JP2725574B2 - Furnace body protection wall for metallurgical furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace body protection wall for protecting a furnace wall of a metallurgical furnace such as a blast furnace against a heat load from inside the furnace.

[0002]

2. Description of the Related Art Conventionally, a furnace body protection wall for protecting a blast furnace steel shell against a thermal load from the inside of a furnace is disclosed in, for example, Japanese Unexamined Patent Publication No.
As shown in FIG. 10, the brick support metal 24 is cast into the stave body 23, or the furnace wall bricks 25, 26 or A furnace body protection wall in which a pre-formed amorphous refractory is integrally cast is used. The wall of the furnace body was made thinner with the intention of stabilizing the profile, simplifying the construction work, and reducing the cost, without performing brickwork lining the inside of the furnace.

[0003] By the furnace body protection wall, the lining brick built inside the conventional stove cooler is consumed and disappears in two to three years, while the furnace wall bricks 25 and 2 are further consumed for two to three years.
6 is expected to extend the life. However, the furnace body protection wall also has a structure in which the brick support 24 is sandwiched between the stave bodies 23, and the cooling effect due to the heat transfer from the stave body 23 to the brick support 24 is deteriorated. 600-1200 ° C.) The gas loses its function of supporting the furnace wall brick, such as being melted or embrittled by the gas.
When 26 is dropped, the cast portion of the stove cooler on the entire inner surface of the furnace is exposed, and the furnace interior material at the relevant portion is excessively cooled to generate a supercooled portion. May fall.

The present applicant has previously invented a furnace body protection wall for improving the stability of supporting a furnace wall brick of a stove cooler (Japanese Patent Application No. 4-71266). The configuration will be described with reference to FIG. 11 and FIG. Furnace interior A is a ceramic material 4 _1, and with Tetsugawa surface B is made of a metal material 5 ₁ such cast iron, in a thickness direction of the stave cooler 23 _1, the ceramic material 4 ₁ and the metal material 5 ₁ By forming a macro-inhomogeneous functionally graded material with a composition that transitions continuously so that the interface does not substantially form an interface, a composite layer having a thermal stress relaxation function against fluctuations in the furnace thermal load is formed. It is a stave cooler.

However, the ceramic material 4 ₁ and the metal material 5 ₁
The interface to substantially formed so as not to continuously transition macro having a composition heterogeneity of the stave cooler, iron skin surface side B of the ceramic material 4 ₁ of the as shown in the drawing round bar from a furnace inside A , The outer dimensions and the arrangement density are sequentially reduced, and the casting is performed.
While ensuring the _first molten metal has fabricated on a variety of problems to prevent floating of the ceramic material 4 _1, industrially efficiently be manufactured at low cost is difficult, method of arranging the ceramic material 4 ₁ It is necessary to improve the manufacturing process.

[0006]

As described above, the conventional furnace body protective wall has various drawbacks, and a stave cooler improved to eliminate those drawbacks also has manufacturing problems. The appearance of a completed furnace protection wall is desired.

[0007] In view of the above situation, the present invention solves a manufacturing problem found in the conventional method, and provides a furnace body protective wall which has a tilting function between a ceramic material and a metal material and is easy to manufacture. Things.

[0008]

In order to achieve the above object, a furnace body protective wall for a metallurgical furnace according to the present invention is a stave cooler for protecting a furnace body shell from heat load in the furnace. And, the furnace outer surface side is made of a metal material such as cast iron, and in the thickness direction of the stave cooler main body, the volume ratio of the ceramic material is gradually reduced, and conversely, the volume ratio of the metal material is gradually increased. The stave cooler body is composed of a macro-inhomogeneous functionally graded material formed by laminating and forming an interface with a joint-like thin metal material layer between the respective step layers, and cooling water is provided outside the furnace inside the stave cooler body. A plurality of steel pipes through which the steel pipes pass are provided and integrally cast.

Further, in the furnace body protection wall for a metallurgical furnace,
A laminated composite layer having a thermal stress relaxation function is formed in a stave cooler body made of a ceramic material and a metal material in response to a temperature change due to a heat load in a furnace.

