JPH08217551A - Basic amorphous refractory for induction furnace - Google Patents

Abstract

(57) [Abstract] [Purpose] It is intended to provide a refractory capable of attempting a long life by sufficiently effectively utilizing the refractory constructing the refractory wall. [Composition] In an lining refractory for an induction furnace for melting and refining a metal, a magnesia material is constituted by 50% to 90% by weight, and a chromium-containing refractory material is constituted by 10% to 50% by weight.
The total content of the seeds is 90% by weight or more. [Effects] Cracks and groove-like abnormal damage on the lining refractory have been greatly improved, the refractory can be used fully and stable, stable operation can be performed, and the lining refractory can be comprehensively operated. The amount of damage has also been greatly improved, and the effects on both service life and operation are enormous.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a basic amorphous refractory for an induction furnace used for lining an induction furnace used for melting metals.

[0002]

2. Description of the Related Art Melting of metals in the casting industry has high melting efficiency in terms of productivity, labor saving, quality of molten metal and working environment. Easy operation and easy labor saving. There are few pollution problems. A molten metal with high quality stability and high homogeneity can be easily obtained. Easy adjustment of composition and temperature. Induction furnaces, which have many advantages, are rapidly becoming widespread. At present, the crucible type induction furnace has an electric induction heating coil on the outer circumference, and if necessary, the inside of this coil is covered with coil cement for protection, and further a hot water sensor, an insulating material, a heat insulating material, etc. are arranged inside. A fire-resistant wall is constructed with one layer of refractory inside. This refractory wall is generally installed in the furnace by using an inner mold made of steel (hereinafter referred to as a former) designed to have a refractory wall having a predetermined thickness in the furnace body. After the dry powdery amorphous refractory is put into the gap between the furnace body and the former, the refractory is put into the building while vibrating from the inside of the former while being vibrated and built. The goodness of vibrating and filling of this dry powder indeterminate refractory material greatly affects the life of the refractory material and, in turn, the operation rate of the foundry. Need a degree. In this way, the refractory used for this is especially examined and the refractory used for it is also examined as a refractory suitable for its usage condition so that a long life can be obtained, silica stone material, high alumina material and alumina material, magnesia and, Alternatively, spinel or the like is used as a high-purity refractory material, and if necessary, a sintering aid such as boric anhydride is added and used. When it is used, it is lysed by a reaction with a lysate, or the lysate penetrates into the tissue to form an altered layer, causing internal peeling and causing layered peeling along the operating surface, resulting in large damage. On the other hand, the infiltration of these melts into the structure leads to a decrease in heat resistance, the amount of vitreous matter increases, and it becomes oversintered, which leads to volume contraction, large cracks occur, and groove-like abnormal damage. There are many problems, such as inability to operate stably, the occurrence of ingots from this part, and shortening of the life, and there is a strong demand for improvement of these.

[0003]

At present, the molten metal temperature is 1650 for melting and refining casting materials such as cast steel and stainless steel.
Since magnesia-based material and / or magnesia-alumina-based spinel material is used because of high temperature of ℃ to 1700 ℃, penetration of foreign matter into refractory as usage progresses,
Due to the generation of an altered layer due to heat reception, volume contraction occurs, and cracks occur inside the structure and in the surface layer part, and this crack becomes a groove-like abnormal melt loss and delamination along the operating surface Therefore, it is not possible to withstand the use, and the fireproof wall material cannot be fully used, and it is forced to replace with a new material while leaving a residual thickness of 60% to 80% depending on the site. It is a technical subject to eliminate such defects and provide a refractory material for an inner lining which is intended to have a long life.

[0004]

In view of the above situation, the inventors of the present invention have developed a refractory material which can be made to have a long life by fully utilizing the refractory material constructing the refractory wall effectively. As a result of various studies, it has been found that it can be solved by using at least three kinds of composite materials of magnesia material-chromium-containing refractory material-alumina material. Specifically, by combining a magnesia material with a chromium-containing refractory material such as chrome ore, it is possible to suppress heat spalling resistance, foreign matter permeation resistance, and internal crack generation, and to permeate foreign matter into the tissue. It is possible to improve the stable operation of the furnace and improve the service life by suppressing It provides refractory materials that can be extended. The composition range of this refractory material is 50% to 90% by weight of magnesia material, 10% to 50% by weight of chromium-containing refractory material, and the total amount of these two kinds is 90% by weight.
The above is desirable.

