Title of Invention

METHOD AND APPARATUS FOR POURINGSTEEL FROM AN IMMERSION SPOUT

Abstract The invention relates to a method and to an apparates for in£luencing the spreading of the flow of a metal liquid, in particular steel, which is guided from a melt container 41 via a first immersion spout part II, and an intermediate part 31 through a second immersion spout part 21, which has an elongate cross-section, into a stationary mould 51 for producing slabs. The apparatus is designed such that the main flow stream of melt (8) leaving the first immersion spout part (11) is throttled which serves to increase the angle of spread and reduce the central volumetric flow in the inlet region of the second immersion spout part 21. This results in the liquid metal leaving the second immersion spout part 21 flowing with a velocity profile, the velocity vectors of which are smaller in the centre of the mouth 28 than in the regions of the narrow sides.
Full Text METHOD AND APPA^TUS FOR POURING STEEL FROM AN IMMERSION SPOUT
T
The invention relates to a method and to an apparatus for influencing the spreading of the flow of a metal liquid, in particular steel, which is guided from a melt container via a first immersion spout part, which has a polygonal oval or circular cross-section, and an intermediate part through a second immersion spout part, which has an elongate cross-section, into a stationary mould for producing slabs.
A pouring spout for metallurgical vessels is known from DE 3 7 09 188, said pouring spout being subdivided into an upper tubular longitudinal portion and a lower rectangular longitudinal portion, a conical transition piece being provided between the two longitudinal portions. In this regard, it is possible for the rectangular cross-section to have a length to width ratio of 20:1 to 80:1.
At the mouth of the immersion spout, a transverse bar is provided for directing the liquid steel into the side openings of the mouth. In so doing, the steel enters the mould with a relatively high kinetic energy. In addition, the transverse bar is exposed to considerable wear.
An immersion spout comprising a shaped brick, which has a tubular shape and is connected, via a conical structural part.

^^ >-L j.wwc;j., j.c:i_i-ciiiyaxd.x aiiapea DricK wnicn dips into the melt, is known from DE 43 20 723. Longitudinal webs are provided in the flow cross-section in the lower shaped brick.
In the region of the inlet to the lower rectangular shaped brick, a transverse bar is provided for deflecting the flow of melt in the direction of the widening of the flow shaft. As a result of this transverse bar, which is designed to be a deflector plate, considerable turbulence will occur in the melt, in a disadvantageous manner.
The object of the invention is to prevent the afore-mentioned disadvantages and, in a simple manner, to provide a method and an apparatus relating to an immersion spout for guiding metal melts, by means of which it is possible for the turbulence in the immersion spout itself, as well as in the mould, and, at the same time, the penetration depth of the melt introduced into the liquid phase disposed in the mould, to be reduced to a minimum.
According to one aspect of the invention there is provided a method for influencing the spreading of the flow of a metal liquid, in particular steel, which is guided from a melt container via a first immersion spout part, which has a polygonal, oval or circular cross-section, and an intermediate part through a second immersion spout part, which has an elongate cross-section, into a stationary mould for producing slabs, which includes the following steps:

a) the central volumetric flow stream is reduced in the inlet region of the second immersion spout part,
b) at the same time, the angle (6) of spread of the liquid flow stream is enlarged such that a backflow in the side regions of the intermediate part and of the second immersion spout part is substantially prevented, and
c) when leaving the second immersion spout part, the melt flows with a velocity profile, the velocity vectors of which are smaller in the centre of the mouth than in the regions of the narrow sides.
According to another aspect of the invention there is provided an immersion spout for pouring metal liquid, in particular steel, comprising a first immersion spout part, which is connected to a melt vessel and has a polygonal, oval or circular cross-section, and a second immersion part which is connected to the first immersion spout part via an intermediate part and has an elongate cross-section, and the cross-sectional surface area of which is the same or smaller than that of the first immersion spout part, wherein the immersion spout projects into a stationary mould for producing slabs to an extent such that the mouth of the second immersion spout part dips into the melt, for carrying out the above method, in which, in the region of the centre axis of the immersion spout, the intermediate part and/or the inlet of the second immersion spout part is/are designed such that the main flow stream of melt leaving the first immersion spout part is throttled.

