JP6645444B2 - Slag pot - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a slag pot for receiving, transporting, and discharging molten slag generated in an iron making process.

Molten slag generated in an iron making process such as a blast furnace, a converter, and an electric furnace is discharged to a transport container called a slag pot, and is transported to the slag processing plant by the slag pot. Then, the slag in the pot is discharged by tilting the slag pot around the tilt axis in the slag processing plant. In the slag pot, no refractory is laid to make it easy to peel off the slag at the time of discharging, and the slag is directly loaded on the cast iron slag pot.
Here, the shape of the upper end opening of the slag pot (hereinafter, also simply referred to as the opening shape) is usually an elliptical shape, a perfect circle shape, a rectangular shape, or the like.

In the case of a slag pot having an elliptical opening (see Patent Document 2), a tilt axis is generally set in the major axis direction of the ellipse. Then, the pot that has received the molten slag is tilted around a tilt axis at a predetermined location where the slag processing is performed, so that the molten slag in the pan is discharged from a discharging position having a large radius of curvature. The slag pot is repeatedly used in the operation of receiving and discharging such molten slag.
Deformation and cracks occurring in the slag pan have become a problem due to the deterioration over time due to the repetition of the waste and the waste. Above all, deformation and cracking due to thermal stress, which occurs because only the area in contact with the slag is partially hot, rather than cracking due to thermal fatigue caused by repeated heating and cooling of the pot steel skin, is a serious problem. The deformation and cracks caused by this thermal stress limit the life of the pot. Therefore, it is urgently necessary to suppress the deformation of the pot due to the thermal deformation and to extend the life.

Patent Literature 1 arranges a reinforcing rib inside a pot, arranges the reinforcing rib so as to bridge between opposing wall surfaces, and optimizes the thickness and height of the pot body and the reinforcing rib, It has been proposed to suppress the deformation and cracking of the pot. In addition, the slag pot of patent document 1 differs from the opening shape which this application targets, and an opening shape is a rectangular pot.
Further, in Patent Literature 2, a heat insulating layer utilizing high heat insulating property of the slag is formed in the pot by attaching the received slag to the inner surface of the container. Thereby, it has been proposed to suppress the temperature change to be small and to prevent thermal deformation and cracking of the pan.
Patent Literature 3 discloses a slag cooling container manufactured by welding a steel plate used in an electric furnace or the like. In Patent Document 3, by disposing a reinforcing material having a larger linear expansion coefficient than the base material of the pot at a position where the slag cooling container is easily deformed, a force acts in a direction to offset the deformation of the base material, thereby suppressing the deformation. It has been proposed.

JP 2001-49311 A JP-A-2003-294376 (see FIG. 4) JP 2005-156005 A

However, in the slag pot described in Patent Literature 1, since the reinforcing ribs are arranged inside the pot, there is a problem that it is difficult to find a crack generated from the reinforcing ribs as a starting point during operation. There is also a problem that the unevenness inside the pot deteriorates the slag removability.
In the slag pot described in Patent Literature 2, the slag needs to be constantly attached to the inner surface, and thus there is a problem that the loadable capacity of the slag is reduced. Generally, once a slag layer is formed in a pot, the affinity of the slag is good, so the slag layer in the pot continues to increase by repeating slag reception and drainage. Therefore, when using the slag pot described in Patent Literature 2, it is necessary to set the number of continuous slag receptions smaller than usual.

Since the slag cooling container described in Patent Document 3 is formed by welding a plurality of thick steel plates, stress concentrates on the welded portion, and cracks cannot be avoided. On the other hand, a slag pot is usually a pot that is integrally molded from a casting, and it is very difficult to form a structure in which materials having different linear expansion coefficients are combined.
The present invention has been made by paying attention to the above points, and aims to extend the life of a slag pot by improving pot rigidity against thermal stress at the time of discharging while securing a slag loading capacity. .

  In order to solve the problem, a slag pot according to one aspect of the present invention is a slag pot that discharges molten slag from a preset discharge position in a pan upper end opening, and a slag pan around the pan upper end opening. In the slag pan having at least the above-mentioned waste position and the left and right portions continuous to the waste position among the contour shapes along the direction, in the arc-shaped slag pot, the lower part of the left and right portions continuous to the above-mentioned waste position and the waste position And one or more oblique ribs extending in an oblique direction closer to the center in the circumferential direction of the drainage position as going upward.

