JPH0126749Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention is aimed at improving the pig iron receiving port of a pig iron mixer car used for transporting and storing hot metal when charging hot metal from a blast furnace into a steelmaking furnace. This relates to the middle frame for construction.

[Prior Art] As is well known, a pig iron mixer has a tiltable cylindrical furnace body, and an pigtail receiving port is provided in the upper part of the cylindrical furnace body. Then, by tilting the furnace body, the molten pig iron stored inside is discharged by pouring it out from this pigtail receiving port.

FIG. 2 is a schematic diagram of this pigtail receiving port viewed from above.
is enclosed, and a refractory 3 is provided on the inner circumferential surface of this iron shell 2, thereby forming a pigtail receiving port 4.

Conventionally, the pigtail receiving port of a pig iron mixer car has been constructed using irregularly shaped bricks, but integral construction using castables is also being carried out for the purpose of shortening construction time, reducing refractory costs, and reducing construction costs.

[Problems to be solved by the invention] However, when the castable was used as a single-piece construction for the mixed pig iron car receiving hole, cracks occurred on the long axis side of the ellipse, and during use, the cracks expanded deep and wide (so-called groove-like welding). There is a disadvantage that the life of the pigtail hole is determined even though there is sufficient remaining thickness in other parts (due to loss).

That is, as shown in FIG.
has an elliptical shape with its long axis in the width direction of the pig iron mixer car 1, and when the pig iron receiving port 4 is integrally constructed with castable as a refractory, the inner surface (operating surface) of the pig iron receiving port 4 is free from hot metal. It is repeatedly subjected to radiant heat and atmospheric cooling after hot metal discharge. Therefore, expansion stress and contraction stress are repeatedly applied to the castable, and cracks 5 occur on the operating surface of the castable. In particular, as shown in FIG. 2, the cracks 5 are largely generated in a portion (hereinafter sometimes referred to as the discharge side) in the long axis direction of the ellipse of the pigtail hole. Therefore, while the pig iron mixer 1 was tilted and the slag and hot metal were discharged repeatedly, the third
As shown in the figure, a crack 5 that has occurred in the pigtail hole 4 becomes a groove-shaped erosion 6 and expands, eventually forcing the hole to be repaired.

[Means for Solving the Problems] The present applicant has proposed a receiving device in which a slit for forming a crack starting point is provided at a specific part of the inner circumferential surface of the castable refractory in a pigtail receiving port in which a castable refractory is installed. A method for constructing a pigtail hole has been proposed in Japanese Patent Application No. 61-25928 (hereinafter referred to as the "prior application").

That is, the slit is provided between the short axis and the long axis of the ellipse on the inner circumferential surface of the castable refractory and is not in contact with the melt wash when the pig iron mixer is tilted, and cracks are generated from the pre-provided slit. By doing so, the thermal stress load on other locations is reduced and cracks are prevented from occurring at other locations.

The present invention provides an inner frame used in the construction method of the previous application, and uses punched metal or a belt-shaped plate material made by pasting a sheet-like material on one side of punched metal to form the slits. It is attached to a predetermined location on the outer peripheral surface of the core.

[Function] The function achieved by such a configuration will be described below with reference to the process that led to the invention of the present invention.

The inventor of the present invention proposed the following as a measure to prevent cracks occurring on the long axis side (discharge side) of the elliptical shape of the castable construction body of the pigtail car receiving pigtail hole. ), we attempted a countermeasure in which two precast blocks 7 were arranged symmetrically at the receiving port in the direction of the minor axis of the ellipse, and castable was poured into the back and discharge side of the blocks.

According to this measure, cracks that would have occurred on the discharge side when integral construction was carried out are resolved by cracks occurring at the boundary 8 between the precast block 7 and the poured castable 3, thereby preventing the occurrence of cracks on the discharge side. The effect was recognized.

However, as the precast block 7 becomes thinner due to erosion, as shown in FIG. It was also recognized that there was a problem in which the pigtail hole had to be repaired even though it had some life expectancy. (The code 9 is the fallen part,
10 indicates the remaining portion. ) Also, as a method of forming such a crack initiation part,
As shown in Figures 7 and 8, two castable
An attempt was made to construct the project in stages. That is, as shown in Fig. 7, first, the space into which the castable is poured is divided into a discharge side part and other parts by a partition plate 11, and one of the parts (the discharge side part in Fig. 7) is first divided into a first part. After performing the first application and allowing it to harden, a second application is performed on the other side.

