JPH08268767A - Metallic fiber reinforced monolithic refractory - Google Patents

Abstract

PURPOSE: To obtain a refractory improved in toughness while maintaining is workability and particularly excellent in prevention of flawing and peeling at the time of using it by adding a combination of several kinds of metallic fiber having different lengths from each other to a monolithic refractory in specified ratios. CONSTITUTION: This reinforced refractory is obtained by adding to a monolithic refractory, a combination of metallic fiber I having a 0.2 to 1.5mm cross-sectional maximum diameter and a 20 to 50mm length and one kind of metallic fiber II having a 0.2 to 1.5mm cross-sectional maximum diameter and a 1 to 20mm length or two or more kinds of the metallic fiber II having different lengths from each other to reinforce the refractory. Therefore, the metallic fiber I has a longer length than that of the metallic fiber II. In the reinforced monolithic refractory, the amount of the metallic fiber I and the total amount of the metallic fibers I and II added to the unreinforced monolithic refractory are 1 to 5 pts.wt. and <=35 pts.wt., respectively, based on 100 pts.wt. of the unreinforced refractory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal fiber reinforced amorphous refractory, and more specifically, toughness while maintaining workability,
The present invention relates to an amorphous refractory material having improved heat resistant spalling property and the like.

[0002]

2. Description of the Related Art In recent years, the demand for amorphous refractories has increased as the quality stability has been evaluated in addition to the voluntary construction, labor saving, etc. Has been widely used in the field of. However, along with it, it has become more important to solve the problem of damage due to cracking and peeling during use.
To solve this problem, by adding metal fibers to the amorphous refractory, it is possible to improve the strength and toughness of the material,
Techniques have been proposed to prevent cracking caused by thermal spalling or structural spalling during use and prevent delamination.

For example, Japanese Laid-Open Patent Publication No. 62-143880 discloses an amorphous refractory to which stainless steel fibers are added in an amount of 2 to 4% by weight in order to increase the breaking energy of the refractory. This refractory contains silicon carbide fine powder, alumina and silica as main components, and the addition of stainless steel fibers suppresses the occurrence of cracks. However, with the upper limit of 4% by weight of the metal fiber added, the fracture energy of the refractory is not sufficient and the crack generation preventing action is insufficient. On the other hand, if the addition amount of the stainless steel fiber exceeds 4% by weight, there is a problem that workability of the refractory material deteriorates.

Further, JP-A-6-144938 discloses that a length of 10 is used for the purpose of preventing cracks and peeling from occurring in a basic amorphous refractory material.
Disclosed is a refractory to which 1 to 10 parts by weight of a metal fiber having a diameter of -30 mm is externally added. However, this refractory also has insufficient spalling resistance, and if the amount of the metal fiber added exceeds 10 parts by weight, the workability during kneading is impaired and the amount of slag infiltrated increases. There's a problem.

In any case, there is a contradiction that the workability decreases when the toughness of the refractory is improved.
Due to recent advances in refining technology, requirements for refractory materials are becoming more and more severe, and in order to meet the requirements, amorphous refractory materials having improved workability and toughness are desired.

[0006] Therefore, an object of the present invention is to provide an amorphous refractory material which is improved in toughness while maintaining workability and is extremely excellent in preventing cracks and peeling during use.

[0007]

As a result of earnest research in view of the above problems, the present inventor has combined metal fibers having different lengths at a specific ratio and adding them to an amorphous refractory material to form an amorphous refractory material. The present invention has been completed by discovering that an irregularly shaped refractory material that is significantly excellent in preventing cracking and peeling can be obtained without impairing workability.

That is, the metal fiber reinforced amorphous refractory of the present invention has a maximum cross-sectional diameter of 0.2 to 1.5 mm and a length of 20 to
50 mm metal fiber I and maximum cross-section diameter 0.2-1.5
It is reinforced by adding one type of metal having a length of 1 to 20 mm or two or more types of metal fibers II having different lengths,
The metal fiber I is longer than the metal fiber II, and when the content of the amorphous refractory excluding the metal fiber is 100% by weight, the addition amount of the metal fiber I is 1 to 5% by weight on the outer shell, and It is characterized in that the total amount of the metal fibers is 35% by weight or less on the outside.

Hereinafter, the present invention will be described in detail. The metal fiber reinforced amorphous refractory of the present invention is formed by adding metal fibers to the amorphous refractory.

