JPS6230067B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of installing and using a fixed plate and a sliding plate in a spout opening/closing device for a molten metal container, and an object of the present invention is to extend the life of the sliding plate. FIG. 1 is a longitudinal sectional view showing an example of a spout opening/closing device for a molten metal container such as a ladle. Reference numeral 1 denotes an upper nozzle, which is fixed to the bottom of the container 12 with mortar, and a plate-shaped fixing plate 3 is joined to the bottom of the nozzle with mortar, and is set by a fixing metal fitting 13 so as not to move. Reference numerals 2 and 4 denote nozzle holes provided in the upper nozzle 1 and the fixed plate 3, which are in a penetrating state to form a passage for molten steel. Reference numeral 5 denotes a plate-shaped sliding plate, which is pressed against the fixed plate 3 by a spring 15 via a support fitting 14. This sliding plate 5
is rotated by a drive mechanism or performs reciprocating motion (the figure shows a case where it is rotated by a gear 16). The sliding plate 5 is provided with one or two nozzle holes 6, 7 (two nozzle holes are shown in the figure), and one of the nozzle holes 6, 7 is provided on the fixed plate 3. When the slide plate 5 is aligned with the nozzle hole 4, the flow of hot water is performed, and when the slide plate 5 is rotated and aligned with the nozzle hole 6 or 7, the flow of hot water is interrupted. 8,9
is the lower nozzle that rectifies the flow of molten steel, and the support fitting 1
4, the nozzle holes 10 and 11 are mounted at positions that are aligned with the nozzle holes 6 and 7 of the sliding plate 5, respectively. Note that the above-mentioned upper nozzle 1, fixed plate 3, sliding plate 5, and lower nozzles 8 and 9 are all made of refractory material. Methods of using the spout opening/closing device configured as described above can be roughly divided into injection by repeatedly opening and fully closing the nozzle hole 4 of the fixed plate 3 and the nozzle hole 6 of the sliding plate 5, and squeezing injection. In the former case, the nozzle hole 6 (or 7) of the sliding plate 5 is aligned with the nozzle hole 4 of the fixed plate 3 and molten steel is injected, and when stopping, the sliding plate 5 and the molten steel are moved to a position where the molten steel does not flow out. This is a method of closing the nozzle hole 4 of the fixed platen 3. This method is used for ingot making, in which molten steel is injected into each mold, in other words, the nozzle holes 4 and 6 are fully opened when injecting molten steel, and are fully closed after injection before moving to the next mold. . On the other hand, the latter is a method used in continuous casting, in which molten steel is first received in a tundish placed under a ladle and then poured into a mold below. When pouring into the tundish, first fully open the nozzle holes 4 and 6 and inject to the specified position, and then replenish the amount of molten steel in the tundish as it decreases by pouring into the mold. , In order to secure a corresponding amount of injection, move the sliding plate 5 and adjust the opening degree of the nozzle hole 4 of the fixed plate 3 and the nozzle hole 6 of the sliding plate 5, and continue injection in this state. (See Figure 2). Of course, as time passes and the static pressure of molten steel in the ladle decreases, the sliding plate 5 is moved in the fully open direction accordingly. By the way, the fixed platen 3 created by pouring molten steel
Of the above-mentioned injection methods, damage to the sliding plate 5 is generally more severe when fully opening and fully closing are repeated. The injection operation, which repeats full opening and closing, closes the nozzle hole 4 in such a manner as to cut off the flow of molten steel passing through, so as shown in FIG. 51 is easily damaged. In addition, as shown in Figure b, the sliding plate 5 has a long movement distance to fully close and is in contact with molten steel during that time, so the refractory deteriorates to that part. Furthermore, when cutting the flow of molten steel, a small amount of molten steel is drawn in, which promotes damage to the refractory. This condition is particularly severe when the surface of the refractory begins to become rough, and the more times the refractory is fully opened and closed, the more severe the damage will be. In the case of squeeze injection, as shown in Fig. 3c, the edge 32 and part of the lower surface of the fixed platen 3, and the part of the upper surface and edge 52 of the sliding plate 5 are always in contact with the molten steel, so the edge The melting loss of 32 and 52 is particularly significant. However, the damage range on the lower surface and the upper surface is narrow, and a step is formed between the damaged part and the undamaged part. In other words, a second edge is created. In this way, the former type of damage gradually progresses from the edge to the inside, whereas the latter type of damage occurs in a small area with the edge, so molten steel may invade the contact surface between the fixed platen 3 and the sliding platen 5. The latter is preferable as a mechanism for preventing this. Note that damage does not only progress to the sliding plate 5 that cuts the molten steel, but if the sliding plate 5 is damaged, damage also progresses to the fixed plate 3, so both are always disposed of in pairs. . The fixed plates, sliding plates, upper and lower nozzles, and other refractories used in the spout opening/closing device for molten metal containers are expensive, so it is desirable to use them for as long as possible.
