UA75633C2 - Process for repairing refractory plate - Google Patents

Abstract

The invention relates to a process for repairing refractory plate (1), having a pouring hole (3), circumscribed by a circle C of center (4), at least a portion of the edges (15, 16, 17, 18) of the plate (1) are angularly oriented so as to focus the clamping forces optimally in the throttling area and around the pouring hole.

Description

Description of the invention

This invention relates generally to a method of repairing worn gate plates used in 2 gate valves to control the flow of molten metal, and in particular relates to a gate plate resistant to cracking caused by thermomechanical stress.

Gate valves are commonly used to control the flow of molten metal in steelmaking and other metallurgical processes. Such valves usually consist of a support frame, an upper fixed gate plate, which has an opening in the gate with a pouring device or a cup of a steel pouring ladle for passing the flow of molten metal 70, and a throttle valve, which also has an opening for passing metal, which is sliding movable under the stationary slide plate. In gate valves used in conjunction with continuous casting machine crystallizers, the lower fixed gate plate is mounted below the movable throttle valve, which also has a metal flow opening which generally aligns with the opening of the upper fixed gate plate. The power of the flow of molten metal depends 12 on the degree of alignment of the opening of the sliding movable throttle valve with the opening of the upper fixed plate.

A movable choke is usually longer than a fixed choke, so that it has the ability to throttle the flow of molten metal at the front and rear edges of its orifice, and the ability to completely shut off the flow by fully shifting its orifice out of alignment with the orifices of the fixed plate. Usually, the throttle is moved by sliding between fixed plates using a hydraulic lever mechanism.

The throttle valve and the fixed plate are mounted in a respective lower recess and upper recess and each is recessed in a surface which becomes its support surface and interacts with the other plate/damper through a surface which becomes its sliding or working surface.

Both the throttle valve and the fixed plates of such gate valves are made of heat-resistant and c 29 erosion-resistant refractory materials, such as alumina, carbon-treated alumina, zirconium dioxide (Ge). However, despite the heat resistance and erosion resistance of such refractories, the serious thermomechanical loads to which they are subjected eventually cause the formation of certain cracks. For example, in steelmaking, each slide gate plate is exposed to temperatures of approximately 1600 9C in the area immediately surrounding its opening, which passes the flow of metal, while its outer edges are exposed Shk only to the ambient temperature. The resulting large temperature gradient creates a large thermomechanical stress because the area of each plate that immediately surrounds the hole expands to a much greater extent than the rest of the plate. These loads cause the formation of cracks that diverge outward from the plate opening. If nothing is done to control the expansion of these cracks, they can reach the outer edges of the plate, causing it to fail.

In order to prevent the expansion of such cracks and further destruction of the shutter plates, various solutions have been developed in the known state of the art. The first attempt was the development of improved clamping devices. The purpose of these devices is to apply sufficient pressure around the perimeter of the plate so that cracks radiating from the hole do not extend to the edges of the plate. One such device consists of a frame having screw-adjustable wedges that engage the corners of a plate cut at an angle that is complementary to the angle of the wedges. Such a system is described in |document OE-С2-3,522,134)|. Although such a frame and c wedge clamping device is an advance, the inventors noted some shortcomings in this design that "prevent it from achieving its full crack retarding potential. Generally, clamping forces are not concentrated uniformly at the point where the maximum number of cracks appears, i.e., near the opening, where the greatest thermomechanical stresses are present. Furthermore, the applicants observed that the usual angular orientation of the 75 cut corners in such plates does not optimally prevent crack propagation, as previously thought. This suboptimality results from the fact that the crack formation is not uniformly distributed at 3602 around the hole, and 1 is instead displaced along the longitudinal axis of all the damper plates, both fixed and movable. b" Such an asymmetric distribution of cracks around the plate holes is believed to occur as a result of the longitudinal sliding movement of the throttle valve on the surfaces of the fixed plates (95) 20 (OBR Patent 5,626,164) describes the resistance to the formation of wood remove the gate plate; the shape of the specified plate c" was designed to prevent the formation and expansion of cracks in it. This plate has an axis and an opening for the passage of molten metal located on said axis, and cut angles to concentrate the clamping force to said axis near said opening, and each of said cut angles is orthogonal to a line passing between a point of contact with said hole , through the specified axis and through the 59 intersection of lines parallel to the converging edges of the plate, which are distant from the specified edges by a distance,

GF) which is equal to half the width of the specified hole. 7 In document M/O-A1-98/05451) a variant of this solution is described, in which the angles between the side faces of the plate are defined in order to increase the durability of the plate.

