JPH09125216A - Roll apparatus for hot dip metal coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the wear resistance of a shaft and a bearing by constituting a roll shaft member and the sliding surface of a bearing sliding member by a combination of a ceramics hardly causing wetting to molten metal with a member in which specific hard grains are dispersed and which has solid lubricity. SOLUTION: In hat dip metal coating equipment, a roll shaft member of at least either of a sink roll and a guide roll and at least sliding part surface of a bearing sliding member are constituted of a ceramics (sialon, etc.) hardly causing wetting to molten metal, and a member (carbon, etc.) in which grains (MoSi2 grains, etc.) having a hardness lower than that of the ceramics and higher than that of dross in molten metal are dispersed and which has solid lubricity. By this method, the wear resistance of the shaft and bearing can be improved, and a roll apparatus for hot dip metal coating, having long service life, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal plating apparatus, and more particularly to a bearing for a roll that rotates in molten metal.

[0002]

2. Description of the Related Art The roll shaft and bearing of a conventional hot-dip galvanizing apparatus have been made of stainless steel, high chrome steel, cemented carbide or the like having excellent corrosion resistance. However, even with these materials, when rotating in a molten metal, for example, a zinc plating bath, rattling occurs between the roll shaft and the bearing in about one week, and the roll and plating equipment vibrate accordingly, and the adhesion characteristics of the plating film are There was a problem of lowering it. The reason is that even with a metal material having excellent corrosion resistance, the sliding surface between the roll shaft and the bearing is corroded by the molten metal to cause wear. Therefore, in order to reduce the wear of these roll shafts and bearings, it is important to select a material having excellent corrosion resistance against molten metal. To solve this problem, Japanese Patent Laid-Open No. 3-177552 discloses that the roll shaft is made of ceramic and the roll bearing is made of carbon having solid lubricity. This configuration solves the problem that the roll shaft is corroded by the molten metal and is worn.

Further, Japanese Patent Laid-Open No. 2-101150 discloses that a roll bearing is made of a carbon-metal composite material having solid lubricity. This is to strengthen the mechanical strength of carbon with a metal.

[0004]

In the combination of the above-mentioned prior art ceramic as a roll shaft and a member having solid lubricity as a bearing, a problem occurs in continuous operation in a molten metal plating bath. Dross generated in the bath
(Intermetallic compounds such as Zn-Fe and Al-Fe) enter the sliding surface between the roll shaft and the bearing and cause friction, and at this time dross adheres to the sliding surface of the roll shaft and Shaving and shortening its life. Dross is a component of molten metal, Zn or Al, and a component of the steel sheet to be plated, Fe.
Is a reaction. This hardness is higher than the hardness of a member having solid lubricity, and therefore, if it adheres to the sliding surface of the roll shaft, it will abrade the sliding surface of the bearing. JP-A-2-101150
The invention disclosed in the publication uses a metal for the purpose of improving the strength of the carbon material. Since the hardness of the contained metal is aluminum which is smaller than the dross, there is no effect of suppressing the wear of the bearing.

The object of the present invention is to improve the wear resistance of the shaft and the bearing of the combination of the ceramic and the member having the solid lubricating property even if the dross adheres to the sliding surface of the roll shaft, and to provide a long-life molten metal plating. It is to provide a roll device for use.

[0006]

Means for Solving the Problems The above-mentioned problems are solved by one of a roll shaft which is supported by a bearing and rotates in a metal bath and a bearing sliding surface which is hard to be wetted by molten metal, and the other which is solid lubricity. In a roll apparatus for hot-dip metal plating, which comprises a combination of members having a molten metal, a member having solid lubricity is characterized in that ceramic particles softer than the ceramic and harder than particles (dross) present in a metal bath are dispersed. It is solved by a plating roll device. When there are many types of dross, which are the reaction of Zn and Al, which are the components of the molten metal, and Fe, which is the component of the steel sheet to be plated, the dross with the highest hardness among them is used as the standard and is greater than the hardness. Ceramic particles having hardness may be used.

The term "hardly wet with molten metal" means that the contact angle with the molten metal is as large as possible, preferably 90 ° or more. For example, when the molten metal is aluminum, ceramics such as aluminum oxide, sialon, silicon nitride and titanium nitride have a contact angle of 90 ° or more. Further, the hardness of the material that is difficult to wet with the molten metal needs to be higher than the dross existing in the molten metal and higher than the ceramic particles dispersed in the member having solid lubricity. These depend on the type of dross formed in the molten metal. When the hardness of the generated dross is low, that is,
In the case of plating a molten metal that produces an intermetallic compound having a low hardness, a material having a low hardness such as aluminum oxide can be used as the material that is difficult to wet with the molten metal.

