JPS59156970A - Refractory brick - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metallurgical refractory brick having excellent mechanical shock and thermal shock resistance. In particular, it relates to a refractory brick suitable for parts that require mechanical shock and thermal shock resistance, such as large ladle bed bricks, converter charging side bricks, converter bottom bricks, and kundish hot water contact parts.

Taking a ladle, especially a large ladle, as an example, the part that touches the hot water is more likely to be damaged than before, and it needs to be repaired more frequently than other parts, which is a major hindrance to reducing unit costs and improving operational efficiency. It became. The forms of damage to the hot water contact area that govern the life of the bed are mainly peeling wear and joint wear due to mechanical shock, abrasion, and thermal shock during pouring of molten steel.

In recent years, attempts have been made to use large block bricks to prevent joint damage in the hot water contact area, but this has been difficult to achieve due to problems such as cracking, chipping, and shrinkage due to thermal shock and mechanical shock of 2 m. The benefits have not yet been realized.

In addition, the application of carbon-containing bricks, especially MgO-C bricks, to the hot water contact area has been attempted with relatively small capacity ladles such as electric furnace ladle and LP ladle, and good results have been obtained. Many problems remain in terms of mechanical impact and abrasion resistance for the hot-water contact part of a large ladle into which a large amount of molten steel is poured from a high place.

The present invention improves the drawbacks of bricks commonly used in such places, and is a base material of carbon-containing bricks that has high thermal conductivity, excellent heat spalling resistance, and is resistant to corrosion by slag and I1'8 steel. The object of the present invention is to provide a refractory brick which has excellent heat resistance, spalling properties, and mechanical strength by arranging a long carbon fiber network having high tensile strength perpendicularly to the molding direction during molding.

The base materials used in the present invention include MgO and CaO.

AQ203+ Cr2O31S+02 + ZrO2
+MgOAQ2031 It can be applied to any refractory such as AQ203-5i02 series, but in particular, adding AQ, Mg-based metal bi-metallic powder to carbon-containing refractories such as MgO-C-based large-sized refractories improves hot strength. Bricks with enhanced abrasion resistance are particularly preferred in terms of improving the resistance of bricks to mechanical and thermal shock.

The long carbon fiber network is preferably placed in the matrix by embedding it at an appropriate depth in a direction perpendicular to the molding direction. In addition, when arranging two or more layers of carbon fiber networks, a cross-sectional plan view of the installation surface of the first layer (cut surface taken along line II in Figure 2)
As shown in Fig. 1, if the carbon fiber network (2) and the lower layer fiber network (2') (indicated by dotted lines) are arranged in a crosswise manner in the refractory base material (1), the durability can be further increased. I can do it.

Furthermore, when arranging multiple layers, the directions of the fibers are made to intersect one after another, and as shown in FIG. 2, which is a cross-sectional view taken along the line ■-■ in FIG. Net (2
) in the base material (11) is more effective in terms of reinforcement.

In addition, the carbon fibers used in the present invention include rayon-based, pi-
There are noti type, acrylonitrile type, lignin poval type, etc., but for the purpose, it is necessary to have a tensile strength of at least 50 kg/- or more.

When the fiber network is arranged in layers in a brick, it is desirable that the fiber network be maintained in such a state that when stress is applied from the outside, it can immediately be reinforced by the tension, that is, in a state without sagging.

To achieve this, it is necessary to take the following measures.

1) During molding, the fiber mesh is fixed to the metal frame and molded simultaneously with the base material under tension.

2) The fiber network is solidified with a resin in advance to give it sufficient strength and simultaneously molded.

The present invention will be explained below based on examples.

The first example examines the mechanical strength when a carbon fiber network is placed on an alumina-based refractory, and the second example is a molten steel ladle using bricks made by applying it to a magnesia-based refractory. This shows the case where it is used for the floor area.

(First Example) A refractory having the composition shown in Table 1 was sufficiently kneaded, and this was used as a base material to obtain a tensile strength of 60 kg/cJ and an average length of 50 I.
Two layers of fiber networks made of lllIl carbon fibers were arranged horizontally at equal intervals and pressurized in the vertical direction to form a 80 x 30
After drying, it was molded to a size of 1400 x 2011 m in a reducing atmosphere.
A sample was prepared by heating and firing at ℃. Each sample was directly subjected to a bending test at room temperature. After the same sample was fired, it was further heat-treated at 1500°C for 5 hours in an airflow, cooled to room temperature, and then subjected to a bending test. Table 1 shows the results.
0 Shown in the lower column.

Table 1 Blend ratio of various matrix parts and strength after heat treatment of laminate (Second Example) The blends shown in Table 2 were kneaded to prepare a refractory material to serve as a base material. A fiber network consisting of carbon fibers with a tensile strength of 6 layers kg/cnl and an average length of 50 mm was arranged horizontally in 3 layers, and the above refractory base material was filled into a forming frame, and then a pressure of 500 kg/c++1 was applied using a friction press. In addition, it is molded, dried and hardened to form a refractory base material fl as shown in the figure.
) in which carbon fiber networks (2) are arranged at equal intervals
A large brick of 500×23f) was obtained. When this brick was used for the hot water contact part of a 330-ton molten steel pot, the result was 60.
It can withstand multiple charges and has a durability that is more than 5 times longer than conventional raw stone bricks.

Table 2

[Brief explanation of drawings]

The attached drawings show one embodiment of the arrangement of the carbon fiber network based on the present invention. It is a cross-sectional view taken along the -■ line. (1): Refractory base material (2), (2'): Carbon fiber mesh (3): Cold end side Patent applicant Masu Tegori (Kurosaki Ceramics Co., Ltd. agent) (2 people)

Claims (1)

[Claims] 1. A refractory brick characterized by having one or more layers of fiber networks made of long carbon fibers embedded in a refractory matrix. 2. The refractory brick according to claim 1, wherein the refractory matrix is a carbon-containing refractory. 3. The refractory brick according to claim 2, characterized in that the refractory brick contains aluminum, magnesium, or an alloy powder thereof in a carbon-containing refractory matrix. 4. Carbon fiber weighs 50 kg/cn! The refractory brick according to claim 1, which has a tensile strength of at least 10%. The refractory brick according to claim 1, characterized in that a fiber network made of 5° long carbon fibers is arranged and buried in the forming direction. 6. In the case where two or more layers of fiber networks made of long carbon fibers are embedded, the fiber networks are arranged so that the fiber directions intersect with each other, as set forth in claim 1. Refractory brick.