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According to the invention, in an immersion spout, the mouth"^ part of which dips into the melt disposed in the mould and has an elongate cross-section, the central volumetric flow stream is reduced in the inlet region of this immersion spout part. This reduction in the volumetric flow stream is achieved by throttling the central region, thereby simultaneously enlarging the angle of spread of the liquid flow stream to an extent such that a backf low into the lateral regions of the immersion spout part having an elongate cross-section is substantially prevented.
As a result of the throttling and the simultaneous spreading of the central volumetric flow stream, the melt flows out of this immersion spout part with a velocity profile, the velocity vectors of which are smaller in the centre of the mouth than in the regions of the narrow sides.
The quantity fed through the immersion spout comes into contact at this adjusted velocity profile with the liquid phase which is disposed in the mould and from which, depending on the rate of discharge of the continuous casting, 1 to 10 m/min are drawn off, and penetrates into this liquid phase to only small depths corresponding to a mixing length of L = 0.2 to 4 m.
As a result of the intensive spreading of the central volumetric flow stream, the velocity profile in the region of the narrow sides on the mouth of the immersion spout part having an elongate cross-section has velocity vectors which

have components which permit a backflow on the narrow sides of the mould. As a result hereof, a sufficient quantity of fresh melt is fed to the bath level in the mould, and this has a positive influence on the casting powder applied to the surface area. In addition, this melt flows, with only a small bow wave but in a sufficient quantity, to the centre between the immersion spout and the mould. The melt flow streams unite in the middle of the mould and then flow into the liquid phase in the direction of discharge of the casting. In that region, they fill the volumetric flow stream discharged from the second immersion spout part in the centre of the mouth.
The consequence hereof is a virtually flat and, all in all, only very slight penetration depth into the liquid phase, with the advantage that, for example in the event of change in quality of the melt, there is only a small mixing length and, thus, a short piece of unwanted slab quality.
The throttling of the central volumetric flow stream is achieved in that the region upstream of the inlet into the immersion spout part having an elongate cross-section, or the inlet itself, is designed in a particular manner. At any rate, the free space is kept sufficiently clear, such that a defined quantity always flows in the central region of the second immersion spout part.
For the purpose of throttling the central volumetric flow stream, it is possible for the walls of the broadside of the

intermediate part, which is arranged, in the direction of casting, upstream of the immersion spout part having an elongate cross-section, to comprise a concave bulge. In an advantageous design, said bulge is designed in the manner of a quarter of a hollow sphere. In a further development, it has the shape of a tubular segment having a predetermined contour.
Throttling is also achieved by a narrowing of the free space of the inlet of the immersion spout part. It is possible for this narrowing to be brought about by means of flow bodies, which are arranged on the broadside of the immersion spout part, or by moulding protuberances in the latter.
In an advantageous manner, the narrowing has dimensions such that its width corresponds substantially to the diameter of the series-connected tubular immersion spout part, and the length corresponds to 0.2 to 1.2 times its width.
The leading and the trailing edges are designed to be sharp-edged, in this regard having an angle S from the leading edge and the inner wall of 90 to 150°. it is possible for the shaping of the intermediate part and the narrowing to be combined. In such a combination, it is suggested that the contour of the bulge of the intermediate part be adapted to the leading edge of the flow element in the second immersion part spout.
An example of the invention is illustrated in the attached

drawing, in which:
Figures 1-3 show an immersion spout comprising a bulge;
and Figures 4-5 show an immersion spout comprising a narrowing.
In connection with the above, Figures 1 and 4 show longitudinal sections, and Figures 2, 3 and 5 show cross-sections of an immersion spout which comprises a first immersion spout part 11, an intermediate part 31 and a second immersion spout part 21. The centre axis is designated by I.
Using the same reference numbers in respect of all Figures, the first immersion spout part 11 is secured to a melt vessel 41 via a flange 12. It is possible for the outlet 42 of the melt vessel 41 to be sealed off by means of a stopper 43. The first immersion spout part 11 has a round, oval or even polygonal cross-section and is connected, via the intermediate part 31, to the second immersion spout part 21 which has broad sides 25 which are distinctly larger than the narrow sides 26. The first immersion spout part 11 is provided with a slit 13 in the region of the intermediate part 31.
The second immersion spout part 21 projects into a mould 51, the mouth 28 dipping into the melt S which is disposed in the mould 51. Casting powder P is provided on the melt S.
In Figure 1, the intermediate part 31 is provided with a bulge

34 which is designed to have a spherical shape 35 in the right-hand side and, in the left-hand side, is designed to be a tubular segment 36.
In the left-hand side of Figure 1, the bulge 34 in the form of the tubular segment 3 6 follows directly on the round immersion spout part 11. Relative to its principal axis II, it is possible for the tubular segment 3 6 to have a constant radius or it may be designed to be parabolic.
Figure 2 shows the plan view of the bulge 34 which, in this instance, is a tubular segment 36.
Figure 3 shows the plan view of the bulge 34 having a spherical shape 35. The pointed opening of the quarter hollow sphere 35 is clearly shown at the transition to the broadside 25 of the second immersion spout part 21.
The first immersion spout part 11, shown herein as a pipe, opens up in the upper parts of Figures 2 and 3, the slit 13 being provided at the mouth. The intermediate part 31, which covers the broad sides 32, is illustrated at the beginning of the slit at both sides of the narrow side 33. The narrow side 33 is inclined at an angle 7 with respect to the approach channel 22.
Figure 2 is a view of the broad side 32 of the intermediate part 31. In the middle region, the bulge 34 is designed to be