The ceramic particles to be dispersed do not have to be of one type, and for example, particles of solid lubricity such as MoS ₂ and WS ₂ and Y ₂ O ₃ particles having a hardness higher than that of dross may be mixed.

The material having solid lubricity is carbon,
It is a material such as BN. In the case of carbon, it is like a carbon / carbon composite sintered body (C / C composite) obtained by impregnating carbon particles between carbon fibers and sintering, and in the case of BN, a single sintered body or carbon fiber. A material in which BN particles are dispersed in between can be applied.

[0010] Further, a ceramic roll bearing surface which is supported by bearings and rotates in a metal bath has a sliding surface which is hard to be wetted by molten metal.
In a roll device for hot-dip metal plating in which a bearing sliding surface is composed of a combination of members having solid lubricity, ceramic particles softer than the ceramic and harder than particles (dross) present in a metal bath are dispersed in the member having solid lubricity. This is solved by a roll device for hot-dip metal plating characterized by the above.

In a roll apparatus for hot-dip galvanizing, which comprises a combination of a member having a solid lubricating property for a roll shaft sliding surface which is supported by a bearing and rotates in a metal bath, and a ceramic whose sliding surface is hard to be wetted by the molten metal. A roll device for hot metal plating is characterized in that ceramic particles, which are softer than the ceramic and harder than particles (dross) present in a metal bath, are dispersed in a member having solid lubricity.

Further, the molten metal plating bath has at least one sink roll and at least one guide roll, and the sink roll and the guide roll shaft sliding surface are hard to be wetted by the molten metal. In a roll device for hot-dip metal plating, the surface of which is composed of a combination of members having solid lubricity, ceramic particles which are softer than the ceramic and harder than particles (dross) present in the metal bath are dispersed in the member having solid lubricity. It is solved by a roll device for hot-dip galvanizing. A member in which ceramic particles that are softer than the ceramic and harder than particles (dross) present in the metal bath are dispersed in a member having solid lubricity is particularly preferably used for a roll bearing. As the roll shaft member, sialon is preferable as a ceramic that is hard to be wet by molten metal. What is sialon?
_{5.5 A} silicon nitride-based compound represented by a general formula such as Al _0.5 O _0.5 N _7.5 .

It is preferable that the ceramic particles are oxide, carbide, nitride, boride, or silicide ceramic particles, and particularly considering use in a high temperature metal bath, Y ₂ O ₃ , TiO ₂ Oxides, etc., ThC carbides, M
O ₂ N nitride, ThB ₄ boride, MoSi ₂ silicide ceramic materials are preferred.

In a roll apparatus for hot metal plating, which comprises a combination of a ceramic in which at least one of the roll shaft and the bearing sliding surface is hard to be wetted by the molten metal, and the other is a member having solid lubricity, one of the members having solid lubricity is If a member in which ceramic particles that are softer than ceramic and harder than dross are dispersed is used, even if dross enters the sliding surface and adheres to the sliding surface, the ceramic particles act as a scraper, thus suppressing wear. Also, the rotation of the roll is smooth.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) Since the friction coefficient at the sliding surface between the roll shaft and the bearing has a great influence on the wear, the composition of the molten metal was changed to perform the verification by the friction / wear test. The test method was a friction / wear test method in which a test piece was pressed against the side surface of a rotating disk. The test conditions are as follows.

[0016] 1. 1. Rotating test piece: outer diameter 100 mm x thickness 10 mm 2. Fixed test piece: outer diameter 3 mm, length 25 mm Surface pressure: 4 MPa 4. Sliding speed: 10 to 32 m / min 5. Test bath, temperature, time: Zn bath (Zn: 99.40, Pb: 0.18, Fe: 0.02, Al: 0.14) 460 ° C Zn-Al bath (Zn: 44.20, Al: 54) .24, Fe: 0.06) 600 ° C. Al bath (Al: 99.20, Si: 0.50, Fe: 0.06) 680 ° C. 5 h each Sialon ceramic (Vickers hardness; 1300) was selected. As the fixed test piece, a carbon / carbon fiber composite material having solid lubricity (hereinafter abbreviated as C / C composite) and a ceramic particle having different hardness dispersed in the C / C composite were used. C / C
The composite is obtained by preliminarily including a matrix (pitch type) component on the surface of carbon fiber (diameter 1 to 5 μm), hot pressing a fiber bundle having a diameter of 80 to 120 μm into a block, and then firing. Ceramic particles are 2.5% when the matrix component is included in the carbon fiber bundle.
(Vol) was added. The fibers are oriented in a certain direction,
Its content is about 50%. Vickers hardness is 180
SiC, Al as ceramic particles of 0 to 3000
₂ O ₃ , TiC. As ceramic particles having a Vickers hardness of 800 to 1200, Y ₂ O ₃ , TiO ₂ , ThC, Mo
₂ N, ThB ₄ , MoSi ₂ . Vickers hardness is 300 ~
BN, Nb ₂ S ₃ , LaS as 700 ceramic particles
i ₂ was selected. The friction coefficient was obtained by measuring torque.
The amount of wear was determined by the change in the dimensions of the test piece. The above test results are summarized in Table 1.