[1] Irregular refractory material As the irregular refractory material used in the present invention, it is preferable to use a so-called casting irregular refractory material. The composition of the castable amorphous refractory is not particularly limited, but as an example, alumina, silica, mullite, magnesia, zircon,
Examples of the main material include one or more refractory aggregates such as zirconia, spinel, silicon carbide and carbon. In addition to refractory aggregates, binders such as alumina cement, dispersants,
A flocculant, an anti-explosion-proof agent, a thickener, etc. are added as appropriate.

[2] Metal Fibers The metal fibers added to the above-mentioned amorphous refractory have a maximum cross-sectional diameter of 0.2 to 1.5 mm and a length of 20 to 50 mm, and a maximum cross-sectional diameter of 0.2 to 1.5 mm. 1 to 20 in length
mm or two or more types of metal fibers with different lengths
II. However, the metal fiber I is longer than the metal fiber II.

(1) Material and shape The material of the metal fiber is a metal having excellent heat resistance and oxidation resistance at 1000 ° C. or higher, and includes stainless steel, carbon steel, high tensile strength steel, heat resistant steel, Cu, Al, Mo, Ti, Nb, B
Examples include special alloy steels containing one or more elements such as e, N, and B. Above all, it is most preferable to use stainless steel from the viewpoint of corrosion resistance. The shape of the metal fiber may be linear or curved (mountain shape, corrugated shape, dog bone shape, etc.). The metal fibers I and II may have the same length, but may be a mixture of different lengths within the above range.

(2) Maximum cross-sectional diameter With respect to the maximum cross-sectional diameter, both metal fibers have a maximum diameter of 0.2.
The range is up to 1.5 mm. If it is less than 0.2 mm, the strength of the metal fiber itself is weak, so that it is not effective in improving the toughness of the amorphous refractory material. It serves as an infiltration route for molten pig iron and the like and impairs the durability of the material. The maximum cross-sectional diameter of the preferred metal fiber is 0.3-0.8
mm. Also, metal fiber I and metal fiber II
The maximum cross-sectional diameters of and may be the same or different as long as they are within the above range, but it is preferable that they are substantially the same from the viewpoint of manufacturing cost.

(3) Metal fiber I The length of the metal fiber I is 20 to 50 mm. When the metal fiber I is shorter than 20 mm, the breaking energy due to the entanglement of the metal fiber is not improved, and when it is longer than 50 mm, the workability is deteriorated. The preferred length of the metal fiber is 20-30 mm.

The amount of the metal fiber I added is 1 to 100% by weight of the amorphous refractory excluding the metal fiber in an external amount.
It is 5% by weight. Addition amount of metal fiber I is 1% by weight
If it is less than the above, the breaking energy is not improved and the effect of adding the metal fiber is not obtained. On the other hand, if it exceeds 5% by weight, the fibers are entangled with each other during kneading, not only the workability is significantly deteriorated, but also the durability of the material is rather deteriorated. The preferable addition amount of the metal fiber I is 2 to 4% by weight.

(2) Metal Fiber II The metal fiber II is composed of one kind having a length of 1 to 20 mm or two or more kinds of metal fibers having different lengths. The metal fiber II is shorter than the metal fiber I regardless of one kind or two or more kinds. As a result, two or more kinds of metal fibers having different lengths are present in the amorphous refractory, and the synergistic effect of both metal fibers can be obtained.

The addition amount of the metal fibers II is set so that the total amount of the metal fibers (I + II) is 35% by weight or less, with 100% by weight of the amorphous refractory excluding the metal fibers. Therefore, the amount of the metal fiber II added is 34% by weight or less on the outside. The total amount of metal fibers (I + II) is 35
When it exceeds the weight%, workability is significantly deteriorated. If the addition amount of the metal fiber II is less than 3% by weight, the breaking energy is not improved, and if it exceeds 34% by weight, the workability is remarkably deteriorated.
It is preferably about 34% by weight.

When the metal fiber II is composed of two kinds of metal fibers having different lengths, the metal fiber II _A having a length of 10 to 20 mm and the metal fiber II _B having a length of 1 to 10 mm
It is preferable to set so that the metal fiber II _A is longer than the metal fiber II _B. At this time, the weight ratio of the metal fiber II _A and the metal fiber II _B is preferably 1:10 to 10: 1. If the amount of the metal fibers II _B is too large, the effect of preventing crack growth immediately after fracture is insufficient, and if it is too small, the effect of preventing crack growth at the end of fracture becomes insufficient. Naturally, it is also possible to combine three or more kinds of metal fibers II having different lengths.

