JP2007152403A - Upper nozzle for molten metal vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an upper nozzle for a molten metal vessel which can be easily installed in the central position of a nozzle receiving brick installed in the bottom part of a vessel for molten metal, and also can suppress the intrusion of molten steel into a gap between the upper nozzle and the nozzle receiving brick. <P>SOLUTION: In the upper nozzle 1 installed in the bottom part of the molten metal vessel 7 storing molten metal and composing a part of a outflow hole for molten metal, a hoop ring 3 made of iron is shrinkage fitted to the outer circumference of the lower edge part in the nozzle body 2 of the upper nozzle, and also, at least three or more metallic spacers 4 are arranged at the outer circumference of the hoop ring. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an upper nozzle that is installed at the bottom of a molten metal container such as a ladle or a tundish and constitutes a part of the molten metal outflow hole. Specifically, the upper nozzle is accurately positioned at the center of the nozzle receiving brick. The present invention relates to an upper nozzle for a molten metal container that can be installed.

  A molten steel outflow hole for discharging the molten steel to another container such as a tundish is provided at the bottom of the ladle that houses the molten steel in the steel making process. The uppermost part of this molten steel outflow hole is comprised by the upper nozzle fitted to the nozzle receiving brick arrange | positioned at a ladle. That is, the molten steel outflow hole is constituted by the upper nozzle, the sliding nozzle immediately below the upper nozzle, the long nozzle immediately below the sliding nozzle, and the like. In addition, due to the rapid thermal shock when high-temperature molten steel passes, tensile stress is generated in the upper nozzle, and a crack perpendicular to the circumference of the upper nozzle tends to occur. In many cases, an iron hoop ring is shrink fitted to the lower end of the upper nozzle.

  This upper nozzle is coated with fireproof mortar on the outer periphery, and is inserted and fixed in the inner hole of the nozzle receiving brick, and the ladle is inserted sideways in consideration of workability. It is common to do. Therefore, due to the weight of the upper nozzle having the refractory mortar coated on the outer periphery, the upper nozzle is lowered vertically in the inner hole, and the construction thickness of the joint of the refractory mortar is often not constant.

  When the upper nozzle is mounted eccentrically with respect to the inner hole, a uniform mortar joint thickness cannot be obtained, and there are almost no joint thickness parts and abnormally thick joint parts. To do. In addition, the uniformity of the contact surface of the sliding nozzle with the plate brick that is constructed immediately below the upper nozzle cannot be obtained. In particular, molten steel can be easily inserted into the joint where the joint thickness has increased, and ingots can enter the gap between the upper nozzle and the nozzle receiving brick, or in the worst case, the molten steel can be inserted between the upper nozzle and the plate brick. There is a possibility that troubles such as leakage will occur.

Therefore, in order to solve this problem, Patent Document 1 discloses an upper nozzle in which a plurality of metal spacers (metal protrusions) for adjusting the nozzle center of the upper nozzle are arranged on the outer periphery. According to Patent Document 1, the upper nozzle is mounted at the center position of the nozzle receiving brick inner hole by the metal spacer, and the joint thickness of the refractory mortar is equalized.
Japanese Utility Model Publication No. 5-78364

  As a result of detailed studies on Patent Document 1, the present inventors have found that the method of Patent Document 1 is an excellent method, but Patent Document 1 also has a problem.

  That is, the presence of a metal part is not preferable between the upper nozzle and the nozzle receiving brick. In particular, when a metal part is present at the upper end of the upper nozzle, the metal part may melt and promote leakage of molten steel. is there. In Patent Document 1, the installation position of the metal spacer for adjusting the nozzle center is not clear. With reference to the drawing of Patent Document 1, an example in which a metal spacer, that is, a metal portion is disposed up to the upper end of the upper nozzle is disclosed. Yes. In such a case, there is a possibility that the metal part is in direct contact with the molten steel and melts to promote leakage of the molten steel from the gap between the upper nozzle and the nozzle receiving brick.

  The present invention has been made in view of the above circumstances, and the object of the present invention is that it can be easily installed at the center position of the nozzle receiving brick installed at the bottom of the molten metal container, and the upper nozzle and It is an object of the present invention to provide an upper nozzle for a molten metal container that can suppress the intrusion of molten steel into a gap with a nozzle receiving brick.

  An upper nozzle for a molten metal container according to an invention for solving the above-mentioned problems is installed at the bottom of a molten metal container that contains molten metal, and is an upper nozzle that constitutes a part of an outflow hole of the molten metal. An iron hoop ring is shrink-fitted on the outer periphery of the lower end of the nozzle body, and at least three metal spacers are arranged on the outer periphery of the hoop ring.