According to one aspect of the present invention, the oblique rib improves rigidity in a main stress direction with respect to thermal stress generated in the pan at the time of slag discharge. For this reason, the stress generated at the time of waste can be reduced, and thermal deformation can be suppressed. In addition, the rib constitutes the overhang portion, but since the oblique rib as a reinforcing member having the above-mentioned action is provided on the outer wall surface side of the pot, the removability of the slag is further reduced without reducing the loading capacity. In addition, it is possible to improve the suppression of deformation at the time of the above-mentioned waste.
As a result, according to one aspect of the present invention, thermal deformation of the pan over time can be suppressed, and the life of the slag pan can be extended.

  Here, in the case of a pot in which the contour shape (opening shape) of the upper end opening is a continuous arc shape, such as an elliptical shape or a perfect circular shape, in order to increase the rigidity of the pot, In some cases, a plurality of vertical ribs extending in the vertical direction or horizontal ribs extending in the circumferential direction are provided on the outer wall surface. However, although effective in preventing the pan from deforming outward, the inventors have found that the thermal stress due to the waste may cause the vicinity of the waste position to be deformed inward with time. .

It is a figure explaining the example of a slag pan, (a) is a top view, (b) is a side view, (c) shows the AA sectional view of (b). It is a side view explaining reinforcement of a slag pot concerning an embodiment based on the present invention. It is a perspective view which shows the example of arrangement | positioning of an oblique rib. It is a figure showing the example of thermal deformation. It is a top view explaining thermal deformation by thermal analysis at the time of the start of waste. It is a side view which shows the range which a slag contacts, (a) shows the case at the time of conveyance, (b) shows the case immediately after the discharge start. It is a figure which shows the main stress direction with the arrow to the thermal stress produced by the temperature distribution of a slag pan. It is a figure showing a measurement position of a main stress. It is the figure which evaluated the main stress which occurs in a slag pan.

Next, an embodiment based on the present invention will be described with reference to the drawings.
In the following description, a case of a slag pot having an oval opening will be described as an example.
However, a slag pot whose opening shape is a perfect circle may be used, or a slag pot in which only a portion of the opening shape that tends to the upper end on the waste side is partially arc-shaped. However, the present invention is applicable. That is, the slag pot targeted by the present invention is a slag pot in which at least a drain position and a left and right portion continuous to the drain position in the contour shape along the circumferential direction of the pan upper end opening are arc-shaped. is there. That is, a slag pot in which the shape of the opening along the circumferential direction in the vicinity of the position of the end of the opening where the slag is drained and the vicinity thereof is a circular or elliptical part. The length of the left and right portions is, for example, 2 m.

(Constitution)
As shown in FIG. 1A, a slag pot 1 according to the present embodiment has an elliptical opening. Further, in plan view, an axis P of tilting is set in the major axis direction LL of the opening-shaped ellipse, and the slag pan 1 has a pair of tilting shaft sections 2 projecting in the major axis direction LL.
Further, in the slag pot 1 of the present embodiment, as shown in FIG. 1, an outward flange 3 is formed at the entire opening of the upper end of the pot in the circumferential direction. Further, a lateral rib 4 extending in the circumferential direction (lateral direction) is formed on the outer wall surface of the upper part of the pot so as to project outward. The height of the horizontal ribs 4 is set, for example, to be a height near the average height of the slag contained in the pot or less than the average height of the slag. The slag is received, for example, so as to be about 80% of the pot volume.

Further, a plurality of vertical ribs 5 are provided on the upper outer wall surface at predetermined intervals along the circumferential direction so as to connect the outward flange 3 and the horizontal ribs 4. Vertical ribs 6 extending vertically are also provided at predetermined intervals along the circumferential direction on the outer wall surface below the horizontal ribs 4.
Here, in FIG. 1, a position indicated by a reference sign H is a waste starting position when the slag is discharged. When the pan is slowly tilted around the tilting axis P, the slag flows out from a predetermined circumferential range of the upper end opening, with the position of the minor diameter direction LS of the ellipse as the central position in the circumferential direction of the waste (start position H of the waste). . The position through which the flowing slag passes is the waste position in the waste.

Here, the position of the inner wall surface of the upper part of the pot through which the slag passes (contacts) at the start of the waste is a triangular range in which the width decreases as approaching the upper end of the opening as shown in FIG. In the present embodiment, the triangular area where the slag comes into contact at the time of the waste is referred to as a slag passage area E at the time of the waste.
In the present embodiment, the oblique rib 10 extending obliquely with respect to the upper portion of the outer wall surface located below the portion of the opening located on the waste side of the pair of tilt axes P at the opening end. Is provided. The upper end of the outer wall surface where the oblique rib 10 is provided may have a lower end position higher or lower than the molten metal surface. However, the upper side of the oblique rib 10 is set to a position higher than the molten metal surface.