[0010]

FIG. 1 is a perspective view of a stave cooler body 1 according to the present invention.
As shown in the schematic cross-sectional view of the main part of (a), it has a thermal stress relaxation function in which different characteristics such as a heat shielding characteristic on the heating side A and a mechanical strength characteristic as a structure on the cooling side B are shared. It is a macro heterogeneous structure. Moreover, the composition of the structure made of dissimilar materials having the respective functions is represented by the composition distribution in the cross-sectional thickness T direction of the stave cooler main body 1 in FIG.
As shown in the figure, the ceramic material 2 is disposed on the heating side A and the metal material 3 is disposed on the cooling side B, and the density of the ceramic material 2 is gradually reduced from the heating side A to the cooling side B. The metal material 3 is gradually increased, and the intermediate portion C has a functionally graded structure forming a composite phase of the ceramic material 2 and the metal material 3. As a result, as shown in FIG.
The heat-shielding characteristic (curve x) is excellent on the heating side A, and a thermal stress relaxation function (curve z) that appropriately disperses local thermal stress generated inside the stave cooler body under the temperature gradient of heating and cooling of the furnace body.
And the cooling side to which the stave cooler body is attached is made of a high-strength metal material, so that it can have mechanical strength characteristics (curve y).

In order to manufacture the above-described stave cooler main body, it is necessary to simultaneously achieve both optimization of the heat shielding characteristics and the mechanical strength characteristics and optimization of the thermal stress relaxation function.

When the ceramic material 2 is exposed to a high-temperature gas flow, it must have heat-shielding properties, low thermal conductivity, heat resistance, non-oxidizing properties, and wear resistance to cope with the burden drop. In addition, when repeatedly heated, it must be able to withstand thermal fatigue fracture due to inelastic strain. Therefore, the ceramic material 2 disposed on the heating side A
In terms of its properties or functions, it is necessary to balance the heat shielding properties and the thermal stress relaxation function so that the temperature of the heating-side ceramic material surface, which is the starting point of thermal stress, is equal to or lower than the elasto-plastic transition temperature. . On the other hand, from the viewpoint of the material, it is necessary to apply a material having an elasto-plastic transition temperature as high as possible and a material having an appropriate coefficient of thermal expansion.

In view of the above, it is desirable to arrange alumina Al ₂ O ₃ ceramic or silicon carbide SiC ceramic on the outermost surface layer on the heating side A. In order to improve the mechanical properties of the alumina Al ₂ O ₃ ,
It is desirable to add silicon carbide SiC-based ceramic as a reinforcing material.

On the other hand, as the metal material 3 disposed on the cooling side B, gray cast iron FC150 (JIS-G550), which has been used abundantly as a base material such as a stove cooler of a blast furnace, is used.
1), Spheroidal graphite cast iron FCD440 (JIS-G550)
2) and the like are preferred.

FIG. 2 is a conceptual diagram showing the structure of a functionally graded stave cooler according to the present invention, which is constructed based on the above matter.
Shown in In the figure, the A side shows the heating side (furnace inside),
Towards the thickness T direction of the cooling side of the B-side (Rosotogawa), referred to as the volume ratio of the ceramic material 4 having a thickness of t (hereinafter Vf, V _f
= 1 indicates a ceramic material, and V _f = 0 indicates that the volume of the ceramic material is zero). The volume ratio of the metal material 5 is gradually reduced stepwise by dividing it into five layers. The interface d of the metal material increases in the form of a macroscopic laminate.
The in which it is formed a shaped joints brickwork was transition to a thickness of T ₁ than A surface. Then, the T ₂ of the portion of the B-side, arranging a steel pipe 6 through which cooling water to the metal material 5 to absorb the heat load from the furnace as a stave cooler.

According to the furnace body protective wall having the above-mentioned structure, the function of relieving thermal stress can be fully exhibited against temperature fluctuations in the furnace, cracks can be significantly suppressed, and the furnace wall can be prevented from being worn. Therefore, a stable furnace wall profile can be maintained for a long period of time.

