JP2017133720A - Melting material component for induction electric furnace, and builing method for induction electric furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melting material component for an induction electric furnace which enables effective preheating and in-furnace melting during an in-furnace melting for sintering process of refractory lining material at the time of building the induction electric furnace, and a building method for the induction electric furnace using the melting material component.SOLUTION: In a component 20 composed of a melting material for an induction electric furnace 10, a plurality of longitudinal materials 21 are integrally bundled to form an outer diameter approximate to an inner diameter of the furnace using the longitudinal materials 21 which is ferrous and has a length dimension adjusted to satisfy a dimension up to an upper end of a refractory lining layer 11 composing a part from a bottom to a wall inside the induction electric furnace 10 to be used.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a melting material structure for an induction electric furnace and a method for constructing an induction electric furnace.

Low frequency induction electric furnaces and high frequency induction electric furnaces are often used as melting furnaces for cast iron, cast steel, and the like.
These induction electric furnaces require refurbishment of the furnace refractory, referred to as a built-in furnace, on a regular basis or when a hot water leak or other problems occur.
As the refractory lining material constituting the inner wall of the furnace, powder refractories such as silica, magnesia, and alumina are often used. Since these refractories are in powder form, it is important to sinter and strengthen the inner surface layer of the refractory to a predetermined depth through a sintering process called sinter at the time of building.
In the sintering process of the furnace inner wall refractory called the sinter, an inner mold called a steel former that is in the furnace shape is disposed inside the furnace body in which the water-cooled copper coil is arranged, and the inner mold A powder refractory lining material is filled behind the frame and in the gap with the furnace body. Thereafter, an iron-based melting material is inserted into the inner mold (inner space, ie, the furnace space), induction heating is started, and the inner mold and the melting material are heated and melted. Thereby, a refractory lining material is heated from the inner surface side, and sintering is started. When the melting material and the inner mold are all melted and filled to the top of the furnace, the sintering process is completed.

In the sintering step, the melting material to be put inside the inner mold is preferably heated efficiently, so that a lump-shaped material conventionally called a starting block has been used. In particular, in the case of a low-frequency induction electric furnace, it does not melt unless a lump of melting material is added.
As shown in FIG. 4, a lump of melting material used conventionally as a starting block uses a relatively flat lump of about 1/5 to 1/3 of the furnace capacity. One 200 is arranged on the furnace bottom 101 in the induction electric furnace 100, or scrap is thrown on it, or two or three flat lumps 200 are further stacked.
However, in such a conventional sintering process, due to the characteristics of the induction furnace 100, only the flat mass 200 of the lowermost starting block is well heated, and the melted material on the starting block tends not to be heated very smoothly. The situation was easy to fall into. Therefore, the refractory lining material 120 in the vicinity of the furnace bottom 101 is smoothly sintered at a predetermined depth from the inner surface, while the refractory lining material 120 in the vicinity of the furnace top from the furnace top 102 is not preheated. Because it suddenly comes into contact with the molten metal, the sintering depth from the inner surface becomes insufficient, or the sintered state itself is uneven and uneven, resulting in poor sintering. For this reason, during the melting operation immediately after the start of operation of the furnace, the refractory lining material 120 from the furnace top 102 to the upper part of the furnace is peeled off or a hot water bottle is generated from the inner surface. There was a problem that was likely to cause trouble.

JP-A-6-42879 JP-A-7-260363 JP-A-9-303967 JP 2004-340413 A

In the inventions of Patent Documents 1 and 2 described above, a configuration using a fixed refractory is disclosed as a technique for improving the variation in sintering of the lining material. That is, the furnace refractory has a two-layer structure of a regular refractory and a lining material, thereby solving the variation in sintering.
However, in the inventions of Patent Documents 1 and 2, there are a problem that the cost of manufacturing the fixed refractory is high, and there is a problem that when the fixed refractory is used, the fixed refractory is weak against physical impact and easily cracked.
The invention of Patent Document 3 discloses a technique using a lining material having a two-layer structure using a lining material that is easily sintered on the furnace inner surface side.
However, in the invention of Patent Document 3, there is a problem that a lining material having two different properties must be prepared. In addition, there is a problem that it is necessary to re-tighten the gap after the separation cylinder is extracted.
The invention of Patent Document 4 discloses a technique in which a lining material at the front of the furnace, which is likely to cause problems such as hot water, is made of a material different from the lining material at the rear of the furnace.
However, in the invention of Patent Document 4, the consideration for the rear part of the furnace tends to be insufficient, and the lining material at the rear part of the furnace is easily peeled off.

