JP6862657B2 - Sliding gate plate - Google Patents

Description

The present invention particularly relates to a plate refractory for a sliding nozzle used as a flow control device for discharging molten steel from a molten metal container such as a ladle or a tundish in the steel industry. Hereinafter, the plate refractory for the sliding nozzle is referred to as a sliding gate (SG) plate.

The sliding nozzle used as the flow rate control device is used by combining two or three SG plates. In recent years, in order to reduce the workload and cost of the SG plate replacement work, the weight of the SG plate has been reduced, that is, the size of the SG plate has been reduced. In addition, the SG plate is being regenerated and reused.

On the other hand, after the casting is completed, the SG plate is inspected by opening the gate cassette in order to observe the damaged state of the sliding surface and determine whether or not it can be used for the next charge.

Since the molten steel passes through the hole provided in the central portion of the SG plate, the peripheral portion of the hole becomes hotter than the outer peripheral portion of the SG plate and thermal stress is generated.

Therefore, when the gate cassette is opened during the inspection work, the surface pressure acting on the SG plate is released, so that a force acts in the direction of pushing up the peripheral portion of the hole of the SG plate constrained by thermal expansion, and the SG The plate will warp.

Since this warp tends to occur as the thickness of the SG plate becomes thinner, the metal may invade through the gap between the contact surfaces of the SG plates generated by this warp during casting and lead to steel leakage.

Therefore, Patent Document 1 discloses an SG plate capable of suppressing warpage generated in the SG plate by devising the shape of the SG plate.

Further, Patent Document 2 discloses a brick having excellent strength in an intermediate temperature range of 1000 ° C. or lower so that the occurrence of warpage can be suppressed even when used in a constrained form such as an SG plate. ..

Further, in Patent Document 3, the SG plate is manufactured by dividing it into an interpolator having a hole through which molten steel passes and an outer body forming an outer peripheral portion of the interpolator, and the inner body is fitted into the outer body. An SG plate that becomes an integral structure by interpolating is disclosed.

In the SG plate disclosed in Patent Document 3, the gap between the interpolator and the exterior body exerts a stress relaxation effect, so that warpage can be suppressed.

However, with the techniques disclosed in Patent Documents 1 to 3, it is not possible to eliminate the bullion insertion from the gap between the contact surfaces of the SG plates caused by the warp, especially when the thickness of the SG plate is thin.

Further, in the case of the SG plate disclosed in Patent Document 3, a high-temperature interpolation body may be lifted from the surface of the exterior body due to thermal expansion during hot inspection. If the interpolator lifts off the surface of the exterior, it cannot be used for the next charge.

Japanese Patent No. 4456363 Japanese Unexamined Patent Publication No. 2000-29080 Japanese Unexamined Patent Publication No. 2012-121049

The problem to be solved by the present invention is that in the techniques disclosed in Patent Documents 1 to 3, especially when the thickness of the SG plate is thin, the bare metal from the gap between the contact surfaces of the SG plates generated by the warp. The point is that the sword cannot be eradicated. Further, in the case of the SG plate disclosed in Patent Document 3, the high-temperature interpolation body may be lifted from the surface of the exterior body due to thermal expansion during hot inspection.

The present invention suppresses the insertion of the bullion from the gap between the contact surfaces of the SG plates due to the warp of the SG plates, and prevents the interpolation body from floating from the surface of the exterior body even during hot inspection. The purpose is to do that.

The inventors considered to suppress the bullion insertion from the gap between the contact surfaces of the SG plates due to the warp of the SG plates by improving both the manufacturing method and the material of the SG plates.

In order to suppress the warping of the SG plate, it is effective to relax the generated stress that causes it. In order to relax the generated stress, it is sufficient that there is a gap between the peripheral portion and the outer peripheral portion of the hole of the SG plate. This gap can be formed by separately manufacturing and combining the outer body and the inner body.

However, when the interpolation body is at a high temperature and the exterior body is at a relatively low temperature, the interpolation body is lifted due to the difference in thermal expansion from the exterior body. Therefore, in order to suppress the lifting of the interpolated body, it was considered to make the coefficient of thermal expansion of the outer body smaller than the coefficient of thermal expansion of the interpolated body.

