JP2016085202A - Life prediction method for refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a life prediction method for a refractory, enabling life of a refractory in a furnace body which is actual equipment to be accurately predicted.SOLUTION: There is provided a method for predicting life of a refractory 9 which is lined to an inner wall face 4 of a furnace body 1, a first refractory 9a and a second refractory 9b which is a substitute for a part of the first refractory 9a being disposed on the inner wall face 4 of the furnace body 1. In the furnace body 1 in which the first refractory 9a and the second refractory 9b coexist, an actual operation is performed, after the actual operation, wear speed (F1) of the first refractory 9a and wear speed (F2) of the second refractory 9b are measured. Then, using the measured wear speed (F1) of the first refractory 9a, the measured wear speed (F2) of the second refractory 9b, and estimated life (L1) of the first refractory 9a which is known, estimated life (L2) of the second refractory 9b is obtained.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for predicting the life of a refractory that predicts the life of a refractory provided inside a furnace body used in the steelmaking field.

  As is well known, various furnace bodies for heating and heat-treating a target material such as a slab, for example, a heating furnace, a soaking furnace, a moving hearth furnace, a fixed hearth furnace, and the like are used in the steelmaking field. Although the refractory is provided on the inner wall surface (furnace wall) of these furnace bodies, the refractory is gradually worn out by the temperature and atmosphere during the treatment process in the furnace body. In addition, dust scattered from the target material may adhere to the surface of the refractory, and the dust scattered and refractory may react to accelerate wear. Under such circumstances, it will lead to troubles such as holes in the furnace wall.

Therefore, in an actual furnace body, the amount of wear of the refractory is appropriately controlled. For example, when the amount of wear of the refractory reaches a threshold value, the refractory is replaced with a new refractory.
The above-mentioned refractories have different wear resistance characteristics with respect to atmosphere, temperature, and dust scattered materials depending on the material (quality). Further, it is preferable that the lifetime is as long as possible from the viewpoint of the cost when performing heating or heat treatment. Therefore, it is necessary to select a refractory according to the use conditions (processing conditions) of the furnace body.

In selecting a refractory, it is necessary to test whether or not the refractory has a predetermined performance when actually operating in a furnace body lined with the refractory.
The method for measuring the wear amount of a refractory, that is, a method for predicting the life of a refractory is, for example, a test cut into a fixed shape in a test container in which a molten erosion material (eg, slag) is charged. Immersing a refractory for use and measuring the amount of wear of the refractory and immersing the molten erosion into a container lined with a test refractory to cause erosion It can be classified into the “lining method” that measures the amount of wear.

In addition, both the dipping method and the lining method can be divided into several test methods in which the heating method and the shape of the container are different in order to approach the actual operation.
For example, a test refractory is put into the erodible material melted in a high-frequency induction furnace, and the refractory and the molten erodible material are relatively vibrated to cause erosion and reduce the amount of wear of the refractory. A test method (test method using a high frequency induction furnace) to be measured or a crucible created using a refractory is used as a sample, and an erosion material such as slag is charged into the crucible. The crucible is heated by a burner or arc to melt the internal erosion material. Thereafter, the crucible is cooled, and the state of erosion / dissolution of the refractory due to the influence of the molten erodant is evaluated, that is, a test method for measuring the amount of wear of the refractory (test method using the crucible method: JIS R 2214) Can be mentioned.

In addition, the container is formed in a drum shape, and a test refractory is attached to the inside. The erosion material is put into the drum and heated and melted with a burner or the like, and the drum is rotated to melt the erosion material. And a test method (a test method based on a rotating drum method) that erodes a refractory and measures the amount of wear of the refractory.
However, when the refractory wear test is conducted in the laboratory, the reaction between the refractory and the erodible material (slag, etc.) is slow, so the absolute amount of wear due to erosion is small, and whether the refractory can be used or not. The problem that it is difficult to put on arises.

Therefore, in order to increase the absolute amount of wear of the refractory due to erosion, it is conceivable to devise the arrangement position of the refractory when providing the refractory inside the container, such as the technique disclosed in Patent Document 1 Exists.
In Patent Document 1, in a method in which a refractory sample is lined on the inner surface of a rotating drum, an erosion material is added, the drum is rotated, and an erosion test of the refractory sample is performed, the refractory sample is projected from the inner surface side. A test method is disclosed in which the absolute amount of wear due to erosion is increased by lining, the difference in wear amount between materials is expanded, and simultaneously the corrosion resistance of many types of refractory samples is evaluated.

