JP2008184663A - Refractory-coated lance and repairing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refractory-coated lance with which the worn portion of the refractory can stably and economically be repaired without falling down the sound portion. <P>SOLUTION: The refractory-coated lance obtained by coating the outside of a core-metal of the lance having a nozzle at the tip end part with the refractory is equipped with a flange-type partition plate for parting the above refractory with the peripheral direction of the core-metal of the lance in at least one portion in the longitudinal direction of the core-metal of the lance. Since the refractory is cut off with the partition plate in the longitudinal direction, when the worn refractory portion at the one range parted with the partition plate is disassembled, the shock is difficult to be propagated onto the other range of the sound refractory portion, and further, since a crack generated in the disassembled refractory portion, is not propagated onto the sound refractory portion, the fall-down of the refractory in the sound portion can suitably be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refractory-coated lance used for blowing gas or powder into a high-temperature melt such as molten metal.

In the metal refining process, a refractory-coated lance is used as a means for blowing a stirring gas or powdered refining agent (+ Carriers) into molten metal placed in a ladle or other container. Yes. For example, in a steel manufacturing process, such a refractory-covered lance is used in a desiliconization process or a dephosphorization process that is a hot metal preliminary process.
The refractory-covered lance has a structure in which the outside of a lance core (metal tube) having a nozzle at the tip is covered with a refractory, and the lance core usually has a stud for preventing the refractory from falling off. Is provided. Moreover, as a refractory, a castable refractory is usually used.

  This refractory-covered lance (hereinafter simply referred to as “lance”) is usually used with its lower part immersed in molten metal (for example, hot metal or molten steel), and it is used as a stirring gas or a powdered refining agent ( + Carrier gas) is introduced from the upper end of the lance core into the molten metal and blown into the molten metal from the nozzle at the tip (lower end). The lance is repeatedly used in such a usage pattern.

  When the lance is used as described above, the refractory on the lower side of the lance in contact with a high-temperature molten material such as molten metal is severely worn (melted). In particular, in the molten metal refining process, in many cases slag exists on the surface of the molten metal in the container, but this slag reacts with the refractory of the lance, and the refractory in that part preferentially melts down. There are many cases. Therefore, the lance mandrel and other refractory parts do not wear much, and the slag line part (the part in contact with the slag) and the refractory part on the lower side of the slag line are worn out even when in a healthy and usable state. As a result, the lance cannot be used as a whole.

  In order to effectively use the covered refractory as a countermeasure, it is possible to leave a healthy refractory part, disassemble only the worn refractory part, and add and install new refractory. Since the refractory in the healthy part falls off due to the impact at the time of dismantling of the part, and the worn part and the healthy part are an integral refractory, the crack generated in the worn part at the time of dismantling propagates to the healthy part. In many cases, the phenomenon of dropping off occurs, and the effect of the addition cannot be obtained.

Conventionally, Patent Document 1 discloses a technique in which a stud is provided in a specific form on a lance mandrel in order to prevent the refractory covering lance from falling off. Patent Document 2 discloses a technique in which a special member for preventing cracking is provided on the lance core bar in place of the stud in order to prevent the lance covered refractory from falling off due to cracking.
On the other hand, as a method of repairing a lance in which a part of the refractory is worn, when the refractory on the lower side of the lance is worn, the lance is cut and divided into two in the longitudinal direction. Patent Document 3 discloses a repairing method for a lance in which a core metal on the lower side of the lance is welded and joined, and then a refractory is applied to the outer periphery of the core metal in the welded portion. .

JP-A-10-287913 JP-A-10-280028 JP 2002-60830 A

However, even if the refractory drop-off prevention technology such as Patent Documents 1 and 2 is applied, it cannot sufficiently cope with the occurrence of impacts and cracks when dismantling the refractory worn parts, and the refractory drop-off is appropriate. It is difficult to prevent.
Moreover, since the repair method of patent document 3 requires the cutting | disconnection and welding of a lance mandrel, there exists a difficulty that work is complicated and repair cost becomes high.

Accordingly, an object of the present invention is to provide a refractory-covered lance capable of repairing a worn portion of a refractory appropriately and economically without causing problems such as dropping off of a healthy portion.
Another object of the present invention is to provide a repair method capable of appropriately and economically repairing such a refractory coating lance.

The gist of the present invention for solving the above problems is as follows.
[1] In a refractory coated lance in which the outside of a lance core bar having a nozzle at the tip is coated with a refractory,
A refractory-coated lance having a flange-shaped partition plate for partitioning the refractory in the lance core metal circumferential direction at least at one place in the lance core metal longitudinal direction.
[2] The refractory-covered lance according to [1], wherein a partition plate is provided at a boundary position between at least the lance lower side including the slag line portion and the lance upper side.

[3] The refractory-covered lance according to [1] or [2], wherein the outer peripheral portion of the partition plate is covered with a refractory.
[4] The refractory-coated lance according to any one of [1] to [3], wherein the partition plate has a gap between the lance cored bar.
[5] After using the refractory-covered lance of any one of [1] to [4] one or more times, dismantle the refractory in one area partitioned by the partition plate, and then add a new one to the area. A repair method for a refractory-covered lance, characterized by constructing a special refractory.
[6] A repair method for a refractory-covered lance according to the repair method of [5], wherein the refractory in one region partitioned by the partition plate is disassembled by crushing.

