JP2014161880A - Sliding nozzle plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress lowering of a binding force due to a metal hoop in a sliding nozzle plate in which the metal hoop is provided along in a circumferential direction of an outer peripheral side surface of a sliding nozzle plate body made of a refractory material.SOLUTION: A sliding nozzle plate has a region, in which a heat insulation material 4 is provided, between an outer peripheral side surface of a sliding nozzle plate body 2 and a metal hoop 4. The metal hoop 3 is linear in a circumferential direction of the outer peripheral side surface of the sliding nozzle plate body 2 in the region in which the heat insulation material 4 is provided, and the outer peripheral side surface of the sliding nozzle plate body 2 and the metal hoop 3 directly contact to each other in a region other than the region in which the heat insulation material 4 is provided.

Description

  The present invention relates to a sliding nozzle plate (hereinafter referred to as “SN plate”) used in a sliding nozzle device (hereinafter referred to as “SN device”) for controlling the flow rate when discharging molten metal from a molten metal container.

  The SN plate is a plate-like structure having an inner hole for discharging molten metal. In addition, the SN device controls the flow rate of molten metal by sliding two or three independent SN plates relative to each other and changing the area of the opening that overlaps the inner holes of each SN plate. To do.

  The SN plate is exposed to high temperatures above the melting point of the molten metal, and the SN plate is repeatedly used, so that it undergoes a large temperature change between the high temperature range and the atmospheric temperature range. Used under various conditions. Further, the SN plate is fixed inside the SN device, and a high pressure is applied between the surfaces so that molten metal leakage does not occur between the surfaces of the SN plate. In the SN plate, cracks and cracks due to various mechanical stresses and thermal stresses are likely to occur.

  As a countermeasure, many means for installing a band-shaped metal hoop along the circumferential direction on the outer peripheral side surface of the SN plate main body made of refractory are employed. This is because the stress generated in the SN plate body is relaxed to suppress the generation of the crack itself, the expansion of the crack after the crack is generated, and the SN plate body divided by the crack is The purpose is to make it possible to recover the integrated structure without collapsing at the time of replacement.

  As a method of installing the metal hoop on the outer peripheral side surface of the SN plate main body as described above, for example, as described in Patent Document 1, a metal plate is wound around the outer peripheral side surface and the bottom surface portion of the SN plate main body via mortar. A method of wearing was implemented. However, in the case of this method, the mortar itself between the metal hoop and the SN plate body relaxes the stress, the binding force of the SN plate body by the metal hoop is reduced, and the occurrence and expansion of cracks are suppressed. I can't. Furthermore, the mortar itself may break down, and the metal hoop may loosen and lose its restraining function.

  Therefore, a method in which the metal hoop is brought into direct contact with the SN plate main body, specifically, the metal hoop is expanded at a high temperature, mounted on the SN plate main body kept at room temperature, cooled, and the metal hoop is used. A method of increasing the binding force (so-called shrink fitting method) has been widely adopted.

  However, in the SN plate, during the molten metal discharge, the vicinity of the inner hole becomes the highest temperature region, and a continuous temperature distribution occurs from the inner hole to the outer peripheral side surface. Therefore, in the method in which the metal hoop is brought into direct contact with the SN plate body, there is a problem that the metal hoop receives a large amount of heat from the SN plate body and becomes high temperature. The thermal expansion coefficient of the metal hoop is larger than the thermal expansion coefficient of the SN plate body made of refractory. Further, depending on the temperature range, the creep property of the metal hoop appears remarkably. Due to these causes, the high temperature of the metal hoop causes a reduction in the binding force of the SN plate body.

  As a countermeasure against such a high temperature of the metal hoop, for example, in Patent Document 2, there is a method of fixing a metal hoop provided with unevenness on the entire inner peripheral surface to the outer peripheral side surface of the SN plate body by a shrinkage fitting method. Proposed. As a result, the contact area of the metal hoop with respect to the SN plate main body is reduced, and the amount of heat transfer from the SN plate main body to the metal hoop is reduced by the ventilation effect between the SN plate main body and the metal hoop. It is said that overheating and expansion are suppressed, the function of reinforcing or restraining the SN plate body is maintained, and effects such as an increase in the life of the SN plate are obtained.

  In Patent Document 2, the metal hoop directly contacts the SN plate main body only at the top of the convex portion, and the portion other than the contact point of the metal hoop with the SN plate main body is substantially similar to the outer shape of the SN plate main body. However, direct contact with the SN plate main body only at the convex portion vertex of the metal hoop causes a restraint force to be held only at the convex portion vertex, and stress concentrates on the convex portion vertex. As a result, cracks and cracks are likely to occur in the SN plate body starting from the top of the convex part, and since the periphery of the starting point is a concave part, that is, a space, expansion of cracks and the like cannot be prevented. , Cracks and cracks are easier to expand. In addition, during use at high temperatures, portions other than the contact point of the metal hoop with the SN plate body are deformed in a straight line, and the metal hoop is loosened.

Japanese Utility Model Publication No. 51-15113 Japanese Patent Laid-Open No. 9-285861

  The problem to be solved by the present invention is to suppress a reduction in restraining force caused by a metal hoop in an SN plate in which a metal hoop is installed along the circumferential direction of the outer peripheral side surface of the SN plate body made of refractory. In addition, the SN plate body is prevented from cracking or breaking when used under high temperature, and the crack is prevented from expanding, and further, the SN plate body is prevented from easily coming off the metal hoop after use. It is in.

  The present invention relates to an SN plate in which a metal hoop is installed along the circumferential direction of the outer peripheral side surface of a refractory SN plate body having an inner hole for discharging molten metal, and the length of the metal hoop is increased. Provided is an SN plate that suppresses a reduction in restraining force due to the operation. That is, the present invention provides the following SN plates (1) to (7).