Moreover, if more can be used continuously, the amount of work required for replacement etc. will be reduced accordingly, and the operation will be more stable. However, if you forcefully try to extend the usage time, molten steel may be drawn in, which can easily cause an accident. In continuous casting, when the fully open/fully closed method was used, the average lifespan of fixed plates and sliding plates was approximately two cycles, but later on, the squeeze pouring method was adopted, and refractories were improved and damage was prevented. As a result of repairing the damaged parts, 4
The lifespan could be extended up to 5 times. Table 1 shows the average life of the sliding plate in a spout opening/closing device that combines a fixed plate with one nozzle hole and a rotating sliding plate. In addition, in this case, the ladle capacity
180t, fixed plate weight 14.1Kg/piece, sliding plate weight 14.0
Kg/unit was used.

[Table] As is clear from Table 1, the average lifespan of conventional sliding plates is limited to five cycles, and the current challenge is to extend this. The present invention was made in order to solve the above-mentioned problems at hand, and the critical number of fixed plates and sliding plates is set to approximately 1/2 of the predetermined usage limit number.
When the fixed plate reaches near the critical number of uses, the fixed plate and the sliding plate are dismantled, and then the unused fixed plate and the sliding plate that has reached the critical number of uses are combined and installed, and the sliding plate is installed. By using the number of movable plates up to their usage limit, the life of the sliding plate is approximately doubled compared to the conventional one. The present invention will be explained below. The fixed plate and sliding plate always face each other and are in contact, so the damage range is limited. Therefore, if one part is damaged, the other will also be damaged. If these damaged areas are facing each other, molten steel will penetrate into those areas and accelerate deterioration.
From this, if one side was not damaged at all, the damage would be less and progress would be slower. As a result of experiments, the inventors were able to prove that the above assumption is true. Next, examples of the present invention will be described. Example 1 In the present invention, a fixed plate with one nozzle hole was used, and a rotating sliding plate was used. In this case, two fixed plates are prepared for one sliding plate. First, the first fixed plate (hereinafter referred to as A fixed plate) is 4
After using ~5 times, dismantle the fixed plate and sliding plate, then install the unused fixed plate (hereinafter referred to as fixed plate B) and the sliding plate that has been used until now, and replace the sliding plate. It was used until the damage reached its limit. At this time, care must be taken when using fixed platen A, not to use it until the sliding plate has reached its limit of damage, and to replace it with fixed platen B while still having some residual strength. Table 2 shows the results of repeating the above operations. Note that the ladle capacity and the weight of the fixed plate and sliding plate are the same as in Table 1.

[Table] As is clear from Table 2, by using fixed plate A about 4 times and then replacing it with fixed plate B, the sliding plate could be used more than twice as much as before, or about 10 times. . Additionally, the amount of bricks used per ton of molten steel has also been significantly reduced to 0.023Kg, compared to the conventional 0.033Kg. Example 2 In this example, a fixed plate with two nozzle holes was used. In this fixed plate, the nozzle hole used first will be called the a nozzle, and the nozzle hole used later will be called the b nozzle. First, a new fixed plate and a new sliding plate were combined and set.