The present invention has been made based on the above ideas of the inventors.
SG consisting of an interpolator having a hole through which molten steel passes in the central part and an outer body arranged on the outer periphery of the inner body, and the inner body is fitted into the outer body to form an integral structure. On the plate
The outer peripheral surface of the internal body and the inner peripheral surface of the outer body into which the internal body is fitted have the same shape without a step in the thickness direction, and the thickness t of the internal body and the length of the internal body are long. The most important thing is that the ratio of the side length b (thickness t / long side length b) is 0.04 or more, and the coefficient of thermal expansion of the exterior body is smaller than the coefficient of thermal expansion of the insert body. It is a feature.

In the present invention, the thickness t / long side length b of the interpolator is set to 0.04 or more because when the ratio is less than 0.04, the strength against the warp of the SG plate becomes weak and the warp occurs. This is because the metal insert is generated from the gap between the contact surfaces of the SG plates. The upper limit of the thickness t / long side length b of the interpolator is not particularly specified, but it is 0.20 or less in consideration of the installation space of the sliding nozzle.

Further, the coefficient of thermal expansion of the exterior body is made smaller than the coefficient of thermal expansion of the inner body. By doing so, the stress caused by the thermal expansion of the outer body is relaxed, and the inner body is lifted. Because it disappears.

In the above invention, it is possible to suppress the insertion of the bullion from the gap between the contact surfaces of the SG plates due to the warp of the SG plates, and the interpolation body is lifted from the surface of the exterior body even during hot inspection. Can be prevented.

Further, in the present invention, the long side length b of the interpolation body is in the range of 50 to 75% of the long side length a of the exterior body, and the area of the interpolation body including the holes is the outer body. It is also a main feature that the area including the hole of the SG plate integrated by fitting the interpolator is in the range of 30 to 45%.

In the present invention, if the long side length b of the interpolator is 50 to 75% of the long side length a of the outer body, it is less than 50%, and the outer body of the interpolator is subjected to during use. This is because the molten steel is in constant contact with the fitting portion of the above, and there is a risk of steel leaking from the fitting portion. On the other hand, if it is larger than 75%, the strength of the exterior body is insufficient.

Further, it is the length of the long side of the interpolator that the area of the interpolator including the hole is 30 to 45% of the area including the hole of the SG plate integrated by fitting the interpolator into the outer body. This is the same reason as when the length b is 50 to 75% of the long side length a of the exterior body.

Further, in the present invention, it is desirable that the coefficient of thermal expansion of the exterior body at 500 to 1000 ° ^{C. is less than 7.5 × 10 -6 / ° C.} If the coefficient of thermal expansion at 500 to 1000 ° C is 7.5 × 10 ^-6 / ° C or higher, the compressive stress applied to the interpolator during use will increase, causing a shift in the installation position of the interpolator. is there. If the position of the interpolator is displaced, a gap is created between the SG plate surfaces, which increases the risk of steel leakage. The lower limit of the coefficient of thermal expansion is not particularly specified, but considering the existing bricks, the lower limit is 5.0 × 10 ^-6 / ° C.

In the present invention, it is possible to suppress the bullion insertion caused by the warp of the SG plate, and it is possible to prevent the interpolation body from floating from the surface of the exterior body even during hot inspection, so that the life of the SG plate can be reduced. It can be extended and steel leakage can be prevented.

It is a perspective view explaining the SG plate of this invention. It is a figure explaining the sliding nozzle which consists of three SG plates.

In the present invention, the object of suppressing the bullion insertion due to the warp of the SG plate and preventing the interpolation body from rising from the outer body surface is realized by improving both the manufacturing method and the material of the SG plate. did.

Hereinafter, the sliding nozzle composed of three SG plates will be described with reference to FIG. 2, and then the SG plate of the present invention will be described in detail with reference to FIG.

1a to 1c are refractory brick SG plates, of which fixed SG plates (hereinafter referred to as fixed plates) 1a and 1c are sandwiched from both sides so as to sandwich the sliding SG plates (hereinafter referred to as slide plates) 1b. Are arranged. The holes 1aa and 1ca provided in the fixing plates 1a and 1c are attached so as to be coaxial with the holes 3a of the bottom nozzle 3 attached to the bottom of the ladle 2, for example.

