JPS6053274B2 - Method for constructing hearth bricks and construction jig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and a jig for constructing hearth bricks, and particularly to a method and a jig suitable for constructing a hearth bottom of a bottom-replaceable type bottom blowing or top-bottom blowing converter. It's about the ingredients.

Refractories in steelmaking containers that involve intense stirring of molten steel are now subject to severe wear and tear that was previously unseen.

The main cause of this is abrasion of the moving surface of the bricks due to the flow of molten steel. In particular, brick joints have a weaker structure than bricks, so they are more susceptible to wear and tear, and there is a problem in that joint construction conditions, such as joint thickness and variations in joint thickness, directly affect the lifespan of refractories. Ta.

On the other hand, in the case of refractory linings for containers that directly contact and process molten steel, such as steel manufacturing containers, it is necessary to uniformly disperse residual thermal expansion and contraction caused by the thermal expansion of bricks during operation and changes in the brick structure. Preventing the brick structure from loosening or opening the joints by absorbing it will prevent local melting of the bricks,
This is an important issue in preventing steel leakage. For example, magnesia carbon bricks, which have recently been widely used as bricks for converters, generally exhibit a residual linear expansion of about 2% at most.

(An example of the residual linear expansion rate of magnesia carbon bricks is shown in Table 1.) Therefore, during construction, the joint thickness should be relatively large to absorb the thermal expansion and residual expansion of the bricks during operation. is taken.

However, some magnesia-lime bricks exhibit residual shrinkage, and normal joint construction methods may cause the joints to open and the bricks to melt away, causing construction problems. I was getting used to it.

(An example of the residual linear shrinkage rate (negative value) of magnesia-lime bricks is shown in Table 2.) In order to solve this problem, it is necessary to make the joint thickness uniform and at the same time make the joint thickness as small as possible. It was necessary to prevent the brick joints from opening locally due to wear and tear on the joints.

On the other hand, if the shape of the bricks is enlarged to increase the working surface area of each brick, the number of joints can be reduced, but the thermal stress inside the bricks will increase and the thermal spalling tendency of the bricks will be promoted. However, this resulted in a decrease in durability.

Therefore, the brick shape should be divided into as small pieces as possible.
The aim was to make the joint thickness uniform and minimize it. Appropriate joint thickness was determined by repeating actual furnace tests.

In the case of the above-mentioned magnesia-lime bricks (Table 2), improvements were made to make the joint thickness as thin as possible.
．． We reached the 5T1m thick joint.

The durability of bricks improved as the joint thickness became thinner and the bricks were built tighter. In this case, an essential requirement in terms of construction technology was the development of a method of building the bricks in complete contact with each other.

When constructing the converter bottom bricks, in order to reduce damage caused by thermal spalling of the bricks, the joint thickness between each brick should be uniform, as shown in Figure 1. It is necessary that each brick is in surface contact with each other and arranged regularly.

In Fig. 1, 10 is a brick and 12 is a metal fitting for the brick.
<Firing conditions> 1.500°C x 5H (reducing atmosphere) Brick component MgO: 80%, carbon dioxide 20% <Firing conditions> 1
．． 750°C x 3H (Note) Negative values indicate shrinkage rate.

Ingredients: MgO: 77%, CaO: 20%, other 3%, that is, when variations in joint thickness or distortion in brick arrangement occur as shown in Figure 2, thermal spalling occurs because the bricks are heated from multiple surfaces on the operating surface. At the same time, the thermal expansion of the bricks causes them to compete with adjacent bricks at points or lines, further increasing the tendency of the bricks to thermally spall.

Conventionally, when building replaceable hearth bottoms for bottom-blown or top-bottom blowing converters, workers used a trowel to apply mortar on long hearth bottom bricks and stack them vertically. ing.

However, when constructed using such a conventional method, the joint allowance is not uniform, and the joint mortar sag, resulting in variations in joint thickness as shown in FIG. 2, and at the same time, the surfaces tend to be distorted in arrangement. Therefore, for the reasons mentioned above, there was a risk that the durability of the hearth bottom would be reduced. The object of the present invention is to solve the above-mentioned problems of the prior art, to provide a method for constructing furnace bottom bricks in which the bricks are correctly arranged and in surface contact with each other, thermal spalling is reduced, and the lifespan is significantly extended; The object of the present invention is to provide a construction jig used for this purpose.

In order to achieve this object, the method for constructing hearth bottom bricks according to the present invention is such that when rectangular bricks are laid and built on the hearth bottom, after aligning the bricks in at least one row through joint mortar, This row of bricks is pressed from all four sides perpendicular to each brick surface to align them, and then at least one row of bricks is aligned through joint mortar along the row of aligned bricks, and the aligned bricks are aligned. The process of aligning the rows of bricks and the rows of bricks aligned along these rows by pressing them from all sides perpendicular to each brick surface is repeated.

Further, the construction jig according to the present invention includes a pair of parallel pressing plates that are held between a U-shaped frame and a pressing means that urges these pressing plates in the approaching direction. It is what it is.

The present invention will be explained in more detail below with reference to embodiments shown in the drawings.