After using the a nozzle 3 to 5 times, it was disassembled, then switched to the b nozzle on the same fixed plate, set in combination with the sliding plate in use, and used until the sliding plate was damaged to the limit. In this case, the fixed plate was hot because the molten steel had just passed through it, making handling and setting difficult, and the adhesion of mortar was poor, so it was set after cooling for a short time. Example 3 In this example, a plurality of fixed plates each having two nozzle holes were prepared. As shown in Figure 6, first, the new C fixed plate and the new sliding plate are combined and set, and after using the A nozzle 3 to 5 times, they are disassembled, and the C fixed plate is left idle and allowed to cool. . Next, the new fixed plate D was set in combination with the sliding plate in use, and the A nozzle was used until the sliding plate was damaged to the limit. When the sliding plate reaches the end of its life, it is dismantled, the sliding plate is disposed of, and the D fixed plate is left to cool. Next, set the cooled C fixed plate and a new sliding plate, use the B nozzle, use the C fixed plate 3 to 5 times, then disassemble it, and replace the new E fixed plate and the used sliding plate. set and use the a nozzle. In this way, if the fixed plates are replaced and used one after another, the b nozzle is always assigned to the new sliding plate except for the first time. Note that the fixed platen that uses both nozzles a and b will be discarded. As a result of investigation, the inventors concluded that the reason why the life of the sliding plate is twice as long as that of the conventional slide plate when used in combinations such as those in Examples 1 to 3 above is due to the following reasons. First, since the fixed plate is changed while the sliding plate has some extra force, the gap in the damaged area is halved. Although this may be half the size, it is more effective when considering the degree of damage that will occur later. By halving this gap, less molten steel is drawn in, contributing to longer life. Second, since the stationary plate is new, its nozzle holes are smaller in diameter than the nozzle holes of the sliding plate.
For this reason, the nozzle hole of the sliding plate is covered, delaying damage. Third, both the fixed plate and the sliding plate are usually impregnated with an organic substance such as pitch. This is to protect the refractory by impairing the wettability of the molten steel and the refractory. Refractories are damaged from the parts that come into contact with molten steel, and as this organic material decreases, damage progresses rapidly. According to the present invention, when a new fixed plate is used while the sliding plate still has residual force, the sliding plate is protected by the organic substances flowing out from the fixed plate, thereby extending its life. The synergistic effect of the above three actions made it possible to extend the life of the sliding plate to twice that of the conventional one. As detailed above, according to the present invention, the life of the sliding plate can be doubled compared to the conventional one.
This not only saves resources, but also greatly contributes to reducing casting costs.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of an example of a spout opening/closing device for a molten metal container, Figure 2 is a plan view of its fixed plate and sliding plate, and Figures 3 a, b, and c are its fixed plate and sliding plate. A sectional view showing a damaged state, and FIG. 4 are explanatory views showing a combination of a fixed plate and a sliding plate according to an embodiment of the present invention. 1: Upper nozzle, 3: Fixed plate, 5: Sliding plate, 8,
9: Lower nozzle, 2, 4, 6, 7, 10, 11: Nozzle hole.

Claims (1)

[Claims] 1. In a spout opening/closing device for a molten metal container equipped with a fixed plate and a sliding plate, approximately 1/2 of the predetermined usage limit number is set as the critical number of the fixed plate and sliding plate, and the fixed plate and the sliding plate are When the plate reaches near the critical number of use, the fixed plate and sliding plate are dismantled, and then the unused fixed plate and the sliding plate that has reached the critical number of use are combined and installed, and the sliding plate is removed. A method for installing and using a fixed plate and a sliding plate in a spout opening/closing device for a molten metal container, which is characterized by being used up to the limit number of uses.