JPH032362A - Thermal spray roll for steel processing and its manufacturing method - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thermal spray roll, particularly for processing steel billets, steel plates, copper strips, etc., which require anti-glare properties, seizure resistance, and peeling resistance. The present invention relates to a roll for a steel manufacturing process and a manufacturing method thereof.

[Prior art and problems to be solved] Conventionally, thermal spray rolls for treating steel materials that require properties such as wear resistance, peeling resistance, and seizure resistance include (a) JP-A-1507-1507
61, a thermal spraying roll sprayed with a Ni-based or Go-based self-fluxing alloy containing Si% BlC and Fc; (b) chromium carbide (hereinafter referred to as Cr, C2 ) or hard particles such as tungsten carbide (hereinafter referred to as WC) and C01 (: "・5i-B
- There are thermal spray rolls that are sprayed with a material mixed with metals such as Ni-based or CO-based self-fusing alloys containing C and re.

However, although the above-mentioned thermal spray rolls are recognized to function to a certain extent for their respective purposes, they have disadvantages or problems as shown below.

That is, among the above-mentioned thermal spray rolls, the self-fluxing alloy thermal spray roll (a) has excellent peeling resistance and seizure resistance, but is insufficient in terms of wear resistance. In addition, the mixed material thermal spray roll at (mouth) uses Cr during thermal spraying and in the process of feeding the powder to the thermal spraying machine.
Separation occurs between hard particles of 5G or WC and metals such as self-fusing alloys due to differences in particle size and specific gravity, so component segregation is likely to occur in the sprayed coating, and the adhesion yield of Cr, C2 and alumina is low. It becomes a porous film, and not only is it not effective in terms of properties such as abrasion resistance, but also
It has disadvantages such as easy cracking and short life.

The present invention eliminates the drawbacks of the prior art described above, and the produced film is uniform.
It is an object of the present invention to provide a thermal spray roll that is strong and has excellent abrasion resistance, peeling resistance, and seizure resistance, and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above-mentioned [] objective, the present inventors conducted multifaceted research on powder composition, properties, thermal spraying methods, etc. in order to obtain a thermal spray roll with desired characteristics. As a result, we obtained a composite powder that not only has hard particles uniformly dispersed in the metal phase, but also has a novel composite structure in which the hard particles and some of the metal phase are bonded by a partial melt reaction. By thermal spraying on the surface of a metal roll, we succeeded in creating a thermal spray roll with excellent wear resistance, peeling resistance, and seizure resistance.

That is, the present invention basically consists of 10 to 50 area % of hard particles with a particle size of 1 to 100 μm and 90 to 50 area % of a metal phase, which is a matrix alloy phase. A thermal spray roll having a tough thermal spray coating obtained by thermal spraying a composite material powder, which is bonded by melting reaction and in which hard particles are uniformly dispersed in a metal phase, onto the surface of the body. and its manufacturing method.

The composite powder for thermal spraying used in the present invention is composed of composite alloy particles in which hard particles are dispersed and bonded to a metal matrix in a state where they have undergone a partial melting reaction. The structure of each particle of this composite powder is as shown in FIG. It has a strongly bonded composite structure.

The powder with such a composite structure is completely different from the conventional product shown in FIG. 2, which is a simple mixture of self-fusing alloy powder 5 and hard particle powder 6, and is also different from the conventional product shown in FIG. It has a different bonding structure from the other conventional products shown in the figure, in which the surface of self-fusing alloy powder 5 is coated with hard particle powder 6 using an organic or inorganic binder to form a composite. Since the hard particles are partially reacted with the metal matrix to create a composite state, the hard particles and matrix will not separate during thermal spraying.
Compared to conventional thermal spray coatings obtained by properly mixing self-fusing alloy powder and carbide powder, or by thermal spraying using a binder and granulating composite, It has excellent uniformity, density, and wear resistance.

The hard particles to be dispersed have hardness and wear resistance P[, Jf6 royality to Cr3C, (chromium carbide), and carbides such as tungsten carbide, niobium carbide, and titanium carbide can be used, and economically, chromium carbide is optimal. The hard particles are effective if they are uniformly and finely dispersed in the matrix, and the appropriate size of the hard particles is 1 to 100 μm.