Then, by sliding the slide plate 1b in the left-right direction of the paper surface of FIG. 1 with a drive cylinder (not shown), the positions of the holes 1aa and 1ca provided in the fixed plates 1a and 1c and the holes 1ba provided in the slide plate 1b can be determined. Adjust to adjust the passage area of molten steel.

Note that 4 in FIG. 2 is a connection nozzle attached so as to have a coaxial core with the hole 1ca provided in the fixing plate 1c on the downstream side, and 5 is held by the connection hardware 6 attached to the connection nozzle 4. It is a long nozzle.

The present invention relates to an SG plate used as the fixing plates 1a and 1c and a slide plate 1b, and employs the following configuration.

That is, the SG plate 11 of the present invention is composed of an interpolation body 12 having a hole 12a through which molten steel passes in the central portion and an exterior body 13 arranged on the outer periphery of the interpolation body 12, for example, a press-molded exterior. A press-molded interpolation body 12 is fitted into the body 13 to form an integral structure.

Then, in the present invention, the ratio (thickness t / long side length b) of the thickness t of the interpolation body 12 and the long side length b of the interpolation body 12 is set to 0.04 or more. In addition, smaller than the coefficient of thermal expansion of the refractory bricks thermal expansion coefficient of the refractory bricks forming the outer body 13 forming the inner interposer 12, for example, coefficient of thermal expansion at 500~1000 ℃ 7.5 × 10 ^{- The ones below 6} / ° C are used.

Further, in the present invention, it is desirable that the long side length b of the interpolating body 12 is in the range of 50 to 75% of the long side length a of the exterior body 13. Further, the area of the interpolation body 12 including the hole 12a through which the molten steel passes is in the range of 30 to 45% of the area including the hole 12a of the SG plate 11 in which the interpolation body 12 is fitted and integrated into the exterior body 13. Is desirable.

In the present invention having the above configuration, it is possible to suppress the bullion insertion caused by the warp of the SG plate 11, and it is possible to prevent the interpolation body 12 from rising from the surface of the exterior body 13, so that the life of the SG plate 11 can be extended. At the same time, steel leakage can be prevented.

Hereinafter, the results of experiments conducted to confirm the effects of the present invention will be described.
Table 1 below shows examples of the present invention, Table 2 below shows reference examples of the present invention, and Table 3 below shows comparative examples of the present invention. Tables 1 to 3 below show the material of the SG plate, the thickness t of the interpolator / the long side length b of the interpolator, and the ratio of the long side length b of the interpolator to the long side length a of the exterior body. The ratio of the area of the interpolated body including the hole to the area including the hole of the SG plate integrated by fitting the interpolated body into the outer body, the coefficient of thermal expansion of the outer body and the interpolated body at 500 to 1000 ° C. Whether or not the interpolation body and the exterior body are press-molded products, whether or not the interpolation body is lifted from the exterior body, and whether or not a metal insert is generated are shown.

Example 1 to 3 and 5 the embodiment satisfies all of the claims 1-3, Example 4 is an embodiment which satisfies the claims 1, 2.

Since the first to third and fifth embodiments satisfy all of the first to third aspects, it is possible to suppress the insertion of the bullion from the gap between the contact surfaces of the SG plates due to the warp of the SG plates, and the hot metal is inserted. It was possible to prevent the interpolator from rising from the surface of the exterior during inspection. Therefore, the interpolation of the interpolator and the occurrence of the bullion were not generated at all.

Further, since the fourth embodiment satisfies the first and second claims but does not satisfy the third aspect, the installation position of the interpolator is slightly displaced, but the interpolation body is lifted and the bullion is inserted. I didn't.

On the other hand, Reference Examples 1 to 5 are reference examples that do not satisfy a part of the configuration specified in Claims 1 to 3, and Reference Example 1 is the long side length of the interpolated body with respect to the long side length a of the exterior body. the proportion of b is 49%, since the point the thermal expansion coefficient of the outer package is 7.7 × 10 ^-6 / ℃ does not meet the prescribed composed claims 1, 3, interpolation of the outer body Some steel leakage occurred from the fitting part of the body, and the installation position of the interpolator was slightly displaced . However , the interpolation body did not float and the bullion was not inserted.