JP 2000-9633 A

  In the furnace body described above, for some reason, another refractory (alternative refractory) different from the refractory that has been employed so far may be employed. In that case, the alternative refractory is often unclear about the life difference (difference in wear) from the existing refractory. If an alternative refractory is adopted while the life difference from the existing refractory remains unknown, the furnace body may be damaged during actual operation. For example, if the life of the alternative refractory is shorter than the existing refractory (the wear rate is faster), the refractory is worn more than necessary during actual operation, and a hole is formed in the furnace wall. There is a risk of trouble.

Therefore, it is considered that the wear amount of the refractory is measured using the technique of Patent Document 1 described above, and the life of the refractory is predicted from the wear amount.
In Patent Document 1, a specimen (refractory material) is provided inside a rotating drum, and the amount of wear is measured by eroding the molten erosion material into the refractory material, that is, a test body (rotation) different from the actual machine (furnace body). Drum) is a technique for measuring the amount of wear (life prediction) of refractories, so that relative evaluation between samples is possible.

However, regarding the refractory used in the furnace body, which is an actual machine, when the life of the refractory is predicted from the amount of wear by applying the technique of Patent Document 1, the test conditions of the same document differ from the usage environment such as the atmosphere and temperature of the actual machine. It is often difficult to accurately predict the life of a refractory in an actual machine.
Then, this invention is made | formed in view of the said problem, and it aims at providing the lifetime prediction method of the refractory which can estimate the lifetime of the refractory in the furnace which is an actual machine correctly. .

In order to achieve the above object, the present invention takes the following technical means.
The method for predicting the life of a refractory according to the present invention is a method for predicting the life of a refractory lined on the inner wall surface of a furnace body, and the inner wall surface of the furnace body includes a first refractory, and A second refractory provided in place of a part of the first refractory is provided, and in the furnace body in which the first refractory and the second refractory are mixed, After the actual operation, the wear rate (F1) of the first refractory and the wear rate (F2) of the second refractory are measured, and the measured wear rate of the first refractory ( F1), the measured wear rate (F2) of the second refractory, and the known predicted life (L1) of the first refractory, using the formula (1), the second The predicted life (L2) of the refractory is obtained.

Preferably, a test region is provided on the inner wall surface of the furnace body, and the second refractory is disposed adjacent to the first refractory in the test region.
Preferably, when the furnace body is a moving hearth furnace, at least two test regions may be provided on the inner wall surface of the furnace body.
Preferably, among the at least two test regions, one test region is installed in a region where the furnace temperature is highest, and the other test region is installed in a region where the furnace temperature is lowest. Good.

  Preferably, the wear rate ratio (F2 / F1) obtained in each of the at least two test areas and the in-furnace temperature (T) of each test area are calculated according to the equation (2). From the equation (1), the temperature function is obtained and the wear rate ratio (F2 / F1) obtained from the temperature function of the obtained wear rate ratio and the predicted life (L1) of the first refractory are used. The predicted life of the second refractory (L2) may be obtained.

Preferably, a preliminary test for measuring the wear rate (F2) of the second refractory is performed, and in the preliminary test, when the wear rate (F2) of the second refractory is a predetermined speed or less, The predicted life (L2) of the second refractory may be obtained using the refractory life prediction method according to claim 1 or 2.
Preferably, the first refractory is an existing refractory conventionally employed in a furnace body, and the second refractory is an alternative refractory employed in place of the existing refractory. Good.

  According to the method for predicting the life of a refractory according to the present invention, it is possible to accurately predict the life of a refractory in a furnace as an actual machine.

The top view of a U-shaped furnace is shown. Sectional drawing (AA cross section) of a U-shaped furnace is shown. It is the figure which showed typically a part of inner wall surface of the U-shaped furnace by which the refractory was lined. It is a figure which shows the estimated lifetime of the alternative refractory estimated with the lifetime prediction method of the refractory concerning this invention.

Hereinafter, an embodiment of a method for predicting the lifetime of a furnace refractory according to the present invention will be described with reference to the drawings.
First, the furnace body 1 to which this invention is applied is demonstrated based on a figure.
In the steelmaking field, various furnace bodies 1 for heating and heat-treating the target material W, for example, a heating furnace, a soaking furnace, a moving hearth furnace, a fixed hearth furnace, and the like are used. A refractory 9 is lined inside these furnace bodies 1. In this embodiment, a U-shaped furnace (moving hearth furnace) having an internally curved shape will be described as an example of the furnace body 1. In addition, this invention is applicable also to various furnace bodies 1, For example, it can apply also to a fixed hearth furnace.