Although the solution (OBR patent 5,626,164) is already an obvious progress compared to the previously known solution, because the applicants tried to further optimize the shape of the plate.

Obviously, what is needed is a gate plate whose shape optimally concentrates the clamping force in the most crack-prone areas of the plate in order to maximally slow down the elongation of any such cracks. Ideally, the corners should be long enough to avoid unwanted local mechanical loads on the corners. b5: no

International patent application MU0O01/41958)| describes a crack-resistant gate plate used in a gate valve which eliminates or at least reduces all the disadvantages associated with the prior art, or at least has the same characteristics as the plate described in (OBR patent 5,626,1641.

Thus, this document relates to a refractory plate for a gate valve, which can be defined as an elongated rectangle K, which has two sides parallel to the direction of its elongation.

Rectangle K has a longitudinal axis, defined as its longest axis of symmetry, which coincides with the predominant sliding trajectory of the plate. However, it must be clearly understood that this notion of a preferred sliding trajectory is an intrinsic characteristic of the plate herein, and that the plate may slide in the gate valve in a direction that is not optimal or preferred. The plate has an opening (drain hole) for the passage of 7/0 molten metal. Most often, the specified hole is round, more precisely, it is outlined by a circle C with a diameter Ф.

For the purpose of construction, the rectangle K is divided into four quadrants by two perpendicular lines that intersect at the center of the circle C, and one of these lines passes in the middle between the parallel sides of the rectangle K. Each quadrant has intersecting diagonals: diagonals 01, 03, 05, 07, which with connect the center of the circle C with the corners of the rectangle K, and the diagonals 02, 04, 06 and 08, which connect the adjacent intersections of the perpendicular lines, 7/5 intersecting in the center of the circle C, with the sides of the rectangle Kk.

The drain hole can be located in the center of the plate, but most often it is offset along the longitudinal axis so that throttling can be carried out on a larger area. The drain hole can also be slightly offset along the axis perpendicular to the longitudinal axis.

The plate has angled edges (shown as the truncated corners of the K rectangle) to concentrate the 2o Clamping Force to the area near the orifice and to the choke area to prevent the formation and propagation of cracks therein.

According to (application МУО01/41956) at least part of the edges is determined as follows: - the edges furthest from the drain hole (therefore, closest to the throttling zone) deviate by a maximum of 52 from the directions of the diagonals that do not cross the corresponding corner, and сч - the edges closest to of the drain hole (therefore, the furthest from the throttling zone) deviate by a maximum of 52 from one of the following directions: o (I) - the direction perpendicular to the diagonal crossing the corresponding corner; (I) - the direction of another corresponding quadrant; (I) - a direction intermediate between directions (1) and (1). co

Applicants have indeed found that this shape of the plate optimally concentrates the clamping forces on two different areas of the plate. On the one hand, the throttling zone is kept in compression, thus preventing the occurrence of cracks in this area Shk, and on the other hand, the perimeter of the drain hole is also kept in compression, Ge) thus preventing the expansion of cracks that diverge from the drain hole.

Applicants have observed that the new plate design has extraordinary advantages. First, there are much fewer cracks. Second, even if they still appear, the cracks do not extend to the edges of the h-plate, so air penetration is noticeably reduced. | thirdly, when the plate of this European application is used in conjunction with a suitable clamping device, cracks, if any, are formed only in the permissible zone. That is, they are not formed in the throttling zone and are also not formed "directly in the zone between the drain hole and the nearest edges.