The oblique rib 10 extends obliquely toward the center in the circumferential direction of the discharging position (starting position H of the discharging position) from the lower side to the upper side, and the axis is horizontal with respect to the horizontal direction in a side view. It is inclined by a predetermined inclination angle θ.
The predetermined inclination angle θ is, for example, 45 degrees with respect to the horizontal direction. By finite element analysis, due to the thermal stress at the time of waste, when discharging slag, the predetermined inclination angle θ to the same inclination as the main stress direction of the thermal stress generated on the outer wall near the position of the waste in the upper part of the pot It is preferable to set. As a result of analysis by the inventors, it was confirmed that the main stress direction of the thermal stress was generated so as to extend in the direction of 45 degrees or an angle in the vicinity of the position near the discharge position in the upper part of the pot. The predetermined inclination angle θ is set, for example, in a range from 30 degrees to 60 degrees.

In the present embodiment, the oblique rib 10 is formed at a position between the outward flange 3 and the lateral rib 4. At this time, the oblique rib 10 is preferably provided so as to be bridged between the outward flange 3 and the lateral rib 4. Here, when the vertical ribs 5 exist in the middle of providing the oblique ribs 10, they are provided so as to connect the outward flange 3 and the horizontal ribs 4 via the vertical ribs 5 as shown in FIG. 3. FIG. 3 illustrates a case where a reinforcing member is separately arranged so as to connect the horizontal ribs 4 and the vertical ribs 6 therebelow.
The area where the oblique rib 10 is provided is set closer to the discharge position than the tilt axis P of the pot when viewed from above. However, it is preferable that the oblique rib 10 is set so that the lower position is located on the outer side in the circumferential direction (closer to the tilt axis P) than the slag passage area at the time of starting the waste. Further, it is preferable that the oblique ribs 10 are provided so as to be symmetrically arranged with respect to a vertical line passing through the tailing start position H, that is, to form a pair.

  Here, the oblique rib formation region where the oblique rib 10 is provided is, for example, 7% or more and 49% of the circumferential length of the opening centered on the circumferential center position (the waste start position H) of the waste position in top view. The range is as follows. The oblique rib formation region is, for example, a range from the upper end of the opening to the vicinity of the standard molten metal level of the slag to be slag in a side view. The vicinity of the height means including a difference in height of, for example, about 1 m.

(Operation and others)
Molten slag generated in an iron making process such as a blast furnace, a converter, and an electric furnace is received in the slag pan 1. The slag pan 1 having received the slag is transported to a slag processing plant by a transport vehicle such as a slag dump truck. In the slag processing plant, the molten slag is discharged from the waste disposal position, starting from the waste disposal start position H where the slag pan 1 tilts around the tilt axis P. The temperature of the molten slag is, for example, 700 ° C.
As described above, the slag pan 1 repeats receiving, transporting, and discharging. Due to the repeated thermal deformation, as shown in FIG. 4, the upper part of the pot in the direction of the waste is deformed inward.

When the thermal stress analysis at the time of waste was performed, the slag passage area E at the time of the waste through which the slag in the upper part of the pot passes expands, and the outward flange 3 at that position is deformed in the direction in which it rises, as shown in FIG. In addition, by deforming so that the outside of the slag passage area E at the time of slag overhangs outward, thermal deformation such that the vicinity of the slag passage area E at the time of slag becomes convex inside the pot in plan view. An analysis result was obtained that the occurrence of. FIG. 5 shows the deformation amount by 200 times.
On the other hand, in the present embodiment, this deformation is restrained by the oblique ribs 10 to prevent the waste position from being thermally deformed inward.

Here, as shown in FIG. 6, the slag receives and transports about 80% of the pot capacity and carries out the slag, so that the range that comes into contact with the slag at each time is the range indicated by the broken line in FIG. 6. . FIG. 6A shows a state at the time of transportation, and FIG. 6B shows a state at the time of starting waste.
Further, when the temperature of the pot is measured by the thermo camera during the transportation of the slag and immediately after the start of the waste discharge, the temperature distribution of the pan heated by the heat from the slag can be obtained.
By applying the temperature distribution obtained by the above measurement to the finite element analysis model that reproduces the pan shape and conducting thermal stress analysis, the thermal stress distribution generated in the pan during the waste disposal operation and the deformation shape of the pan are estimated You can do it. In FIG. 7, the direction of the main component of the thermal stress obtained by analyzing the state immediately after the start of the waste is indicated by a thick arrow. In the present embodiment, the oblique rib 10 is arranged in the same direction as the direction of the symbol S in FIG.