FIG. 1A shows a plan view of a U-shaped furnace, and FIG. 1B shows a cross-sectional view (A-A cross section) of the U-shaped furnace.
As shown in FIG. 1A, the U-shaped furnace has a curved portion 2 having a substantially semicircular shape, and the curved portion 2 has a large outer diameter of several tens of meters. Moreover, as shown to FIG. 1B, the cross section (AA cross section) of the curved part 2 is made into the rectangular shape which reaches several m in both an internal width and height.

The inside of the U-shaped furnace has a furnace wall 3 composed of a side wall part 3 a and a ceiling part 3 b, and a hearth 5 disposed below the furnace wall 3. A rail 8 is laid on the lower side of the hearth 5, that is, on the floor surface.
A refractory 9 for protecting the furnace wall 3 from heat is stretched on the inner side of the furnace, that is, the inner wall surface 4 of the side wall 3a and the ceiling 3b. The side wall 3a is provided with a maintenance door (not shown) for maintaining the furnace body 1 such as replacing the worn refractory 9 or the like.

  On the other hand, the hearth 5 is movable and includes a mounting table 6 on which a cast slab W (target material) and the like are mounted, and a wheel 7 that moves the mounting table 6. The movable hearth 5 moves on a rail 8 laid on the floor surface. The rail 8 that passes through the bending portion 2 is laid with the same curvature as that of the bending portion 2, and the hearth 5 moves along the curvature of the rail 8. The slab W placed on the hearth 5 is heated as the hearth 5 moves through the curved portion 2 of the U-shaped furnace.

In the present embodiment, a U-shaped furnace has been described as an example. However, as a matter of course, the present invention can also be applied to other heating furnace bodies. For example, the present invention can also be applied to a rotary furnace in which a steelmaking raw material such as pellets is charged into the hearth 5 and the reaction proceeds while rotating the hearth 5 along the rail 8.
The refractory 9 attached to the inside of the furnace body 1 is gradually worn out by the temperature and atmosphere during the course of the treatment process in the furnace body 1 (actual operation). Therefore, the refractory 9 is carefully managed according to the amount of wear, and when it exceeds a predetermined amount of wear, it is replaced with a new refractory 9.

  However, it is possible to adopt another refractory (alternative refractory 9b) different from the refractory (existing refractory 9a) used so far for some reason (for example, a low-cost product or a new product). is there. These refractories 9a and 9b have different wear resistance characteristics with respect to atmosphere, temperature and dust scattering depending on the material (quality), and there is a difference in life (difference in wear amount) between the alternative refractory 9b and the existing refractory 9a. Often unknown.

For example, when the life of the alternative refractory 9b is shorter than the existing refractory 9a (the wear rate is faster), or when the life difference between the alternative refractory 9b and the existing refractory 9a is unknown at the time before adoption, Troubles such as opening a hole in the furnace wall 3 during actual operation occur, and the actual operation must be stopped.
Also, in laboratory tests conducted in the prior art, the evaluation of the amount of wear of the alternative refractory 9b may be as small as around 1 mm. Therefore, when the predicted life of the alternative refractory 9b is obtained with an actual machine, it varies greatly. There is also a problem.

Therefore, the inventors of the present application are deployed on the inner wall surface 4 of the furnace body 1 using the furnace body 1 (actual machine) pasted to the inner wall surface 4 so as to mix the existing refractory 9a and the alternative refractory 9b. Invented a method for predicting the lifetime of the alternative refractory 9b.
Next, an embodiment of a method for predicting the lifetime of the refractory 9 according to the present invention will be described with reference to the drawings.

FIG. 2 shows a part of an inner wall surface 4 of a U-shaped furnace lined with an existing refractory 9a (first refractory in the claims) and an alternative refractory 9b (second refractory in the claims). It is the figure shown typically.
In the life prediction method of the present invention, the actual operation is performed in the furnace body 1 in which the existing refractory 9a and the alternative refractory 9b are mixed, and in this actual operation, the wear rate (F1) of the existing refractory 9a is replaced. The wear rate (F2) of the refractory 9b is measured, the measured wear rate (F1) of the existing refractory 9a, the measured wear rate (F2) of the alternative refractory 9b, and the known prediction of the existing refractory 9a The life expectancy (L2) of the alternative refractory 9b is obtained using the life (L1).