  Therefore, the present invention solves the problems in the conventional induction electric furnace, and in the melting in the furnace for sintering the refractory lining material performed at the time of building the induction electric furnace, good preheating and melting in the furnace are achieved. It is an object to provide a melting material structure for an induction furnace that can be performed. Another object of the present invention is to provide a method for constructing an induction electric furnace using such a melting material structure.

  As a result of repeating various experiments to investigate and investigate the cause in order to solve the problem at the time of building a conventional induction electric furnace, the present inventor has found that the cause of the problem at the time of building an induction electric furnace is refractory. It was found that the starting block used for melting in the furnace in the sintering process of the material lining material, that is, the melting material has the greatest cause, and the present invention was completed.

The melting material structure for an induction electric furnace according to the present invention is a structure made of a melting material for an induction electric furnace, and the upper end of the refractory lining layer constituting the furnace inner wall from the furnace bottom of the induction electric furnace to be used. The first feature is that an iron-based long material adjusted to a length satisfying the above dimensions is used, and a plurality of the long materials are bundled and integrated into an outer diameter that approximates the furnace inner diameter.
In addition to the first feature, the melting material structure for an induction electric furnace according to the present invention is a melting material structure used in a sintering process of a refractory lining layer on the inner wall of the furnace in the construction of an induction electric furnace. The length of the long material is higher than the upper end of the refractory lining layer constituting the inner wall of the induction furnace by the height that is reduced when the melted material structure formed by bundling the long material is melted. The second feature is that the size is adjusted so as to project.
In addition to the first or second feature, the melting material structure for an induction electric furnace of the present invention uses a prismatic billet as a long material, and a plurality of them are bundled into a predetermined length. The third feature is that they are integrated with each other.
An induction electric furnace building method according to the present invention is an induction electric furnace building method using the melting material structure for an induction electric furnace according to any one of the first to third aspects, the inner wall of the furnace After filling the refractory lining layer that constitutes the back of the iron-based inner mold in an unsintered state, the molten material structure is inserted into the furnace space surrounded by the inner mold, The entire space inside the furnace surrounded by the inner mold is filled with a bundle of long materials that are continuous in the vertical direction, and then electricity is applied, from preheating to melting of the melting material component and the inner mold. The fourth feature is that the inner surface of the refractory lining layer is sintered by performing the above.

According to the melting material structure for an induction electric furnace according to claim 1, the length is adjusted so as to satisfy the dimension from the inner bottom of the induction electric furnace to be used to the upper end of the refractory lining layer constituting the inner wall of the furnace. By using an iron-based long material that has been bundled and integrated into an outer diameter that approximates the furnace inner diameter,
With the iron-based long material adjusted to the length that satisfies the dimension from the furnace bottom to the top of the refractory lining layer, the induction heating and heat conduction in the vertical direction in the furnace of the molten material structure is quickly performed. Done. And the long material bundled to the outer diameter that approximates the furnace inner diameter is inserted and arranged in the furnace, so that the melted material structure and the furnace inner wall can be brought close to each other, and thus before the melted material structure melts In addition, heat conduction from the melting material constituting body to the furnace inner wall side can be performed quickly.
Therefore, when induction heating is started in the induction electric furnace, the entire melting material constituting body of the present invention disposed in the furnace is heated more rapidly and uniformly, and the whole is melted in a short time. Along with this, the entire inner wall of the furnace from the lower part to the upper part is heated more quickly and uniformly.
Therefore, the refractory lining material according to claim 1 is used in the sintering process of the refractory lining material constituting the inner wall of the induction electric furnace when constructing the induction electric furnace. As a result, the refractory lining material can be uniformly and uniformly sintered at a uniform sintering depth quickly and satisfactorily.
Of course, by using the melting material structure of the present invention, this can be a good iron core of the induction electric furnace, so that the heat generation efficiency as the induction electric furnace can be increased. Therefore, not only at the time of building an induction electric furnace but also at the time of normal operation by an induction electric furnace, by using the melting material structure of the present invention, it is possible to melt a very good and energy-saving iron-based material. .