(1) In the SN plate in which a metal hoop is installed along the circumferential direction of the outer peripheral side surface of the SN plate body made of refractory having an inner hole for discharging molten metal,
It has the area | region in which the heat insulating material was installed between the outer peripheral side surface of SN plate main body, and metal hoop, and the metal hoop in the area | region in which the said heat insulating material is installed is the circumferential direction of the outer peripheral side surface of SN plate main body. The SN plate, which is linear and has an outer peripheral side surface of the SN plate body and a metal hoop that are in direct contact with each other in a region other than the region where the heat insulating material is installed.
(2) The region where the heat insulating material is installed is a continuous region including a point at the shortest distance from the center of the inner hole of the SN plate body on the outer peripheral side surface of the SN plate body, or the continuous region and other continuous regions. The SN plate according to (1).
(3) The continuous region including the point at the shortest distance from the center of the inner hole has a length equal to or greater than the diameter of the inner hole along the circumferential direction of the outer peripheral side surface of the SN plate body (1) or (2 ) SN plate.
(4) The thermal expansion amount of the metal hoop in the region where the heat insulating material is installed is equal to or less than the thermal expansion amount of the SN plate body at the same position, and the SN according to any one of (1) to (3) plate.
(5) The SN plate according to any one of (1) to (4), wherein the metal hoop is made of stainless steel.
(6) The SN plate according to (5), wherein the metal hoop is made of SUS430 out of stainless steel.
(7) The sliding nozzle plate according to (5), wherein the metal hoop is made of SUS304 out of stainless steel.

  This will be described in detail below.

In the SN plate, the molten metal passes through the inner hole of the SN plate body at the time of casting, so that the vicinity of the inner hole becomes a high temperature and a temperature distribution is generated toward the outer peripheral side surface. Thus, since the vicinity of the inner hole becomes high temperature, this portion expands relatively larger than other regions. Due to this expansion, a strong tensile stress is generated on the outer peripheral side surface of the SN plate main body during casting. Normally used shrink-fitted metal hoops have the effect of suppressing the tensile stress generated on the outer peripheral side surface of the SN plate body by the restraining force at the initial stage of casting, but the metal hoops eventually expand due to heat transfer. The thermal expansion coefficient α _HB of the metal hoop is about 11 × 10 ⁻⁶ / ° C. in the case of ordinary steel, whereas the thermal expansion coefficient α _R of the SN plate body made of refractory is about 5 to 7 ×. The coefficient of thermal expansion of the metal hoop is 10 ⁻⁶ / ° C., which is larger. Therefore, the restraining force by the metal hoop is reduced, and the effect of suppressing the tensile stress on the outer peripheral side surface of the SN plate body may be reduced or may not be obtained.

  In this invention, the area | region where a heat insulating material exists is provided between the outer peripheral side surface of SN plate main body, and metal hoops, the amount of heat transfer to the metal hoops by which shrink fitting was carried out is reduced, and the thermal expansion is made small. This suppresses a decrease in the binding force on the SN plate body.

  In the region where the heat insulating material is not installed in the present invention, the outer peripheral side surface of the SN plate main body and the metal hoop are in direct contact. Among these direct contact portions, the metal hoop generates a restraining force, that is, a compressive stress on the SN plate main body at the contact point of a portion that is mainly bent or curved on the outer peripheral side surface of the SN plate main body. Restrain the body.

  Moreover, in this invention, the metal hoop in the area | region in which the heat insulating material is installed needs to be linear in the circumferential direction of the outer peripheral side surface of SN plate main body. When the metal hoop is not linear in the region where the heat insulating material is installed, the metal hoop is relatively longer than the length of the outer peripheral side surface of the SN plate body in the region, and the metal hoop at a high temperature The expansion amount becomes relatively large, and the deformation due to the softening of the metal hoop at a high temperature increases, and the holding ability and restraining force of the SN plate main body by the metal hoop decrease.

  Suppressing the decrease in the binding force of the SN plate main body due to the metal hoop is to minimize the difference in the increase in length due to the thermal expansion of the outer peripheral side surface of the SN plate main body and the metal hoop. Ideally, the increase in the length of the hoop is smaller than the increase in the outer peripheral side length of the SN plate body.

  In the casting operation, the SN plate provided with a metal hoop is installed in a metal SN device, and is used in a state where at least a part of its side surface is strongly pressed or restrained. Further, in installing the metal hoop on the SN plate body, the metal hoop is fitted into the SN plate body at room temperature in a state where the metal hoop is heated and expanded. Then, the cooled metal hoop contracts, but the size of the SN plate main body is substantially constant, so the contraction behavior becomes compressive stress on the SN plate main body and strongly restrains the SN plate main body (so-called shrink fitting). Law).

  That is, in the shrink-fit method, at least the temperature region below the time of shrink-fit and the state in which the thermal expansion amount of the metal hoop exceeds the thermal expansion amount of the SN plate body is shorter than the length of the outer peripheral side surface of the SN plate body. The SN plate body is restrained by the hoop. Even if there is a part where the metal hoop does not exceed the temperature during shrink fitting even during operation, the entire outer peripheral side surface of the SN plate body during operation, even if there is a part that exceeds the temperature during shrink fitting Then, when the length of the metal hoop is smaller than the length of the outer peripheral side surface of the SN plate main body, a strong restraint state can be maintained. This also applies to the local area. That is, during operation, a part of the metal hoop becomes hot, and the length of the region is partially increased by thermal expansion, resulting in a portion that is larger than the length of the outer peripheral side surface of the SN plate body in the region. Even so, the difference between the increase in the length of the metal hoop at that portion and the increase in the length of the SN plate main body is the amount of contraction of the metal hoop when the metal hoop is fitted in that portion (hereinafter referred to as , Simply referred to as “the shrinkage of the metal hoop”), the local restraint state can be maintained.

  In addition, SN plate body shape, material, physical properties, metal hoop installation structure, material, characteristics, installation method, SN device structure, specifications such as pressure, operating conditions, changes in various elements during the operation, etc. The conditions for individual products and operations vary widely and are not constant. The degree of contraction of the metal hoop, whether or not the metal hoop is loosened, or the degree of looseness depends on these individual conditions. The degree of deviation of the SN plate due to a decrease in binding force is not compatible with absolute quantification.