a tubular segment 36. In Figure 3, the bulge 34 is designed to be a quarter hollow sphere 35.
The arrows in Figures 2 and 3 illustrate the velocity vectors. Figure 2 shows the manner in which the melt volume and quantity are reduced in the central region, downstream in the direction of flow of the throttling element. The melt, distinctly spread through an angle 5 of spread, flows into the second immersion spout part 21.
In the region of the mouth of the second immersion spout part, the velocity profile in the region of the narrow side walls is such that there is a lower velocity in the centre of the mouth.
In the mould itself (Figure 3), the velocity vectors have a component which permit a portion of the melt to flow back to the surface of the bath. Here, they are directed to the middle of the mould 51 and, in the centre of the mould 51, between the broad side 2 5 of the immersion spout 21 and the broad side 52 of the mould 51, are redirected into the direction of discharge of the casting.
The narrow side 26 opens up toward the mouth of the second immersion spout part conically at an angle a relative to the centre axis I. It is possible for this angle a to distinctly in excess of the 7° acceptable for free jetting, and may have a value up to 15° (Figure 5).

Figure 4 shows a flow body 62 or a protuberance 61 in the inlet 22 below the first immersion spout part 11.
In the left-hand side of Figure 4, the first immersion spout part 11 is designed to be a pipe, the end of which is sealed off by means of an end plate 27. A tubular segment 36 is arranged in the inner spandrel between the end plate 27 and the pipe 11. The contour 37 is designed to be parabolic. From its mouth, the tubular segment comes into contact with the leading edge of a flow body 62.
In the present instance, the leading edge 64 is arranged with respect to the inner side of the flow body 62 at an angle of 90°. The trailing edge 65 of this flow body 62 also has an angle & of 90°.
On the right-hand side, the pipe 11 blanks off in an inclined face 3 8 which is directed toward the inlet 22 to the second immersion spout part 21. The inlet region 22 is designed to be a protuberance 61. The outer surface of the leading edge 64 has the same angle of inclination as the inclined face 38.
The trailing edge 65 in the present instance has an angle E of about 45°. The broad side 25 of the second immersion spout part 21 has the same wall thickness as the protuberance and rebounds outwardly in the region of the trailing edge 65. In the direction of flow downstream of the flow bodies 61 and 62, the free space 23 is of equal size as the entire second

immersion spout part up to its mouth.
Figure 5 shows the plan view in respect of the cross-section of. the second immersion spout part 21 comprising the narrowing 61, 62 as illustrated in Figure 4. A flow body 62, having the dimensions A = 1 x D, is arranged below the first immersion spout part 11, in the inlet region 22 of the second immersion spout part 21. The length 1 in this regard has a value 1 = 0.2 to 1.2 X D, corresponding to the diameter D of the tubular first immersion spout part 11.
In Figure 5, in contrast to the preceding Figures 2 and 3, the angle y in the upper region of the possible inclination is 7 = 0 to 40°. The angle a is also selected to be greater than that of Figures 2 and 3, a possibly being between 0 and 15°.

LIST OF REFERENCE NUMBERS
Immersion spout inlet part
11 first immersion spout part
12 securing flange
13 slit
2 0 immersion spout outlet part
21 second immersion spout part
22 inlet
23 free space
24 narrowing
25 broad side
26 narrow side
27 end plate
28 mouth
Immersion spout intermediate part
31 intermediate part
32 broad side
3 3 narrow side/cover
34 bulge
35 quarter hollow sphere 3 6 tubular segment
3 7 contour of the bulge
38 inclined face
Melt feeding unit
41 melt vessel

42 outlet
43 stopper
Continuous-casting means
51 mould
52 broad side
53 narrow side
Narrowing elements
61 protuberance
62 first flow body
63 second flow body
64 leading edge
65 trailing edge
I centre axis
II principal axis of tubular segment
S melt
P casting powder
1 length of the flow element
0! angle of the second immersion spout part
iS angle of leading edge
7 angle covering intermediate part
5 angle of spread