FIG. 3 is a side view illustrating the method of the present invention, and FIG. 4 is a sectional view taken along the line ■-■ in FIG.

14 is the bottom surface of the converter, and 16 is its side wall.

A brick receiving hardware 20 is arranged on the bottom surface 14, and bricks 10 are arranged in one row on this brick receiving hardware 20. Joint mortar is applied to each brick 10 with a trowel or the like and is interposed between each brick 10, but is not shown. The aligned bricks 10 are pressed and aligned by a construction jig 22 and a jack device 24 from all sides perpendicular to the brick surfaces.

The construction jig 22 includes a U-shaped frame 26, a pair of pressing plates 28, 28 sandwiched between the frame 26 and placed parallel to each other, a screw hole 30 drilled in the frame 26, and a screw hole 30 drilled in the frame 26. A means for biasing the pressing plate 28 in the approach direction is comprised of a screw 32 screwed into the screw hole 30 and a rotating handle 34 fixed to the end of the screw 32. That is, when the handle 34 is rotated, the screw 32 can urge the press plate 28 in the tightening direction since it is engaged with the screw hole 30. Further, by rotating the handle 34 in the opposite direction, the pressing plate 28 can be retreated to the standby position before being tightened. In addition to the screw type, a jack type or the like may be used as the means for biasing the pressing plate 28 in the approach direction. The jack device 24 includes a jack body 36, a jack rod 38, and a pair of pressing plates 40 attached to the tip of the jack rod 38.

The jack rod 38 is a connected type jack rod in which a plurality of short small jack rods are connected, and as the construction progresses in the width direction of the bricks, these small jack rods are removed one by one and the length of the jack rod 38 is gradually shortened. It is configured to do this. An example of the construction method is as follows.

Bricks 10 are arranged on a brick receiving hardware 12 using a trowel or the like while applying joint mortar, and are sequentially tightened from four directions using a construction jig 12 and a jack device 24. Due to this tightening, the joint mortar oozes out from between the bricks, but at least about 0.5W1R remains.
Next, the handle 34 is rotated to retract the pressing plate 28 to the standby position, and the jack body 36 is actuated to retract the jack rod 38. Then, at least one row of bricks is aligned along the row of aligned bricks with joint mortar, and the row of aligned bricks and the row of bricks aligned along this are placed in a construction jig. 22 and jack device 24 from all sides to align them. By repeating this process, the bricks are laid regularly. FIG. 5 shows a state in which a row A of bricks is first tightened and aligned, and then a row B of bricks is aligned and then pressed from four directions to align them.

42 in the figure is a tuyere hole. Note that the upper surface of the frame 26 is not shown in FIG. In the above explanation, the row of bricks is 1
Although they are aligned and pressed in rows, they may be tightened after arranging, for example, 3 or 4 rows.

If a fast-curing adhesive that cures at room temperature is used at the joints between the bricks, the bricks will adhere to each other and become integrated, allowing the construction of the bricks to proceed one after another.

In addition, since the brick receiving hardware 20 is circular, the jig 22
For this, prepare 2 to 4 types with different frame lengths,
As construction progresses and the rows of bricks become shorter, bricks with shorter frame lengths will be used.

By using the construction method of the present invention, the joint mortar becomes uniform and distortions in the arrangement of the bricks are also eliminated. Damage due to thermal spalling of the bricks is thereby reduced. As detailed above, the method for constructing hearth bricks of the present invention involves arranging the bricks and then tightening them from four directions. Polling is reduced and lifespan is significantly extended.

Moreover, according to the construction jig of the present invention, this construction method can be carried out quickly.

The construction jig of the present invention can also be applied to work in which precast monolithic refractories or bricks are made into blocks in advance, such as the construction of ladle beds, molten metal container lids, etc. using this jig. You can also do that.

[Brief explanation of drawings]

Figures 1 and 2 are side views explaining the arrangement of bricks, Figure 3 is a side view explaining the method of the present invention, and Figure 4 is a side view explaining the method of the present invention.
The figure is a cross-sectional view taken along line 3--2 in FIG. 3, and FIG. 5 is a plan view illustrating the method of the present invention. 10... Brick, 12, 20... Brick receiving hardware, 22... Construction jig, 24...
・Jack device, 26... U-shaped frame body, 28・
...Press plate, 30...Screw hole, 32...
・Screw, 34...Handle, 40...
Pressure plate.

Claims (1)

[Claims] 1. When constructing a furnace by laying rectangular bricks on the bottom of the furnace, after aligning the bricks in at least one row with joint mortar, the rows of bricks are arranged in four directions perpendicular to the faces of each brick. After that, at least one row of bricks is aligned through joint mortar along the row of aligned bricks, and the row of aligned bricks and the bricks aligned along this are aligned. 1. A method for constructing hearth bricks, characterized in that the process of aligning rows of bricks by pressing them from all sides perpendicular to each brick surface is repeated. 2. A jig for constructing hearth bricks, which comprises a pair of pressing plates placed in parallel and held in a U-shaped frame, and a pressing means for urging these pressing plates in the approaching direction.