  In the upper nozzle according to the present invention, an iron hoop ring is shrink-fitted on the outer periphery of the lower end portion thereof, so that extension of cracks due to rapid thermal shock when high-temperature molten metal passes is suppressed, and the nozzle center Since the metal spacer for adjustment is disposed on the hoop ring, the upper nozzle can be quickly and easily installed at the approximate center position of the nozzle receiving brick. In addition, since the metal spacer is arranged at the lower end of the upper nozzle, there is no metal part in the majority of the gap between the upper nozzle and the nozzle receiving brick, and only fire-resistant mortar is applied. Intrusion of the molten metal into the gap between the upper nozzle and the nozzle receiving brick can be suppressed.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an embodiment of the present invention, a schematic diagram showing a construction example in which the upper nozzle according to the present invention is installed at the bottom of the molten metal container, and FIG. 2 is a schematic diagram of the upper nozzle according to the present invention. It is a top view.

  As shown in FIGS. 1 and 2, the upper nozzle 1 is disposed at the bottom of a molten metal container 7 for containing molten metal such as molten steel, and is an inner hole installed through the upper nozzle 1 in the vertical direction. 5 has a function of flowing out the molten metal from the molten metal container 7. The upper nozzle 1 has an inner hole 12 composed of two types of nozzle receiving bricks, a nozzle receiving brick 10 and a nozzle receiving brick 11 which are arranged at the bottom of a molten metal container 7 whose outer shells are an iron skin 8 and an iron skin 9. Moreover, it is mounted from the outside of the molten metal container 7. In this case, since the upper nozzle 1 is inserted and mounted in the inner hole 12 with the refractory mortar 6 applied to the outer periphery thereof, the upper nozzle 1 and the inner holes 12 of the nozzle receiving bricks 10 and 11 are installed after construction. The space is filled with refractory mortar 6. In FIG. 1, the nozzle receiving brick is composed of two types of nozzle receiving bricks 10 and 11. However, the nozzle receiving brick may be composed of one type of nozzle receiving brick, or may be composed of three or more types of nozzle receiving bricks. May be. A plate brick (not shown) of a sliding nozzle is disposed below the upper nozzle 1.

  In the upper nozzle 1 according to the present invention, an iron hoop ring 3 is shrink-fitted on the outer periphery of a lower end portion of a nozzle body 2 made of a refractory material, and at least three or more (see FIGS. In FIG. 2, four metal spacers 4 are arranged. The metal spacer 4 is made of steel or brass. The metallic spacer 4 is attached by an appropriate method such as welding, soldering, or adhesive.

  From the viewpoint of installing the upper nozzle 1 at the center position of the inner hole 12 of the nozzle receiving bricks 10 and 11, the metal spacers 4 are preferably installed at equal intervals on the outer periphery of the hoop ring 3. In particular, when only three metal spacers 4 are installed, it is necessary to install them at equal intervals. The number of metal spacers 4 is not limited as long as it is three or more, but it is more preferable from the viewpoint of quickly installing the upper nozzle 1 at the center position of the inner hole 12. The thickness of the metal spacer 4 is set such that the outer periphery of the metal spacer 4 contacts the inner hole 12 of the nozzle receiving bricks 10 and 11.

  In this case, the difference between the outer diameter of the upper nozzle 1 and the inner diameter of the inner hole 12 of the nozzle receiving bricks 10 and 11 is preferably 2 to 8 mm. Therefore, the outer diameter of the upper nozzle 1 and the inner diameter of the inner hole 12 are preferred. The thickness of the metal spacer 4 is determined according to the difference between the two. That is, when the difference between the outer diameter of the upper nozzle 1 and the inner diameter of the inner hole 12 is 2 to 8 mm, the thickness of the metal spacer 4 is set according to the difference between the outer diameter of the upper nozzle 1 and the inner diameter of the inner hole 12. What is necessary is just to be about 1-4 mm of the half. However, the outer diameter connecting the outer circumferences of the metal spacers 4 does not need to match the inner diameter of the inner hole 12, and may be smaller by about 1 to 2 mm than the inner diameter of the inner hole 12. Of course, the thickness of the metallic spacer 4 should not be such that the outer diameter connecting the outer periphery of the metallic spacer 4 is larger than the inner diameter of the inner hole 12. If the gap between the outer diameter of the upper nozzle 1 and the inner diameter of the inner hole 12 of the nozzle receiving bricks 10 and 11 exceeds 8 mm, it is not preferable because the possibility of molten metal entering the gap increases.

  The nozzle body 2 of the upper nozzle 1 is made of a conventional refractory material such as high alumina brick, MgO brick, or zircon brick. An inert gas such as Ar gas may be blown into the inner hole 5 using at least a part of the nozzle body 2 as a porous brick.