In this method, the pouring layer 14 between the first construction body 12 and the second construction body 13 acts like a joint and becomes the site where cracks occur, so cracks occur on the discharge side of the pigtail hole. It has the effect of suppressing this.

However, since the construction will be carried out in two parts,
It usually takes two days to construct just the pigtail hole, which poses a problem of poor work efficiency. Also, middle frame 15 and iron skin 2
The lower part of the partition plate 11 that is set between the two parts is in contact with the pig iron car ceiling brick 16 (see FIG. 6), which results in a complicated shape and is difficult to fix.There are also problems in that construction errors are likely to occur.

Therefore, the present inventor believes that in order to prevent the occurrence of cracks on the discharge side of the pigtail receiving port of the pig iron mixer car, it would be extremely effective to create cracks in a predetermined area other than the discharge side of the pigtail receiving port. The effect was investigated using a 1/8 model of the pigtail hole. In this method, a slit forming plate 17 is installed in a truncated ellipsoidal inner frame as shown in FIGS. 9 and 10 (a cross-sectional view of FIG. The occurrence of cracks was investigated for samples constructed without using the slit forming plate 17. Specifically, after heating the inner surface of a sample of the same shape to 1500℃ for 15 minutes,
We investigated the occurrence of cracks in the castable after repeating the heating/cooling cycle of 10 minutes of air cooling.

As a result, in the case of the sample constructed integrally without using the slit forming plate, the inner ellipse long axis surface (discharge side)
A crack of 0.5 mm occurred on both sides, whereas in the sample in which the slit forming plate was set, a crack occurred in the part of the slit forming plate, and a crack of 0.5 mm or less occurred on the long axis side of the inner ellipse. The occurrence of micro-cracks is limited to
It was found that creating slits at the pigtail receiving port of a pig iron mixer car is effective in suppressing cracks on the discharge side.

As is clear from the above findings, by forming slits at specific locations on the inner circumferential surface of the castable refractory of the pigtail car receiving hole, it is possible to prevent the occurrence of cracks and band-like melting damage on the discharge side of the pigtail receiving hole.

Therefore, the inner frame provided by the present invention employs a sheet-like material affixed to one surface of punched metal as a band-like plate material for forming the slits.

When such a punching metal is employed, the volume of the void formed by thermal melting of the punching metal becomes smaller. (In other words, since the punched holes are filled with castable refractories, the volume of the cavity created by melting and flowing out of the punched metal is smaller than in the case without punched holes.) Therefore, the molten pig iron and slag in the slit are The intrusion of
The life of castable refractories is extended.

Furthermore, since there is little intrusion of hot metal or slag, there is no risk of erosion of the castable refractory even if the slits are formed deep. Therefore, by forming deep slits, it becomes possible to grow cracks in a direction perpendicular to the inner circumferential surface of the refractory.
(Incidentally, if the slit is shallow, cracks will easily grow in the direction parallel to the inner peripheral surface of the castable refractory.
Such cracks in the direction parallel to the inner circumferential surface tend to cause peeling of the castable refractory. In contrast, in the present invention, the slits are formed deeply to allow the cracks to grow in the vertical direction, thereby reliably avoiding such peeling of the castable refractory. ) Furthermore, the punching metal used in this invention has high strength and rigidity, and it is easy to attach the main body of the inner frame.

[Embodiment] Fig. 1a is a perspective view showing the structure of an inner frame according to an embodiment of the present invention, and Fig. 1b is a plan view thereof. Moreover, FIG. 11 is a front view of the punching metal 21.

Reference numeral 19 denotes the main body of the middle frame, which has an elliptical outer circumferential surface that follows the inner circumferential surface of the pigtail hole, and gradually expands downward. It is the shape. Therefore, a punching metal 21 is provided on the outer peripheral surface of this middle frame main body 19.
A strip-shaped plate material 20 with a sheet-like material pasted on one side of the
is installed.

The manner in which this strip-shaped plate material 20 is installed will be explained below.

(a) The installation position of the strip plate material 50 is preferably such that the opening angle α between the two plate materials 20 in FIG. 1b is 60° to 70°.

