Dispensing – Molten metal dispensing – With subjacent flow guide
Patent
1992-10-21
1994-07-12
Batten, Jr., J. Reed
Dispensing
Molten metal dispensing
With subjacent flow guide
164437, 222606, B22D 4150, B22D 4154
Patent
active
053280644
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an improvement in a submerged nozzle for continuous casting, and more particularly to a submerged nozzle for continuous casting, the molten steel pouring hole of which is provided with a plurality of steps.
PRIOR ART
A system of blowing inert gas is well-known as means for preventing a nozzle from fouling which impedes a multicontinuous casting and which is caused by adhesive sedimentation of an Al.sub.2 O.sub.3 deposit to the inner wall of the submerged nozzle.
Further, in such kind of continuous casting there is proposed (as in Utility Model Publication No. 61-6987) a technique that intends to swallow up the scum and pour the melt in the non-oxidation state by means of a long nozzle which is connected to a ladle nozzle and only the submerging portion of which is made large-diameter, said submerging portion being submerged into the molten steel in a mold.
It is known that said system of blowing inert gas has the following disadvantages.
(1) As will be seen from FIG. 7, the fouling of the nozzle caused by the adhesion of deposit such as of Al.sub.2 O.sub.3 takes place in the upper portion within the nozzle and in the inner surface near pouring outlet.
(2) If a gas blowing nozzle as illustrated in FIG. 6 is used to avoid the disadvantage (1) above, the inner surface of the pouring outlet of the nozzle vigorously melts down due to the bubbling agitation action of the inert gas.
SUMMARY OF THE INVENTION
The inventors of this invention have made their extensive researches in an attempt to avoid the various drawbacks of the known system. As a result, they have been successful in developing a multi-stepped submerged nozzle of the present invention. In the preferable technical constitution of the invention, a plurality of steps are provided in the molten steel pouring hole of a submerged nozzle for continuous casting, the inside diameters of said steps in the pouring hole to the inside diameter d of the main pipe is d.sub.1 >d.sub.2 >d.sub.3 . . . d.sub.n >d, the inside diameter d of the main pipe is disposed in the respective spaces of said steps where d.sub.1 >d.sub.n where n is greater than 1, said steps is arranged in the pouring direction of the molten steel in the order of the inside diameters d.sub.1 -d.sub.n, said steps may also be arranged doubly for the same inside diameter, d.sub.n is d+10 mm.gtoreq.d.sub.n, and the material of the inner peripheral wall close to the melt pouring outlet is boron nitride-carbon.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2 and 8 are vertical sectional views showing embodiments of the invention;
FIGS. 3 and 4 show relationships among the state, quantity and speed of the melt flow in the molten steel pouring hole of the present submerged nozzle; and
FIGS. 5 to 7 are vertical sectional views showing a conventional submerged nozzle and states of deposition of Al.sub.2 O.sub.3 to the nozzle.
BEST MODE OF CARRYING OUT THE INVENTION
In order to solve the problems of a submerged nozzle in multi-continuous casting the following matters are important.
a) A deposit of Al.sub.2 O.sub.3 is likely to take place in the upper, inner periphery of the submerged nozzle and the inner surface near the pouring outlet, and it is important to solve the means for avoiding the deposition.
b) It is also important to select a material to which an Al.sub.2 O.sub.3 deposit hardly adheres.
Also in an attempt to solve these problems the inventors of this invention have made the invention.
EXAMPLES
The invention will now be described more in detail, by way of some examples, with reference to the accompanying drawings.
FIGS. 1 and 2 are vertical sectional views showing embodiments of nozzles of the present invention. FIG. 1 is an embodiment where the steps are double and the inside diameters of the molten steel pouring hole are d.sub.1 >d.sub.2 >d, while FIG. 2 is another embodiment where the steps are triple and the inside diameters of the pouring hole are d.sub.1 >d.sub.2 >d.sub.3 >d. Further, FIG. 8 shows an embodimen
REFERENCES:
patent: 3727805 (1973-04-01), Shapland
patent: 3907022 (1975-09-01), Simons et al.
patent: 4566614 (1986-01-01), Frykendahl
patent: 4877705 (1989-10-01), Polidor
Kanamaru Kozo
Kurashina Yukinobu
Nanba Yasutoshi
Batten, Jr. J. Reed
Shinagawa Refractories Co. Ltd.
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