In the refractory-coated lance of the present invention, since the refractory is divided in the longitudinal direction of the lance by the partition plate, the refractory in one region partitioned by the partition plate is worn out. When dismantling the part, the impact is not easily transmitted to the refractory part (healthy part) in the other region, and cracks in the worn part to be dismantled do not propagate to the healthy part. It is possible to stably repair the refractory covering lance by adding the refractory while appropriately preventing the falling off of the object.
Further, according to the repair method of the present invention, it is possible to perform the above-described stable repair, and in particular, by dismantling the refractory in the worn portion by the crushing action, the impact on the refractory in the healthy portion is reduced. Propagation can be reduced and more stable repairs can be performed.

1 to 3 show one embodiment of a refractory-coated lance (hereinafter simply referred to as “lance”) according to the present invention. FIG. 1 is a side view showing the refractory in a cross-sectional view, and FIG. 2 is a lance core. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 is a scale of the longitudinal direction of the lance cored bar with respect to FIG.
This embodiment is a lance used for hot metal preliminary treatment (for example, desiliconization treatment, dephosphorization treatment, desulfurization treatment, etc.) of a steel manufacturing process.

This lance has a structure in which the outer side of a lance metal core 1 made of a metal tube for passing gas or a refining agent (powder) is covered with a refractory 2.
The lance core 1 has a nozzle 10 at the front end (lower end), and gas, a refining agent, and the like are introduced from the rear end (upper end). Usually, a large number of studs (not shown) for preventing the refractory 2 from falling off are provided outside the lance mandrel 1. Further, a flange 5 for attaching to the lance lifting device is provided on the upper end side of the lance mandrel 1. The lance core 1 is usually made of stainless steel, alloy steel, carbon steel, or the like.
As the refractory 2, a castable refractory is usually used. As the castable refractory, a suitable material such as high alumina or alumina-silica may be used.

In the basic structure of the lance as described above, a flange-like partition plate 3 that partitions the refractory 2 in the circumferential direction of the lance core metal is provided in the middle of the lance core metal 1 in the longitudinal direction.
The slag line part (SL part) which contacts a slag when a lance is actually used is shown in FIG. As mentioned above, the lower part of the lance including this slag line part is immersed in the slag and hot metal, so it receives a lot of heat and the refractory 2 is worn out heavily. The refractory 2 is a portion that is particularly susceptible to melting damage by reacting in contact with the slag. On the other hand, since the refractory part above the slag line part basically does not come into contact with the high-temperature melt (slag, molten iron), the melting loss is slight. For this reason, in this embodiment, the partition plate 3 is provided at a boundary position between the lance lower side and the lance upper side including the slag line part, more specifically, at a position immediately above the slag line part not in contact with the high temperature melt. Yes.

  The partition plate 3 does not need to completely divide the refractory 2 in the thickness direction, but preferably divides a substantial portion of the refractory thickness. The outer periphery of the partition plate 3 can be made to be substantially flush with the outer surface of the refractory 2 or protrude from the outer surface of the refractory 2, but the outer periphery of the partition plate 3 protrudes from the outer surface of the refractory 2 Then, the setting of the formwork when constructing the refractory becomes complicated. Further, in a structure in which a part of the partition plate 3 is exposed to the outside of the refractory 2, the partition plate 3 is oxidized during the use of the lance, the life is shortened, and there is a possibility that it cannot endure repeated use. For this reason, the partition plate 3 has a structure in which the outer peripheral portion is not exposed to the outside of the refractory 2 and is covered with the refractory 2 (that is, the entire partition plate is embedded in the refractory 2). Is preferred. In this case, the depth of the outer peripheral part of the partition plate 3 from the outer surface of the refractory 2 can be, for example, about 10 to 30 mm.

Further, when the thickness of the refractory material that the partition plate 3 divides becomes small, the function of preventing the propagation of cracks and the like deteriorates. Therefore, the partition plate 3 divides 30% or more of the refractory material thickness, preferably 50% or more. It is preferable that Moreover, it is preferable that the outer peripheral part of the partition plate 3 is not exposed outside the refractory 2 as described above, that is, the partition plate 3 divides less than 100% of the refractory thickness.
The partition plate 3 is usually made of stainless steel, alloy steel, carbon steel or the like, like the lance core 1, and is usually fixed to the lance core 1 by welding.

The partition plate 3 according to the present embodiment includes a ring plate 30 constituting a partition plate main body and a plurality of support members 31 that support the ring plate 30 with respect to the lance core metal 1. Each support member 31 is an elongated plate member that is disposed along the longitudinal direction of the lance core metal and is fixed to the outer surface of the lance core metal 1 (usually, fixed by welding). A plurality are arranged at appropriate intervals in the circumferential direction. These support members 31 (ribs) also function as reinforcing materials for preventing the lance from being damaged.
The ring plate 30 is configured such that the inner diameter of the ring is sufficiently larger than the outer diameter of the lance core 1 and the outer diameter of the ring is smaller than the outer diameter of the refractory 2 after construction. The ring plate 30 is fixed to one end of each of the support members 31 in a state where the ring plate 30 is externally mounted on the lance core bar 1 so as to form a gap 4 in the circumferential direction between the ring plate 30 (outer surface) (usually). The partition plate 3 is configured by being supported by being fixed by welding. Therefore, this partition plate 3 has an appropriate gap 4 between it and the lance core 1.