  As described above, the metal hoop in the region where the heat insulating material is installed in the present invention needs to be linear in the circumferential direction of the outer peripheral side surface of the SN plate body. In other words, the metal hoop has one contact portion with the SN plate main body (start point of the region where the heat insulating material is installed) and another contact portion adjacent thereto (end point of the region where the heat insulating material is installed). In between, it is necessary to be linear in the circumferential direction of the outer peripheral side surface of the SN plate main body. When it is non-linear, the length of the portion is longer than when the portion is linear. By making it straight, the length between the two contact portions of the metal hoop can be minimized, and the amount of thermal expansion after the temperature rise can be minimized.

  In addition, metal hoops tend to soften or deform when exposed to high temperatures for a long time, but if there is a non-linear part in the region between the two contact parts, The increased amount increases the gap between the SN plate body. When it is linear, it is possible to suppress an increase in length due to this deformation or a decrease in the restraining force of the SN plate body due to a metal hoop.

  On the other hand, the temperature distribution of the SN plate main body is highest near the inner hole through which the molten metal passes, and decreases radially from the inner hole (center). The amount of expansion is a distribution in which the inner hole portion that is the highest temperature region is the largest according to the temperature distribution and gradually decreases as the distance from the inner hole portion increases.

  Further, the SN plate adjusts the flow rate while sliding, and has a function of stopping the molten metal flow (hereinafter, the position to move for the stop is referred to as “stop position”). As for the distance from the outer peripheral side to the outer peripheral side, the stop position direction is long, and the vicinity of the inner hole in the direction perpendicular to the opposite side of the stop position or the sliding direction is the shortest. And the temperature of the outer peripheral side surface of SN plate main body becomes so high that the distance from the inner-hole center is near. Therefore, when installing a heat insulating material between the metal hoop and the SN plate body, install it in a relatively high temperature region, that is, in the region of the outer peripheral side surface of the SN plate body close to the inner hole as described above. Is effective. That is, it is preferable to install the heat insulating material in one continuous region including a point at the shortest distance from the center of the inner hole of the SN plate main body or in a plurality of continuous regions in the vicinity thereof. In addition, in the outer peripheral side surface having a point that is at the shortest distance from the center of the inner hole of the SN plate main body, the portion having the same length as the diameter of the inner hole including the point becomes high temperature. It is preferable that the length is equal to or larger than the diameter of the inner hole.

  By installing a heat insulating material in such a place and range, the temperature rise of the metal hoop is effectively suppressed, and the difference in thermal expansion between the SN plate body and the metal hoop in the portion is more effective. It becomes possible to reduce it.

  The relative relationship between the increase in length due to the thermal expansion of the metal hoop and the increase in the length of the outer peripheral side due to the thermal expansion of the SN plate body takes into account the thermal conductivity and thermal expansion coefficient of the SN plate body. Thus, it can be known and optimized by any method such as computer simulation using general thermal calculation or simulation software, or experiment.

  In this specification, as shown in a calculation example to be described later, the SN plate body has a circular shape and is simply modeled and modeled with a general SN plate shape. The temperature of the metal hoop, the metal hoop The amount of thermal expansion and the amount of thermal expansion of the SN plate main body were determined by FEM simulation. The preconditions for this FEM simulation are as follows. That is, the temperature of the inner hole is “1823” because the molten steel temperature is generally 1550 ° C. (1823 K), and the temperature of the outer peripheral side surface of the SN plate body is about 30 ° C. which is almost equal to the normal outside air temperature in the casting operation. Since it is (303K), it was set to "303". For this simulation, a self-developed three-dimensional FEM was used to calculate the heat transfer and stress deformation calculations for the shaft.

  Next, the case where a heat insulating material is installed between the metal hoop and the SN plate body will be described.

  When the heat insulating material is installed, the thermal conductivity and heat transfer resistance as a structure in which the heat insulating material and the SN plate main body are integrated are considered. And based on the temperature obtained in this way, the expansion | swelling amount of SN plate main body and metal hoop is calculated | required.

  The temperature of the SN plate main body and the metal hoop, and the difference between the expansion amounts thereof depend on the thickness t of the heat insulating material installed between the SN plate main body and the thermal conductivity λs. The thickness t of the heat insulating material and the size of the thermal conductivity λs are preferably set so that the value obtained by subtracting the thermal expansion amount of the SN plate body from the thermal expansion amount of the metal hoop is as small as possible. More preferably, the value is set to zero or a negative value, that is, the thermal expansion amount of the metal hoop is equal to or less than the thermal expansion amount of the SN plate body.

  By the way, about the length of the metal hoop after installing in a SN plate main body by shrink fitting, the length in the temperature at the time of shrink fitting and the length in the subsequent room temperature differ. In the unconstrained state, the length is reduced by this difference (this difference is the “contraction of the metal hoop”). However, since the outer peripheral side length of the SN plate main body does not substantially change before and after the shrink fitting, the length of the metal hoop is not actually shortened, and the metal hoop always has a residual tensile stress. become. That is, the difference increases the binding force of the SN plate body by the metal hoop. And since the coefficient of thermal expansion of the metal hoop is larger than the coefficient of thermal expansion of the SN plate body which is a refractory, the restraining force due to the difference gradually decreases as the temperature of the SN plate body and the metal hoop rises. . The restraint force due to this difference is exhibited in the temperature range until it becomes zero.

  On the other hand, metal hoops tend to stretch due to plastic deformation caused by tensile stress. This elongation characteristic varies depending on the type of metal. Even if the metal hoop expands (extends) by being exposed to a high temperature in the casting operation, the extended length is subtracted from the difference in length between the shrink-fit temperature and the room temperature. If the length is maintained, the length becomes a source for restraining the SN plate body. Therefore, it is preferable that the elongation due to plastic deformation is small.

  Generally, ordinary steel (SS type) is used as a metal hoop material. However, since the inventors of the present invention have less plastic deformation and less variation in stainless steel (SUS system) than in normal steel (SS system), stainless steel (SUS system) is used as a metal hoop material. It has been found that it is preferable to adopt.