  Then, thermal stress analysis was performed on the slag pan 1 of the comparative example without the oblique rib 10 and the slag pan of the embodiment with the oblique rib 10 (see FIG. 2), and three points A, B, and B shown in FIG. The principal stress generated at each point of C was determined and evaluated. FIG. 9 shows the evaluation results. Here, the yield point of the material (SCW450) of the slag pot 1 was set to 255 MPa. The predetermined inclination angle θ was set to 45 degrees at a position outside the slug passage area at the time of waste disposal in the circumferential direction. One oblique rib 10 was provided at each position symmetrical with respect to a vertical line passing through the tailing start position H in a side view.

As can be seen from FIG. 9, in the pan of the comparative example, the main stress above the yield point is generated in a wide range, whereas in the pan of the embodiment, the generated stress is reduced to below the yield point at all positions. You can see that is done. That is, it is understood that the deformation caused by the temperature distribution of the slag pot 1 can be reduced by the reinforcement with the oblique rib 10 in the main stress direction. In particular, since the main stress in the outer circumferential direction is significantly reduced, it can be seen that thermal deformation such that the left and right directions of the waste position project outward is suppressed.
In the above example, a pair of oblique ribs 10 is provided, but it is presumed that providing two or more pairs of oblique ribs 10 at symmetrical positions further suppresses thermal deformation. Here, it is preferable that the oblique ribs 10 are arranged in pairs with respect to a vertical line passing through the slag starting position H at a symmetrical position.

As described above, the slag pot 1 of the present embodiment can suppress deformation by improving rigidity against deformation generated by heat from slag. That is, since the rigidity was improved in the main stress direction of the thermal stress generated in the pot during operation, the generated stress could be reduced, and the deformation could be suppressed. Further, since the ribs protruding from the outer surface of the pot are used as the reinforcing members, the above-described deformation can be suppressed without reducing the loading capacity and further reducing the removability of the slag.
As a result, the thermal deformation of the pot over time can be suppressed, and the life of the slag pot 1 can be extended.

In addition, even if the shape, loading capacity, and temperature distribution of the pan are different, this method can design the optimal reinforcing member to suppress the deformation by giving the temperature distribution assuming the use environment of the pan. .
Here, it is preferable that the oblique rib 10 be provided so as to connect the outward flange 3 and the lateral rib 4. The rigidity of the pot is further improved by transmitting the axial force applied to the oblique rib 10 to the outward flange 3 and the lateral rib 4.
In addition, an oblique rib may be provided on the outer wall portion in the slag passage area E at the time of slag discharge.

  Also, when the radius of curvature along the circumferential direction of the opening at the tailing position is large, such as the shape along the opening on the side of the minor diameter direction LS of the ellipse, the above-described inward thermal deformation Is presumed to occur easily. However, even if the shape of the opening is elliptical, in the present embodiment, thermal deformation at the time of discharging the waste can be suppressed as compared with the related art.

DESCRIPTION OF SYMBOLS 1 Slag pot 2 Tilt shaft part 3 Outward flange 4 Horizontal rib 5 Vertical rib 10 Slant rib E Slag passage area H at the time of waste Drain start position P Tilt axis θ Predetermined inclination angle

Claims (6)

A slag pot for discharging slag in a molten state from a preset discharging position in a pan upper end opening, wherein at least the above-mentioned discharging position and the drainage are included in a contour shape along the circumferential direction of the pan upper end opening. In the slag pot where the shape of the left and right part continuous to the position is an arc shape,
The upper part of the upper wall of the pot located below the left and right portions that are continuous with the above-mentioned waste position and the diagonally extending upper part of the waste position is closer to the circumferential center of the waste position 1 or A slag pot comprising two or more oblique ribs. In a slag pot having an outward flange extending along the circumferential direction at the upper end opening of the pot and a lateral rib formed on the outer wall portion below the outward flange and extending in the circumferential direction,
The slag pot according to claim 1, wherein the oblique rib is formed at a position between the outward flange and the horizontal rib.   3. The slag pot according to claim 1, wherein the oblique rib is disposed closer to the waste position than a pair of tilt shaft positions provided on the pan when viewed from above. 4.   At least the lower position of the oblique rib is characterized in that, when the discharge of the slag from the pan is started, it is located on the outer side in the circumferential direction from the upper pot outer wall position corresponding to the upper pot inner wall surface through which the slag passes. A slag pot according to claim 3.   The contour shape along the circumferential direction of the upper end opening of the pot is an elliptical shape, and a tilt axis is set along a major axis of the elliptical shape. Or the slag pot described in item 1. Diagonal direction of extension of said first diagonal rib, when Haikasu slag, and sets the direction along the principal stress direction of the thermal stress generated in the outer wall portion of Haikasui location in pan upper The slag pot according to any one of claims 1 to 5.

Images