JPS621678Y2 - - Google Patents

Description

[Detailed explanation of the idea]

INDUSTRIAL APPLICATION FIELD The present invention relates to carbon-containing basic bricks used as lining bricks for metal melting furnaces, scouring furnaces, molten metal containers, etc. Conventional technology and its problems Conventionally, the above-mentioned lining bricks have been made of carbon-containing bricks such as magnesia-carbon bricks and alumina-carbon bricks, which have excellent slag resistance and heat spalling resistance due to carbon. It was often used because of its unique properties. However, because of the carbon it contains, it is slippery and has poor wettability to slag, making it difficult for slag to adhere to it, preventing slag from penetrating, and causing it to fall off the lining surface when the furnace or containers are tilted or vibrated. Ta. As a countermeasure to this problem, it was proposed to coat the bricks with metal to improve the bond between the bricks. However, in this case, the metal melts first, causing the joints to open and molten steel to enter. Due to advanced melting or the difference in thermal expansion between the metal and the brick, the metal is pushed out, and by the time there is only a small amount left, the metal is already gone, or the metal is not sufficiently bonded to the brick. It was not possible to effectively prevent bricks from falling off. Attempts have also been made to form recesses or protrusions called dowels on the connecting surfaces of the bricks, and to make them fit together to prevent them from falling off. The effect could not be expected at all, and if one brick fell out, there was a risk that other bricks would fall out in a chain reaction, so in reality, a fully satisfactory effect could not be obtained. In view of the above-mentioned circumstances, an object of the present invention is to provide carbon-containing basic bricks that can strengthen the bond between the bricks and reliably prevent them from falling out. Means for Solving Problems In order to achieve the above object, the carbon-containing basic brick according to the present invention has at least two
A heat-weldable bonding layer mainly composed of one or more of magnesia, dolomite, magnesia-dolomite, spinel, and alumina is provided on the surface. The surfaces on which the bonding layer is provided are at least two of the four surfaces in the longitudinal direction. For example, in FIG. 1, bonding layers 2,
2 is provided. And these bonding layers 2, 2
comes into contact with the bonding layer of adjacent bricks on the left and right during furnace construction. Even if the bonding layer is provided on the entire surface of the two left and right sides 1a and 1b, as shown in FIG. It may be provided. In the latter case, there is no risk of the brick falling off even if the brick melts and the remaining length becomes about half of the length. In addition, the bonding layer is
Instead of the two left and right surfaces 1a and 1b, they may be provided on the other two surfaces 1c and 1d in the longitudinal direction, or may be provided on all three or four surfaces in the longitudinal direction. The thickness of the bonding layer is appropriately selected in the range of 3 to 50 mm, preferably 5 to 35 mm, depending on the shape, size, and material of the carbon-containing basic brick. If the thickness is less than 3 mm, the bond between adjacent bricks will not be sufficient and there is a risk of them falling off.
If it exceeds 50 mm, the excellent properties of carbon-containing basic bricks will not be utilized, and the joints will suffer preliminary melting loss, which is not preferable in either case. The material of the bonding layer is mainly composed of one or more of magnesia, dolomite, magnesia-dolomite, spinel, and alumina, with magnesia and dolomite being particularly preferred. These materials are selected from among substances that exhibit welding properties by heat and slag penetration, taking care not to cause the bonding layer to be excessively melted and lose the excellent properties of carbon-containing basic bricks. The selection was made taking into account the material of the bricks and the position in which they would be placed in the furnace. In addition, carbon may be contained in the bonding layer at 3% by weight or less to suppress advance melting loss of the same layer, and low-melting components such as slag may be included in the bonding layer to increase the thermal weldability of the same layer. You can do it like this. The bonding layer is formed by a conventional method.
For example, there is a method in which a potting soil for carbon-containing basic bricks and a potting clay for a bonding layer are separately prepared, and then a carbon-containing basic brick having a bonding layer is integrally molded from these, or a method in which carbon-containing basic bricks are first made from prepared potting clay. A common method is to mold the bricks and then decarburize the required surfaces to form a bonding layer. Functions and Effects of the Invention As described above, the carbon-containing basic brick according to the invention has heat-weldable properties mainly containing one or more of magnesia, dolomite, magnesia dolomite, spinel, and alumina on the required surface. When the same brick is used for lining, the excellent properties of the carbon-containing basic brick can be maintained and the bond between the bricks can be strengthened. Therefore, falling of the bricks from the lining surface can be reliably prevented. The reason for this is that slag adheres to the bonding layer due to the furnace heat during operation and penetrates into the layer, bonding the bonding layers of adjacent bricks to each other and bonding adjacent bricks to each other. it is conceivable that. Moreover, since the surface of the bonding layer has low slipperiness, there is no risk of the bricks slipping or falling during furnace construction, and therefore the furnace construction work can be done safely and easily. Embodiment Next, an embodiment of the present invention will be described based on FIG. Note that all percentages in the examples are percentages by weight. A magnesia-carbon brick potting soil consisting of 80% magnesia clinker and 20% natural graphite, and a magnesia-only potting clay for the bonding layer were prepared respectively, and from these, as shown in Figure 1, the left and right two Surfaces 1a and 1b have bonding layers 2 and 2 with a thickness of 5 mm.
Magnesia-carbon bricks, that is, carbon-containing basic bricks 1 measuring 360 x 160 to 180 x 150 mm were made by integral molding. Bricks with bonding layer thicknesses of 10 mm and 30 mm were also made from the same material as above. In addition, three types of magnesia-carbon bricks having bonding layers of different thicknesses were created in the same manner as above using dolomite instead of magnesia. The materials and thicknesses of these bricks and the bonding layer are summarized in Table 1. Bond strength test Cylindrical bodies were constructed from each of the above bricks, and heated with a burner while rotating at a speed of 2 times/minute. Put slag inside and melt it,
After maintaining the temperature at 1700° C. for 1 hour, the furnace was tilted to discharge the slag, and then the slag was introduced again. After repeating this operation five times, the length of the welded portion of the bonding layers between adjacent bricks was measured. In order to investigate the improvement in bonding strength due to slag adhesion, the welded portion was cut out and its room temperature bending strength was measured. In addition,
For comparison, a magnesia-carbon brick without a bonding layer was also tested in the same manner as above. The test results are summarized in Table 1.

[Table] As is clear from Table 1 above, in magnesia carbon bricks with a bonding layer, the bonding layers between adjacent bricks are welded to each other and the bricks are firmly bonded, and the bonding layer has a large bending strength. This makes the joint of the bricks even stronger and reliably prevents the bricks from falling off.

[Brief explanation of the drawing]

1 and 2 are perspective views of bricks showing an embodiment of the present invention. 1... Carbon-containing basic brick, 1a, 1b
...2 left and right sides, 1c, 1d...2 upper and lower sides, 2, 3
...Joining layer.

Claims (1)

[Scope of utility model registration request] A carbon-containing basic brick, which is provided on at least two sides in the longitudinal direction with a heat-weldable bonding layer mainly composed of one or more of magnesia, dolomite, magnesia-dolomite, spinel, and alumina.