  SUS430 is higher than ordinary steel and SUS304 among stainless steels at room temperature, and the plastic deformation rate of SUS304 is lower than ordinary steel and SUS430 among stainless steels until it exceeds about 600 ° C. and exceeds at least 800 ° C. (described later) See Example B). In addition, although normal steel has a large variation in these characteristics, in the comparison of the above-described characteristics in the present invention, measurements and comparisons were made by selecting comparative steels having relatively high characteristics.

In addition, the thermal expansion coefficient of general ordinary steel (carbon steel) is about 10 to 12 × 10 ⁻⁶ / ° C., but the thermal expansion coefficient of SUS304 is 17 to 18 × 10 ⁻⁶ / ° C. Carbon steel) is about 50 to 60% higher, and the reduction of the restraining force due to the high thermal expansion amount is larger than when ordinary steel is used. Therefore, in determining the thermal conductivity, thickness, installation range, etc. of the heat insulating material when installing the heat insulating material, the difference between the thermal expansion amount of the metal hoop and the thermal expansion amount of the SN plate body at the highest temperature reached during use. It is necessary to design in accordance with the thermal expansion coefficient specific to the material of the metal hoop in the direction of zeroing.

  Furthermore, since there is no strict component standard or the like in ordinary steel, there are large variations in strength and heat resistance (plastic deformation rate, etc.). If such a large variation is adopted for the metal hoop, the metal hoop has a large variation in binding force, crack generation, loosening, and the like. On the other hand, since stainless steel has relatively strict component standards and the like, when stainless steel is employed in a metal hoop, it is possible to obtain a stable restraining force with little variation, a degree of cracking, a degree of loosening, and the like.

In addition, since the thermal expansion coefficient of SUS430 is 10-12 × 10 ⁻⁶ / ° C., which is similar to the thermal expansion coefficient of general ordinary steel (carbon steel), 10-12 × 10 ⁻⁶ / ° C. In terms of expansion, SUS430 is more advantageous than SUS304 in terms of restraint force, crack generation, loosening, and the like. Therefore, it is preferable to adopt SUS430 over ordinary steel at least at 600 ° C. or less.

  According to the present invention, it is possible to suppress loosening, displacement, etc. from the SN plate body of the metal hoop installed around the outer peripheral side surface of the SN plate body, or a reduction in binding force caused thereby. Thereby, generation | occurrence | production of the crack of SN plate main body, expansion, destruction are suppressed, and the durability of SN plate improves. Also, when the SN plate used for operation is removed from the SN device and installed in the SN device again, so-called reuse, the metal hoop falls off the SN plate body, and the cracked SN plate body Although it may be scattered without maintaining its original shape, the occurrence of these is reduced, and the reuse rate can be improved.

One Embodiment of SN plate of this invention is shown, (a) is a top view, (b) is an enlarged view of the I section in (a). It is a top view of the principal part which shows other embodiment of SN plate of this invention. The relationship between the ratio λs / t obtained by dividing the thermal conductivity λs of the heat insulating material by the thickness t of the heat insulating material and the expansion difference is shown. The shape figure (image) in FEM simulation is shown. The element division | segmentation figure (image) in the same FEM simulation is shown. The element division | segmentation figure (image) which installed the heat insulating material in the same FEM simulation is shown. The temperature distribution of the SN plate main body by the FEM simulation is shown (when no heat insulating material is installed). The temperature distribution of the SN plate main body by the FEM simulation is shown (when a heat insulating material is installed). In the experimental example in which the temperature distribution of the metal hoop was investigated, the installation location and the temperature measurement location when the heat insulating material was installed at two locations are shown. In the same experimental example, the installation location and the temperature measurement location when the heat insulating material is installed at 4 locations are shown. The temperature measurement result in the same experimental example is shown, (a) when no heat insulating material is installed (comparative example), (b) when the heat insulating material is installed at two places (Example 1), (c) is the heat insulating material. (Example 2) is shown when installed in four places. The plastic deformation rate of each metal type is shown. The stress-strain relationship at room temperature for each metal species is shown.

  FIG. 1 shows an embodiment of the SN plate of the present invention. FIG. 4A is a plan view thereof, and FIG. 4B is an enlarged view of a portion I in FIG.

  The SN plate body 2 forming the body of the SN plate 1 is made of a refractory material and has an inner hole 2a for discharging molten metal. And the metal hoop 3 is installed along the circumferential direction of the outer peripheral side surface of this SN plate main body 2. This metal hoop 3 can be installed by shrink fitting.

  In such a basic configuration, the SN plate 1 of the present invention has a region S in which the heat insulating material 4 is installed between the outer peripheral side surface of the SN plate main body 2 and the metal hoop 3. Moreover, the metal hoop 3 in this region S is installed in a straight line in the circumferential direction of the outer peripheral side surface of the SN plate body 2. Further, in the region other than the region S where the heat insulating material is installed, the outer peripheral side surface of the SN plate body 2 and the metal hoop 3 are in direct contact.

  In the embodiment of FIG. 1, the region S where the heat insulating material 4 is installed includes a continuous region including a point P at the shortest distance from the center of the inner hole 2 a of the SN plate body 2 on the outer peripheral side surface of the SN plate body 2. And other continuous areas. Further, the continuous region (region S) including the point P has a length equal to or larger than the diameter of the inner hole 2a.

  FIG. 2 is a plan view of a main part showing another embodiment of the SN plate of the present invention. In the embodiment of FIG. 2, the heat insulating material 4 is installed in a portion where the outer peripheral side surface of the SN plate body 2 was originally curved. Specifically, in order to install the heat insulating material 4, the outer peripheral side surface of the SN plate main body 2 is cut, and in the region S where the heat insulating material 4 is installed, the metal hoop 3 is attached to the outer peripheral side surface of the SN plate main body 2. It is arranged in a straight line in the circumferential direction. In this way, regardless of the outer shape of the SN plate body 2, the metal hoop 3 is linearly installed in the circumferential direction of the outer peripheral side surface of the SN plate body 2 in the region S where the heat insulating material is installed. This is a feature of the present invention. Therefore, the thickness of the heat insulating material 4 does not need to be constant, and the metal hoop 3 can be installed in a straight line by changing the thickness of the heat insulating material 4.