Specifically, as shown in FIG. 2, the inner wall surface 4 of the side wall 3a of the furnace body 1 includes a plurality of existing refractories 9a and an alternative refractory 9b provided in place of a part of the existing refractories 9a. Is set to the test area 10. It can be said that the test area 10 includes an area where the existing refractory 9a and the alternative refractory 9b are mixed.
The test area 10 can be set at an arbitrary location inside the furnace body 1. In the case of this embodiment, the test area 10 is set inside the furnace door of the maintenance door in consideration of the ease of performing the test and the simplicity of the test work. It is preferable to do. Moreover, it is also preferable to set the test region 10 in a severe environment with respect to the location where the amount of wear of the existing refractory 9a is the largest on the inner wall surface 4 of the furnace body 1, that is, the existing refractory 9a. For example, it may be set near the flame burner or on the inner wall surface 4 of the ceiling 3b.

  For example, in the test area 10 set in the area shown inside the thick solid line in FIG. 2, three alternative refractories 9b that are stacked in the vertical direction and arranged in the horizontal direction are arranged correspondingly. The 12 existing refractories 9a to be removed are deployed on the inner wall surface 4 (space). That is, the existing refractory 9a is arranged adjacent to the outer periphery where the 12 alternative refractories 9b are gathered.

In addition, the arrangement | positioning relationship of the existing refractory 9a and the alternative refractory 9b in the test area | region 10 is not limited to what is shown in FIG. For example, you may arrange | position so that the existing refractory 9a and the alternative refractory 9b may mutually adjoin alternately. That is, the existing refractory 9a and the alternative refractory 9b may be arranged in a mosaic shape.
In the furnace body 1 in which the existing refractory 9a and the alternative refractory 9b are mixed, actual operation (actual machine test) is performed for a predetermined period. For example, the slab W to be processed is heated until it reaches a predetermined temperature. After actual operation, the wear rate (F1) of the existing refractory 9a and the wear rate (F2) of the alternative refractory 9b are measured.

The wear rate (F1) of the existing refractory 9a is calculated from the difference between the thickness of the existing refractory 9a before actual operation and the thickness of the existing refractory 9a after actual operation, The wear thickness is calculated by dividing by the actual operation time. The wear rate (F2) of the alternative refractory 9b is calculated in the same manner.
Then, using the measured wear rate (F1) of the existing refractory 9a, the measured wear rate (F2) of the alternative refractory 9b, and the predicted life (L1) of the existing refractory 9a, The expected life (L2) of the alternative refractory 9b is obtained.

  The predicted life (L1) of the existing refractory 9a may be obtained in advance from known data such as the specifications of the existing refractory 9a (product), or may be obtained from past operation data, It is possible to use the predicted life (L1) of the existing refractory 9a obtained from the operation data at the same time as calculating the wear rate (F1) of the existing refractory 9a and the wear rate (F2) of the alternative refractory 9b. desirable.

  By the way, in a furnace (for example, a moving hearth furnace) that is heated by moving the hearth, the temperature is often different depending on the region in the furnace. When performing life prediction in such a furnace, it is possible to perform life prediction with high accuracy by treating the wear rate ratio (F2 / F1) as a function of the furnace temperature as shown in the second embodiment. Specifically, in the life prediction method of the second embodiment, at least two or more test areas are set on the inner wall surface of the furnace body.

  For example, the test area is a place where the wear amount of the existing refractory 9a is the largest, that is, a place where the wear amount of the existing refractory 9a is the least, ie, the existing refractory 9a. Set in an environment that is gentle to the environment. If a plurality of wear rate ratios (F2 / F1) are obtained from a plurality of test regions having different furnace temperatures, the wear rate is correlated with the furnace temperature (T). By making F1) a function of the temperature shown in equation (2), it is possible to perform life prediction more accurately.

Next, a procedure for actually predicting the lifetime of the alternative refractory 9b using the wear rate ratio (F2 / F1) will be described.
In the following description, assuming that the wear rate ratio (F2 / F1) is constant (the value does not change even when the furnace temperature changes), the life prediction of the alternative refractory 9b is performed.
First, it is preferable to perform a preliminary test for measuring the wear rate (F2) of the alternative refractory 9b before performing the actual operation (actual machine test) for obtaining the predicted life (L2) of the alternative refractory 9b.