According to the melting material structure for an induction electric furnace according to claim 2, in addition to the operational effect of the structure according to claim 1, in the construction of the induction electric furnace, the refractory lining layer of the furnace inner wall is sintered. It is a melting material structure used in the ligation process, and the length dimension of the long material is the same as that of the induction electric furnace inner wall by a height that decreases when the melting material structure formed by bundling the long material melts. Since it has been adjusted to be a dimension that protrudes from the upper end of the refractory lining layer that constitutes,
During the sintering process of the refractory lining layer on the inner wall of the furnace, even if the molten material structure is melted in the furnace, the liquid level of the dissolved molten material structure is higher than the upper end of the refractory lining layer. It can prevent becoming low. Therefore, heat conduction from the melted dissolved material structure can be carried out well and promptly until reaching the upper end of the refractory lining layer, and sintering of the refractory lining layer is homogeneous in all regions up to the upper end. Can be done well.

Moreover, according to the melting | dissolving material structure for induction electric furnaces of Claim 3, in addition to the effect by the structure of the said Claim 1 or 2, a long material uses a prism-shaped billet, and this is used in multiple numbers. Because it is integrated in a bundled state to a predetermined length,
By using a prismatic billet obtained as a standard product by continuous casting, partial rolling, or the like, a uniform and uniform long material can be easily adjusted and obtained. Also, by bundling them, it is always possible to easily procure and obtain a melting material structure having a uniform and uniform shape. Therefore, according to the melting material structure using such a billet, it is possible to always perform homogeneous melting, which is very good not only when the induction electric furnace is built but also during normal operation with the induction electric furnace. Can be quickly dissolved.

According to the method for constructing an induction electric furnace according to claim 4, the refractory lining layer constituting the furnace inner wall is filled in an unsintered state behind the iron-based inner mold, and then the inner mold The melted material structure is inserted into the furnace space surrounded by, and then electricity is applied to the furnace, so that the melted material structure and the inner mold are preheated and eventually melted. This refractory lining layer receives heat from the melted material structure that has been preheated through the inner mold, and after the melted material structure and the inner mold are melted, The surface is sintered to a predetermined depth.
The molten material component is an iron-based long material adjusted to a length that satisfies the dimension from the inner bottom of the induction electric furnace to be used to the upper end of the refractory lining layer, and a plurality of the long materials are used. Since it is bundled and integrated into a shape approximating the furnace inner diameter, by inserting this molten material structure into the furnace space surrounded by the inner mold, the furnace space enclosed by the inner mold is The entire area is filled with a bundle of long materials continuous in the vertical direction. Therefore, when electricity is applied in this state, the entire melted material structure filled in the furnace space is uniformly preheated, and the inner mold form that is in close proximity to the melted material structure as a whole. Preheated uniformly. The melting material structure is melted from the lower end to the upper end by the uniform preheating in a relatively short time, and accordingly, the inner mold is also melted from the lower end to the upper end. It takes place in a relatively short time. As a result, the refractory lining layer is heated relatively uniformly and rapidly from the lower side to the upper end, and the heating state is less likely to be uneven. Therefore, the sintering treatment of the refractory lining material becomes relatively uniform and stable throughout the entire area from the lower end to the upper end, and a uniform and good sintered layer throughout the entire area is stably formed at a predetermined depth. be able to.

It is a longitudinal cross-sectional view which shows the state which inserted and arranged the melting | dissolving material structure which shows embodiment of this invention in the induction electric furnace in a building furnace. It is a top view which shows the state which inserted and arranged the melting | dissolving material structure which shows embodiment of this invention in the induction electric furnace in a building furnace. It is a longitudinal cross-sectional view which shows the state of the induction electric furnace in the construction of a furnace which shows the state which the melting material structural body melt | dissolved. It is a longitudinal cross-sectional view which shows the state which inserted and arranged the lump-shaped melt | dissolution material called the starting block used conventionally in the induction electric furnace in a building furnace.