(Reason for limitation) 50% to 90% a) When the magnesia material is 50% or less, heat resistance and corrosion resistance are deteriorated. b) When it is 90% or more, the permeability of foreign matter becomes high at the time of use, cracking and peeling inside the tissue and groove-like abnormal damage resulting from this tend to occur, and the metal insertion phenomenon is likely to occur. Chromium-containing refractory material 10% to 50% a) If it is 10% or less, the effect of suppressing penetration of foreign substances and cracks during use cannot be obtained. When the total amount of the magnesia material and the chromium-containing refractory material is 90% or less, the heat resistance and the corrosion resistance are largely impaired due to the mixing of other materials.

[0006]

EXAMPLES Next, examples will be described in detail. 1. The quality characteristics of the materials used in the examples are shown in Table 1.

Basic tests and examples using these refractory materials are shown in Tables 2 and 3. The sample preparation for this basic test is 230 × 30 × 1 on a vibrating table with a frequency of 1800 times / min.
A 0.5 mm stainless steel metal case was placed in a 14 mm mold, and vibration-filled for 5 minutes under static pressure. After heating the molded body at 800 ° C for 2 hours, the stainless steel metal was held. Take it out from the case and use it as a sample.
Heat treatment at 0 ° C to check the quality. As for the slag erosion test, a sample heat-treated at 800 ° C. for 2 hours is divided into various materials in a high-frequency induction furnace and subjected to a test. The test material is CaO / SiO ₂ ratio, slag of 1.5 and cast iron 92
%, Si3%, Mn2%, C3%, added and dissolved to 160
Hold at 0 ° C. for 5 hours. Table 2 shows the basic test results of magnesia and chrome ore.

[0008]

[Table 1]

As a result of this basic test, when chromium ore is added to the magnesia material, the corrosion resistance is gradually improved from the addition of 15%, and when it exceeds 40%, it tends to be worse, but up to the addition of 50%. Improved from additive-free material 6
At 0%, it gets worse. In addition, the degree of penetration of foreign matter is suppressed and improved as the amount of addition increases, so that the desirable range is 50% to 90% by weight of magnesia material and 10% to 50% by weight of chromium-containing refractory material. It was Based on these results, Table 3 shows practical examples of the products of the present invention.

[0010]

[Table 2]

[0011]

[Table 3]

The conditions of the practical example are shown below. Practical furnace 5T high-frequency induction furnace construction Dry vibration vibration filling method with amorphous material Melting material Mn cast steel Melt temperature 1680 ° C to 1700 ° C Melting time 1 hour / ch Thickness of lining material 100 mm

[0013]

EFFECTS OF THE INVENTION As a result, compared to the magnesia refractory shown in Comparative Product 1 which is generally used at present, cracks in the lining refractory and groove-like abnormal damage are greatly improved, and the refractory is fully utilized. Can be used as a stable and safe operation, and the bonding damage amount of the refractory lining is 3 in comparison with the comparative product 1.
8.7% and 39.5%, compared with the comparative product 2, the product of the present invention is greatly improved to 63% and 64.4%, respectively, and the effect is to achieve a great effect in terms of both service life and operation. I was able to do it. p) However, for chromium-containing refractory materials: 1. Chromium 2. MgO containing Cr ₂ O ₃ 5% or more, Cr ₂ O ₃ based refractories 3. Any refractory material of a composite synthetic refractory material of magnesia-chromite can be used as the chromium-containing refractory material of the present invention.

Claims (1)

[Claims] In an induction furnace lining refractory for melting and refining metals, it is composed of 50% to 90% by weight of magnesia material and 10% to 50% by weight of chrome-containing refractory material.
A basic amorphous refractory for an induction furnace, which is characterized by being 0% by weight or more.