JPH11315320A - Monolithic refractory body for loading heavy material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monolithic refractory body capable of sufficiently preventing the collapse caused by the extension of crack even to loading impact when being heated together with a material to be heated such as a steel slab in a heating furnace and loading the heavy material such as the steel slab. SOLUTION: In the inner part of the refractory body 1 installed for loading the steel slab on a mobile carriage for taking in/out the steel slab to the furnace for heating the steel slab, metallic bars for metallic wires is having 0.5-5 mm diameter are disposed in length wise and breadthwise and enclosed. It is desirable that the metallic bars or metallic wires 2 are arranged at mutual interval of >=10 mm and the continued length of one piece of the metallic bar or metallic wire 2 is <=1 m.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory used in a heating furnace, a soaking furnace, or the like, in which a heated object is placed on a movable carriage for loading and unloading the object and heated in the furnace. It relates to a construction object.

[0002]

2. Description of the Related Art In the steel industry, in addition to a continuous heating furnace using a walking beam or a walking hearth as a furnace for heating a slab, the quality, shape, size, and lot size of a slab to be heated are large. Various types of heating furnaces are used accordingly. Many of them depend on a mobile trolley for loading and unloading billets.

In such a bogie, a refractory is used as a member on which a billet is placed. The refractory is drawn out of the furnace together with the bogie when the billet is placed, and after being placed on the billet, is heated together with the billet in the furnace. And when taking out a billet, it is pulled out of a furnace again. for that reason,
This refractory is subject to severe temperature fluctuations due to heating and cooling,
Crack damage due to thermal spall is apt to occur. In addition, when placing a billet, a crack is easily generated in the refractory due to a load impact applied to the refractory. These cracks gradually evolve during repeated use, eventually leading to refractory collapse. When the refractory collapses, it becomes impossible to load steel billets, so another truck is required while repairing the collapsed refractory truck, but in some cases the furnace must be stopped, This is an increase in cost burden or an obstacle to production.

Techniques for suppressing the refractory from collapsing due to crack propagation include JP-A-63-310773, JP-A-63-128151, and JP-A-63-128156.
There is a method of adding a metal fiber as disclosed in Japanese Patent Application Laid-Open No. H10-163, etc.

On the other hand, as for a reinforcing bar structure known as a technique for preventing cracks in concrete, JIS G 311
2 and JIS G 3191.

[0006]

However, the metal fiber added to the above-mentioned refractory of the prior art is effective in suppressing the growth of cracks due to thermal spall, but the fiber is not affected by physical external force such as load impact. It is easily pulled out and does not provide a sufficient effect.

[0007] Further, since the steel bar for concrete reinforcing bars has a diameter of at least 6 mm, even if this technology is applied to the above refractory construction body as it is, the amount of thermal expansion of the reinforcing bars during heating is large, and The refractory is cracked by the expansion difference between the object and the reinforcing bar, and the shape as the structure cannot be maintained. For this reason, it is impossible to put a billet.

Therefore, the present invention advantageously solves the above-mentioned problems, so that the object is heated together with an object to be heated such as a billet in a heating furnace, and is resistant to a load impact caused by the loading of a heavy object such as a billet. It can sufficiently prevent collapse due to crack propagation,
It is an object of the present invention to provide an amorphous refractory construction body for mounting a heavy load.

[0009]

The gist of the present invention for achieving the above object is as follows.

(1) A refractory construction body for mounting a bill on a movable trolley for loading and unloading the bill in a furnace for heating the bill, and having a diameter of 0.5 to 5 m inside.
An amorphous refractory construction body for mounting a heavy object, wherein m metal rods or metal wires are arranged vertically and horizontally and installed.

(2) The irregular shaped refractory for mounting a heavy object according to the above (1), wherein the metal rods or metal wires to be installed are arranged with a distance of 10 mm or more from each other. Construction body.

[0012] (3) The heavy metal mounting according to the above (1) or (2), wherein the length of one continuous metal rod or metal wire to be installed is within 1 m. Irregular refractory construction body.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A metal rod or a metal wire provided in a refractory construction body according to the present invention becomes a hindrance to cracks caused by thermal spalls generated in the refractory due to severe temperature fluctuations caused by heating and cooling. Progress can be prevented. In addition, even when a load is applied to the refractory when the steel slab is placed, the load impact can be dispersed and absorbed by the metal rod or the metal wire structure to prevent the refractory from collapsing.

As the material of the metal rod or the metal wire, if the temperature in the heating furnace is lower than 600 ° C., mild steel equivalent to that shown in JIS G 3112 can be used. On the other hand, when the temperature in the heating furnace is 600 ° C. or more, it is desirable to use stainless steel or heat-resistant steel.

When the diameter of the metal rod or the metal wire exceeds 5 mm, the refractory construction is cracked by thermal expansion due to heating as described above. On the other hand, if the diameter is less than 0.5 mm, the steel slab or the like cannot withstand the load and breaks.

In the case where the metal rods or metal wires to be provided in the refractory are installed in parallel in the length direction, the metal bars or the metal wires are installed at a distance of 10 mm or more from each other. The length of one continuous metal rod or metal wire shall be within 1 m, and in the construction requiring a longer length, a plurality of metal rods or metal wires may be mutually expanded by the amount of expansion in the longitudinal direction. Arrange them side by side so that they do not push each other. Further, the metal rods or metal wires to be installed can be combined in a wire mesh shape in advance. Also in this case, the interval between the parallel metal wires is 10 mm or more.