An additional advantage of this plate is that since very few cracks were observed, plate - c can be easily and quickly repaired after use. That is why the present invention relates to the method of repairing used plates, described in the application MUMO01/41956). "» The plate can be symmetrical about its longitudinal axis, but in the preferred embodiment, the plate is asymmetrical about the longitudinal axis.

Due to this asymmetry, the plate can be installed in only one position in the upper recess -I and in one position in the lower recess, so that the bearing surface of the plate becomes its sliding or working surface when the plate moves from one position to another in the event that the desired repeat about the use of plates.

Ge) A plate can only have the four edges defined above, but to avoid sharp corners, it can have more edges. In such a case, the additional edges may (or may not) be parallel and/or perpendicular to the longitudinal axis. c» It is necessary to understand that the plate does not necessarily have to be polygonal. Conversely, if a clamping band is used around the plate, such a clamping band may apply local mechanical stresses (which may cause cracks) to the vertex defined by the adjacent edges. Therefore, it is beneficial for the corner to be rounded.

In a preferred embodiment, only parts of the edges meet the above definition. It is preferable that the rest of the edges consist of curves connecting the specified parts of the edges, and most preferably of the transition radius of the specified edges.

It is also to be understood that within the scope of this invention, "plate" also means an assembly plate (whether fixed or removable), such as an outlet monoblock plate, an internal outlet monoblock plate, a tube board monoblock plate, etc.

Thus, the present invention relates to a method of repairing a worn refractory plate for a gate valve, which may be defined by an elongated rectangle K, having two sides parallel to the direction of its elongation, and having a drain hole placed asymmetrically about the center midway between the 65 parallel sides of the rectangle K and circumscribed by the circle C, the rectangle K is divided into four quadrants by two perpendicular lines intersecting at the center of the circle C, one of these lines passing midway between the parallel sides of the rectangle K, each quadrant having intersecting diagonals: 01, 02 and 03, 04, and 05, Об, and 07, ОЮ8, respectively, where the corners of the rectangle K are cut off and replaced by inclined edges, and the direction of at least part of these edges, which are farthest from the drain hole, deviates by a maximum of 52

From the direction of the diagonal, which does not cross the corresponding angle; and - the direction of the edges, which are closest to the drain hole, deviates by a maximum of 5 2 from one of the following directions: (I) - the direction perpendicular to the diagonal crossing the corresponding corner; (I) - the direction of the other diagonal of the corresponding quadrant; (I) - a direction intermediate between directions (1) and (1).

Any suitable repair method may be used. It should be understood that these plates can be easily, quickly and effectively repaired precisely because of their exceptional resistance to cracking.

Usually, the repair method includes the stage of covering the cracks with a solution, in the optimal version - a solution capable of resisting the influence of molten steel, such as a phosphate solution, for example, KERKASOI 620 RI 45.

If necessary, it may be necessary to treat the surface of the plate before filling the cracks. For example, to remove the steel residue from the surface of the plate. Any conventional technique such as grinding, sandblasting, water jetting, etc. can be used.

After covering the cracks, the excess solution is removed and the plate is allowed to dry. Drying can be carried out at ambient temperature for at least 4 hours, in the optimal version - at least 8 hours, or in an oven, for example, at 1202C for 1 hour.

After that, the plate can be cured. This stage of hardening can be carried out at 350-4502C for one hour. In one embodiment, curing may also occur during use of the repaired plate when it is exposed to high operating temperatures. Gee!

In a separate version of the embodiment, the plate is preheated, for example, at a temperature of approximately (5) 80-1202C, so that the solution penetrates deep into the cracks and hardens quickly.

In another version of the embodiment, the solution includes a hardening accelerator, so that even at ambient temperature it hardens quickly.