  Hereinafter, calculation examples by FEM simulation related to the present invention will be shown.

[Calculation Example A]
Calculation example A is an example of calculating the difference between the expansion amount of the metal hoop and the expansion amount of the SN plate in the case where the conventional technique, that is, the heat insulating material is not installed.

The calculation conditions in this calculation example are as follows.
・ Inner hole diameter Ri (inner radius) of SN plate body = 32.5mm
-SN plate body outer periphery R (outer radius) = 110 mm
・ Heat transfer coefficient of metal hoop Hh = 5W / m ²・ K
・ Heat transfer coefficient of SN plate body H = 50W / m ²・ K
・ Coefficient of thermal expansion of metal hoop α _HB = 11 × 10 ⁻⁶ / ° C.
-Thermal conductivity of SN plate body λ = 5 W / m · K
・ Inner hole temperature Ti = 1823K (same as molten steel)
・ Outside air temperature To = 303K

In this calculation example, the influence of the magnitude of the thermal expansion coefficient of the SN plate body on the difference in the expansion amount was calculated. Specifically, the thermal conductivity λ of the SN plate body is set to 5 W / m · K, and the thermal expansion coefficient α is the same as that of the general SN plate body. calculated in the range of ^{× 10 -6 ~7 × 10 -6 /} ℃. Table 1 shows the results.

  Thus, as the thermal expansion coefficient of the SN plate main body increases, the thermal expansion amount of the SN plate main body increases, and the difference in thermal expansion amount from the metal hoop tends to decrease. Further, as shown in this result, in the range of the general thermal expansion coefficient of the SN plate body, the thermal expansion amount of the metal hoop is still larger than the thermal expansion amount of the SN plate body. It can be seen that the force tends to decrease.

[Calculation Example B]
In the calculation example B, the influence of the level of the thermal conductivity of the SN plate body on the difference in the expansion amount when the conventional technique, that is, the heat insulating material is not installed, was calculated. Specifically, the thermal expansion coefficient α of the SN plate body is set to 6.5 × 10 ⁻⁶ / ° C., and the thermal conductivity λ is the same as that of the general SN plate body. It calculated in the range of 4-7 W / m * K which is conductivity. Table 2 shows the results. Other conditions are the same as those in Calculation Example A.

  Thus, the higher the thermal conductivity of the SN plate body, the larger the thermal expansion amount of the SN plate body, but the larger the thermal expansion amount of the metal hoop, the greater the difference in the expansion amount. In addition, as shown in this result, in the range of the thermal conductivity of the general SN plate body, the thermal expansion amount of the metal hoop is larger than the thermal expansion amount of the SN plate body, that is, the binding force. It can be seen that there is a tendency to increase the decline.

[Calculation Example C]
In Calculation Example C, the effect of the magnitude of the thermal expansion coefficient of the SN plate body on the difference in expansion amount was calculated when a heat insulating material was installed. Here, assuming that the thickness t of the heat insulating material is 2 mm, the heat conductivity λs of the heat insulating material is 0.2 W / m · K, and λs / t = 100 W / m ² · K, The thermal conductivity of the SN plate body is 5 W / m · K, and the thermal expansion coefficient α is 5 × 10 ^{−6 to} 7 × 10 ⁻⁶ / ° C. which is the thermal expansion coefficient of a general SN plate body as in the calculation example A. It was made the range. Table 3 shows the results. Other conditions are the same as those in Calculation Example A.

  Thus, it turns out by the effect of a heat insulating material that the temperature of the heat insulating material outer side (metal hoop side) has fallen significantly compared with the thing which does not arrange | position a heat insulating material. As a result, the larger the thermal expansion coefficient, the larger the expansion amount of the SN plate body. However, in both cases, the expansion amount of the SN plate body is larger than the expansion amount of the metal hoop, and the restraining force is increased. It can be seen that the behavior does not decrease.

[Calculation Example D]
In the calculation example D, when the heat insulating material was installed, the influence of the level of thermal conductivity of the SN plate body on the difference in expansion amount was calculated. Here, as in calculation example C, the thickness t of the heat insulating material is 2 mm, the thermal conductivity λs of the heat insulating material is 0.2 W / m · K, and λs / t = 100 W / m ² · K, and the heat of the SN plate body The coefficient of expansion α is a thermal expansion coefficient of a general SN plate body of 6.5 × 10 ⁻⁶ / ° C., and the thermal conductivity λ is the same as that of the calculation example B, which is the thermal conductivity of a general SN plate body 4˜ The range was 7 W / m · K. Table 4 shows the results. Other conditions are the same as those in Calculation Example A.

  Thus, it turns out by the effect of a heat insulating material that the temperature of the heat insulating material outer side (metal hoop side) has fallen significantly compared with the thing which does not install a heat insulating material. In addition, the higher the thermal conductivity of the SN plate body, the higher the temperature on the outside of the heat insulating material (the metal hoop side), and the amount of thermal expansion of the metal hoop tends to be slightly higher. It can be seen that the expansion amount of the plate body is larger than the expansion amount of the metal hoop, and the restraining force of the SN plate body by the metal hoop does not decrease.

[Calculation Example E]
The calculation example E is a calculation example performed by changing the inner radius Ri and the outer radius R from the center of the inner hole of the SN plate body when the heat insulating material is installed. Here, as in the calculation examples C and D, the thickness t of the heat insulating material is 2 mm, the thermal conductivity λs of the heat insulating material is 0.2 W / m · K, and λs / t = 100 W / m ² · K. The thermal expansion coefficient α of the general SN plate body was 6.5 × 10 ⁻⁶ / ° C., and the thermal conductivity λ was also the general SN plate body thermal conductivity of 5 W / m · K. Table 5 shows the results. Other conditions are the same as those in Calculation Example A.

