occur, the undissolved, molten alloying ingredient can 
flow downstream to the tundish outlet opening, which is undesirable. In 
addition, there may be other ways for unremoved, undissolved, molten 
alloying ingredient to find its way to the tundish outlet opening, all of 
this being undesirable. 
In another embodiment, there is one dam upstream of the passageway, between 
the passageway and the tundish inlet location, and other dams downstream 
of the passageway, between the passageway and the tundish outlet openings. 
These dams wall off a portion of the tundish and define a tundish holding 
compartment. Molten steel flows over the tops of the dams and then flows 
to the tundish outlet openings. Undissolved, molten alloying ingredient 
accumulates in the holding compartment, and one or more passageways of the 
type described above are provided in the holding compartment to remove the 
accumulations. These passageways can be in the floor of a sump, or they 
can be merely in the bottom of the holding compartment, outside of a sump. 
In the case where a holding compartment is sump-less, the entire holding 
compartment is tantamount to one large sump. 
The problem of plugged passageways, described above in connection with a 
passageway located in a sump floor, is also present when passageways are 
located in the bottom of a holding compartment, outside of a sump. When a 
passageway in the holding compartment becomes plugged, the accumulations 
of undissolved, molten alloying ingredient in that compartment become 
larger and larger, and that is undesirable. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, expedients are provided to 
prevent the passageways, which are permeable to the undissolved, molten 
alloying ingredient, from being blocked by solidified or cooled, viscous 
molten alloying ingredient. Structure is provided which maintains the 
passageways at a temperature which prevents undissolved, molten alloying 
ingredient which descends into a passageway from cooling to a temperature 
at which the alloying ingredient blocks the passageway against further 
passage by undissolved, molten alloying ingredients. 
In one embodiment, the desired temperature is maintained by providing at 
least one high-conductivity, refractory brick in that part of the tundish 
refractory lining which underlies the sump floor or which abuts a 
passageway. The interior of the tundish bottom is lined with refractory, 
and the refractory surrounding the high-conductivity, refractory brick may 
be rammed refractory. In such a case, the interface between the 
high-conductivity, refractory brick and the rammed refractory defines one 
of the passageways along which undissolved, molten alloying ingredient may 
be removed from an accumulation at the bottom of the sump. Other such 
passageways are defined by the vertical joints between adjacent 
high-conductivity, refractory bricks which underlie the floor of the sump 
or which are included in that part of the refractory lining which abuts a 
passageway. 
Preferably, at least one high-conductivity, refractory brick has a portion 
extending above the floor of the sump and into the molten steel contained 
in the tundish. With or without an extension into the molten steel, the 
upper part of the high-conductivity, refractory brick is heated by the 
molten steel in the tundish, and the high conductivity of the refractory 
brick conducts the heat downwardly through the brick to maintain the 
entire brick and each adjacent passageway at a temperature above that at 
which undissolved, molten alloying ingredient will solidify or become so 
viscous as to cause plugging of the passageway. 
In another embodiment, the temperature of the high-conductivity, refractory 
brick underlying the floor of the sump or abutting the passageway is 
maintained at the desired level by employing a heating element which 
underlies the brick and/or extends upwardly into the brick from the bottom 
thereof. 
The expedients for preventing plugging of a passageway located in a sump 
floor can also be used to prevent plugging of a passageway which is in the 
bottom of a holding compartment and which is not located in a sump. 
The sump and/or the passageway is typically disposed on the tundish bottom 
at any location between the entry location and the outlet openings. In one 
embodiment, a sump is located immediately adjacent the downstream side of 
a refractory dam intended to prevent undissolved, molten alloying 
ingredient from moving downstream toward the tundish outlet opening. As 
thus located, the sump will capture undissolved molten alloying ingredient 
which works its way under the refractory dam or through cracks in the 
bottom of the refractory dam. 
Other features and advantages are inherent in the structure claimed and 
disclosed or will become apparent to those skilled in the art from the 
following detailed description in conjunction with the accompanying 
diagrammatic drawings.

DETAILED DESCRIPTION 
Referring initially to FIG. 1, indicated generally at 10 is a tundish into 
which a stream of molten steel is introduced from above through a 
vertically disposed conduit 11 which directs the stream of molten steel 
into the tundish at an entry location 12. As shown in FIGS. 3 and 4, 
tundish 10 comprises a steel outer shell 13 and an interior refractory 
lining 14. The tundish comprises a bottom 15 having a plurality of outlet 
openings 23. Entry location 12 is spaced upstream from outlet openings 23. 