[0017]

The present invention will be described more specifically with reference to the following examples.

FIGS. 1 to 4 show an embodiment of the present invention, and FIGS.
Shows a comparative example. Table 1 shows the results of a thermal spall test and a load impact test using a falling weight for each of the examples and comparative examples.

[0019]

[Table 1]

The heat spall test was performed at 230 × 110 × 65.
Each of the construction bodies having a size of mm was heated to 1200 ° C. at a heating rate of 50 ° C./hr in advance, fired at 1200 ° C. for 2 hours, and then heated in an electric furnace maintained at 1300 ° C. for 30 minutes,
The test cycle of cooling at room temperature for 30 minutes was repeated up to a maximum of 20 cycles, and the number of cycles at which the construction collapsed was recorded.

The load impact test was conducted at 1200 ° C.
After firing, place a 20 kg weight on the sample at a height of 1.5 kg.
m and dropped vertically to record the appearance of the construction.

In Example A, as shown in FIG. 1, a metal wire 2 having a diameter of 3 mm was placed inside a refractory construction body 1 at a position of about 15 mm from the construction body surface at intervals of about 20 mm along the construction body side surface. Place at a height of about 10 mm below the upper end of the construction body,
Furthermore, the upper end of the metal wire was connected with the same metal wire in the short side direction of the construction body.

In the embodiment B, as shown in FIG. 2, a 10-mm wire mesh 3 made of a metal wire having a diameter of 1 mm is provided inside a refractory construction 1 so as to be parallel to the long side direction of the construction.
It was arranged vertically at 0 mm.

In the embodiment C, as shown in FIG.
The same wire mesh 3 as above was horizontally arranged at intervals of 20 mm from a position 10 mm below the upper end of the construction body.

In Example D, as shown in FIG. 4, a box was formed using the same wire mesh 3 as in Examples B and C so as to be positioned 15 mm inward from the side surface of the construction and 10 mm inward from the upper end.

In all of these examples, in the thermal spall test, although the surface was cracked, the construction body did not collapse after 20 repetitions of heating and cooling. In the load impact test, in Examples B and C, a part of the refractory on the short side surface on which the wire mesh was not arranged was peeled off, but almost the original shape was maintained.

In Comparative Example E, as shown in FIG. 5, there is only the refractory material 1 without any reinforcement. In Comparative Example E, as shown in Table 1, in the heat spall test, the construction body collapsed by repeating heating and cooling five times. Moreover, in the load impact test, it collapsed completely with a falling weight from 1.5 m.

Comparative Example F, as shown in FIG. 6, is a construction body to which 3% by mass of stainless steel (SUS) fiber 4 was added, and did not collapse in the heat spall test as in Examples A to D. However, in the load impact test, about half of the construction body volume was chipped off.

In Comparative Example G, as shown in FIG. 7, a round bar 5 having the same diameter of 9 mm as the reinforcing steel used for reinforcing concrete was used.
Were arranged at intervals of 30 mm, and a large crack was generated in the execution body due to expansion of the round steel 5 at 1200 ° C. firing. In the heat spall test, the refractory peeled off for the first time.

This test confirmed that the refractory construction of the present invention had very effective resistance to thermal spall and load impact.

[0031]

According to the present invention, the repair life of a refractory for a mobile trolley which loads and takes out an object to be heated in a heating furnace can be greatly extended, and the repair cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an irregular-shaped refractory construction body of Example A which is one embodiment of the present invention.

FIG. 2 is a perspective view schematically showing an irregular-shaped refractory construction body of Example B which is one embodiment of the present invention.

FIG. 3 is a perspective view schematically showing an irregular-shaped refractory construction body of Example C which is one embodiment of the present invention.

FIG. 4 is a perspective view schematically showing an irregular-shaped refractory construction body of Example D which is one embodiment of the present invention.

FIG. 5 is a perspective view schematically showing an amorphous refractory construction body of a comparative example in which no reinforcement is performed.

FIG. 6 is a perspective view schematically showing an amorphous refractory construction body of a comparative example to which 3% by mass of SUS fiber is added.

FIG. 7 is a perspective view schematically showing an amorphous refractory construction body of a comparative example reinforced with a reinforcing steel structure of concrete.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refractory construction body 2 Metal wire 3 Wire mesh 4 SUS fiber 5 Round steel

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Matsuda 5-3 Tokaicho, Tokai City Nippon Steel Corporation Nagoya Works

Claims (3)

[Claims] 1. A refractory construction body for mounting a bill on a movable trolley for loading and unloading the bill in a furnace for heating the bill, wherein the refractory construction body has a metal having a diameter of 0.5 to 5 mm inside. An amorphous refractory construction body for mounting a heavy object, wherein a rod or a metal wire is arranged vertically and horizontally and installed inside. 2. The irregular-shaped refractory construction body for mounting a heavy object according to claim 1, wherein the metal bars or the metal wires to be installed are arranged at a distance of 10 mm or more from each other. . 3. The irregular shape for mounting a heavy object according to claim 1, wherein a length of one continuous metal rod or metal wire to be installed is within 1 m. Refractory construction body.