Further, even if the inner wall surface of the furnace wall is worn out, the functional function in the thickness direction does not change, the inner surface of the furnace shell is not exposed, and the furnace is not excessively cooled. In addition, the temperature loss near the furnace wall does not occur, and the heat loss of the furnace body can be suppressed.

Further, since the ceramic material and the metal material of the stave cooler main body are attached to the furnace wall as an integral block, the construction period can be shortened by reducing brick work in the furnace, and the stave cooler main body can be shortened in the furnace height direction. Can be arbitrarily changed, and equipment costs can be reduced.

[0019]

An embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows a part of a case where a blast furnace wall is constructed with a furnace body protection wall according to the embodiment of the present invention. Stave during casting cooler body 1, as mentioned several steel pipe 6 and the ceramic material 4 in the description of FIG. 2, a laminate shape gradually decreased V _f stepwise toward the furnace inside A in Rosotogawa B And cast in one piece. Then, the plurality of stave cooler bodies 1 having the above configuration are attached to the blast furnace iron shell 20 at regular intervals in the vertical direction and the circumferential direction of the blast furnace using the mounting bolts 22. At this time, a filling material 21 made of an amorphous refractory such as a castable is filled between the stave cooler main body 1 and the blast furnace steel shell 20 and between the adjacent stave cooler main bodies 1.

[0020] The stave cooler body 1 in this embodiment.
FIG. Alumina Al ₂ O ₃ -based refractory 7, from the furnace inside A at the bottom to the furnace outside B at the top,
The volume ratios _{Vf of} 8 and 9 are arranged so as to decrease stepwise based on the concept of the optimum gradient composition described later.

That is, as the refractories 7, 8 and 9 from the inside A of the furnace to the third layer, honeycomb-shaped refractory panels having holes formed in a honeycomb shape were used. This refractory panel is obtained by molding an amorphous refractory into a frame mold, curing it, and then firing it at a high temperature using a firing furnace to give sufficient strength.

Each honeycomb-shaped refractory panel is provided with circular openings 7 ₁ , 8 ₁ , 9 ₁ having a predetermined volume ratio V _{f in} a staggered arrangement. The arrangement of the openings is not limited to a staggered pattern, but may be another arrangement such as a grid pattern, but it is preferable that the openings of the panels in each layer are arranged so as not to be continuous.

The refractory disposed outside the refractory 9 was not a honeycomb-shaped refractory panel but a plug-shaped column. That is, when the volume ratio _Vf is reduced, in the honeycomb-shaped panel shape, it is necessary to increase the hole diameter or increase the number of holes, and the distance between the holes is reduced. In the manufacturing process, cracks are easily generated from the site, and the strength is increased. Is insufficient.

The plug-shaped cylindrical refractories 10, 11 are:
As with the honeycomb refractory panel, a fired product of an amorphous refractory can be used, but a brick formed in advance may be used. Then, contrary to the idea of perforating the panel in the honeycomb refractory panel, the diameter or the number of the columns may be determined along a predetermined volume ratio _Vf .

In order to form the stave cooler main body, in order to integrally cast a refractory ceramic material and a cast iron metal material, a predetermined run distance d is set so that the molten cast iron is evenly filled between the refractories. In the embodiment in which the refractory panels 7, 8, and 8 are used to maintain the casting thickness shown in FIG.
9 and the refractory panels are laminated appropriately. Also,
A plug-like refractory 10 laminated on the outside of the refractory panel 9;
11 is laminated using, for example, a plate-shaped punching metal 12 having a thickness of 0.5 to 2 mm and Keren 14. In addition, outside the plug-shaped refractory 11, a steel pipe 6 for cooling water is provided on a punching metal 12 by arranging a keel 13 for supporting a cylinder shown in FIG. 6. It is desirable that the supporting height h of the Kerens 13 and 14 be 8 mm or more in order to secure the flow of the molten metal.

FIG. 5 shows an example of the shape of the holes provided in the refractory panels 7, 8, and 9. It is preferable to add R (R) so that the corners of the holes of the refractory panel do not become crack starting points. 5 (a) is a case where with the R chamfered lower end faces of the straight hole _71. FIG. 5 (b)
Is a case where with the R chamfered lower end faces of the tapered hole 7 _2. The tapered hole 7 _2, when the stave cooler is subjected to wear and impact by the contact with the inserts in movable metallurgical furnace, it is effective to prevent the falling off.