As shown in FIG. 1, tundish 10 includes a plurality of vertically disposed 
dams 16, 17 and 18 dividing the tundish interior into a series of 
compartments, namely an entry compartment 20 containing entry location 12, 
a holding compartment 21 and a pair of outlet compartments 22 each 
containing a pair of outlet openings 23. Molten steel is introduced into 
entry compartment 20 at entry location 12, flows over dam 16 into holding 
compartment 21 and then flows over dams 17, 18 into outlet compartments 22 
for removal through outlet openings 23. 
Dam 16 is composed of refractory and is typically supported on refractory 
lining 14 (FIG. 3). Dams 17 and 18 may be composed of refractory-encased 
steel having a bottom edge which rests directly atop tundish outer steel 
shell 13 (not shown). Dams of this type are described in detail in Moscoe, 
et al. U.S. Pat. No. 4,828,014, dated May 9, 1989, and the disclosure 
thereof is incorporated herein by reference. 
The molten steel introduced into tundish 10 may contain a molten alloying 
ingredient which has a density greater than the density of molten steel. 
Such alloying ingredients include lead and bismuth. Some of this dense, 
molten alloying ingredient may be undissolved in the steel, and the 
undissolved, molten alloying ingredient will settle to tundish bottom 15. 
Dams 17 and 18 are intended to minimize the entry of such undissolved, 
molten alloying ingredient into outlet compartments 22. This causes the 
undissolved, molten alloying ingredient to accumulate in holding 
compartment 21. More particularly, steel dams 17 and 18 have a bottom 
resting atop tundish outer steel shell 13. As a result, undissolved, 
molten alloying ingredient is prevented from passing under darns 17, 18 to 
outlet compartments 22; instead the undissolved, molten alloying 
ingredient is retained in holding compartment 21 and accumulates there in 
large quantities unless removed. 
Undissolved, molten alloying ingredient may enter compartment 21 by flowing 
over the top of dam 16 with the molten steel. Other undissolved, molten 
alloying ingredient may work its way under dam 16, at the interface 19 
between (a) the bottom of dam 16 and (b) refractory lining 14 or may 
penetrate through darn 16 if there are cracks in darn 16 near the bottom 
thereof. In addition, there may be cracks in refractory lining 14, below 
the bottom of dam 16, and undissolved, molten alloying ingredient can work 
its way from compartment 20 to compartment 21 through these cracks, unless 
the cracks become plugged. If these cracks are relatively close to the 
molten steel above tundish bottom 15, the temperature at these cracks will 
be high enough to prevent the undissolved, alloying ingredient passing 
through these cracks from plugging the cracks. 
As a result of the occurrences described above, holding compartment 21 may 
contain a substantial amount of undissolved, molten alloying ingredient, 
and that is undesirable. In the absence of dams 17 and 18, some of this 
undissolved, molten alloying ingredient could work its way through 
refractory lining 14 on tundish bottom 15 to tundish outer shell 12 and 
from there work its way along the top surface of shell 12 to an outlet 
opening 23, causing the undissolved, molten alloying ingredient to flow, 
with the molten steel undergoing withdrawal through outlet opening 23, 
into a casting mold for the molten steel. For reasons described above, 
this is undesirable. 
In order to prevent occurrences of the type described in the preceding 
paragraphs, and for other reasons, it is desirable to prevent large 
quantities of undissolved, molten alloying ingredient which settles to 
tundish bottom 15 in compartment 21 (or elsewhere in the tundish) from 
staying there. This is accomplished in accordance with the present 
invention, utilizing the expedients described below. 
Disposed between entry location 12 and outlet openings 23, on the 
downstream side of dam 16, is a sump 26 in tundish bottom 15. Tundish 
outlet openings 23 are downstream of sump 26. Sump 26 has a floor 27 and a 
plurality of sides 28, 29 and 30 which slope from the interior surface of 
tundish bottom 15 downwardly toward sump floor 27, from a downstream 
direction (FIGS. 3-4). Undissolved, molten alloying ingredient, which 
settles to the bottom of compartment 21, tends to accumulate in sump 26; 
and undissolved, molten alloying ingredient which works its way past dam 
16, either under the darn or through cracks near the bottom of the dam, 
also accumulates in sump 26. It is desirable to withdraw, from the 
tundish, undissolved, molten alloying ingredient which accumulates in sump 
26 or compartment 21, and structure for doing so will now be described. 