If the drain hole is damaged, it can also be repaired. Of course in the drain hole. (9 insert a tubular object (such as a pipe, rod, or core) having a diameter substantially similar to the initial diameter of the drain hole. A solution (usually the same as the solution used for cracking) is applied around the tubular object, dried, and finally subject to hardening. (Se)

In one of the options, it is also possible to drill a hole (optimally coaxial with the original and drain hole, and which has a diameter in the optimal version at least 5095 larger than the initial diameter of the drain hole), place and fix the insert in the newly drilled hole with a solution. Inserts are ideally made from a material that is at least as durable as the original material of the plate. It may be convenient to equip the outer walls of the insert with protrusions or holes so that the solution and the insert penetrate each other. It is also possible to use a stepped insert in the form of two (or more) " superimposed coaxial pipes, which have the same internal diameter, but different external diameters.

Figures 1 and 2 are top views of the plates according to the invention. - c With reference to Fig. 1, in which the corresponding numbers indicate the corresponding details in the figures, this document c describes the gate plate 1, which is used in the gate valve to regulate the flow of molten steel » or other metal from the intermediate pouring device to the mold or from ladle to the intermediate filling device.

Plate 1 has a hole C for spilling a stream of molten metal. The indicated drain hole C is outlined by a circle C with a center 4. Figure 1 shows a plate with a non-circular drain hole, and Figure 2 shows a plate with a drain hole 3, which coincides with the circle C

Rectangle K is shown in Fig. 1 and 2. Rectangle K outlines plate 1 and its longer sides are parallel b" to the sliding trajectory of the plate in the slide latch. For the purpose of construction, it is necessary to draw two perpendicular lines 5 and b at 20, which intersect in the center 4 of circle C and are parallel to the short and long sides of the rectangle K. These lines define, thus, the four quadrants of the rectangle K. Each quadrant c" has intersecting diagonals: 01, 03, 05 and 07, which connect the center 4 of the circle C with the four corners (7, 8, 9, 10) of rectangle K, and 02, 04, 06 and 08, which connect the adjacent intersections (11, 12, 13, 14) of lines 5 and 6 with the sides of rectangle K. 22 Edges of the plate, specially designed to concentrate the clamping forces in the throttling zone, i.e. the edges 15 and

Gee! 16, which are farthest from drain hole C, and thus nearest to the throttling zone, have at least a portion (to which clamping forces will be applied) which is parallel to the diagonal 02 or 04 of the quadrant including said edge.

In Figures 1 and 2, at least part of the edge 15 is parallel to the diagonal 02 and at least part of the edge 16 60 is parallel to the diagonal 04. In Figure 1, the edges 15 and 16 are completely parallel to the diagonals 02 and 04, while in

Fig. 2 only part of the edges 15 and 16 is parallel to the diagonals 02 and 04.

The edges of the plate, which are specially designed to concentrate the clamping forces around the drain hole 3, that is, the edges 17 and 18, which are closest to the drain hole 3, can be placed perpendicular to the diagonals Ю5 or 007 of the quadrant that includes said edge, or, in other words, parallel to the directions 19 or 20, 65 defined as perpendicular to the diagonals О5 or 07. This embodiment is illustrated by the example of both edges 17 and 18 in Fig. 2, which are perpendicular to the diagonals О5 or 07, respectively.

Alternatively, these edges 17 and 18 can be placed parallel to the diagonals OB or 08 of the quadrant that includes them, as illustrated by the example of edges 17 and 18 in Fig. 1, which are parallel to the diagonals OB or 08.

Alternatively, the edges 17 and 18 can be directed in a direction that is between the two directions defined above.

The edges 15, 16, 17 and 18 may touch each other, thus defining a quadrilateral plate 1 defined by the connected diagonals 02, 04, OB and 08. Of course, to avoid mechanical stresses, it is desirable to avoid such sharp corners. Therefore, it is desirable that the edges 15, 16, 17 and 18 do not touch directly. They can be separated by straight lines, preferably parallel to the sides of the rectangle, as shown in Fig.1. 70 It is even more desirable that they be separated by transition curves.

In Fig. 2, edges 15 and 16 and edges 17 and 18 are connected by transition radii 21 and 22.

An important parameter is the orientation of the edges 15, 16, 17 and 18, which determines how they concentrate the clamping forces to avoid cracks. their position relative to the drain hole 3, ie the position of the edges 15, 16, 17 and 18 to the respective diagonals 01, 03, 05 and 07, is less important for these criteria. However, it is desirable that the edges 15, 7/5. 16, 17, and 18 were not too long to avoid mechanical stress due to sharp corners, and not too short to effectively concentrate clamping forces where needed.