Next, a typical example of manufacturing a stave cooler according to an embodiment of the present invention will be described with reference to FIG. The figure shows the casting condition of the stave cooler, where the lower side is the inside of the furnace and the upper side is the outside of the furnace. The refractory panels 7, 8, and 9 shown in FIG. 4 are laminated on the lower sand mold 16 with the interposition of the helium 14 between the panels, and the perforated metal 12, the plug-shaped refractory 11, and the helium 14 are laminated thereon. And then Keren 1
The steel pipe 6 is disposed via the pipe 3. In the figure, 18 is the upper sand mold 15
, 17 is a runner, 19 is a feeder, and 5 is cast iron cast at a casting temperature of 1250-1350 ° C.

The size of the stove cooler manufactured as described above can be arbitrarily set by changing the size of the mold. However, specifically, it is considered in consideration of manufacturing restrictions, transportation and take-in of products, and the balance of arrangement on the inner surface of the furnace.
00 mm, width: 1000 mm, length: about 2000 mm.

FIG. 9 shows an example of a simulation result of temperature and stress distribution of a trial material of the stave cooler body 1 of the present invention.
(A) to (d). FIG. 9 (a) shows that cordierite (SiO ₂ : 50%, A
l ₂ O ₃ : 40%, MgO: 8%, λ = 1.1 Kcal /
m. h ° C) and the steel pipe 6 (STPG37) through which cooling water is passed.
0 40ASch40) with cast iron 5 (FCD440)
It is a body cast. In this case, the thickness T of the stave cooler body 1 is 375 mm, and the thickness T ₁ of the inclined composite region in which the ceramic material and the cast iron are mixed is 275 mm (t = 45 m).
m, d = 10mm), the thickness T ₂ of the single area only cast iron Rosotogawa there is 100 mm.

FIG. 9 (b) shows the structure of the volume ratio _Vf of the ceramic material of the stave cooler body 1 and cast iron. The gradient composition distribution of the ceramic material with respect to cast iron is temperature-analyzed by the heat load inside the furnace, and the volume fraction _Vf distribution of the ceramic material is designed by repeatedly calculating so as to minimize the thermal stress generated between the ceramic material and the cast iron. It is important.

FIG. 9C shows the stave cooler body 1.
4 shows the temperature distribution in the thickness direction when the inside of the furnace received a heat load of 800 ° C. From this figure, it can be seen that as the amount of cast iron increases as compared with the ceramic material, the temperature decreases, and the temperature of the portion where the amount of cast iron is higher on the outside of the furnace than at the center is low and sufficiently cooled.

FIG. 9D shows a thermal stress distribution caused by the temperature distribution. The thickness T ₁ of the inclined composite region compressive stress is generated, the tensile stress is generated in the thickness T ₂ of the single area of the cast iron. Although this tensile stress is somewhat large, the cast iron used has sufficient toughness, and thus there is no problem in the soundness as a stave cooler.

As described above, since the stave cooler body forms a composite phase in which the ceramic material and the cast iron are mixed, the temperature gradient is reduced. As a result, even under fluctuations in heating and cooling, as is clear from the thermal stress distribution in FIG. 9D, the generated thermal stress is greatly reduced, and the thermal stress relaxing function is achieved. Therefore, cracking of the stave cooler body is remarkably suppressed, and even stave cooler body becomes small thickness T ₁ gradually wear from the furnace interior, stepwise FGM structure in the thickness direction to secure Therefore, the above-described thermal stress relaxation function exists.

Further, based on the idea of thinning the wall as a method of solving the drawback of the lack of holding power of the cast brick inside the furnace as seen in the conventional stave cooler shown in FIG. It is also possible to stop the construction of the brick and increase the thickness of the stave cooler itself, so that the space between the furnace inside and the furnace outside can be constituted only by the thermal stress relaxation type functionally gradient material.