Refractory lining 14 has a part thereof, in the form of refractory bricks 
31, 32, which underlies sump floor 27. There is at least one passageway, 
defined by the joint 33 between refractory bricks 31 and 32, extending 
between sump floor 27 and that part of metal shell 13 underlying sump 26. 
Joint 33 may be devoid of mortar, or joint 33 may contain mortar having a 
porosity which is permeable to the undissolved, molten alloying ingredient 
but impermeable to molten steel. 
An example of a mortar composition which may be used at joint 33 comprises, 
in wt. %: 
______________________________________ 
silica (SiO.sub.2) 55.3 
alumina (Al.sub.2 O.sub.3) 
39.2 
titania (TiO.sub.2) 2.0 
iron oxide (Fe.sub.2 O.sub.3) 
1.4 
lime (CaO) 0.3 
magnesia (MgO) 0.4 
alkalies (Na.sub.2 O + K.sub.2 O + Li.sub.2 O) 
l.4 
______________________________________ 
Some of the considerations relevant to the permeability of undissolved, 
molten alloying ingredient and the impermeability of molten steel, 
relative to the passageway defined by joint 33, are described in the 
aforementioned Jackson, et al. U.S. Pat. No. 4,852,632, and the relevant 
description therein is incorporated herein by reference. 
Another passageway which can be permeable to undissolved, molten alloying 
ingredient, while being impermeable to molten steel, is at the interface 
34 between a refractory brick such as 32 and that part 35 of refractory 
lining 14 which surrounds and is adjacent to sump 26, particularly when 
the refractory at 35 is a rammed refractory. 
Rammed refractory 35 is sufficiently porous with respect to the 
undissolved, molten alloying ingredient to permit the latter to permeate 
through the rammed refractory to the upper part of passageway 34, for 
example, while preventing the molten steel from doing so. Passageways 33, 
34 are unsurrounded by (1) any material (such as a steel casing) which is 
impermeable to undissolved, molten alloying ingredient or (2) any material 
which forms a barrier to the passage of undissolved, molten alloying 
ingredient, from (a) refractory lining 35 to (b) passageways 33 or 34. 
Tundish 10 includes a drain 36 in steel shell 13, below passageways 33, 34 
for withdrawing, through shell 13, undissolved, molten alloying ingredient 
which has permeated or descended through the passageways to shell 13. 
A problem can occur which prevents undissolved, molten alloying ingredient 
from descending along passageways 33, 34. This in turn will prevent 
undissolved, molten alloying ingredient from being withdrawn from sump 26. 
This problem arises because of the decreasing temperature between the top 
and bottom of a given passageway 33, 34. If the temperature anywhere along 
a passageway drops below the melting point of the undissolved alloying 
ingredient, the undissolved, molten alloying ingredient descending along 
the passageway can cool to a temperature at which the alloying ingredient 
solidifies or becomes sufficiently viscous to block the passageway against 
further passage by the undissolved alloying ingredient. 
In accordance with the present invention, expedients are provided for 
maintaining each passageway 33, 34 at a temperature which prevents molten, 
undissolved alloying ingredient, which descends along the passageway, from 
cooling to a temperature which blocks the passageway against further 
passage by undissolved, molten alloying ingredient. 
One expedient for maintaining passageways 33, 34 at the desired elevated 
temperature is to include, among the refractory bricks which underlie sump 
floor 27 and abut the passageways, at least one high-conductivity, 
refractory brick, e.g. brick 32. This high-conductivity, refractory brick 
is longitudinally disposed in a vertical direction and has an upper 
portion, shown in dash-dot lines at 38 in FIGS. 3-4. Upper brick portion 
38 in FIGS. 3-4 preferably extends above the surrounding refractory and 
into the molten steel contained in the tundish. In other embodiments, each 
brick 31, as well as brick 32, may be composed of high-conductivity 
refractory, and a given high-conductivity, refractory brick 31 or 32 may 
or may not have an upper extended portion 38 disposed above the 
surrounding refractory. 
The high-conductivity refractory may be of the MgO--C type or the Al.sub.2 
O.sub.3 --MgO--C type for example. Other types of refractory may be 
employed for brick 31, so long as the brick has sufficient conductivity to 
conduct the necessary amount of heat from the overlying molten metal to 
the bottom of the pasageway abutted by the brick; i.e. sufficient heat 
must be conducted along the length of the brick to maintain an entire 
passageway 33 or 34 at a temperature which prevents blocking thereof by 
undissolved alloying ingredient. As used herein, the term 
"highconductivity" refers to a refractory which will perform the function 
described in the preceding sentence. 