Preliminary tests show that the alternative refractory 9b to be predicted has a life that is clearly too short (life difference is large) relative to the life of the existing refractory 9a, that is, the wear rate is too fast. In this test, the object 9b is excluded in advance. This preliminary test may be performed with an actual machine (furnace body 1) or as a laboratory experiment with an experimental machine (a container in which the actual machine is scaled as it is).
In this preliminary test, the wear rate (F2) of the alternative refractory 9b is equal to or lower than a predetermined rate, that is, the wear rate (F2) of the alternative refractory 9b is close to the wear rate (F1) of the existing refractory 9a. In this case, it is determined that the alternative refractory 9b is “predictable life”.

Then, the predicted life (L2) of the alternative refractory 9b determined to be “predictable life” in the preliminary test is obtained using the above-described method for predicting the life of the refractory 9.
In the preliminary test, when the wear rate (F2) of the alternative refractory 9b is equal to or lower than the predetermined speed, “life prediction is possible”, the wear rate (F2) of the alternative refractory 9b is slightly higher than the predetermined speed. It can be fast. In other words, the difference between the performance of the existing refractory 9a and the performance of the alternative refractory 9b may not be significantly different.

  By performing the preliminary test, the alternative refractory 9b exceeding the predetermined standard can be selected in advance, and the predicted life (L2) of the alternative refractory 9b can be efficiently performed.

Next, experimental examples (Examples 1 to 3) of the method for predicting the lifetime of the refractory 9 according to the present invention will be described.
Here, Example 1 is an example in which the life prediction of the alternative refractory 9b is performed on the assumption that the wear rate ratio (F2 / F1) is constant. Example 2 and Example 3 are examples in which the lifetime prediction of the alternative refractory 9b is performed based on the wear rate ratio (F2 / F1) obtained from the furnace temperature.

In Examples 1 to 3, refractories having a thickness of 250 mm were employed as the existing refractory 9a (test material for the existing refractory 9a) and the alternative refractory 9b (test material for the alternative refractory 9b).
<Example 1>
In Example 1, as a procedure for obtaining the predicted life (L2) of the alternative refractory 9b, first, the predicted life (L1) of the existing refractory 9a is obtained.

In the furnace body 1 in which the existing refractory 9 a is lined on the inner wall surface 4 of the furnace wall 3, a region (actual furnace region) for obtaining the predicted life (L1) of the existing refractory 9 a is set. In the present embodiment, five actual furnace zones, Zone A to Zone E, are set.
Immediately after performing maintenance to newly deploy the existing refractory 9a on the inner wall surface 4 of the furnace body 1, the three-dimensional shape of the furnace wall 3 is measured, and the obtained three-dimensional shape of the furnace wall 3 is used as reference data. get.

  Then, actual operation is performed for a predetermined period in the furnace body 1 in which the existing refractory 9 a is newly provided on the furnace wall 3. For example, the slab W or the like is heated to a predetermined temperature. After the actual operation, the three-dimensional shape of the furnace wall 3 is measured, and the obtained three-dimensional shape of the furnace wall 3 is acquired as operation data. For example, the three-dimensional shape of the furnace wall 3 is measured using the technique of a light cutting method (for example, Unexamined-Japanese-Patent No. 2013-148375).

The wear thickness of the existing refractory 9a is obtained from the difference between the reference data and the operation data, and the wear thickness of each existing refractory 9a in each zone is obtained by dividing the wear thickness by the operating time. The time until 9a reaches the effective remaining thickness is estimated, and this estimated value is set as the predicted life (L1) of the existing refractory 9a. Note that the effective remaining thickness of the existing refractory 9a is ½ of the total thickness.
Table 1 shows the results of the predicted life (L1) of the existing refractory 9a obtained by such a procedure.

As shown in Table 1, in Zone A, the predicted lifetime (L1) of the existing refractory 9a is 9.47 years, which is the longest lifetime among Zone A to Zone E. That is, it can be estimated that Zone A has a relatively gentle environment in the furnace body 1 in Zone A to Zone E.
In ZoneC, the predicted lifetime (L1) of the existing refractory 9a is 3.64 years, which is the shortest lifetime among ZoneA to ZoneE. That is, it can be estimated that Zone C has the most severe environment in the furnace body 1 in Zone A to Zone E.

In addition, when calculating | requiring the estimated lifetime (L1) of the existing refractory 9a, as mentioned later, you may measure the remaining thickness of the existing refractory 9a (hand scale), and may calculate wear loss thickness.
Subsequently, the predicted life (L2) of the alternative refractory 9b is obtained.
First, the wear rate ratio (F2 / F1) between the existing refractory 9a and the alternative refractory 9b is obtained. In addition, ZoneC of the area | region with the largest wear amount is set to the test area | region 10 from the result of calculating | requiring the estimated lifetime (L1) of the existing refractory 9a.

