JPH044965A - Lining structure for molten metal vessel - Google Patents

Abstract

PURPOSE:To prevent the development of crack and spalling phenomena of an integral structural monolithic refractory caused by heat stress by constituting an upper end position in a vessel with the monolithic refractory added with the specific wt. ratio of foam skelton and having shrinkability. CONSTITUTION:At place corresponding to the upper end position 6, that is at the space between a monolithic refractory 5 for slag line and a top flange 8, at the time of executing the lining of monolithic refractory 5 for slag line, the monolithic refractory 16 added with 30-70 wt% the foam skelton to 100% of refractory mixed material and having shrinkability is caused to flow in and filling-worked to form the lining structure. In this result, the crack and spalling by integrating the monolithic refractory 16 with the molten metal vessel of ladle 1, etc., are prevented and durability of the vessel can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a lining structure for a molten metal container using a monolithic refractory having excellent shrinkability and excellent ability to absorb thermal stress.

(Prior Art) Traditionally, chamotte, waxite, and zircon materials have been used as refractories for lining molten metal containers, such as ladles.

Calcined refractories such as alumina, magnesia, and silicon carbide were mainly used, but in recent years, from the viewpoint of energy and labor saving, there has been a shift to monolithic refractories for the ladle base or inner circumference, and even removal The use of monolithic refractories for the entire surface of pots is being promoted, and monolithic refractories made of the above materials are being used.

The lining of the ladle with this monolithic refractory material was
A construction method that utilizes the action of a vibrator installed in a metal frame core, as in Publication No. 374 and Japanese Patent Publication No. 54-855. In addition, there are construction methods that utilize various vibrators, such as a construction method that utilizes the action of a rod-shaped vibrator in the filler that is supplied between the metal frame core and the permanent lining material, as disclosed in Japanese Patent Application Laid-Open No. 55-73460. It has been proposed and is lined with monolithic refractories in a continuous, uniform and dense manner.

(Problem to be solved by the invention) In recent years, with the development of steelmaking technology, the production of high-grade steel has increased through continuous casting, vacuum degassing, ladle refining, etc., and the operating conditions of the ladle have changed due to increases in molten steel temperature and residence time. The situation is likely to become even more severe in the future.

For this reason, monolithic monolithic refractories lined with uniform densities as mentioned above frequently crack and peel due to severe thermal stress, and the durability of the ladle is significantly reduced, and improvement is strongly desired. It was rare.

The present inventors have noticed that the expansion due to thermal stress caused by the monolithic structure of monolithic refractories has a limit as the size of the ladle increases, no matter how much the composition, particle size, etc. of the refractory itself is improved. The present invention has conducted various studies on lining structures capable of absorbing the expansion of the refractory material, with the aim of providing a lining structure for molten metal containers that effectively eliminates the conventional drawbacks.

(Means for Solving the Problems) The present invention provides a molten metal container lined with an amorphous refractory, in which the upper end portion of the container is mixed with a foamed aggregate of 30 to 70% by weight based on 100% by weight of the container. The lining structure of a molten metal container is characterized in that it is made of a monolithic refractory material having a shrinkability added in a weight percent.

The foamed aggregate used in the present invention is mainly made of one or more of magnesia, alumina, chamotte, Rouseki, zircon, etc. This raw material is kneaded with a binder added by a conventional method, and dried after granulation. Obtained by firing. The granules thus obtained have a large number of independent pores, a porosity of 10 to 40%, preferably 15 to 35%, and a crushing strength of 10 to 50 kg/cm, preferably 15 to 40 g.
/c+x'. Porosity and compressive strength are related in terms of compressibility, and porosity is less than 10% and compressive strength is 50 kg.
/cm', the shrinkability is impaired and the monolithic refractory integrally lined with the ladle will crack and peel, reducing the durability of the monolithic refractory lined.

If the porosity exceeds 40% and the crushing strength is less than 10%, when adding foamed aggregate to a refractory compound and kneading it, the aggregate may break or the monolithic refractory itself may become compressible. This would defeat the purpose of the invention.

The size of the foamed aggregate is not generally determined, but for example, in the case of a cylindrical shape, 3 to 15 a + mφ x 3 to 30 mrn, and for spherical, elliptical, square, etc., a size of about 3 to 20 mm is used. In consideration of fluidity, spherical or elliptical shapes are preferable. In addition to the above-mentioned foamed aggregates, for example, crushed particles of heat-insulating bricks, perlite, vermiculite, etc. can be used as long as the porosity and crushing strength are within the above-mentioned ranges.

The above foamed aggregate is 30% by weight of the fire-resistant compound.
It is used in a range of 70% by weight. Addition amount is 30% by weight
If it is less than 70, good shrinkability cannot be obtained for the monolithic refractory.
If it exceeds % by weight, fluidity will be insufficient and construction will become difficult.

The method of lining the ladle with monolithic refractories is carried out in the usual manner, and when lining the monolithic refractories for slab lines, the portion corresponding to the upper end, that is, the monolithic refractories for slug lines, is The lining structure of the present invention is obtained by pouring and filling a contractible monolithic refractory between the refractory and the canopy.

The lining height of the retractable monolithic refractory varies depending on the size of the ladle, but is preferably 10 to 500+n+n.

(Example) Examples will be described below based on the drawings.

Embodiment 1 As shown in FIG. 1, the bottom of the ladle 1 is lined with a bed 3 of bricks or monolithic refractories, and a core 2 is placed on top of the lining 3 of the ladle 1.
and set in concentric circles. A monolithic refractory for metal line 4 was poured between the permanent 7 provided on the inner circumferential surface of the iron shell 11 and the core 2. That is, 70% by weight of alumina and 30% by weight of spinel were mixed with cement as a binder, mixed with 5.5% of water in a mixer, poured on a belt conveyor, and degassed by inserting a rod-shaped vibrator.
The tissue was leveled and detailed filling was performed.