  With reference to FIGS. 1-3, the melting | dissolving material structure for induction electric furnaces of this invention and the construction method of an induction electric furnace are demonstrated below about the embodiment.

FIG. 1 and FIG. 2 are views showing a state in which a melting material structure 20 according to an embodiment of the present invention is inserted into an induction electric furnace 10 being built.
The induction electric furnace 10 includes a high frequency induction electric furnace (including a medium frequency) and a low frequency induction electric furnace, and the induction electric furnace according to the present invention is a concept including both of them. However, as a practical problem, the low frequency induction electric furnace with low heat generation efficiency is particularly likely to be a problem at the time of building the furnace in which the induction electric furnace 10 needs to be cold started. Therefore, also in the case of the induction electric furnace 10 of this embodiment, the low frequency induction electric furnace is mainly assumed.

The induction electric furnace 10 includes a refractory lining layer 11 as an inner wall of the furnace as a schematic configuration, and an outer partition wall 12 that separates the refractory lining layer 11 is provided on the outside thereof. An induction coil 13 is disposed further outside the outer partition wall 12. Further, a lower partition wall 15 that separates the refractory lining layer 11 is provided below the refractory lining layer 11.
At the time of building, an inner mold 14 made of an iron-based, for example, steel container called a former is disposed in advance, and a powder refractory lining that has not yet been sintered behind the inner mold 14. The material is filled to form a refractory lining layer 11. More specifically, the space is filled between the inner mold 14 and the outer partition wall 12 and the lower partition wall 15.
As the refractory lining material, for example, a refractory powder mainly composed of silica, a refractory powder mainly composed of magnesia or alumina can be used, and other auxiliary materials and additives such as a binder are necessary. What was contained according to it can be used.
Of course, the refractory lining layer 11 at the time when the refractory lining material is filled is only filled with powder and is not yet sintered.

In order to complete the building furnace, it is necessary to sinter the inner surface of the refractory lining layer 11 through the sintering step of the refractory lining layer 11.
In the sintering process of the refractory lining layer 11, the molten material component 20 is inserted into the furnace space surrounded by the inner mold 14, and the induction electric furnace 10 is cold started. As the time elapses, the melting material structure 20 and the inner mold 14 are eventually dissolved, while the refractory lining layer 11 is preheated and further heated, and sintering proceeds from the inner surface to the inside.

The melted material structure 20 includes an iron-based long material 21 adjusted to a length satisfying the size from the inner bottom of the induction electric furnace 10 to be used to the upper end of the refractory lining layer 11 constituting the inner wall of the furnace. Use. Then, a plurality of long materials 21 are bundled and integrated into an outer diameter that approximates the furnace inner diameter to obtain a melted material constituting body 20.
Here, bundling a plurality of long materials 21 to an outer diameter that approximates the furnace inner diameter is more specifically a state in which a plurality of long materials 21 are bundled and having a smaller diameter than the furnace inner diameter. This means that it is bundled to a diameter close to the furnace inner diameter. Since the induction electric furnace 10 usually has a circular shape in the furnace, the bundle of the long materials 21 constituting the melting material constituting body 20 is also formed in a circle for such a circular induction electric furnace 10. It will be. However, since it is necessary to insert the molten material structure 20 into the induction electric furnace 10, the outer diameter of the bundle of the long materials 21 is made smaller than the inner diameter of the induction electric furnace 10 to such an extent that the insertion can be performed smoothly. . However, the diameter should be as close to the inner diameter of the induction furnace 10 as possible.
Moreover, since the melted material component 20 is a bundle of a plurality of long materials 21, it is natural that the outer peripheral shape of the bundle is not a perfect circle or a regular polygon. Therefore, the outer peripheral shape of the melting material constituting body 20 roughly approximates the in-furnace shape of the induction electric furnace 10, but actually does not have a completely similar shape. In the present invention, the outer diameter of the bundle of long materials 21 is configured to approximate the inner diameter of the induction electric furnace 10 in a wide concept including such a rough similar shape.