In ZoneC selected as the test area 10, a part of the existing refractory 9a is removed, and an alternative refractory 9b is provided. In Example 1, three types of fired bricks (α-1) to (α-3) and four types of amorphous refractories (β-1) to (β-4) are substituted for ZoneC as alternative refractories 9b. Deployed with new existing refractory 9a.
Then, the thickness (total thickness: 250 mm) of the existing refractory 9a and the seven types of alternative refractories 9b is used as reference data. In the furnace body 1 in which the existing refractory 9a and seven kinds of alternative refractories 9b are arranged on the furnace wall 3, the actual operation is performed under the same conditions as when the predicted life (L1) of the existing refractory 9a is obtained for a predetermined period. I do. For example, an operation for heating and holding the slab W or the like until a predetermined temperature is performed for a certain period.

After actual operation, the existing refractory 9a and the seven alternative refractories 9b are recovered from the test area 10 of the furnace wall 3, and the remaining thicknesses of the existing refractory 9a and the seven alternative refractories 9b are measured ( (Hand scale), obtained as operation data.
The wear thickness of the existing refractory 9a and the alternative refractory 9b is measured from the difference between the acquired operation data (remaining thickness) and the reference data (total thickness), and the existing refractory 9a in the actual machine is determined from the wear thickness and operation time. Wear rate (F1) and the wear rate (F2) of each alternative refractory 9b. In addition, about the remaining thickness of the existing refractory 9a and the alternative refractory 9b, an average wear part is made into a measuring object.

And the wear rate ratio (F2 / F1) of the existing refractory 9a and each alternative refractory 9b is calculated | required, respectively.
In the outermost peripheral portion of the test area 10, the alternative refractory 9b is significantly worn out due to the influence other than the adjacent existing refractory 9a and the influence of the adjacent refractory 9 in operation. There may be. At that time, the substitute refractory 9b that has been significantly worn out is excluded from measurement. Moreover, when the alternative refractory 9b is measured at a plurality of locations, the average of the plurality of measured values is taken, and the average value is taken as the wear rate (F2) of the alternative refractory 9b.

  The wear rate ratio (F2 / F1) between the existing refractory 9a and each alternative refractory 9b in the test region 10 obtained by such a procedure, that is, the wear rate ratio (F2 / F1) of Example 1 is shown in FIG. It is shown in 2.

As shown in Table 2, in the test area 10, the wear rate ratio (F2 / F1) between the existing refractory 9a and the fired brick (α-2), which is the alternative refractory 9b, is 1.38, and the existing refractory It can be seen that the difference between the wear rate (F1) of the object 9a and the wear rate (F2) of the alternative refractory 9b is the smallest of the seven types of alternative refractories 9b.
In addition, the wear rate ratio (F2 / F1) between the existing refractory 9a and the irregular refractory (β-4) as the substitute refractory 9b is 3.08, and the wear rate (F1) of the existing refractory 9a is It can be seen that the difference in wear rate (F2) of the alternative refractory 9b is the largest among the seven types of alternative refractories 9b.

And the estimated life (L2) of the alternative refractory 9b in ZoneA-ZoneE is calculated | required. As the wear rate ratio (F2 / F1), the values shown in Table 2 (Zone C, which is the region with the largest wear amount) are used.
The predicted life (L2) of the alternative refractory 9b is obtained from Equation (1) using the wear rate ratio (F2 / F1) in Zone C and the predicted life (L1) of the existing refractory 9a in Zone A to Zone E.

  Table 3 shows the predicted life (L2) of the seven types of alternative refractories 9b in Zone A to Zone E determined by the procedure of Example 1 as described above. The predicted life (L2) of the seven types of alternative refractories 9b shown in Table 3 is calculated using the wear rate ratio (F2 / F1) in the test region 10, that is, Zone C, which is the region with the largest amount of wear. As a result, safety has been emphasized.

Referring to Table 3, for example, in ZoneC, when trying to have an alternative refractory 9b for 1.5 years, fired bricks (α-1), (α-2), (α-3), irregular shapes It can be seen that four alternative refractories 9b of the refractory (β-1) can be selected.
In addition, for example, in Zone A, when it is intended to hold the alternative refractory 9b for 6 years, it can be seen that two alternative refractories 9b of fired bricks (α-1) and (α-2) can be selected.