The amounts of the metal fibers I, II _A and II _B added (expressed as% by weight per 100% by weight of the amorphous refractory excluding the metal fibers) are externally applied to W _I , W _IIA and W, respectively.
_In the case of _IIB , it was discovered that the value of the formula: W _I × (W _IIA + W _IIB ) is an important factor that determines effective fracture energy, corrosion resistance, workability, and the like. Since the workability gradually deteriorates as the amount of the metal fiber I increases, (W
The permissible range of _IIA + W _IIB ) decreases, and vice versa. Therefore, various lengths of metal fibers I, II _A and I
As a result of examining the combination of I _B , from the viewpoint of effective breaking energy, corrosion resistance, workability, etc., W _I × (W _IIA
It has been found that the range of + W _IIB ) is preferably 15 to 120. When the value of W _I × (W _IIA + W _IIB ) is less than 15, the breaking energy is not improved and the addition of metal fiber is insufficient, and when the value of W _I × (W _IIA + W _IIB ) exceeds 120. It is not preferable because the workability is deteriorated, the amount of water added is increased, the structure of the construction body is weakened, and the corrosion resistance is reduced.

[0020]

The long metal fiber has a high resistance to cracking in the refractory and thus increases the breaking strength. The short metal fibers are effective in preventing the propagation of cracks and have little effect on workability. In the present invention, by adding a long metal fiber and a short metal fiber in a desired ratio in combination to an amorphous refractory, while maintaining high workability, while improving the toughness of the refractory, thermal and It is possible to prevent crack initiation and propagation due to structural spalling.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following specific examples, but the present invention is not limited to these examples.

Reference Examples 1 to 4 A high-alumina amorphous refractory having the composition shown in Table 1 was used as a metal fiber having a diameter of 0.5 mm and a length of 25 mm, 15 mm and
7.5 mm stainless steel (SUS430) fibers I, II _A and II _B were added. Table 2 shows the amounts of SUS430 fibers I, II _A, and II _B added in Reference Examples 1 to 4 (% by weight per 100% by weight of the amorphous refractory excluding metal fibers).

Table 1 Amorphous Refractory Composition Composition Addition Amount (wt%) Sintered Alumina Particle Size 10 to Over 1 mm 45 Sintered Alumina Particle Size 1 to 0.075 mm over 25 Sintered Alumina Particle Size 0.075 mm or Less 26 Alumina Cement 4 Dispersant (sodium hexametaphosphate) 0.1

Table 2 Addition amount (wt%) of metal fiber Example No. I (25 mm in length) II _A (15 mm in length) II _B (7.5 mm in length) Reference Example 1 0 0 0 Reference Example 2 3 0 0 Reference Example 3 0 5 0 Reference Example 4 0 0 5

40 mm x 40 mm after kneading the castable refractory of each composition with the same amount of water (7.0% by weight on the outside)
A sample was obtained by casting in a mold of × 160 mm. These samples were subjected to a destructive test after firing at 1000 ° C. for 3 hours. The destructive test is performed by the 3-point bending test method, and the displacement speed of the load roll of the tester is constant (100 μm / min)
As, the displacement amount at each load value was measured. The measurement results are shown in FIG.

As shown in FIG. 1, in the case where the metal fiber I was added (Reference Example 2), the maximum load value at the time of breaking the material was increased as compared with the case where the metal fiber was not added (Reference Example 1). , The effective breaking energy is increasing. From this, it can be understood that the relatively long metal fiber I has an action of increasing resistance to crack generation in the amorphous refractory due to its entanglement. However, if too much metal fiber I is added, the fibers are entangled with each other during kneading, and the amorphous refractory material is involved,
In addition to uneven casting, the workability is deteriorated, for example, the amount of water added increases. As a result, the durability of the material is rather lowered.

Further, as is apparent from FIG. 1, when the metal fiber II _A was added alone (Reference Example 3), it was 100 to 300.
In the displacement region of μm, and when the metal fiber II _B is added alone (Reference Example 4), the displacement region of 200 to 500 μm
Metal fiber I alone added (reference example 2)
The value of the load has increased compared to. Therefore, the metal fiber II _A has a shorter fiber length than the metal fiber I.
It can be seen that and II _B have almost no effect of increasing the maximum value of load, but they are effective in preventing crack growth. That is, since the fiber length is short, it is difficult to get entangled in the amorphous refractory material, and it is possible to add a larger amount than the metal fiber I. Therefore, it is considered that the number of metal fibers can be increased, and as a result, the resistance to crack propagation is increased.