Such metal phase and hard particles must be blended in a predetermined ratio, and hard particles 1 with a particle size of 1 to +00 JJlll
It is preferable to set it as the range of 0-50 area% and metal phase 90-50 area%. If the ratio and particle size are outside this range, at least one of wear resistance, peeling resistance, and seizure resistance will be insufficient. That is, if the hard particle blending ratio is less than 10 area % or the particle size is less than 1 μm, the effect of hard particle addition such as wear resistance cannot be obtained, and if the hard particle blending ratio exceeds 5% by area or the particle size is less than 1 μm. Particle size 100μ
If it exceeds m, poor quality such as deterioration in facing properties, pore defects, and cracks will occur, and the desired effect will not be obtained.

Note that since the thermal spray roll of the present invention is obtained by applying the above-mentioned powder mainly by powder type gas flame spraying or plasma spraying, the thermal spray powder particle size is 150 to 20 IJm, preferably 12
A suitable thickness is 5 to 44 um.

The degree of fine uniformity can be determined by observing the microscopic structure of the cross section of the sprayed coating layer.5 The particle size of the hard particles is 1-100tJ11, the area ratio occupied by the hard particle phase is 10-50%, and the area ratio of the metal matrix phase. is 90 to 50%, and exhibits a structure in which the hard particles are uniformly dispersed in the metal matrix phase. Furthermore, it is recognized that the metal matrix phase exhibits a fine structure. Note that the area ratio of each phase can be determined by image analysis.

On the other hand, when conventional self-fusing alloy powder is sprayed,
Only carbides precipitated from the metal matrix are observed. In addition, when a mixed powder of hard particles and r-J soluble alloy is thermally sprayed, the hard particles segregate in areas far away from the cladding material, and some of them aggregate and become coarse, while in the vicinity of the L material, the hard particles conversely A deficiency phase appears, and it is divided uniformly and finely because it is
It will not become an organization with L/.

11f "A preferred example of the thermal spray material for the roll is G.
":1δ~42!I'fi juice% Si:1.4~4.5
ffl amount% B: 1.4 to 4.5% by weight and C: 1.
4 to 5.1% by weight, with the balance consisting of one or two of Ni or Co, and consists of a metal phase of chromium carbide and a self-fusing alloy, so that the surface of the chromium carbide particles is Examples include those that are integrally bonded to the metal phase through a partial melting reaction, and chromium carbide particles are uniformly dispersed in the metal matrix phase.

Here we will explain the reasons for limiting the numerical values of thermal spray materials.

Cr is added to improve oxidation resistance, but if it is less than 16%, oxidation resistance is insufficient. On the other hand, the upper limit is the matrix (
For example, it is set to 42% or less from the solid solubility limit in Ni).

C is necessary to improve the hardness of the matrix and is 1.4%
If it is less than that, insufficient hardness tends to occur, which is disadvantageous. However, if the amount is too large, the embrittlement of the matrix will increase, so 4
．． It was set to 5% or less.

B and Si are both added to increase the tendency for facing (remelting treatment of thermally sprayed coatings), but if each is less than 1.4%, the facing property is poor. If it is too tight, the matrix will become more brittle, so the upper limit is set at 4.
It was set at 5%.

The surface of the thermal spray roll of the present invention coated with such a composite powder consisting of a metal phase and hard particles is coated with a composite powder sow r-1.
The hard particles and metal matrix do not separate or aggregate during thermal spraying, but the hard particles are bonded to the metal matrix in a partially melted reaction state, and the hard particles are uniformly and finely dispersed. It consists of a thermally sprayed coating layer. For this reason, the thermal spray roll of the present invention uses self-fusing alloy powder and carbide hard particle powder at 111% as in the conventional method. It has far superior uniformity, density, abrasion resistance, etc., compared to thermal spray coating rolls that are coated with a mixture of N-N and granulated with a binder or a binder. The roll to be coated may be a commonly used steel roll. received 3ffl
The first choice is sufficient without considering economical efficiency within the range of 0.2 m + n to 2 mm.