  When the upper nozzle 1 according to the present invention is inserted into the inner holes 12 of the nozzle receiving bricks 10 and 11, if the center position of the inner hole 12 and the center position of the upper nozzle 1 are deviated, the metal spacer 4 becomes the iron skin. 9 impinges on the insertion of the upper nozzle 1. Therefore, by inserting the upper nozzle 1 into the inner hole 12 so that all the metal spacers 4 do not collide with the iron skin 9, the center position of the inner hole 12 and the center position of the upper nozzle 1 naturally match, The upper nozzle 1 is constructed at the center position of the inner hole 12.

  That is, the upper nozzle 1 according to the present invention has an iron hoop ring 3 shrink-fitted on the outer periphery of the lower end thereof, so that a rapid thermal shock occurs when high-temperature molten metal passes through the inner hole 5 which is an outflow hole. The crack extension due to is suppressed. Further, since three or more metal spacers 4 are arranged on the outer periphery of the hoop ring 3, the upper nozzle 1 can be quickly and easily installed at a substantially central position of the nozzle receiving bricks 10 and 11. Further, since the metal spacer 4 is disposed at the lower end portion of the upper nozzle 1, there is no metal portion in the gap between the upper nozzle 1 and the nozzle receiving bricks 10 and 11, and only the refractory mortar 6 is applied. Therefore, it is possible to prevent the molten metal from entering the gap between the upper nozzle 1 and the nozzle receiving bricks 10 and 11.

  The upper nozzle of the present invention is applied to the upper nozzle of the ladle that receives the molten steel discharged from the converter and supplies the accommodated molten steel to the tundish in the continuous casting process. The presence or absence of intrusion of bullion into the gap between the nozzle receiving brick and the nozzle receiving brick was investigated.

  The configuration of the nozzle receiving brick at the bottom of the ladle was the same as the configuration shown in FIG. Moreover, although the structure of the upper nozzle was also the same as that shown in FIG. 1, the metal spacers were evenly arranged at three locations on the outer periphery of the iron hoop ring. Since the difference between the outer diameter of the upper nozzle and the inner diameter of the inner hole of the nozzle receiving brick was 5 mm, the thickness of the metal spacer was 2 mm. The metal spacer was made of steel and was welded and attached to an iron hoop ring.

  For comparison, a ladle with a conventional upper nozzle without a metal spacer was used at the same time, and the presence or absence of metal intrusion into the gap between the upper nozzle and the nozzle receiving brick was investigated. . In FIG. 3, the construction example which installed the conventional upper nozzle 1A in the bottom part of the pan is shown. In FIG. 3, the conventional upper nozzle 1A is not provided with a metal spacer, but the other structure is the same as that of the embodiment of the present invention shown in FIG. 1, and the same parts are the same. This is indicated by a reference numeral and description thereof is omitted.

  While confirming the state of melting of the lower end of the upper nozzle and the inner hole, each time 3 to 5 charges were used, the upper nozzle was replaced with a new one, and about 200 charges of molten steel were received and supplied to the tundish. During the replacement of the upper nozzle, the presence or absence of metal intrusion into the gap between the upper nozzle and the nozzle receiving brick was investigated. As a result, in the ladle in which the upper nozzle 1 according to the present invention was constructed, there was no metal intrusion into the gap between the upper nozzle and the nozzle receiving brick. On the other hand, in the ladle in which the conventional upper nozzle 1A was constructed, intrusion of the metal into the gap between the upper nozzle and the nozzle receiving brick was recognized in about 2% of the used upper nozzle.

  In the ladle in which the conventional upper nozzle is constructed due to the intrusion of the bullion, it is necessary to replace the nozzle receiving bricks 10 and 11 with new ones when the use of the ladle is further continued. The upper nozzle according to the present invention In the ladle that was constructed, it was possible to continue using the ladle without changing the nozzle receiving brick. Comparing the refractory cost by this, the ladle with the upper nozzle according to the present invention was able to reduce about 10% compared to the ladle with the conventional upper nozzle.

  Moreover, when the construction time of the upper nozzle was compared, it was confirmed that the use of the upper nozzle of the present invention shortened to 1/2 to 2/3 of the construction time of the conventional upper nozzle.

It is the schematic which shows the construction example which installed the upper nozzle which concerns on this invention in the bottom part of the molten metal container. It is a schematic plan view of the upper nozzle which concerns on this invention. It is the schematic which shows the construction example which installed the conventional upper nozzle in the bottom part of the pan.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper nozzle 2 Nozzle body 3 Hoop ring 4 Metal spacer 5 Inner hole 6 Fireproof mortar 7 Molten metal container 8 Iron skin 9 Iron skin 10 Nozzle receiving brick 11 Nozzle receiving brick 12 Inner hole

Claims (1)

  In the upper nozzle that is installed at the bottom of the molten metal container that contains the molten metal and forms a part of the outflow hole of the molten metal, an iron hoop ring is shrink-fitted around the outer periphery of the lower end of the nozzle body of the upper nozzle, and An upper nozzle for a molten metal container, wherein at least three metal spacers are arranged on the outer periphery of the hoop ring.

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