From the above, by setting the test region 10 on the inner wall surface 4 of the furnace body 1, it is not necessary to deploy the existing refractory 9 a and the alternative refractory 9 b on all the inner wall surfaces 4 of the furnace body 1. Thus, it is possible to easily obtain the predicted life (L2) of the alternative refractory 9b.
FIG. 3 shows a result of predicting the predicted life (L2) of the alternative refractory 9b by the method for predicting the life of the refractory 9 of the first embodiment described above.

As shown in FIG. 3, the life prediction method of the refractory 9 of Example 1 can be evaluated using data for at least several months. Therefore, the alternative refractory every several years is compared with the conventional laboratory experiment. The predicted life (L2) of the object 9b can be obtained with high accuracy.
Referring to FIG. 3, when the predicted life (L2) of the alternative refractory 9b is obtained by the life prediction method of the refractory 9 of Example 1, the prediction of the alternative refractory 9b predicted by the laboratory experiment in the conventional laboratory. It can be seen that the width of the predicted life (L2) (prediction accuracy) is narrower than the width of the life. That is, the predicted life (L2) of the alternative refractory 9b obtained by the life prediction method of the refractory 9 of the present invention is higher in prediction accuracy than the predicted life of the alternative refractory 9b obtained by the conventional method. Recognize.
<Example 2>
Next, a second embodiment of the method for predicting the lifetime of the refractory 9 according to the present invention will be described.

The major feature of the second embodiment is that the wear rate ratio (F2 / F1) between the existing refractory 9a and the alternative refractory 9b is properly used according to the zone when determining the predicted life (L2) of the alternative refractory 9b. is there. On the other hand, constant (F2 / F1) is used in the first embodiment.
In Example 2, Zone C with the largest amount of wear is set in the test region 10 and Zone A with the smallest amount of wear is set in the test region 10 ′. The wear rate ratio (F2 / F1) with the alternative refractory 9b is obtained, and the wear rate ratio (F2 '/ F1') with the substitute refractory 9b in the test region 10 'is obtained.

  The wear rate thus obtained has a correlation with the furnace temperature (T), that is, the wear rate tends to increase as the furnace temperature (T) increases. Can be expressed as a function of the furnace temperature (T).

The coefficient A and the coefficient B in the equation (2) described above are the wear rate ratio (F2 / F1) indicated as a linear function of the temperature in each test region 10, 10 ′, and each test region 10, 10 ′. It can be obtained by substituting the average furnace temperature (T).
Table 4 shows the coefficients A and B of Zone A to Zone E thus determined.

In addition, in this Example 2, since there were two test areas, the wear rate ratio was arranged by a linear expression of the furnace temperature, but the order of the furnace temperature is not particularly limited.
Calculated using the coefficients in Table 4 and the average furnace temperature (T) of each zone, the average furnace temperature of each zone, and the wear rate ratio between the existing refractory 9a and each alternative refractory 9b (F2 / F1) ) Is shown in Table 5.

  By substituting the wear rate ratio (F2 / F1) shown in Table 5 and the predicted life (L1) of the existing refractory 9a in Zone A to Zone E into the above-described formula (1), the predicted life of the alternative refractory 9b ( L2) is obtained.

  Table 6 shows the predicted life (L2) of the seven types of alternative refractories 9b in Zone A to Zone E determined by the procedure of Example 2 as described above.

  The predicted life (L2) of the seven types of alternative refractories shown in Table 6, in other words, the predicted life (L2) obtained by the method of Example 2, is the test regions 10 and 10 ′, that is, the region with the largest amount of wear. The wear rate ratio in Zone C (F2 / F1) and the wear rate ratio (F2 ′ / F1 ′) in Zone A with the smallest wear amount are arranged as a function of temperature, and the average temperature in each furnace of each Zone Since it is calculated using the wear rate ratio (F2 / F1) according to (T), the result is more accurate.

In particular, in the method of Example 2, the predicted life accuracy is improved in a region where the furnace temperature (T) is low, that is, the amount of wear is small. For this reason, unlike the conventional life prediction method, it is not necessary to consider the safety factor and shorten the use period from the predicted life, and it is possible to extend the use period of the alternative refractory. In addition, it is possible to use a low-cost irregular refractory instead of a high-cost fired brick by improving the predicted life accuracy, and a cost reduction effect can be expected.
<Example 3>
Next, the results of Example 3 will be described.