  When the inner radius Ri (inner hole radius) is constant, the larger the outer radius R, that is, the larger R / Ri, the larger the expansion amount of the SN plate body and the expansion amount of the metal hoop. The ratio of the expansion amount of the plate main body is larger, the difference between the expansion amount of the SN plate main body and the expansion amount of the metal hoop increases, and the binding force tends to become stronger. On the other hand, when the outer radius R is constant and the inner radius Ri (inner hole radius) is increased, both the expansion amount of the SN plate body and the expansion amount of the metal hoop increase, but the expansion rate of the metal hoop is large, and the SN ratio increases. The difference between the expansion amount of the plate body and the expansion amount of the metal hoop is reduced. However, at least in the range where the inner radius Ri is 25 to 50 mm and the outer radius R is 80 to 128 mm, the expansion amount of the SN plate body is larger than the expansion amount of the metal hoop, and the restraining force is maintained.

[Calculation Example F]
The calculation example F is a calculation example performed by changing the heat transfer coefficient H of the SN plate body when the heat insulating material is installed. Here, the thickness t of the heat insulating material is 2 mm, the thermal conductivity λs of the heat insulating material is 0.2 W / m · K, and λs / t = 100 W / m ² · K as in the calculation examples C to E, and the SN plate body The thermal expansion coefficient α of the general SN plate body was 6.5 × 10 ⁻⁶ / ° C., and the thermal conductivity λ was also the general SN plate body thermal conductivity of 5 W / m · K. The heat transfer coefficient of the SN plate body was calculated as 50 W / m ² · K in the calculation examples B to E, but here, the calculation was performed in the range of 40 to 60 W / m ² · K. Table 6 shows the results. Other conditions are the same as those in Calculation Example A.

It can be seen that the change in the heat transfer coefficient H of the SN plate body in the range of 40 to 60 W / m ² · K has little effect on the difference between the expansion amount of the metal hoop and the expansion amount of the SN plate body.

[Calculation Example G]
Calculation example G is a calculation example performed by changing the ratio λs / t between the thermal conductivity λs and the thickness t of the heat insulating material. Here, the thermal expansion coefficient α of the SN plate body is 5.5 × 10 ⁻⁶ / ° C., the thermal conductivity λ is 7 W / m · K, the heat transfer coefficient is 50 W / m ² · K, and the thickness t of the heat insulating material. Was calculated under the conditions of 1 mm, 2 mm, 3 mm, thermal conductivity λs of 0.1 W / m ² · K, 0.3 W / m ² · K, that is, λs / t in the range of 30 to 300 W / m ² · K. . Table 7 shows the results. Other conditions are the same as those in Calculation Example A.

  Thus, it can be seen that the smaller the thermal conductivity λs of the heat insulating material, the lower the temperature on the outer side of the heat insulating material (the metal hoop side), and the smaller the amount of expansion of the metal hoop. It can also be seen that the greater the thickness t of the heat insulating material, the lower the temperature on the heat insulating material outer side (metal hoop side), and the smaller the amount of expansion of the metal hoop. Furthermore, it can be seen that the binding force of the SN plate body by the metal hoop varies depending on the setting and combination of the thickness t of the heat insulating material and the thermal conductivity λs. The binding force of the SN plate body by the metal hoop is higher when the value obtained by subtracting the thermal expansion amount of the SN plate body from the thermal expansion amount of the metal hoop (hereinafter also simply referred to as “expansion difference”) is higher and negative. It is more preferable that the value is.

  Next, the influence of two influence factors on the heat insulating material, that is, the thickness t of the heat insulating material and the thermal conductivity λs of the heat insulating material on the expansion difference will be described from the above calculation results.

When the two influencing factors relating to the heat insulating material are arranged by the relationship between the ratio λs / t obtained by dividing the thermal conductivity λs of the heat insulating material by the thickness t of the heat insulating material and the expansion difference, an approximate expression of Equation 1 below can be obtained. (Decision coefficient R ² = 0.9831).
y = 0.2565 · ln (x) −1.257 Formula 1
This is shown in FIG.

In Equation 1 and FIG. 3, y is the expansion difference (mm), and x is λs / t (W / m ² · K). When λs / t at which y is almost zero is expressed as (λs / t) ₀ , (λs / t) ₀ is obtained by Equation 2 based on the approximate equation 1 and becomes approximately 134.4.
(Λs / t) ₀ = exp (1.257 / 0.2556) ≈134.4 Expression 2

  Therefore, by setting the thermal conductivity λs of the heat insulating material and the thickness t of the heat insulating material so that λs / t is 134.4 or less, the expansion difference becomes zero or a negative value, and the expansion amount of the SN plate body is It can be seen that the amount of expansion of the metal hoop is equal to or greater than that and an ideal restraining force is obtained. In other words, in the region where λs / t is 134.4 or less, there is almost no possibility that the metal hoop is loosened or detached from the SN plate body due to the difference in expansion, and λs / t is 134.4. Is larger than the above phenomenon, it is understood that the possibility of loosening or detachment of the metal hoop from the SN plate main body due to the difference in expansion is increased.

Since (λs / t) ₀ is affected by a variable other than λs and t, the variable other than λs and t is determined according to the specific operation conditions to be performed, and approximation using the variable What is necessary is just to determine the area | region of the value of (lambda) s / t which calculates | requires a type | formula and makes expansion difference zero or a negative value.

The relationship based on such an approximate expression is based on the expression 4 and the expression 4 based on the expression 3 in which λs / t at which y is almost zero is (λs / t) ₀ , the coefficient of the expression 1 is replaced with a, and the intercept is replaced with b. It can be generalized by Equation 5.

y = a · ln (x) −b Equation 3
0 (zero) = a · ln (λs / t) −b Expression 4
(Λs / t) ₀ = exp (b / a) Equation 5

  That is, when λs / t is smaller than the value obtained by Equation 5, an ideal restraining force can be obtained.

[Calculation Example H]
Calculation example H is a calculation of the temperature distribution of the SN plate body by FEM simulation. The calculation conditions in this calculation example are as follows.
・ Inner radius Ri = 50mm
・ Outer radius R = 110mm
・ Inner hole temperature Ti = 1823K
・ Outside air temperature To = 303K
・ Heat transfer coefficient of metal hoop Hh = 5W / m ²・ K
・ The thermal conductivity of SN plate body λ = 5W / m ・ K
・ Thermal conductivity λs = 0.2W / m · K
・ Insulation thickness t = 2mm
・ Λs / t = 100W / m ²・ K

  FIG. 4 shows a shape diagram (image) in this calculation example (FEM simulation), FIG. 5 shows an element division diagram (image), and FIG. 6 shows an element division diagram (image) in which a heat insulating material is installed.