[Function] In the present invention, fine hard particles are used to improve the wear resistance of steel processing rolls, and the hard particles and the metal matrix are partially melted and reacted to form a strong bond. Even during thermal spraying, the two do not separate, achieving fine and uniform dispersion. Moreover, the hard particles firmly adhere to the roll surface. Furthermore, by employing a self-fusing alloy composition as the metal matrix phase, a surface layer that is tough and highly wear resistant can be obtained.

[Example] Next, examples of the present invention will be shown together with comparative examples.

(Example 1) A powder obtained by mixing 85 volume % of a Ni-based self-fusing alloy having the composition shown in Table 1 with 15 volume % of Cr and C2 having a purity of 99% or more is melted, rapidly solidified, and the particle size is adjusted. The composite thermal spraying material shown in Table 2 was sprayed on the rotary shaft 7 shown in Fig. 4 by powder gas flame spraying for 1°, and the hardness was measured and the amount of wear of the coating was measured using a Falex tester (ASTMD2670-67). It was measured. The results are shown in Table 3.

The hardness was measured by cutting and polishing the rotating shaft 7 coated with the thermal spray coating 8, and measuring the cross-sectional hardness of 11ν at a load of 300g using a microhardness meter.
(300) was measured. In the Farex test, as shown in FIG. 5, the test rotating shaft 7 (material 545G, diameter 8.2 mmφ) coated with the above thermal spray coating was fixed to the rotating head 9 with a fixing pin 11, and the rotation speed was 225 rpm. A load of 100 kg was applied to the V block 10 (material 545G) with a 96° V groove with a groove width of 6.35 mm formed on both sides at a sliding speed of 0.097 m/sec without using lubricating oil. After applying a continuous load for 10 minutes, the wear weight of the test rotary shaft 7 was evaluated.

Next, micrographs of the cross section of this sprayed layer are shown in FIGS. 6 and 7. Figure i7 shows a higher magnification. The large black flaky phase in the figure is chromium carbide added as purchased particles. The black parts finely distributed in the matrix are carbides and borides in the self-fusing alloy. The matrix is a Ni-[;r alloy. When the tissue shown in Fig. 6 was analyzed using a Lucex 5000 image analyzer, it was found that
The area ratio occupied by the chromium carbide phase was 18.5%.

This indicates that the amount of carbides is much larger than the microscopic structure of the sprayed layer made of only the self-fluxing alloy of Comparative Example 4 (FIG. 8), which will be described later.

(Actual/Ih Example 2) A powder obtained by mixing 85% by volume of a GO-based self-fusing alloy having the composition shown in Table 1 with 15% by volume of Or, C2 with a purity of 119% or more was treated in the same manner as in Example 1. The composite thermal sprayed materials shown in Table 2 obtained in this manner were evaluated in the same manner as in Example 1. The results are shown in Table 3.

(Example 3) Ordinary steel rolls (φ1:10 x 500L and φ220 x 1800
L) Sprayed on the surface of the body to a size of 1 mm x 1.5 mm.

As a result of using a thermal spray roll as a hot steel billet treatment roll, the wear nl was 0.0% even after one year of use. It exhibited excellent abrasion resistance of less than ll'IIm. Moreover, neither peeling nor burning of the thermally sprayed layer tlQ was observed.

(Comparative Example 1) Example 1 A mixed thermal spraying material shown in Table 2 obtained by mixing 85% by volume of open radical self-fusing alloy powder having the composition shown in Table 1 and 15% by volume of Cr3C2 powder having a purity of 99% or more was used. It was evaluated using the same method. The results are shown in Table 3.

