Casting nozzle for continuous casting

Abstract

A casting nozzle to be used in a nozzle exchange (insert and/or removal) device of nozzle in continuous casting which comprises the nozzle which constitutes a tubular part provided with a channel, a rectangular flange or plate having the channel for casting, wherein the plate has an upper surface and a rear surface having two arcs, which are provided with a radius R arranged on the both sides of the plate in the perpendicular direction of a nozzle insertion (hereafter called X direction) and a supporting faces on both sides of the nozzle in the direction of a nozzle insertion (hereafter called Y direction), and a metal case for reinforcing and covering the flange or plate and the upper part of the tubular part.

Claims

1. A casting nozzle structure, comprising: a tubular part provided with a casting channel for casting molten metal from a tundish; a flange part, provided on an upper portion of the tubular part, having a rectangular upper surface portion, two opposite side plane portions connected to the rectangular upper surface portion, each one of the two opposite side plane portions being positioned in parallel to a horizontal direction in which the nozzle is inserted, and an arc portion of radius R joining each of the two opposite side plane portions with the upper portion of the tubular part in an X direction; a metal case for reinforcing and covering the side plane portions, the arc portion, and the upper portion of the tubular part; and an insert guide extending in a Y direction perpendicular to the X direction in parallel to each of the two opposite side plane portions of the flange part and having an inclined plane with respect to a vertical direction supporting the nozzle, for supporting the arc portion of the flange part via the metal case, wherein the nozzle is inserted into the insert guide only in the Y direction, and the radius R is equal to or greater than 15 mm.

2. The casting nozzle structure of claim 1, wherein the metal case is provided with a protrusion for enabling a contact with a vertical side plane portion of the insert guide connected to the inclined plane when the nozzle is inserted.

3. The casting nozzle structure of claim 2, wherein a cross section in a central portion of the protrusion has a hemispherical shape having a height of a horizontal gap between the metal case and the vertical side plane portion of the insert guide.

4. The casting nozzle structure of claim 1, wherein the metal case covering the arc portion has a quadrant arc shape of a radius R extending from a lower portion of each of the side plane portions to the upper portion of the tubular part.

5. The casting nozzle structure of claim 1, wherein the inclined plane has a concave arc portion having a larger radius than the radius R for accepting the arc portion.

6. The casting nozzle structure of claim 1, wherein the radius R is from 15 to 30 mm.

Description

BRIEF EXPLANATION OF THE DRAWINGS

(1) FIG. 1 shows a sectional view of a conventional casting nozzle.

(2) FIG. 2 explains a support method of a conventional nozzle, either by spring or locker.

(3) FIG. 3 indicates where cracks happen around the flange or the plate of nozzle.

(4) FIG. 4 shows a sectional view of an embodiment of the present invention in X direction.

(5) FIG. 5 is a plain view of the present invention from the top.

(6) FIG. 6 is a sectional view of the present invention in Y direction.

(7) FIG. 7 shows a sectional view of a nozzle invented in X direction and another embodiment how the arc portions of a nozzle is supported by a guide having an arc support.

EMBODIMENT OF THE PRESENT INVENTION

(8) With drawings or figures the present invention is now explained in detail but the invention is not restricted by the presented embodiment.

(9) As disclosed in the recited references the invented casting nozzle is made of alumina-graphite (for example, alumina 65 wt %, graphite 29 wt %) and a flange or a plate of the nozzle is, for example, about 200 mm square and 40 mm thick.

(10) The total length is about 1000 mm and the channel is about 80 mm in diameter and the outer diameter of nozzle is about 150 mm. And at the lower end of nozzle is provided with two bifurcated exits which feed molten metal to the side of a mold.

(11) This bifurcated nozzle is mainly used kind to cast molten steel into a mold, for example, having a cross section of 200 mm1200-2000 mm wide slab.

(12) 200 ton of molten steel can be cast into two strands in about 1 hour.

(13) Preferably, one cycle of a casting operation (6 hours for example) can be continued with a single nozzle. Hence break and erosion of a nozzle should be avoided.

(14) The size of nozzle, mold and casting time are recited as for example. But they are variable depending of operation practice.

(15) An example of present invention is presented in FIG. 4 to FIG. 7. FIG. 4 shows a cross section of a nozzle in a direction of mold thickness (hereafter called X direction). Molten metal flows into channel 20. The nozzle 1 can be inserted and removed in a nozzle exchange device.

(16) The nozzle comprises a square flange or plate (22) having a channel (20) and a tubular part 21 having a channel.

(17) The flange 22 is provided with an upper surface contacting an upper part in the upstream and a lower surface connecting to the upper part of tubular part. The lower surface has two arc portions 27 on both sides of Y direction and two flat plane portions 29 on front and rear sides of nozzle insert and removal direction (hereafter called Y direction) as shown in FIG. 6.

(18) A metal case 23 for reinforcement of nozzle neck, made of steel for example, covers the flange 22 and the upper part of the tubular part 21.

(19) The nozzle is preferably protected by a metal case 23 with a rigidity and further is preferably provided with protrusions 24. The protrusions 24 work to fill the space between the nozzle 1 and a guide 25 when the nozzle 1 is pushed into the guide 25 as shown in FIG. 4.

(20) The protrusion 24 is preferable provided when the metal case is fabricated. The provision of the protrusion is preferably not by welding due to deformation after welding.

(21) The thickness of protrusion 24 in horizontal direction is 6 to 7 mm at maximum and the thickness is 0 mm at the tip and the end of the protrusion in Y direction whereby a nozzle can be smoothly inserted into the supporting guide 25.

(22) The radius of the arc portion 27 of the nozzle 1 is 15 to 30 mm and 20 mm is preferable. The arc portion 27 is supported by a guide 25 having an inclined surface 26 to the vertical direction. In an another embodiment a concave arc 28 having a larger radius than the R can support the arc portion of the nozzle as shown in FIG. 7.

(23) With a conventional nozzle a nozzle can cast 4 hours in average (four charges of 200 ton molten steel). The present nozzle can cast 6 hours (6 charges). It means the cost of nozzle not only reduced but casting hourly efficiency is increased by 50%.