  In this calculation example, the nearest (shortest) outer peripheral side surface portion from the inner hole of the SN plate main body is a point on the side surface in a direction perpendicular to the sliding direction from the inner hole center. The heat insulating material (100% of the inner hole diameter) was installed.

  FIG. 7 shows the temperature distribution of the SN plate main body when the heat insulating material is not installed, and FIG. 8 shows the temperature distribution of the SN plate main body when the heat insulating material is installed.

  It can be seen that the temperature distribution of the SN plate main body is highest near the inner hole through which the molten steel passes, and decreases radially from the inner hole (center). When the heat insulating material is not installed (FIG. 7), the temperature of the side surface portion closest to the inner hole portion is in the range of 800 ° C. to 1000 ° C. On the other hand, when a heat insulating material is installed in the outer peripheral side surface portion closest to the inner hole portion (FIG. 8), it can be seen that the temperature of the outer peripheral side surface portion falls in the range of 500 ° C to 800 ° C.

  In addition, the temperature is the highest in the inner hole portion where the temperature is the highest, and the distribution gradually decreases as the distance from the inner hole portion increases. The region farther from the vicinity of the outer peripheral side surface closest to the inner hole portion (stop) On the position side), it can be seen that it is in the range of 500 ° C. or less, and that both loosening and softening deformation due to the difference in expansion are relatively extremely small or not generated.

  Examples of experiments are shown below.

[Experiment A]
In Experimental Example A, the SN plate of the example of the present invention and the comparative example were heated from the inner hole, and the temperature distribution of the metal hoop, the displacement and detachment of the metal hoop, and the crack occurrence state of the SN plate main body were investigated. It is an experimental example.

  The conditions in this experimental example are as follows.

SN plate body ・ Shape: Inner hole diameter = 100 mm, outer shape 360 mm × 220 mm, thickness = 35 mm,
Corner cutout (see Figure 3)
・ Thermal conductivity: 6 (W / m ・ K)
-Thermal expansion coefficient: 6.7 × 10 ⁻⁶ (/ K)
Metal hoop ・ Shape: Thickness = 3 mm × Width (SN plate body thickness direction) = 25 mm
・ Installation method: shrink fitting by heating at about 600 ℃ ・ Material: SS400
-Heat transfer coefficient: 5 (W / m ² · K)
-Thermal expansion coefficient: 9 × 10 ⁻⁶ (/ K)
Heating method-Heat to about 1400 ° C from the inner hole with an LPG burner (70 minutes).
Temperature measurement method-Inner hole: Temperature is measured by bringing a thermocouple into contact with the SN plate.
・ Metal hoop: The outer surface is measured with a contact thermometer.
Insulating material ・ Shape: Thickness = 3mm
・ Installation location: A and B2 locations in FIG. 9 and A to D4 locations in FIG. 10 ・ A and B2 locations of heat insulating material Total length (circumferential direction of SN plate body outer peripheral side): 120 mm (120 relative to the inner hole diameter) %)
Width (SN plate body thickness direction): 35mm
・ C and D2 heat insulating material shapes
Total length (circumferential direction of SN plate body outer peripheral side) 60mm (60% of inner hole diameter)
Width (SN plate body thickness direction) = 35mm
・ Thermal conductivity: 0.2 (W / m ・ K)
· Λs / t: 67 (W / m ² · K)

  As shown in the calculation example of Table 8, the expansion difference between the metal hoop and the SN plate body in this experimental example is −0.10 at points A and B (near the center of the heat insulating material), and points C and D (heat insulation). It is -0.16 in the vicinity of the center of the material, and both values are negative values.

  Next, specific experimental results of this experimental example will be shown.

  In this experimental example, Example 1 is an example in which a heat insulating material is installed on both outer peripheral side portions (A, B2 locations) of the SN plate main body at a position closest to the inner hole as shown in FIG. As shown in FIG. 10, Example 2 is an example in which a heat insulating material is also installed on both corner cutout surfaces (C and D2 locations) on the short side of the SN plate main body in addition to Example 1. The metal hoops in the region where the heat insulating material was installed had a linear shape between both starting points in contact with the SN plate main body, and the region where the heat insulating material was not installed was brought into direct contact with the SN plate main body. On the other hand, a comparative example is an example which has not installed the heat insulating material.

  The temperature measurement results of Examples 1 and 2 and the comparative example are shown in FIGS. FIG. 11A shows the results of the comparative example, FIG. 11B shows the results of Example 1, and FIG. 11C shows the results of Example 2.

  The temperature at the temperature measurement 2 and temperature measurement 4 positions (see FIGS. 9 and 10) closest to the inner hole was about 700 ° C. in the comparative example, whereas in Example 1, the temperature was about 500 ° C. It is about 200 ° C. lower than the following, and in Example 2, it is about 400 ° C. or lower, which is about 300 ° C. lower.

  In the comparative example, a gap of about 1 mm was generated between the metal hoop and the SN plate main body during heating. Also, when touched immediately after the heating was stopped, the metal hoop came off. On the other hand, in Example 1 and Example 2, such a gap during heating did not occur. Further, when touching immediately after the heating was stopped, the metal hoop was not displaced or detached. As described above, in Example 1 and Example 2, it was confirmed that the metal hoop was not easily displaced (not easily detached), that is, the binding force was increased.

  Regarding the state of the crack after cooling, a large crack in the width direction was generated from the inner hole in the comparative example, whereas the cracks in Examples 1 and 2 were very slight.

[Experiment B]
Experimental example B is an experimental example in which the influence on the binding force of the SN plate body due to the difference in the metal type of the metal hoop was investigated. In this experimental example, SS400 was selected as the normal steel, and SUS304 and SUS430 were selected as the stainless steel. Moreover, in this experiment example, comprehensive evaluation was performed regarding the following evaluations 1 to 3.

