Joint structure for casting nozzle

A casting nozzle joint structure capable of easily positioning and jointing a nozzle without any holder for fixing and supporting a continuous casting nozzle therethrough. The joint structure comprises fitting mechanism formed in and on the mating faces of the continuous casting nozzle and the pressure clamper. The fitting mechanism includes a convex portion and a concave portion formed in and on the mating faces of the continuous casting nozzle and the pressure clamper so that they fit one another. The concave or convex portion formed in the mating face of the continuous casting nozzle is fitted on or in the convex or concave portion formed in the mating face of the pressure clamper, and this pressure clamper clamps the fitted engagement. Thus, the nozzles can have their outlet bores positioned, and the submerged entry shroud can have its discharge port oriented.

BACKGROUND OF THE INVENTION 
1. Field of the Invention: 
The present invention relates to a joint structure for jointing between a 
pressure clamper and a casting nozzle to the lower portion of a casting 
nozzle which is attached to a ladle or tundish of a continuous steel 
casting apparatus. 
2. Description of the Prior Art 
The continuous steel casting apparatus is equipped with a portion, at which 
two nozzles, such as a ladle lower nozzle and a ladle shroud, or a tundish 
lower nozzle and a submerged entry shroud, have to be jointed to each 
other. 
This joint will be described in the prior art by using the joint between a 
submerged entry shroud and a slide gate as an example. 
As shown in FIG. 12 and FIG. 13, presenting a top plan section taken along 
line XIII--XIII of FIG. 12, there is currently adopted a structure in 
which a submerged entry shroud "a" mounted by a hanger-like pressure 
clamper "f" on a holder "e" through mortar "d" is pressed onto a bottom of 
a casting nozzle "c" fixed on the bottom of a slide gate "b". 
However, this joint structure of the prior art is defective in that it is 
deformed in the holder by heat, which is transferred from the molten steel 
flowing through the nozzles, and so requires periodic replacements. 
Another defect is that the mortar used for fixing the nozzles deteriorates 
the working efficiency so that it takes a long time to set and joint the 
nozzles. Still another defect is that the submerged entry shroud requires 
its discharge port to be oriented in a predetermined direction, thus 
making it difficult to position the nozzles relative to each other. 
SUMMARY OF THE INVENTION 
An object of the present invention relates to a casting nozzle joint 
structure capable of easily positioning and jointing a nozzle without any 
holder while eliminating the defects of the prior art. 
According to an aspect of the present invention, there is provided a joint 
structure comprising a pressure clamper for fixing and supporting a 
continuous casting nozzle therethrough, wherein the improvement comprises 
a fitting means formed in and on the mating faces of said continuous 
casting nozzle and said pressure clamper. The fitting means may include a 
convex portion and a concave portion formed in and on the mating faces of 
the continuous casting nozzle and the pressure clamper so that they fit 
one another. The fitting means can be exemplified by any arbitrary type of 
toggle, cotter and bayonet mechanisms known in the prior art. 
According to another aspect of the present invention, the fitting means can 
be provided in a desired number, as necessary. 
According to a further aspect of the present invention, the joint structure 
can comprise a disengagement preventing means for preventing the fitted 
faces of the continuous casting nozzle and the pressure clamper from 
coming apart. 
According to a yet further aspect of the present invention, the joint 
structure can comprise a reinforcing structure including a reinforcing 
metal plate sandwiched between the mating faces of the continuous casting 
nozzle and the pressure clamper for reinforcing the fitted portions by 
receiving the locally concentrated pressure. 
The concave or convex portion formed in the mating face of the continuous 
casting nozzle is fitted on or in the convex or concave portion formed in 
the mating face of the pressure clamper, and this pressure clamper clamps 
the fitted engagement. As a result, the nozzles can have their outlet bore 
positioned and, still the better, the submerged entry shroud can have its 
discharge port oriented.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The embodiments to be described are exemplified by applying the fitting 
means to a joint between the submerged entry shroud and the slide gate, as 
shown in FIG. 12. Illustrations will be made to emphasize the relation 
between the submerged entry shroud 1 and the pressure clamper (or hanger) 
4. 
Embodiment 1: 
FIG. 1 shows a first embodiment, and FIG. 2 is a top plan section taken 
along line II--II. 