[0017]

[Table 1]

A combination having a small coefficient of friction and little wear is desirable. Softer than sialon and harder than dross (Vickers hardness: 400 to 750) Y ₂ O ₃ , TiO ₂ , Th
C / Mo ₂ N, ThB ₄ , MoSi ₂ particles dispersed C /
The friction coefficient of the C composite is as low as 0.10 to 0.20, and the wear is as small as 0.2 mm, which is 1/5 of the conventional wear amount. SiC, Al ₂ O ₃ , T, harder than sialon
The friction coefficient of the C / C composite in which iC particles are dispersed is as high as 0.40 to 0.50, and wear is also large at 1.5 mm. BN, Nb ₂ S ₃ , NiSi ₂ softer than dross
The friction coefficient of the C / C composite in which particles are dispersed is 0.
It is as low as 10 to 0.20, but wear is large at 1.2 to 2.0 mm.

From the above test results, when the sialon ceramic is used as the shaft, the Vickers hardness is 800 to 1200.
It was found that the combination with the ceramic particle-dispersed C / C composite bearing in the range of 10 had a low coefficient of friction and little wear.

(Embodiment 2) An embodiment in which the present invention is applied to a sink roll will be described. FIG. 1 shows a schematic sectional view of the continuous hot-dip metal plating apparatus of this embodiment. The steel plate (strip) 1 is supplied through the snout 2, and the plating tank 3
After the direction is changed by the sink roll 4 in the inside of the chamber and the space is passed between the guide rolls 6, it is drawn out from the plating bath 5, and the plating thickness is adjusted by the gas wiping nozzle 7.

FIG. 2 is a schematic sectional view of the shaft portion of the sink roll of this embodiment. The roll shaft 8 was made by machining stainless steel (SUS316) having excellent corrosion resistance. The ceramic sleeve 9 mounted on the roll shaft is hard to get wet with molten metal and has excellent corrosion resistance.
It was made in n).

The ceramic sleeve 9 was prepared by adding a small amount of binder to sialon powder, then wet kneading in methanol, and granulating by a spray dry method. Then, the granulated powder is cold isostatically pressed to an outer diameter of 200 mm and an inner diameter of 1
Molded to a length of 30 mm and a length of 200 mm. After the molded body was preliminarily fired, it was processed to a predetermined size by a lathe in consideration of the dimensional change due to the main firing and the finishing allowance. The main calcination was performed at 1750 ° C. in a nitrogen gas. The dimensions after finishing are 165 mm in outer diameter, 125 mm in inner diameter and 150 mm in length, and the surface roughness on the outer diameter side is Ra 0.04 μm 2.

For assembly of the shaft, the roll ring 8 is provided with a receiving ring 1
After inserting 1, the stainless steel pipe 10 as a stress buffer material is wound around the surface of the roll shaft 8, the ceramic sleeve 9 is fitted therein, and then the ceramic sleeve 9 is axially moved by the pressing ring 12, the spring 13 and the bolt 14. After pressing, the thrust plate 15 was welded and fixed.

FIG. 3 is a schematic sectional view of the bearing. A semicircular C / C is formed on the inner peripheral surface of the metal receiving metal 16.
The composite 17 is attached.

The metal receiving metal 16 was made by machining the same stainless steel (SUS316) as the roll shaft described above. It has a semi-circular dovetail groove 18 and a screw hole 19 so that the C / C composite 17 can be mounted.

The C / C composite 17 is obtained by preliminarily including a matrix (pitch type) component on the surface of carbon fiber (diameter 1 to 5 μm), hot pressing a fiber bundle having a diameter of 70 to 100 μm into a block, It was baked. 2.5% when Y ₂ O ₃ particles (2 to 5 μm) are included in a carbon fiber bundle with a matrix (pitch type) component.
(Vol) was added. The fibers are oriented in one direction and their content is about 50%. This was ground and finished into a semicircular block. This block is attached to the dovetail groove 18 of the metal receiving metal 16 via the contact plate 20, and the bolt 2
Fixed at 1.