Further, in Reference Example 4, the ratio of the area including the hole to the area including the hole of the SG plate integrated by fitting the interpolation body into the exterior body is 46%, and the coefficient of thermal expansion of the exterior body is 46%. since the point but is 7.9 × 10 ^-6 / ℃ does not satisfy the claims 1, 3, insufficient strength of the exterior body slightly, slight deviation occurs in the installation position of the inner interposer. However , the interpolation body did not float and the bullion was not inserted.

Further, in Reference Example 2 , the point that the ratio of the long side length b of the interpolator to the long side length a of the exterior body is 76% does not satisfy claim 1 , so that the strength of the exterior body is insufficient . However , the interpolation body did not float and the bullion was not inserted.

Further, in Reference Example 3 , the point that the ratio of the area of the interpolator including the hole to the area including the hole of the SG plate integrated by fitting the interpolator into the exterior body is 29% is claimed 1 . Since it was not satisfied, some steel leakage occurred from the fitting portion of the interpolated body into the exterior body . However , the interpolation body did not float and the bullion was not inserted.

Further, in Reference Example 5, the point that the ratio of the long side length b of the interpolator to the long side length a of the exterior body is 45% does not satisfy claim 1 , and the configurations of claims 2 and 3 are satisfied. It does not satisfy even although occurrence of floating and bullion feed the inner interposer not occur, slight leakage steel from the fitting portion of the inner interposer to the exterior body occurs.

On the other hand, Comparative Example 1 is lower than the thermal expansion coefficient of the inner interposer the thermal expansion coefficient of the outer body, the thermal expansion coefficient of the outer package is 7.3 × 10 ^-6 / ℃, the claims 3 However, the thickness t / long side length b of the insert body is 0.03, which does not satisfy claim 1. Further, the ratio of the long side length b of the interpolator to the long side length a of the exterior body is 40%, which does not satisfy claim 1. Therefore, the interpolation body was lifted and the bullion was inserted.

Further, in Comparative Examples 2 and 3, the thickness t / long side length b of the interpolator is 0.07, but the coefficient of thermal expansion of the exterior body is larger than the coefficient of thermal expansion of the interpolator. in addition to not satisfied 1, the thermal expansion coefficient of the outer body is as large as ^{9.0 × 10 -6 /℃,8.4×10 -6 / ℃} .

Further, in Comparative Example 2, the ratio of the area of the interpolated body including the hole to the area including the hole of the SG plate integrated by fitting the interpolated body into the outer body is 25%, which does not satisfy claim 1. On the other hand, Comparative Example 3 includes a hole in the SG plate in which the ratio of the long side length b of the interpolator to the long side length a of the exterior body is 80%, and the interpolation body is fitted into the exterior body and integrated. The ratio of the area of the interpolator including the hole to the area is 55%, which does not satisfy claim 1.

Therefore, in Comparative Examples 2 and 3, neither the bullion was inserted, but the interpolator was lifted.

It goes without saying that the present invention is not limited to the above examples, and the embodiments may be appropriately changed as long as it is within the scope of the technical idea described in each claim.

11 SG plate 12 Interpolator 12a Hole 13 Exterior

Claims (3)

It consists of an interpolator having a hole through which molten steel passes in the central part and an outer body arranged on the outer periphery of the inner body, and the inner body is fitted into the outer body to form an integral structure for sliding. In the gate plate
The outer peripheral surface of the internal body and the inner peripheral surface of the outer body into which the internal body is fitted have the same shape without a step in the thickness direction, and the thickness t of the internal body and the length of the internal body are long. The ratio of the side length b (thickness t / long side length b) is 0.04 or more, and the coefficient of thermal expansion of the exterior body is smaller than the coefficient of thermal expansion of the insert body, and further, the inside The long side length b of the insert is in the range of 50 to 75% of the long side length a of the exterior body, and the area of the insert including the hole is such that the insert is placed on the exterior. A sliding gate plate that is fitted and integrated in a range of 30 to 45% of the area including the hole of the sliding gate plate. The sliding gate plate according to claim 1, wherein the interpolator and the outer body are each integrated by fitting the inner body into the outer body after press molding. The sliding gate plate according to claim 1 or 2, wherein the coefficient of thermal expansion of the exterior body at 500 to 1000 ° C. is less than ^{7.5 × 10 -6 / ° C.}

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