We Claim:
1. A method for pouring steel from an immersion spout, which is guided from a melt container via a first immersion spout part, which has a polygonal, oval or circular cross-section and an intermediate part through a second immersion spout part, which has an elongate cross-section, into a stationary mould for producing slabs, which comprising the following steps: the central volumetric flow stream is reduced in the inlet region of the second immersion spout part, at the same time, the angle (d) of spread of the liquid flow stream is enlarged such that a backflow in the side regions of the intermediate part and of the second immersion spout part is substantially prevented, and when leaving the second immersion spout part, the melt flows with a velocity profile, the velocity vectors of which are smaller in the centre of the mouth than in the regions of the narrow sides.
2. The method according to claim 1, wherein the velocity vectors in the region of the narrow sides, after leaving the mouth of the second immersion spout part, are imparted a component which is directed toward the narrow side of the mould and ensures a controlled backflow of the melt to the surface of the bath in the mould, and the quantity of melt is adjusted such that all the melt penetrates into the liquid phase of the continuous casting, which liquid phase is present in the mould and is drawn off at a rate of 1 to 10 m/min, to a depth which corresponds to a mixing length (L)ofL = 0.2 to 4 m.
3. The method according to claim 2, wherein the melt penetrates into the liquid phase of the continuous casting, which liquid phase is present in the mould and is drawn off at a rate of 4 to 5 m/min, to a depth which corresponds to a mixing length (L)ofL = 0.2to2m.

4. The method according to anyone of the preceding claims, wherein, below the end of the mixing zone, the velocity vectors of the liquid phase are set in the same direction and are of the same magnitude as the casting rate.
5. An immersion spout for pouring metal liquid, in particular steel, comprising a first immersion spout part, which is connected to a melt vessel and has a polygonal, oval or circular cross-section, and a second immersion part which is connected to the first immersion spout part via an intermediate part and has an elongate cross-section, and the cross-sectional surface area of which is the same or smaller than that of the first immersion spout part, wherein the immersion spout projects into a stationary mould for producing slabs to an extent such that the mouth of the second immersion spout part dips into the melt, for carrying out the method according to anyone of the preceding claims, in which, in the region of the centre axis of the immersion spout, the intermediate part or the inlet of the second immersion spout part is designed such that the main flow stream of melt leaving the first immersion spout part is throttled.
6. The immersion spout according to claim 5, wherein the walls of the broad side of the intermediate part below the first immersion spout part has a concave bulge.
7. Immersion spout according to claim 6, wherein the bulge has a spherical shape and is, in this regard, designed in particular to be a quarter of a hollow sphere.
8. The immersion spout according to claim 6, wherein the bulge is designed in the manner of a tubular segment, the principal axis of which is directed parallel to the broad side of the intermediate part.

9. The immersion spout according to claim 8, wherein the contour of the tubular
segment is designed to be parabolic, the smaller radius being inclined in the
direction of the inlet of the second immersion spout part.
10. The immersion spout according to claim 5, wherein the end plate which closes off the upper edge of the broad sides is inclined at an angle y of 0 to 40°.
11. The immersion spout according to claim 5, wherein a narrowing is provided in the free space between the broad sides of the second immersion spout part, below the first immersion spout part.
12. The immersion spout according to claim 11, wherein the narrowing is formed by protuberances in the broad side walls which protrude into the free space of the second immersion spout part.
13. The immersion spout according to claim 11, wherein the narrowing is formed by at least one flow body which extends in the free space of the second immersion spout part.
14. The immersion spout according to claim 12 or 13, wherein the narrowing extends in the direction of flow at a length (1), wherein 1 > 0.2 to 1.2 x D, wherein D = diameter of the tubular first immersion spout part.
15. The immersion spout part according to claim 11, wherein the leading edge or the trailing edge of the narrowing is/are designed to be sharp-edged at an angle P = 90 to 150°.
16. The immersion spout according to anyone of claims 6 to 14, wherein when using the bulge, an intermediate part and a narrowing in the free space of the

second immersion spout part, the contour of the leading face of the narrowing follows the contour of the bulge.

Documents:

1175-mas-1997 abstract duplicate.pdf

1175-mas-1997 abstract.pdf

1175-mas-1997 claims duplicate.pdf

1175-mas-1997 claims.pdf

1175-mas-1997 correspondence others.pdf

1175-mas-1997 correspondence po.pdf

1175-mas-1997 description (complete) duplicate.pdf

1175-mas-1997 description (complete).pdf

1175-mas-1997 drawings duplicate.pdf

1175-mas-1997 drawings.pdf

1175-mas-1997 form-19.pdf

1175-mas-1997 form-2.pdf

1175-mas-1997 form-26.pdf

1175-mas-1997 form-4.pdf

1175-mas-1997 others.pdf

1175-mas-1997 petition.pdf


Patent Number 202069
Indian Patent Application Number 1175/MAS/1997
PG Journal Number 05/2007
Publication Date 02-Feb-2007
Grant Date 19-Sep-2006
Date of Filing 02-Jun-1997
Name of Patentee M/S. MANNESMANN AKTIENGSELLSCHAFT
Applicant Address MANNESMANNUFER 2, D 40213 DUSSELDORF
Inventors:
# Inventor's Name Inventor's Address
1 MANNESMANN AKTIENGSELLSCHAFT MANNESMANNUFER 2, D 40213 DUSSELDORF
PCT International Classification Number B22D 41/50
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 196 23 787.4 1996-06-04 Germany