By providing this gap 4, it is possible to ensure the filling property of the refractory during production, and to suppress the occurrence of distortion in the partition plate 3 due to the heat when using the lance. By providing such a gap 4, the refractory 2 partitioned by the partition plate 3 is integrally connected in the portion of the gap 4, but includes the outer surface side of the refractory 2 by the partition plate 3. Since a corresponding portion in the thickness direction (30% or more, preferably 50% or more of the refractory thickness) is divided, there is no problem.
The partition plate 3 may be provided at a plurality of locations in the longitudinal direction of the lance core 1.

  In the lance as described above, since the refractory 2 is divided in the longitudinal direction of the lance by the partition plate 3, the refractory 2 in the lower lance region A is worn out and disassembled. Since it is difficult for the impact to be transmitted to the refractory 2 (healthy part), and the crack generated in the refractory 2 in the lower lance region A during disassembly does not propagate to the refractory 2 in the upper lance region B. The healthy refractory 2 in the upper lance region B can be stably left without causing dropout. As a result, the amount of refractory construction during lance repair is reduced, and a high cost reduction effect is obtained. Specifically, the ratio of refractory-remaining construction (= repaired lances where the refractory on the upper side of the lance was allowed to remain / number of repaired lances) was increased from 40% to 80% and running Cost can be reduced by about 20%.

Next, the lance repair method of this invention is demonstrated based on FIG. FIG. 4 shows an embodiment of the repair method of the present invention, and is an explanatory view showing the refractory-covered lance after disassembling a part of the refractory in a state where the refractory is sectioned.
When the lance as described above is used at least once and the refractory 2 in the lower lance region A partitioned by the partition plate 3 is worn (melted) that requires repair, the refractory 2 is shown in FIG. After disassembling as shown in FIG. 4, a castable refractory is newly constructed in that region, and the refractory 2 is formed. The partial castable refractory may be constructed in the same manner as conventionally performed. That is, the lance mandrel 1 may be fixed in the mold, and castable refractories may be poured into the mold.
Further, by providing the partition plates 3 at a plurality of locations in the longitudinal direction of the lance core bar, even when the refractory 2 is partitioned into three or more regions in the longitudinal direction of the lance, the refractory 2 needs to be repaired. It is only necessary to dismantle the generated area and apply a new refractory to that part.

As a method for dismantling the worn refractory as described above, a method of dismantling by crushing (crushing) the refractory 2 is particularly preferable. Thus, by disassembling the refractory 2 by the crushing action, the propagation of the impact to the refractory 2 in the sound part can be further reduced, and further stable repair can be performed. As a means for crushing (crushing) the refractory 2, for example, a crushing heavy machine called a nibra can be used. This nibler is a heavy machine widely used for concrete crushing or the like, and has a large scissors-like crushing blade at the tip of an excavator, and crushes the object with this crushing blade. The nibbler used in the present invention is preferably one in which the crushing blade has a concave portion for sandwiching the refractory 2 in order to crush only the outer refractory 2 without damaging the lance core 1.
Note that the crushing (crushing) means of the refractory 2 is not limited to the above nibra, and any appropriate means can be used.

The side view which shows one Embodiment of the refractory covering lance of this invention, and shows the state in which the refractory was cut in cross section Side view of the lance cored bar in the embodiment of FIG. Sectional view along line III-III in FIG. The explanatory view which shows one Embodiment of the repair method of this invention, and shows the refractory covering lance after disassembling a part of refractory in the state which cut the refractory

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lance core metal 2 Refractory material 3 Partition plate 4 Crevice 5 Flange 10 Nozzle 30 Ring plate 31 Support member

Claims (6)

In a refractory coated lance in which the outside of a lance core bar having a nozzle at the tip is coated with a refractory,
A refractory-coated lance having a flange-shaped partition plate for partitioning the refractory in the lance core metal circumferential direction at least at one place in the lance core metal longitudinal direction.   The refractory-covered lance according to claim 1, wherein a partition plate is provided at a boundary position between at least a lance lower side and a lance upper side including at least a slag line portion.   The refractory-coated lance according to claim 1 or 2, wherein an outer peripheral portion of the partition plate is covered with a refractory.   The refractory-coated lance according to any one of claims 1 to 3, wherein the partition plate has a gap between the lance core metal.   After using the refractory-coated lance according to any one of claims 1 to 4 at least once, dismantle the refractory in one region partitioned by the partition plate, and then add a new refractory to the region. A repair method for refractory-covered lances, characterized by construction.   6. The method of repairing a refractory-covered lance according to claim 5, wherein the refractory in one region partitioned by the partition plate is disassembled by crushing.

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