The long material 21 is iron-based. This is because, of course, the iron system is good for promoting the heat generation during the melting operation by the induction furnace 10.
The long material 21 has a length dimension that satisfies the dimension from the inner bottom of the induction electric furnace 10 to be used to the upper end of the refractory lining layer 11. By arranging each long material 21 so as to stand upright in the furnace, the heat generated in the furnace or the long material 21 itself is transmitted through the long material 21 in the vertical direction, that is, in the furnace. It is possible to conduct quickly from the bottom to the furnace top direction. By using the long material 21 having a length satisfying the dimension from the bottom of the furnace to the upper end of the refractory lining layer 11, heat can be quickly transmitted from the bottom of the furnace to the upper end of the refractory lining layer 11. Therefore, the refractory lining layer 11 is preheated uniformly and quickly from the bottom of the furnace to the top of the furnace via the long material 21 and the inner mold 14 and heated. Furthermore, by using a bundle of a plurality of long materials 21 having an outer diameter approximating the furnace inner diameter, the gap between the bundle of long materials 21 and the inner mold 14 is also narrowed, and preheating and heating are more uniform. Can be Therefore, the refractory lining layer 11 can be quickly preheated and heated.
The length dimension satisfying the dimension from the furnace bottom to the upper end of the refractory lining layer 11 means that the length of the long material 21 is the length from the furnace bottom to the refractory lining layer 11 upper end and that. It means that the length is exceeded.

For sintering the refractory lining layer 11, it is important that the refractory lining layer 11 is preheated and heated with an appropriate heating gradient. Before the melting material structure 20 melts, the heat of the melting material structure 20 spreads from the furnace bottom toward the furnace top, so that the refractory lining layer 11 is uniformly preheated through the inner mold 14 and further heated. To be heated. Thus, the refractory lining layer 11 is uniformly preheated and heated from the furnace bottom to the furnace top, so that the refractory lining layer 11 is sintered stably and uniformly from the furnace bottom to the furnace top. It becomes possible.
Another advantage of using the melted material structure 20 in which the long materials 21 are bundled is that the melted material structure 20 is arranged in the furnace, so that the length of the iron system in which the space in the furnace is long in the depth direction. It is filled with the scale material 21, which becomes a good core material for the induction coil 13, and the heat generation efficiency by the induction coil 13 can be greatly improved.
The melted material structure 20 is configured using a long material 21 adjusted to a length that satisfies the dimension from the furnace inner bottom of the induction electric furnace 10 to the upper end of the refractory lining layer 11, all of which are long. It is not limited to the case where only the material 21 is used. Even if the melted material that does not satisfy the dimension from the bottom of the furnace to the upper end of the refractory lining layer 11 is the melted material structure 20 that is supplementarily combined with the long material 21, To the extent that sintering is performed uniformly from the furnace bottom to the furnace top, it is included in the melting material structure 20 in the present invention.
The proportion of the long material 21 in the melting material constituting body 20 is preferably 70% or more, more preferably 90% or more.
In addition, when a melted material with insufficient dimensions is used as a supplement to the long material 21, the length of the melted material with insufficient dimensions is preferably at least half that of the long material 21, more preferably 2 / 3 or more is good.

Since the melting material construct 20 is a bundle of a plurality of melting materials, there are some gaps. For this reason, when the melting material component 20 is melted, its height decreases.
Therefore, the length dimension of the long material 21 is the refractory lining that forms the inner wall of the induction furnace 10 in advance by the height that decreases when the melted material structure 20 formed by bundling the long material 21 is melted. It is preferable to adjust the size so that it protrudes from the upper end of the layer 11. By comprising in this way, even when the melting material structure 20 melt | dissolves, the molten metal surface can reach the upper end of the refractory lining layer 11, and more uniform sintering of the refractory lining layer 11 is achieved. It can be secured well.
When the size of the melting material constituting body 20 is configured to protrude from the upper end of the refractory lining layer 11, the dimension of the inner mold 14 exceeds the upper end of the refractory lining layer 11. It is preferable to adjust the dimensions so as to protrude beyond the upper end of the structure 20. This is to prevent the molten metal from entering the upper end surface of the refractory lining layer 11 when the melting material component 20 is melted. The refractory is prevented from flowing into the refractory lining layer 11 by preventing the molten metal from flowing into the refractory lining layer 11 by making the dimension of the inner mold 14 that is slower to dissolve than the melting material structure 20 higher than the dimension of the melting material structure 20. It becomes possible to ensure uniform sintering and sintering at a uniform depth in the lining layer 11 throughout the entire area.