(Comparative Example 2) Comparative example 2 obtained by processing a powder obtained by mixing 95% Ni-based self-fusing alloy having the composition shown in Table 1 with Cr3C25% having a purity of 99% or more in the same manner as in Example 1. The composite thermal spray materials shown in Table 2 were evaluated in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Example 3) A powder obtained by mixing 40% by volume of a Ni-based self-fluxing alloy with a composition shown in Table 1 with 60% by volume of Cr3C with a purity of 99% or more was treated in the same manner as in Example 1. The composite thermal spray materials shown in Table 2 were evaluated in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Example 4) Ni-based self-fluxing alloy having the composition shown in Table 1 was
The particle size was set to m, and the evaluation was performed in the same manner as in Example 1. The results are shown in Table 3. Furthermore, a micrograph of the cross section of the sprayed layer is shown in FIG.

(Comparative Example 5) A CO-based self-fusing alloy having the composition shown in Table 1 was
The particle size was set to m, and the evaluation was performed in the same manner as in Example 1.

The results are shown in Table 3.

As is clear from Table 3, Examples 1 and 2 of the present invention all have high hardness and excellent wear resistance, and have excellent performance as a steel processing roll as shown in Example 3. On the other hand, all of Comparative Examples 1 to 5 have low hardness and poor wear resistance. In particular, when sandy particles are mixed with a self-fusing alloy (Comparative Example 1), the hardness is improved compared to Comparative Example 2 which does not contain sandy particles, but the wear resistance is hardly improved.

[Effects of the Invention] As detailed above, the thermal spray roll of the present invention has hard particles uniformly dispersed in the metal phase, and a part of the hard particles and the metal phase are bonded by a partial melting reaction. Because the thermal spray roll is made of composite powder, it has excellent wear resistance, adhesion, and seizure resistance, making it suitable for use as rolls for processing steel materials such as billet steel sheets and copper strips. Excellent economical effects such as life extension can be obtained under the same usage environment.

4. Simple explanation of the drawings FIG. 1 is an explanatory diagram showing the structure of individual particles of a composite powder in which hard particles used in the present invention are dispersed. Figures 2 and 3 are explanatory diagrams showing aspects of conventional mixed powders. Figure 2 shows the case where chromium carbide powder and self-fusing alloy are mixed, and Figure 3 shows the case where chromium carbide powder and self-fusing alloy are mixed, and Figure 3 shows the state of self-fusing alloy powder using a binder. This shows the case of a granulated composite powder coated with chromium carbide powder on the surface of the powder.

Figures 4 and 5 are explanatory diagrams of the Falex test used to determine the abrasion resistance at number of the thermal spray roll in the present invention. The figure shows the Farex test method. Figure 6 shows a microscope "5:
True, Figure 7 is a higher magnification photograph of the same tissue as Figure 6.
FIG. 8 is a micrograph showing the metallographic structure of a thermally sprayed coating layer made only of a self-fusing alloy on a conventional roll.

Claims (3)

[Claims] 1. Hard particles with a particle size of 1 to 100 μm account for 10 to 50 area%
and the matrix alloy phase (hereinafter abbreviated as metal phase) is 90-5
Abrasion resistance, peeling resistance, and seizure resistance characterized by having a thermal spray coating on the body surface that is composed of 0 area% and exhibits a metal structure in which hard particles are uniformly dispersed in the metal phase. Thermal spray roll for steel processing with excellent properties. 2. Hard particles with a particle size of 1 to 100 μm account for 10 to 50 area%
and the matrix alloy phase (hereinafter abbreviated as metal phase) is 90-5
A composite powder consisting of 0 area%, in which the hard particles and a part of the metal phase are partially bonded by melting reaction, and the hard particles are uniformly dispersed in the metal phase, is thermally sprayed on the surface of the body. A method for manufacturing a thermal spray roll for treating steel material, which is coated with a coating and has excellent wear resistance, peeling resistance, and seizure resistance. 3. The composite powder contains Cr: 16-42% by weight, Si: 1
．． 4-4.5% by weight, B: 1.4-4.5% by weight and C
: 1.4 to 5.1% by weight, the balance being Ni or Co
The method for producing a thermal spray roll for treating steel materials according to claim 2, characterized in that the roll has a composition consisting of one or two of the following, and is also composed of chromium carbide (Cr_3C_2) and a metal phase of a self-fusing alloy. .