An example of a MgO--C type of high-conductivity refractory is set forth 
below, in parts: 
______________________________________ 
carbon (C) 17.1 
silica (SiO.sub.2) 
1.1 
alumina (Al.sub.2 O.sub.3) 
0.5 
iron oxide (Fe.sub.2 O.sub.3) 
0.3 
lime (CaO) 2.2 
magnesia (MgO) 95.9 
______________________________________ 
Set forth below is an example of a rammed refractory 35 which permits 
undissolved, molten alloying ingredient to permeate through the rammed 
refractory to a passageway such as 34, while preventing molten steel from 
doing so. The rammed refractory comprises, in wt. %: 
______________________________________ 
alumina (Al.sub.2 O.sub.3) 
79.1 
silica (SiO.sub.2) 13.4 
titania (TiO.sub.2) 2.4 
phosphorous pentoxide (P.sub.2 O.sub.5) 
3.1 
iron oxide (Fe.sub.2 O.sub.3) 
1.3 
alkalies 0.2 
______________________________________ 
Dam 16 has an upstream side 24 and a downstream side 25, and sump 26 is 
located adjacent the dam's downstream side 25. As shown in FIGS. 2-3, each 
of refractory bricks 31 has a portion which underlies dam 16 and a portion 
located on the dam's downstream side 25. Refractory brick 32 is located 
downstream of bricks 31 and adjacent thereto. As previously noted, in one 
embodiment, refractory bricks 31 and 32 are all composed of 
high-conductivity refractory. 
In the embodiment illustrated in FIGS. 1-4, sump 26 is located adjacent 
downstream side 25 of darn 16, but other locations may be appropriate for 
such a sump. The important consideration is that the sump be located 
between entry location 12 and outlet openings 23 so as to accumulate 
undissolved, molten alloying ingredient and prevent the latter from 
exiting through outlet openings 23. 
In some embodiments, passageways such as 33, 34 can be located in the 
tundish bottom 15 of holding compartment 21, outside of any sump. Such 
passageways can be located anywhere in holding compartment 21 where the 
passageways will function to remove, from compartment 21, accumulations of 
undissolved, molten alloying ingredient. 
In all embodiments, the passageways 33, 34 extend between (a) the top of 
refractory lining 14 on tundish bottom 15 and (b) the underlying steel 
shell 13. In the embodiments with a sump, the top of the refractory 
lining, at the location of passageways 33, 34, is at sump floor 27. There 
can sometimes be a thin layer of porous, refractory material sprayed atop 
the tundish bottom (refractory brick and/or rammed refractory) to act as a 
parting compound which prevents solidified, residual metal (skull) in the 
tundish from adhering to the refractory lining on the tundish bottom when 
the skull is removed from the tundish. As used herein, reference to the 
top of the refractory lining means the top of the refractory brick and/or 
the top of the rammed refractory underlying the thin, porous, sprayed-on 
layer (when such a layer is employed). 
In all embodiments, refractory lining 14 has a part thereof which abuts 
passageways 33, 34, e.g. refractory bricks 31, 32 and rammed refractory 
35. In the embodiments with a sump, bricks 31, 32 underlie the sump floor 
and rammed refractory 35 surrounds the sump. 
In all embodiments having a high-conductivity, refractory brick with an 
upper, extended portion 38, brick portion 38 extends above the surrounding 
refractory. In the embodiments with a sump, brick portion 38 extends above 
sump floor 27. 
In those embodiments having one or more discrete sumps, each such sump may 
be located in holding compartment 21 in a disposition parallel to dams 17, 
18, on the upstream side of one of these dams, adjacent thereto or spaced 
therefrom. Such a sump may be elongated in the longitudinal direction of 
the dam, or the sump may be unelongated. In other embodiments, a sump 
disposed in a parallel relation to a darn 17 or 18 could be located on the 
downstream side of the dam so long as it was upstream of an adjacent pair 
of outlet openings 23. Similarly, in a tundish without dams such as 17 or 
18, the sump can be longitudinally disposed between walls 41, 42 of the 
tundish, downstream of inlet location 12 and upstream of outlet openings 
23. Such a disposition is shown at 46 in FIG. 5. 
The sump shown at 46 in FIG. 5 can be employed in a tundish which does or 
does not have dams such as 17, 18, and when employed with a tundish having 
dams 17, 18, the sump can be located either on the upstream side of the 
dam or on the downstream side of the dam. 