Next, alumina 7 was used as the monolithic refractory 5 for the slab line.
0% by weight, spinel 20% by weight, magnesia 10% by weight
Then, cement was used as a binder and poured in the same manner as for the metal line.

Furthermore, on top of that, magnesia foam aggregate (porosity 3
5%, crushing strength 15 kg/cm3) and 40% by weight was poured in the same manner as described above to construct the upper end portion 6 of the monolithic refractory 5 for the slag line and the canopy 8. did.

By the way, the height of the monolithic refractory 16 that has shrinkability is 15
It was 0 mm. Comparing the ladle of the present invention thus obtained and a ladle of conventional structure, the state of melting and damage after use is as shown in Fig. 3. Not only did it protrude greatly from the canopy as shown in (A) to (B).

In both the monolithic refractory 4 for metal lines and the monolithic refractory 5 for slag lines, many cracks 9 were observed, and peeling 10 was also observed in some parts, and the life of this ladle was 40 charges.

On the other hand, in the ladle using the foamed aggregate of the present invention, the second
As shown in Figures (A) to (B), the compressible monolithic refractories 16 were compressed by about 50%, but there were cracks 9 in the monolithic refractories 4.5 for metal lines and slag lines. The phenomenon of peeling 10 was not observed, the melting damage state was smooth, and the service life could be extended to 80 charges.

Example 2 As in Example 1, 100% by weight of alumina was applied to the upper end portion 6 of the ladle 1, which was lined with the same material as the bottom portion 3, the monolithic refractory 4 for metal lines, and the monolithic refractory 5 for slag lines. 60% by weight of 5-10m+* spherical alumina foam aggregate (porosity 27%, crushing strength 35kg/cm") in the fireproof compound.
Added monolithic refractory 16 with 200 mm
It was constructed at a height of

The condition of the ladle after use was good, and there was no major difference from Example 1, and the ladle could be operated up to 80 charges.

Example 3 Ladle 1 lined under the same conditions as Example 1 except for foamed aggregate
The upper end part 6 was made of a fireproof compound containing 100% magnesia and 10m+aφ
15% by weight of a monolithic refractory with 16%
It was constructed at a height of 0+am.

This ladle was in good condition after use and was able to withstand 120 charges.

Comparative Example 1 The upper end portion 6 of the ladle 1 lined under the same conditions as Example 3 except for the foamed aggregate was coated with a compound containing 100% magnesia by 7 mm.
φX 10o+m magnesia foam aggregate (porosity 30
%, and a compressive strength of 7 (1 kg/cm3) was added to 40% by weight of a monolithic refractory material 6, which was constructed at a height of 150 m+n.

The state of melt damage after using the above ladle is that both the monolithic refractory for metal line 4 and the monolithic refractory for slag line 5 are peeling 10.
Although there was no such phenomenon, cracks 9 appeared in some places.

The compressible monolithic refractory 6 was compressed to 135 mm, but only 40 charges were used.

Comparative Example 2 The upper end portion 6 of the ladle 1 lined under the same conditions as Example 3 except for the foamed aggregate was coated with 7 ni of a compound containing 100% by weight of magnesia.
mφ x 1011I11 magnesia foam aggregate (porosity 30, crushing strength 5kg/cn+3-) with 40% by weight of a compressible monolithic refractory 16 of 150I
It was constructed at a height of III11.

However, most of the magnesia foam aggregate was broken while the above monolithic refractory 16 was being kneaded with a mixer, so sufficient compressibility could not be obtained by operating the ladle 1, and the monolithic refractory for metal lines and slab lines Cracks 9 occurred in both 4.5 and 40 charges were used.

(Effects of the Invention) As is clear from the above embodiments, the present invention can be applied to a molten metal container such as a ladle by constructing the upper end portion of the ladle with a compressible monolithic refractory material to which foamed aggregate has been added. It was possible to prevent cracking and peeling due to the integration of the monolithic refractories, and the durability of the container could be improved by 20 to 50%, and its industrial effects were remarkable.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional explanatory diagram of a ladle showing an embodiment of the present invention;
Figure 2 (A) is a partially enlarged view of the lining after construction of the present invention;
Figure (B) is a partial enlarged view showing the damaged state after use, Figure 3 (A) is a partial enlarged view showing the conventional lining structure, and Figure 3 (B) is a partial enlarged view showing the damaged state after use.
) is a partially enlarged view showing the damaged state after use. 1... Ladle 2... Core 3... Ladle 4... Monolithic refractory for metal line 5... Monolithic refractory for slag line 6... Upper end portion 7... Perm 8...Canopy 9...Crack 10...Peeling
11... Iron shell 16... Monolithic refractory with shrinkage (A) (B)

Claims (3)

[Claims] (1) In a molten metal container lined with a monolithic refractory material, the upper end portion of the container has a shrinkable monolithic refractory material with foamed aggregate added in an amount of 30 to 70% by weight based on 100% by weight of the refractory compound. A lining structure for a molten metal container characterized by being made of a material. (2) The lining structure for a molten metal container according to claim 1, wherein the foamed aggregate is one or more of magnesia, alumina, chamotte, Rouseki, zircon, etc. (3) The crushing strength of the foamed aggregate is 10 to 50 kg/cm
^3. The lining structure for a molten metal container according to claim 1, having a porosity of 10 to 40%.