The reason why the angle α is set to 70° or less is as follows. In other words, in order to prevent the occurrence of cracks on the discharge side, it is more effective to set α at a position larger than 70 degrees, but when discharging slag and hot metal, if the slit position is close to the discharge side, slag and The maximum α was set at 70° because there is a high possibility that the part will come into contact with hot metal and suffer groove-like damage. On the other hand, if α is less than 60, the length of the castable operating surface on the discharge side becomes long, the effect of expansion and contraction due to repeated heating and cooling in the atmosphere becomes large, and the effect of suppressing cracks on the discharge side becomes small.

(b) It is preferable that the band-like plate material 20 forms an angle as close to perpendicular as possible to the tangential direction θ of the outer circumferential surface of the middle frame main body 19, for example, 90°±10°.

In most cases, the direction in which the crack grows from the tip of the slit is the direction in which the slit extends, but in reality, a slight angular deviation may occur. Therefore, if the attachment angle of the strip plate material is oblique, the direction of crack growth from the slit tip may be closer to the operating surface, which may cause peeling damage. there is a possibility. For these reasons, it is preferable that the belt-shaped plate material 20 has an angle as close to perpendicular as possible to the tangential direction θ of the outer circumferential surface.

(c) The punching metal preferably has a thickness of about 0.5 to 3 mm, particularly about 1 to 2 mm. If the punched metal is too thin, its strength and rigidity will be low, and there is a risk that it will deform when casting the castable refractory. In addition, if the punching metal is too thick, the strength and rigidity will be unnecessarily large, and the price will be high and it will be uneconomical, and the cavities that will be created when the punching metal receives heat and the hot metal flows away will become excessively large. Hot metal and slag can easily enter. Further, it is preferable that the punching metal has a uniform thickness.

In order to similarly reduce the size of the cavity, the punched metal preferably has a punched hole opening area of about 30 to 70%, particularly 40 to 60%, in terms of the opening ratio. (This aperture ratio is determined by the length and width of the punching metal being l and w, and the total area of the punch hole opening being S.
When S/(defined as the percentage of l x w multiplied by 100), suitable punching metals are those with diamond-shaped openings as shown in Figure 11. . However, of course, the shape of the punch hole is not limited to this, and both round holes and square holes can be used. (Figure 11b shows an example of the shape and dimensions of a rhombus, and the unit is mm.) (d) If the width w of the punching metal is too small, it will grow from the tip of the formed slit. Cracks may occur parallel to the operating surface, making it easy to cause peeling damage. Therefore, the width w of this punching metal is preferably 50 mm or more and up to 1/2 of the construction thickness width, especially 150 mm or more and up to 1/3 of the construction thickness width.

(e) A synthetic resin film or adhesive tape (for example, vinyl tape) having a thickness of 1 mm or less, especially about 0.05 to 0.5 mm, is suitable as the sheet material to be attached to the punched metal. This sheet-like material burns out when heated and acts to form slits in the castable refractory, but if it is too thick, the gaps between the slits formed will become large.
Hot metal and slag can easily enter.

(F) The method of attaching the punching metal to the inner frame body is not particularly limited, but it can be attached as shown in FIG. 12, for example.

In FIG. 12, an L-shaped angle 22 is fixed to the long side of the punching metal 21 by welding or the like, and one side of the L-shaped angle 22 is placed against the outer peripheral surface of the middle frame body 19. A nut 23 is fixed to one side of the angle 22 by welding.

On the other hand, a blank hole 25 is bored in the middle frame body 19, and a bolt 26 is inserted from the inside of the middle frame body 19 and screwed into a nut 23. A wing nut 27 is screwed into this bolt 26,
A washer 28 is interposed between the wing nut 27 and the inner peripheral surface of the middle frame body 19. Furthermore, bolt 2
A handle 29 is fixed to the head of 6.

In such a configuration, the bolt 26 is inserted into the blank hole 2.
5 into the nut 23, and then tightening the wing nut 27, the punching metal 21 is attached to the middle frame main body 19. In addition, when demolding the inner frame after castable refractory casting and hardening, the handle 29
The bolt 26 can be removed from the nut 23 by grasping and twisting it.

FIG. 13 is a plan view showing the configuration of a pigtail hole formed using such an inner frame, and FIG. 14 is a sectional view taken along line A-A in FIG. 13.

As shown in the figure, the pigtail receiving port 4 of the pig iron mixer car 1 has an iron skin 2
The castable refractory 3 is constructed by constructing a castable refractory on the inside thereof, and the inner circumferential surface of the castable refractory 3 is provided with slits 18 cut from the inner circumference at four locations. In addition,
This pigtail receiving port 4 has an elliptical shape.