Referring to FIGS. 5-7, sump 46 extends between tundish sidewalls 41, 42 
and is located upstream of outlet openings 23 and downstream of inlet 
location 12 (not shown in FIGS. 5-7). Sump 46 comprises a downstream side 
50 which may slope toward the sump floor from a downstream direction and 
an upstream side 49 which may slope toward the floor of sump 46 from an 
upstream direction. Sump 46 may have a total of four sloping sides, 47, 
48, 49 and 50, which converge in a downward direction toward a pair of 
high-conductivity refractory bricks 51, 51. In sump 46, the sump floor is 
defined by the lower parts of sloping sump sides 47-50. The passageways 
which extend between the floor of sump 46 and the underlying steel shell 
13 are defined by the joint 53 between high-conductivity refractory bricks 
51, 51, and by the interfaces 54, 55, 56 and 57 between (a) bricks 51, 51 
and (b) rammed refractory 35 which is disposed around highconductivity 
refractory bricks 51, 51. 
Passageways 53-57 are maintained at a temperature which prevents 
undissolved, molten alloying ingredient, which descends along these 
passageways, from cooling to a temperature at which the alloying 
ingredient becomes solidified or sufficiently viscous to block the 
passageway against further passage by the undissolved alloying ingredient. 
This is accomplished by the upper portion 58 of each high-conductivity, 
refractory brick 51. Upper brick portion 58 may extend above the floor of 
sump 46 and into the molten steel contained in the tundish, thereby 
heating upper brick portion 58 sufficiently to maintain the desired 
elevated temperature from the top to the bottom of each of the passageways 
53-57. 
Another expedient for maintaining the passageways at the desired elevated 
temperature is illustrated in FIG. 8. In this embodiment, the top of each 
of a plurality of refractory bricks 62 is no higher than the floor 59 of 
sump 46. Refractory brick 62 is preferably composed of high-conductivity 
refractory. That part of refractory brick 62 which underlies sump floor 59 
or which abuts a passageway is heated by a heating element, e.g. an 
electrical heating element, typically comprising a substantially 
horizontally disposed member 60 underlying brick 62 which is in contacting 
relation with the top of heating member 60. In lieu of member 60, or in 
combination therewith, the heating element may comprise a substantially 
vertically disposed member 61 extending upwardly into refractory brick 62. 
In those instances where the heating element at 60, 61 is an electrical 
heating element, heating member 60 and/or heating member 61 may be 
connected to a source of electrical energy in a conventional manner (not 
shown). Members 60, 61 may be composed of copper or other conductors 
conventionally utilized as heating elements under comparable external 
temperature conditions. 
In other embodiments, electrical heating of members 60, 61 may be replaced 
by flame heating of these members from below, or by direct flame heating 
of the bottom of refractory brick 62, without employing member 60 and with 
or without member 61. In still other embodiments brick 62 may be provided 
with a vertical opening where member 61 is located, and a flame may be 
directed upwardly into that opening. 
The expedients for heating refractory brick 62, shown in FIG. 8 or 
otherwise described above, may also be employed to heat refractory bricks 
31-32 shown in FIGS. 2-4 or to heat refractory bricks 51 shown in FIGS. 
6-7. In such cases, no refractory brick need extend above the sump floor, 
although it may. In the embodiments of FIGS. 2-4 and 6-7, the top of a 
high-conductivity, refractory brick need not extend above the surrounding 
refractory (e.g. the sump floor) if, when the brick top is flush with the 
surrounding refractory, sufficient heat is conducted from the overlying 
molten metal to the bottom of the brick so as to keep the abutting 
passageways from being blocked by undissovled alloying ingredient. 
Except for the differences described above, sump 46 and its associated 
structure is essentially the same as sump 26 and its associated structure. 
The upper portion 38 of high-conductivity, refractory brick 32, and the 
upper portion 58 of highconductivity, refractory bricks 51 extend upwardly 
into the molten metal within the tundish to provide good thermal contact 
with the molten steel. The sides of sumps 26 and 46 are sloped downwardly 
so that undissolved, molten alloying ingredient will collect or accumulate 
around the upper end of passageways 33, 34 and 53-57. 
The foregoing detailed description has been given for clearness of 
understanding only and no unnecessary limitations should be understood 
therefrom, as modifications will be obvious to those skilled in the art.