Evaluation 1 (distortion amount of the metal hoop after installing the metal hoop on the SN plate body, that is, the degree of restraint)

  In this evaluation 1, the shape of the SN plate main body was the same as in Experimental Example A. Then, a metal hoop induction-heated to 600 ° C. is installed on the outer peripheral side surface of the SN plate main body at room temperature by a shrink fitting method, and the SN plate main body after the metal hoop installation is cooled to room temperature, and then the strain amount is measured by a strain gauge. Was measured. The measurement location of the strain amount was the outer peripheral side surface portion in the direction perpendicular to the sliding direction from the inner hole center closest to the inner hole of the SN plate body (shortest).

The measurement result of this distortion amount is as follows. Note that the greater the amount of distortion, the greater the restraining force.
SS400: 1531 μm,
SUS304: 1291 μm,
SUS430: 2604 μm,

  From this result, it can be seen that SUS430 has the largest restraining force at least from room temperature to the shrink-fit temperature.

Evaluation 2 (Plastic deformation rate from room temperature to 800 ° C (in increments of 200 ° C, up to 1000 ° C for SUS304))

  In this evaluation 2, for each metal sample having a thickness of 6 mm, a width of 20 mm, and a length of 230 mm, the bending strength and static elastic modulus were measured from room temperature to hot at a distance of 215 mm between the fulcrums to determine the plastic deformation rate.

  The plastic deformation speed calculated from the result is shown in FIG. 12A. There is almost no difference between any of the three metal types from room temperature to 600 ° C. (SUS304 is slightly lower at about 400 ° C. or higher), but it can be seen that the plastic deformation rate of SS400 and SUS430 rapidly increases when the temperature exceeds 600 ° C. . In contrast, SUS304 maintains an almost constant and small plastic deformation rate up to 800 ° C., which is about 1000 ° C., which is similar to that of SUS430 at 800 ° C. (SS400 exceeds 1000 ° C. and exceeds 800 ° C.). It is not measured until.)

  Naturally, the plastic deformation of the metal hoop causes a reduction in restraining force. Therefore, as the material of the metal hoop, stainless steel (SUS304 or the like) is adopted under the conditions of use up to at least about 800 ° C. in the case of conditions / parts where the temperature of the metal hoop exceeds about 600 ° C. It turns out that it is preferable.

Evaluation 3 (Relationship between stress and strain at room temperature)

  In this evaluation 3, for each metal sample of thickness 6 mm × width 20 mm × length 230 mm, stress-strain measurement was performed at a fulcrum distance of 215 mm at room temperature, and the variation in the value of ordinary steel was compared with stainless steel. investigated.

  Using two samples of SS400 as normal steel and SUS430 as an example, the stress-strain relationship at room temperature was investigated. The result is shown in FIG. 12B.

  SS400 has a deformation similar to SUS430 (Sample-1; however, the deformation is larger than that of SUS430), while there is a deformation that is significantly larger (Sample-2), indicating that the variation is large. If such a large variation is adopted for the metal hoop, the metal hoop has a large variation in binding force, crack generation, loosening, and the like.

  In contrast, stainless steel, which has relatively strict component specifications, has been found to have less variation in physical properties than ordinary steel. In addition, since the relative relationship between stress and strain at room temperature does not change even at high temperatures, the stress-strain (including plastic deformation rate) characteristics tend to be similar at high temperatures.

  From the results of the above evaluation 1, evaluation 2 and evaluation 3, SUS430 has the largest binding force in the region where the temperature of the metal hoop is from room temperature to 600 ° C. or less, and SUS304 is in the region exceeding 600 ° C. (at least 1000 ° C. or less). It can be seen that the plastic deformation rate is the smallest and the restraining force is large. Accordingly, in the present invention, it is preferable to determine the thermal conductivity, thickness, and installation range of the heat insulating material to be installed so that the temperature of the metal hoop is 600 ° C. or lower. From this point of view, the material of the metal hoop is preferably SUS430. In addition, there are restrictions such as the shape of the SN plate main body, that is, the length from the inner hole to the outer peripheral side surface where the metal hoop is installed is short, and in conditions where the temperature of the metal hoop often exceeds 600 ° C. In at least a portion where the temperature of the metal hoop exceeds 600 ° C., the material of the metal hoop is preferably SUS304.

DESCRIPTION OF SYMBOLS 1 SN plate 2 SN plate main body 2a Inner hole 3 Metal hoop 4 Thermal insulation

Claims (7)

In the sliding nozzle plate in which a metal hoop is installed along the circumferential direction of the outer peripheral side surface of the sliding nozzle plate body made of refractory having an inner hole for discharging molten metal,
There is a region in which a heat insulating material is installed between the outer peripheral side surface of the sliding nozzle plate body and the metal hoop, and the metal hoop in the region in which the heat insulating material is installed is arranged around the outer peripheral side surface of the sliding nozzle plate main body. A sliding nozzle plate, wherein the sliding nozzle plate is linear in a direction, and the outer peripheral side surface of the sliding nozzle plate main body and the metal hoop are in direct contact with each other in a region other than the region where the heat insulating material is installed.   The region where the heat insulating material is installed is a continuous region including a point at the shortest distance from the center of the inner hole of the sliding nozzle plate body on the outer peripheral side surface of the sliding nozzle plate body, or the continuous region and other continuous regions. The sliding nozzle plate according to claim 1.   3. The sliding nozzle according to claim 2, wherein the continuous region including a point at the shortest distance from the center of the inner hole has a length equal to or larger than the diameter of the inner hole along the circumferential direction of the outer peripheral side surface of the sliding nozzle plate body. plate.   The sliding nozzle plate according to any one of claims 1 to 3, wherein a thermal expansion amount of the metal hoop in the region where the heat insulating material is installed is equal to or less than a thermal expansion amount of the sliding nozzle plate body at the same position. .   The sliding nozzle plate according to any one of claims 1 to 4, wherein the metal hoop is made of stainless steel.   The sliding nozzle plate according to claim 5, wherein the metal hoop is made of SUS430 out of stainless steel.   The sliding nozzle plate according to claim 5, wherein the metal hoop is made of SUS304 of stainless steel.