Therefore, the edges closest to the throttling zone, i.e. edges 15 and 16 (or their projections), should preferentially cross the short side of the rectangle K in the region between 1/8 and 3/8 and between 5/8 and 7/8 of the length, respectively of the short side of the rectangle Kk.

This requirement is less important for the other side of the plate (that is, the side where the edges are closest to the drain hole), so that the edges 17 and 18 (or their projections) should preferably intersect the short side of the rectangle K in the region between 1/10 and 9 /10 the length of the short side of the rectangle K.

ID Document UUO01/41956) describes a method of determining whether a plate is designed according to its description or not. Huh oh

Claims (1)

The formula of the invention 1. The method of repairing a worn fire-resistant plate (1) for a gate valve, which includes the step of smearing cracks with a solution, which is characterized by the fact that the plate (1) is outlined by an elongated rectangle K, which has two sides parallel to the direction of its elongation, and has drain hole (3), placed asymmetrically with respect to the C center in the middle between the parallel sides of the rectangle K and outlined by a circle C with the center (4), so that the rectangle K is divided into four quadrants by two perpendicular lines (5, 6) that intersect in the center (4) circle C, one (b) of these lines (5, 6) passes in the middle between the parallel sides of the rectangle and) K, each quadrant has intersecting diagonals: 01, 02 and ОЗ, 04, and 05, Об, and 07, О8, respectively, where the corners (7-10) of the rectangle K are cut and replaced by inclined edges (15-18), and at least part of these edges (15, 16), which are the furthest from the drain hole (3), deviates by a maximum of 52 from the diagonal direction, which does not cross the corresponding angle, direction of the edges (17, 18), which are the closest to the drain hole (3), deviates by a maximum of 59 from one of the following directions: (i) - the direction perpendicular to the diagonal crossing " Corresponding angle; (her) - in the direction of the other diagonal of the corresponding quadrant; (ii) - the direction intermediate between the directions (i) and (ii). and 2. The method according to claim 1, which differs in that the solution is a phosphate solution. "" C. The method according to claim 1 or 2, which is characterized by the fact that it includes the steps of: a) drilling a hole that is essentially coaxial with the initial drain hole and has a diameter at least 5095 larger than the initial drain hole; b) placement of the insert in the drilled hole; c) overlaying the solution between the insert and the walls - and the drilled hole. 4. The method according to any one of claims 1-3, which is characterized by the fact that it includes the step of drying the plate smeared with an ini solution. Ge") 5. The method according to any of claims 1-3, which is characterized by the fact that it includes the step of hardening the plate smeared with a 5p solution. o 6. Repaired fire-resistant plate (1) for a gate valve, the cracks of which were smeared with mortar, GK) which differs in that the plate is outlined by an elongated rectangle K, which has two sides parallel to the direction of its elongation, and has a drain hole (3) , placed asymmetrically with respect to the center in the middle between the parallel sides of the rectangle K and outlined by a circle C with the center (4), the rectangle K is divided into four quadrants by two perpendicular lines (5, b), which intersect in the center (4) of the circle C, one (6) of these lines (5, 6) passes in the middle between the parallel sides of the rectangle K, each quadrant has Ф) intersecting diagonals: 01, 02 and 03, 04, and 05, Об, and 07, 08, respectively, where angles (7-10) the rectangle K is cut and replaced with inclined edges (15-18), and at least part of these edges (15, 16), which are the furthest from the drain hole (3), deviates by a maximum of 5 g from the direction of the diagonal, which does not cross the corresponding angle , the direction of the edges (17, 18), which are approx adjacent to the drain hole (3), deviates by a maximum of 52 from one of the following directions: (i) -- a line perpendicular to the diagonal crossing the corresponding corner; (ii) - in the direction of the other diagonal of the corresponding quadrant; (iii) - the direction intermediate between the directions (Iii) and (ii). b5