In the third embodiment, when three or more test areas can be set, the life prediction is performed with higher accuracy on the assumption that the relationship of the expression (2) is established between adjacent test areas. .
Specifically, in Example 3, Zone C is set in the test area 10, Zone A is set in the test area 10 ′, and Zone E is set in the test area 10 ″. The wear rate ratio (F2 ′ / F1 ′) and the wear rate ratio between Zones C to E (F2 ″ / F1 ″) were determined.

  That is, when the test areas are installed at three locations, Zone A, C, and E, the coefficients A and B applied to Zones C to E are as shown in Table 7.

  Note that the values shown in Table 4 described above can be applied as they are to the coefficients A and B applied to Zones A to C. The values calculated using the coefficients shown in Tables 4 and 7 and the average furnace temperature (T) of each Zone correspond to the wear rate ratio (F2 / F1) shown in Table 8.

  By substituting the wear rate ratio (F2 / F1) shown in Table 8 and the predicted life (L1) of the existing refractory 9a in Zone A to Zone E into Equation (1), an alternative refractory 9b as shown in Table 9 The predicted life (L2) can be obtained.

In Example 3, compared with Example 2 in which the test area is two places, Zone E is added to the test area 10 ″, so that the accuracy of the predicted life of Zone D to E is improved.
As described above, according to the present invention, when replacing the existing refractory 9a lined on the inner wall surface 4 of the furnace body 1 with the alternative refractory 9b, the alternative refractory 9b has been selected so far in selecting the alternative refractory 9b. It is possible to determine whether or not the lifetime is equivalent to that of the existing refractory 9a, that is, to accurately and easily obtain the predicted lifetime (L2) of the alternative refractory 9b in the actual machine.

The present invention can be applied not only to selection of the alternative refractory 9b in the existing furnace body 1, but also to selection of the alternative refractory 9b in the newly installed furnace body.
By the way, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points.
For example, in this embodiment, the alternative refractory 9b provided on the inner wall surface 4 of the furnace body 1 may be one type or two or more types.

  In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

1 Furnace (U-shaped furnace)
2 Curved part 3 Furnace wall 3a Side wall part 3b Ceiling part 4 Inner wall surface 5 Furnace 6 Mounting platform 7 Wheel 8 Rail 9 Refractory 9a Existing refractory (first refractory)
9b Alternative refractory (second refractory)
10 Test area W Target material (slab)

Claims (7)

A method for predicting the life of a refractory lined on the inner wall of a furnace body,
The inner wall surface of the furnace body is provided with a first refractory and a second refractory provided in place of a part of the first refractory,
In the furnace body in which the first refractory and the second refractory are mixed, actual operation is performed,
After actual operation, the wear rate (F1) of the first refractory and the wear rate (F2) of the second refractory are measured,
Using the measured wear rate (F1) of the first refractory, the measured wear rate (F2) of the second refractory, and the known predicted life (L1) of the first refractory Then, the predicted life (L2) of the second refractory is obtained by the equation (1).
A test area is provided on the inner wall surface of the furnace body,
The refractory life prediction method according to claim 1, wherein the second refractory is disposed adjacent to the first refractory in the test region.   When the furnace body is a moving hearth furnace, at least two or more test regions are provided on the inner wall surface of the furnace body, and the lifetime prediction method for a refractory according to claim 1 or 2.   Among the at least two test regions, one test region is installed in a region where the furnace temperature is highest, and the other test region is installed in a region where the furnace temperature is lowest. The method for predicting the life of a refractory according to claim 3. From the wear rate ratio (F2 / F1) obtained in each of the at least two test areas and the furnace temperature (T) in each test area, Seeking
Using the wear rate ratio (F2 / F1) obtained from the temperature function of the obtained wear rate ratio and the predicted life (L1) of the first refractory, the second refractory is obtained from the equation (1). 5. The method for predicting the life of a refractory according to claim 3, wherein the life expectancy of (L2) is obtained.
Conducting a preliminary test to measure the wear rate (F2) of the second refractory,
In the preliminary test, when the wear rate (F2) of the second refractory is equal to or lower than a predetermined rate, the second refractory life prediction method according to claim 1 or 2, A method for predicting the life of a refractory, characterized by obtaining a predicted life (L2) of the refractory. The first refractory is an existing refractory conventionally employed in a furnace body,
The refractory life prediction method according to any one of claims 1 to 6, wherein the second refractory is an alternative refractory employed in place of the existing refractory.