Example 1 and Comparative Example 1 A high-alumina amorphous refractory having the composition shown in Table 1 above,
SUS430 fibers I and II _A with the same diameter and length as the reference example
And II _B were added. SUS430 Fiber I, II _A and II
Table 3 shows the amount of _B added (based on 100% by weight of amorphous refractory excluding metal fiber).

Table 3 Addition amount of metal fiber (% by weight) Example No. I (length 25 mm) II _A (length 15 mm) II _B (length 7.5 mm) Example 1 3 5 5 Comparative Example 1 0 0 0

A sample was prepared under the same conditions as the reference example and a destructive test was conducted. In the three-point bending test method, the displacement speed of the load roll of the tester is constant (100 μm / min),
The displacement amount of the roll at each load value was measured. The measurement results are shown in FIG.

As shown in FIG. 2, metal fibers I and II
_The amorphous refractory of Example 1 to which all _A and II _B were added,
The load value is remarkably improved as compared with the additive-free Comparative Example 1. Further, the amorphous refractory material of Example 1 is referred to as Reference Examples 2 to 4.
The load value is improved over a wider displacement range than that of This is because, when all the metal fibers I, II _A and II _B are contained, the value of load is remarkably increased due to the synergistic effect of each metal fiber and the effective breaking energy is remarkably increased.

Example 2 Using the same material and method as in Example 1, W _I × (W _IIA + W
Samples were prepared by variously changing the addition amounts of SUS430 fibers I, II _A and II _B so that the value of ( _IIB ) became 0 to 160. However, when W _I × (W _IIA + W _IIB ) = 0, the SUS430 fiber was not added. The following composition was used as an erosion agent: CaO 42 wt% SiO ₂ 14 wt% Al ₂ O ₃ 29 wt% Fe ₂ O ₃ 10 wt% MnO 5 wt% slag was used.
An immersion test was carried out at 00 ° C. for 5 hours to determine the amount of melting loss. SUS4
30 Fibers I, II _A and II _B addition, W _I × (W
_IIA + W _IIB ) and the typical measured values of the amount of erosion are shown in Table 4.

Table 4 No. I II _A II _B W _I × (W _IIA + W _IIB ) Melt loss (mm / 5h) 1 0 0 0 0 0 3.0 2 5 5 1 1 10 10 3.0 3 3 3 3 3 18 30 3.0 4 3 16 16 16 96 3.2 5 5 12 12 120 3.3 6 5 13 13 13 130 3.8 7 5 14 14 140 140 4.2 8 5 16 16 16 160 4.5

The relationship between the value of W _I × (W _IIA + W _IIB ) and the amount of erosion is shown in FIG. From FIG. 3, W _I × (W _IIA +
It can be seen that when the value of W _IIB ) exceeds 120, the amount of melting loss increases and the corrosion resistance decreases.

Next, the same materials as described above were kneaded and cast into a flow cone, deframed on a flat table, and dropped for 15 times. Then, the extent of spread of the sample was measured and the tap flow value was measured. I asked. The tap flow value of each sample when the tap flow value when no metal fiber was added was 100 was determined as the workability index. FIG. 4 shows the results. The smaller the workability index, the worse the liquidity. From FIG. 4, W _I ×
It can be seen that when the value of (W _IIA + W _IIB ) exceeds 120, workability deteriorates, the amount of water added increases, the structure of the construction body becomes brittle, and the fracture energy decreases.

Further, a destructive test was conducted in the same manner as in Example 1,
From the obtained load-displacement curve, the effective fracture energy (Γeff) of the sample was calculated by the following formula. Γ eff = U / 2A (where U represents the work amount obtained from the area surrounded by the load-displacement curve and the displacement axis, and A represents the fracture area of the sample).

The value of the effective fracture energy represents the magnitude of toughness at the time of fracture of the sample. The result of effective breaking energy is shown in FIG. From FIG. 5, W _I × (W _IIA +
It can be seen that when the value of W _IIB ) is less than 15, the improvement in fracture energy is small and the effect of adding metal fibers is insufficient. From the results of FIGS. 3, 4 and 5, W _I × (W _IIA
It can be seen that the value of + W _IIB ) is preferably in the range of 15 to 120.