The melted material structure 20 can be integrated by bundling the long material 21 and welding the parts. It is preferable that the bundled dissolved material structure 20 has as small a gap as possible. For this reason, a melting material having an appropriate shape and size can be inserted into the gap between the long materials 21. Further, the melting material constituting body 20 can be configured so as to approximate the furnace inner diameter by combining melting materials having different horizontal cross-sectional shapes.
FIG. 2 shows, as an example, a dissolved material structure constituted by using two types of long materials 21a and 21b having different cross-sectional areas.
The long material 21 can be a prismatic billet. More generally speaking, the long material 21 can be used in the form of a rectangle whose horizontal cross section is rectangular or other polygons, either alone or in combination, but a long material having as large a horizontal cross sectional area as possible is preferable. Moreover, the elongate material 21 from which a horizontal cross-sectional area differs can be used individually or in combination.

With reference to FIGS. 1-3, the construction method of the induction electric furnace 10 using the above-mentioned melting material structure 20 is demonstrated.
In constructing the induction furnace 10 of this type, a container-shaped inner mold 14 that constitutes the space shape of the furnace space is disposed. On the outer side and the lower side of the inner mold 14, an outer partition wall 12 made of coil cement or the like and a lower partition wall 15 made of fireproof castable or the like are arranged in advance through a gap corresponding to the thickness of the refractory lining layer 11. It is installed. Thereafter, a refractory lining material is filled into the refractory lining layer 11 behind the inner mold 14 and between the outer partition 12 and the lower partition 15. In this state, the refractory lining layer 11 is in an unsintered state in which the sintering process has not yet been performed. The sintering process is carried out as a substantially final construction work.
The sintering process is started by inserting the melting material structure 20 into the inner mold 14 and applying electricity to the induction coil 13. By applying electricity, heating of the melting material structure 20 is started, and the generated heat is quickly transferred by the long material 21 of the melting material structure 20 from the lower part to the upper part in the furnace. The heat of the melting material constituting body 20 is transferred to the refractory lining layer 11 through the inner mold 14, and the refractory lining layer 11 is preheated and further heated to a high temperature. Thereafter, the melting material constituting body 20 is melted, and then the inner mold 14 is melted and disappears as shown in FIG. The volume of the melting material constituting body 20 is adjusted in advance so that the molten metal surface has a liquid level close to the refractory lining layer 11. In this case, the height of the long material 21 of the melting material constituting body 20 is higher than the upper end of the refractory lining layer 11. The height of the inner mold 14 is also higher than the upper end of the refractory lining layer 11.
The refractory lining layer 11 is gradually sintered from the inner surface thereof, and the molten metal in the furnace is discharged after the time required to achieve a predetermined sintering depth, and the sintering process is completed.

  In addition, the melting material structure 20 according to the present invention is not only used when the induction electric furnace 10 is built, but is naturally used also during normal operation after the induction electric furnace is completed. By using the melting material structure 20 of the present invention even during normal operation, the melting efficiency by the induction electric furnace is improved and the workability is improved because there is no need to add additional melting material, and the temperature rises quickly. The accompanying rapid dissolution can be realized.