As shown in these Figures, the submerged entry shroud 1 has its support 
face 2 formed with a semicircular recess 3, and the pressure clamper 4 of 
hanger type, for example, is formed with a ridge 5 which is sized and 
positioned to correspond to the recess 3 of the casting nozzle. Thus, the 
ridge 5 is press-fitted in the recess 3 by the pressure clamper 4. 
Embodiment 2: 
FIG. 3 shows a second embodiment, and FIG. 4 is a top plan section taken 
along line IV--IV. 
In this embodiment, the recess 3 formed in the submerged entry shroud 1 is 
circular so as to extend around the root of the support face 2 of the 
submerged entry shroud 1, and a ridge 5 is also formed in the hanger type 
pressure clamper 4 so that it is sized and positioned to correspond to the 
recess 3. 
Embodiment 3: 
FIG. 5 shows a third embodiment, and FIG. 6 is a top plan section taken 
along line VI--VI. 
In this embodiment, the support face 2 of the submerged entry shroud 1 is 
formed on the center of its base with straight recesses 3 which are to fit 
the ridges 5 of the pressure clamper 4. This structure is additionally 
given a function to prevent the fitting from faltering between the nozzle 
1 and the pressure clamper 4, the faltering being caused by the 
deformation coming from a thermal load carried over a long period. This 
structure provides the straight fitting means with another advantage in 
that it can be set relatively simply. 
Embodiment 4: 
FIG. 7 shows a fourth embodiment, and FIG. 8 is a top plan section taken 
along line VIII--VIII. 
In this embodiment, another straight recess 31 is formed at a right angle 
with respect to the straight recesses 3 formed on the center of the base 
of the support face 2 in the embodiment 3 shown in FIGS. 5 and 6. The 
pressure clamper 4 is also formed with a corresponding ridge 51 at a right 
angle with respect to the ridges 5, and the pressure clamper 4 is 
reinforced by a reinforcing bottom plate 41 extending therefrom. 
As a result, the fitting joint between the submerged entry shroud 1 and the 
pressure clamper 4 is strengthened when pressed by the clamper 4, so that 
the connection to the tundish nozzle, as shown in FIG. 12, can be better 
ensured. 
Embodiment 5: 
In FIG. 9 and FIG. 10, presenting the longitudinal section taken along line 
X--X, there is shown the fifth embodiment, in which the support face 2 of 
the submerged entry shroud 1 is formed therein with a recess at a right 
angle with respect to the recess or recesses 3 of the foregoing individual 
embodiments, whereas the pressure clamper 4 is formed with a ridge at a 
right angle with respect to the ridge or ridges 5 to be fitted in the 
recess or recesses 3, thus constituting a disengagement prevention 
mechanism 6. Thanks to this mechanism 6, the ridge 5 of the pressure 
clamper 4 is prevented from moving in the direction indicated by the arrow 
out of engagement with the recess 3 formed in the support face 2 of the 
submerged entry shroud 1. 
Embodiment 6: 
FIG. 11 shows a reinforcing structure for receiving the pressure to be 
concentrated in the recess 3, which is formed in the support face 2 of the 
submerged entry shroud shown in the foregoing individual embodiments, when 
the projection of the pressure clamper is fitted in the recess 3, thereby 
preventing the recess 3 from being broken. 
As shown in the same Figure, the reinforcing structure includes a 
reinforcing metal plate 8 which is formed with a recess 7 corresponding to 
the recess 3 formed in the support face 2 of the submerged entry shroud 1. 
This metal plate is arranged on the support face 2 of the submerged entry 
shroud 1 for reinforcing the fitted portions by receiving the locally 
concentrated pressure. In a modification, this metal plate 8 may be shaped 
into a casing shape covering the supporting face 2 of the submerged entry 
shroud 1. 
The joint structures thus embodied above were adopted for connecting the 
ladle lower nozzle of 300 tons, and the submerged entry shroud, and were 
subjected to casting operations of eight charges for 400 minutes. It was 
confirmed that the joint experienced no such deterioration as to cause 
either the invasion of air or leakage of molten steel. 
According to the casting nozzle joint structure of the present invention, 
neither mortar nor any holder need be used for ensuring the reliable 
positioning and connection when a nozzle is to be attached to the ladle or 
tundish of an ordinary casting nozzle or a continuous casting nozzle such 
as the ladle shroud or the submerged entry shroud.