Examples 3 to 7 and Comparative Examples 1 to 5 With respect to 100% by weight of the high-alumina amorphous refractory material shown in Table 1, SUS430 fibers I and II were used in the proportions (outer coating) shown in Table 5.
_A and II _B were added. The diameter of each SUS430 fiber was 0.5 mm. Similar to Examples 1 and 2, workability, effective breaking energy, bending strength, and melt loss were determined. The results are shown in Table 6. The bending strength is Japanese Industrial Standard R
Calculated according to 2553-72.

Table 5 Addition amount of SUS430 fiber (100% by weight of amorphous refractory) I II _B II _B W _I × Example No. (length 25 mm) (length 15 mm) (length 7.5 mm) (W _IIA + W _IIB ) Example 3 3 3 3 18 Example 4 3 16 16 96 Example 5 5 3 2 25 Example 6 2 9 9 36 Example 7 4 10-40 Comparative Example 1 − − − 0 Comparative Example 2 5 16 16 160 Comparative Example 3 10 −− 0 Comparative Example 4 − 10 10 0 Comparative Example 5 − 14 − 0

Table 6 Experimental Results Effective Fracture Energy Bending Strength Melt Loss Amount Example No. Workability ⁽¹⁾ (× 10 ⁶ erg) (kgf / cm ² ) (mm / 5hr) Example 3 ○ 0.96 110 3.0 Example 4 ○ 1.45 115 3.2 Example 5 ○ 1.12 120 3.0 Example 6 ○ 1.23 108 3.0 Example 7 ○ 1.15 116 3.1 Comparative Example 1 ○ 0.10 100 3.0 Comparative Example 2 × 0.63 80 4.5 Comparative Example 3 × 0.65 78 3.8 Comparative Example 4 ○ 0.32 98 3.4 Comparative example 5 ○ 0.20 95 3.1 Note (1) ○: Workability index is 90 or more. X: Workability index is less than 90.

As is clear from Table 6, in Examples 3 to 7, by adding metal fibers having different lengths in combination to the amorphous refractories, the toughness was significantly improved without impairing workability. As a result, it was possible to obtain an excellent construction body having a sufficient durability for a site requiring high heat-resistant spalling property such as rapid heating and quenching.

[0042]

As described in detail above, by adding a combination of metal fibers having different lengths to an irregular shaped refractory, it is possible to maintain high workability, high toughness, thermal and structural spalling. It is possible to obtain a refractory having cracks prevented. The amorphous refractory material of the present invention having such characteristics is suitable for use as a refractory material for molten metal and molten slag such as tapping gutter, ladle, tundish, pig iron wheel, lance, tuyere, dip pipe, etc. is there.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between load and displacement in Reference Examples 1 to 4.

FIG. 2 is a graph showing the relationship between load and displacement in Example 1 and Comparative Example 1.

FIG. 3 shows the amount of erosion loss and W _I × (W _IIA + W in Example 2
_IIB ) is a graph showing the relationship with the value.

FIG. 4 is a workability index and W _I × (W _IIA in Example 2;
3 is a graph showing the relationship with the value of + W _IIB ).

FIG. 5: Effective breakdown energy and W _I × in Example 2
It is a graph which shows the relationship with the value of ( _WIIA + _WIIB ).

Claims (3)

[Claims] 1. The maximum cross-sectional diameter is 0.2 to 1.5 mm and the length is 20.
~ 50mm metal fiber I and maximum cross section diameter is 0.2 ~ 1.
In an irregular shaped refractory reinforced by adding one kind of 5 mm and a length of 1 to 20 mm or two or more kinds of metal fibers II having different lengths, the metal fiber I is longer than the metal fiber II, When the amorphous refractory excluding the metal fiber is 100% by weight, the addition amount of the metal fiber I is 1 to 5% by weight on the outside, and the total amount of the metal fibers is 35% by weight or less on the outside. Irregular shaped refractory characterized by being present. 2. The amorphous refractory material according to claim 1, wherein the metal fiber II comprises a metal fiber II _A having a length of 10 to 20 mm and a metal fiber II _B having a length of 1 to 10 mm. II _A is the metal fiber
Irregular refractory characterized by being longer than II _B. 3. The amorphous refractory material according to claim 2, wherein the amorphous refractory material excluding the metal fibers is 100% by weight, and the amount of the metal fibers I, II _A and II _B added (% by weight). If the numerical values (displayed in) are W _I , W _IIA, and W _IIB , respectively, then W _I ×
An amorphous refractory material having a value of (W _IIA + W _IIB ) of 15 to 120.