A melting material construct 20 was manufactured for a low frequency induction electric furnace having a furnace inner diameter of 900 mm, a furnace depth of 1400 mm, and a capacity of 5 tons. A 150 mm square iron billet was used as the long material 21, and the billet was cut to 100 mm longer than 1400 mm which is the furnace depth, that is, 1500 mm. A plurality of long materials (billets) 21 each having a 150 mm square and a length of 1500 mm were combined to obtain a diameter close to a furnace inner diameter of 900 mm, and bundled and integrated to obtain a melted material structure 20. The melted material structure 20 was inserted and placed in the inner mold 14 of the low frequency induction electric furnace 10 being built. A pig iron or other iron-based material was inserted as a melting material into the gap formed between the melting material constituting body 20 and the inner mold 14 to fill the gap.
Electricity was applied to the low frequency induction electric furnace 10 to start heating. After the energization, the lower part of the billet of the molten material structure 20 integrated in about 4 hours begins to red heat, and after about 6 hours, the upper part of the molten material structure 20 becomes red hot, and the entire inner mold 14 is red hot. It became.
Thereafter, melting of the melting material constituting body 20 started, and after about 9 hours, the entire furnace was filled with the molten metal. The temperature of the molten metal was raised to 1600 ° C., which is 100 ° C. higher than the melting temperature of normal operation, and maintained for about 4 hours, and the sintering process was completed.

After the sintering process, the thickness of the sintered layer from the inner surface of the refractory lining layer 11 was measured. As a result, a sintered layer having a thickness of 20 to 25 mm was uniformly formed throughout the refractory lining layer 11. Under similar sintering conditions in the prior art, there are many variations in sintering at the lower and upper portions of the refractory lining layer 11, and even though a 20 to 25 mm thick sintered layer is formed at the lower portion, 3 to 3 at the upper portion. Only a sintered layer having a thickness of about 10 mm was formed, and the sintering itself was non-uniform and many portions with poor sintering occurred.
Further, in this example, it took 9 hours for the melting material structure 20 to be melted in the furnace. On the other hand, in the past, there are many gaps between the melting material (starting block) inserted into the furnace in the sintering process, so it is necessary to replenish the melting material repeatedly during the sintering process. In addition, since the added melting materials are sequentially melted from the lower part of the furnace, the thermal efficiency is actually poor, and it takes about 12 hours for the entire furnace to be filled with the molten metal.
That is, when the melting material construct 20 of the present invention is used, a good and uniform sintered layer can be obtained while greatly shortening the time of the sintering process.
Of course, by using the melting material structure 20 of the present invention, the melting operation during the normal operation by the induction electric furnace can be greatly shortened as compared with the prior art.

  According to the present invention, as a furnace building method capable of quickly and satisfactorily performing melting in a furnace for sintering treatment of a refractory lining material constituting an inner wall of a furnace performed at the time of building an induction electric furnace, As a melting material structure that can realize the good sintering process, it has high industrial applicability.

DESCRIPTION OF SYMBOLS 10 Induction electric furnace 11 Refractory lining layer 12 Outer partition wall 13 Induction coil 14 Inner formwork 15 Lower partition wall 20 Melting material structure 21 Long material 21a Long material 21b Long material

Claims (4)

  It is a structure made of a melting material for an induction electric furnace, and is an iron-based material adjusted to a length satisfying the dimension from the inner bottom of the induction electric furnace used to the upper end of the refractory lining layer constituting the inner wall of the furnace. A melting material structure for an induction furnace, wherein a long material is used, and a plurality of the long materials are bundled and integrated into an outer diameter that approximates the furnace inner diameter.   In the construction of an induction electric furnace, a melting material structure used in the sintering process of the refractory lining layer on the inner wall of the furnace, the length of the long material is a melting material structure formed by bundling the long material 2. The induction according to claim 1, wherein the dimension is adjusted so as to protrude from the upper end of the refractory lining layer constituting the inner wall of the induction electric furnace by a height that decreases when the metal melts. Melting material composition for electric furnace.   The melting material structure for an induction electric furnace according to claim 1 or 2, wherein the long material is a prismatic billet and is integrated in a state where a plurality of billets are bundled in a predetermined length. body.   A method for constructing an induction electric furnace using the melting material structure for an induction electric furnace according to any one of claims 1 to 3, wherein the refractory lining layer constituting the furnace inner wall is iron in an unsintered state. After filling the back of the inner mold of the system, by inserting a melting material structure into the furnace space surrounded by the inner mold, the entire area of the furnace space surrounded by the inner mold, It is filled with a bundle of long materials that are continuous in the vertical direction, and then, by applying electricity and performing from the preheating to melting of the melting material component and the inner mold, the inner surface of the refractory lining layer A method for constructing an induction furnace characterized in that sintering is performed.

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