[0035]

According to the stave cooler provided with the stave cooler body made of the thermally stress-relaxed functionally graded material of the present invention, the heat shielding characteristics on the inside of the furnace (heating side) and on the outside of the furnace (cooling side). It is possible to remarkably suppress the occurrence of cracks by exhibiting the thermal stress relieving function against the temperature fluctuation, and to prevent the wear of the furnace wall, and to maintain a stable furnace wall profile for a long time. it can.

Even if the inside of the furnace is worn, the function of the function of inclination in the thickness direction does not change, the inner surface of the furnace shell is not exposed, and the furnace is not excessively cooled. The furnace body heat loss can be suppressed without causing a temperature drop near the wall.

Therefore, a metallurgical furnace such as a blast furnace having a furnace body protection wall according to the present invention can stably operate for a long time without any modulation of the discharge of the charged material and disturbance of the gas flow, and can improve the productivity. Operability such as improvement and reduction of fuel cost can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram and a graph showing characteristics of a stave cooler main body according to the present invention. FIG. 1 (a) is a schematic diagram showing a cross section of the stave cooler main body, and FIG. 1 (b) is a schematic diagram showing a composition distribution in a cross-sectional thickness direction. FIG. 3C is a graph showing characteristics.

FIG. 2 is an explanatory view showing a basic structure of a functionally graded stove cooler of the present invention.

FIG. 3 is a partial cross section when a stave cooler according to an embodiment of the present invention is used in a blast furnace.

FIG. 4 is an exploded perspective view for explaining a configuration of a stave cooler main body according to the present invention.

5A and 5B are explanatory views showing the shapes of holes of a honeycomb refractory panel which is a component of the stave cooler body according to the present invention, wherein FIG. 5A shows a straight hole and FIG. 5B shows a tapered hole.

FIG. 6 is a perspective view showing a steel pipe for passing cooling water.

FIG. 7 is a perspective view showing a helium used for holding a honeycomb refractory panel and a plug-like refractory.

FIG. 8 is a cross-sectional view of a mold showing a casting state of a stave cooler body in one embodiment of the furnace body protection wall of the present invention.

9A and 9B show the shape and specification of a prototype material according to an embodiment of the present invention. FIG. 9A is an explanatory view showing a cross-sectional dimension of a stave cooler body, and FIG. 9B is a volume ratio Vf of a ceramic material and a casting. , FIG. (C) is a graph showing the temperature distribution in the thickness direction, and FIG. (D) is a graph showing the thermal stress distribution in the thickness direction.

FIG. 10 is a partial sectional view showing an example of a conventional stove cooler of a blast furnace.

FIG. 11 is a partial sectional view of a stave cooler of another conventional blast furnace.

FIG. 12 is an enlarged sectional view of a portion X in FIG. 11;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stave cooler main body 2, 4 Ceramic material 3, 5 Metal material 6 Steel pipe 7, 8, 9 Honeycomb refractory panel 10, 11 Plug-like refractory 12 Punching metal 13, 14 Keren 15 Upper sand mold 16 Lower sand mold 17 Runner 18 Tap DESCRIPTION OF SYMBOLS 19 Hot water 20 Iron shell 21 Filler 22 Mounting bolt 23, 23 ₁ Stave cooler main body 24 Brick supporting hardware 25, 26 Furnace wall brick A Inside furnace B Outside furnace

Claims (2)

(57) [Claims] 1. A stave cooler for protecting a furnace shell from heat load in a furnace, wherein the inside of the furnace is made of a ceramic material, and the outside of the furnace is made of a metal material such as cast iron. The volume ratio of the ceramic material is reduced step by step, and conversely, the volume ratio of the metal material is increased stepwise, and the interface is formed and laminated by the jointed metal material layer between the respective layers of the ceramic material. A furnace for a metallurgical furnace, comprising: a stave cooler main body made of a macro-inhomogeneous functionally graded material; and a plurality of steel pipes through which cooling water is passed on a steel shell side in the stave cooler main body and integrally cast. Body protection wall. 2. A laminated composite layer having a thermal stress relieving function against a temperature fluctuation due to a heat load in a furnace is formed in a stave cooler body made of a ceramic material and a metal material. Furnace protection wall for metallurgical furnace.