A specific example will be explained below.

As shown in Fig. 1, 100w x 850l x 1.2t (unit: mm) is used as a plate material for forming slits in the middle frame body 19.
punched metal (as shown in Figure 11)
Four plates with vinyl tape of 0.3 mm thickness attached were set at an angle of α60° as shown in Figure 1. The punching metal was fixed in a direction perpendicular to the tangent to the curved surface of the inner frame as shown in FIG.

The inner frame with the plates attached was set in the receiving port of the pig iron mixer car, and the low cement castable was poured in using a rod-shaped vibrator. After the castable had hardened, the inner frame was removed while leaving the board inside the castable.

The pig iron mixer constructed in this way will not have a short service life due to groove erosion on the discharge side, unlike conventional castable integral construction, and will not have the lower part of the block falling off, as in the case of using a precast block. An excellent effect was obtained in extending the life of the pigtail car receiving port without causing any problems.

Conventionally, the throughput was 50,000 to 70,000 tons with integrated construction and 60,000 to 80,000 tons when using precast blocks, but in this example, 70,000 to 90,000 tons were obtained.
This is a 1.2 to 1.4 times longer lifespan than conventional products.

[Effects] As is clear from the above explanation, according to the middle frame of the present invention, slits are formed at specific locations of the castable refractory on the inner circumferential surface of the pigtail hole, thereby preventing castable refractories on the discharge side of the pigtail hole. It is now possible to install castable refractories at the pigtail opening, which can reliably prevent cracks from forming in the refractories and suppress the groove-like erosion that grows from cracks, which has conventionally occurred.

Construction using such an inner frame eliminates erosion of the discharge gutter caused by integral processing, and provides a long service life.

The lining is integrated all the way to the back, so it won't fall off during use.

In order to reliably generate cracks at the slit positions, a double construction method using a partition plate is effective, but it requires two days of construction and is expensive, but with this invention it can be done in one day. Almost the same effect can be obtained.

Since the slit is formed from a plate material made by pasting a sheet-like material to punched metal, the slit is formed with a small cavity volume and little intrusion of hot metal or slag.

Deep slits can be formed, cracks can easily grow vertically on the inner peripheral surface of the castable refractory, and peeling of the castable refractory can also be prevented.

The plate material can be easily attached to the inner frame body, and has excellent workability during castable casting.

Excellent effects such as these can be achieved.

[Brief explanation of the drawing]

FIG. 1 shows an inner frame according to an embodiment, with figure a being a perspective view and figure b being a plan view. Figures 2 and 3 are plan views for explaining cracks or groove-like erosion, Figures 4, 7, 8 and 9 are plan views for explaining crack countermeasures, and Figures 5 and 6 are Figure and Figure 10 are the same sectional views,
FIG. 11 is a front view of the punched metal, FIG. 12 is a cross-sectional view of the punching metal attachment part, FIG. 13 is a plan view showing an example of construction, and FIG. 14 is a cross-sectional view of the same. 1...Pig mix car, 2...Steel skin, 4...Pigtail receiving port, 1
8...Slit, 19...Inner frame main body, 20...Band-like plate material, 21...Punching metal, 23...Bag nut.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) For the construction of castable refractories in the pig iron receiving port of a pig iron mixer car that has a substantially elliptical shape with its long axis in the width direction of the pig iron mixer car body and whose inner peripheral surface is coated with castable refractories. In the middle frame, a slit for forming a crack initiation point is provided inside the castable refractory at a part between the short axis and the long axis of the ellipse on the inner circumferential surface of the castable refractory and not in contact with the hot metal discharged when the pig iron mixer is tilted. An inner frame in which a strip-shaped plate for forming the slit is protruded from the inner frame main body in order to be cut into a shape from the peripheral surface, and the strip-shaped plate is made of punching metal;
Alternatively, an inner frame for construction of a mixed pig iron car receiving pigtail hole, which is made by pasting a sheet-like material on one side of punched metal. (2) The thickness of the punched metal is 0.5 to 3 mm.
The middle frame according to claim 1 of the utility model registration claim, wherein the frame has a width of 50 mm or more and an aperture ratio of 30 to 70%. (3) The inner frame according to claim 1 or 2 of the utility model registration claim, wherein the sheet-like material is a synthetic resin film or an adhesive tape, and the thickness thereof is 1 mm or less.