The wear of the roll shaft and the bearing was examined when the sink roll having the shaft and the bearing was continuously plated with zinc for 7 days. The wear of the bearing of the conventional method was 8 mm, whereas the wear of the bearing of this embodiment was 2 mm, and the wear on the bearing side was reduced to 1/4. No wear on the sialon sleeves was observed.

(Embodiment 3) An embodiment in which the present invention is applied to a guide roll will be described.

As the roll shaft, the same sialon sleeve as in Example 2 was used. The final finish of the sleeve has an outer diameter of 80
mm, inner diameter 60 mm, length 50 mm, the surface roughness on the outer diameter side is
Ra 0.03 μm. The structure of the shaft is similar to that of the second embodiment.

FIG. 4 is a schematic sectional view of the bearing. A semicircular C / C is formed on the inner peripheral surface of the metal receiving metal 16.
The composite 17 is attached.

The metal receiving metal 16 was made by machining the same stainless steel (SUS316) as the roll shaft described above. It has a semi-circular dovetail groove 18 and a screw hole 19 so that the C / C composite 17 can be mounted.

The C / C composite 17 is obtained by preliminarily including a matrix (pitch type) component on the surface of carbon fiber (diameter 1 to 5 μm), hot pressing a fiber bundle having a diameter of 70 to 100 μm into a block, It was baked. 2.5% when TiO ₂ particles (1 to 5 μm) are included in a carbon fiber bundle with a matrix (pitch type) component
(Vol) was added. The fibers are oriented in one direction and their content is about 50%. This was ground and finished into a semicircular block. This block is attached to the dovetail groove 18 of the metal receiving metal 16 via the contact plate 20, and the bolt 2
Fixed at 1. This guide roll was examined for wear of the roll shaft and the bearing when the zinc-aluminum alloy was continuously plated for 4 days. The wear of the bearing of the conventional method was 6 mm, whereas the wear of the bearing of this embodiment was 2 mm, and the wear on the bearing side was reduced to 1/3. No wear on the sialon sleeves was observed.

[0033]

According to the roll apparatus for hot-dip metal plating of the present invention, since it has a long service life, it can be continuously operated and the productivity is improved. In addition, since the coefficient of friction is low, the rotation of the roll becomes smooth and uniform plating can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a continuous hot-dip metal plating apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a roll shaft used in Examples 2 and 3.

FIG. 3 is a schematic cross-sectional view of a bearing used in Example 2.

FIG. 4 is a schematic cross-sectional view of a bearing used in Example 3.

[Explanation of symbols]

1 ... Steel plate (strip), 2 ... Snout, 3 ... Plating tank, 4 ... Sink roll, 5 ... Plating bath, 6 ... Guide roll, 7 ... Gas wiping nozzle, 8 ... Roll shaft, 9 ... Ceramic sleeve, 10 ... Stainless steel Pipe, 11 ... Receiving ring, 12 ... Retaining ring, 13 ... Spring, 14 ... Bolt, 15 ... Thrust plate, 16 ... Receiving metal, 17 ... C /
C composite, 18 ... Dovetail groove, 19 ... Screw hole, 20 ... Contact plate, 21 ... Bolt.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihiko Okochi Two shares at 832 Horiguchi, Hitachinaka City, Ibaraki Hitachi, Ltd.

Claims (7)

[Claims] 1. A molten metal plating apparatus having at least one sink roll and at least one guide roll in a molten metal plating bath, wherein at least one roll shaft member of the sink roll or the guide roll roll and a bearing slide. A member having solid lubricity in which at least a sliding surface of a member is dispersed with a ceramic which is hard to be wetted by the molten metal, and particles having a hardness lower than that of the ceramic and higher than a dross existing in the molten metal. A roll device for molten metal plating, characterized in that 2. The combination according to claim 1, wherein the roll shaft sliding surface which is supported and rotated by the bearing in the metal bath is made of a ceramic whose sliding surface is hard to be wetted by the molten metal, and the bearing sliding surface of which has solid lubricity. A roll device for hot dip metal plating. 3. A roll apparatus for hot-dip metal plating according to claim 1, wherein particles having a hardness lower than that of the ceramic and higher than a dross existing in the molten metal are ceramic particles. 4. The ceramic particles according to claim 3, wherein the ceramic particles are Y ₂ O ₃ , TiO ₂ , ThC, Mo ₂ N, ThB ₄ , or M.
A roll apparatus for hot-dip metal plating, which comprises at least one of oSi ₂ . 5. A roll apparatus for hot metal plating according to claim 1, wherein the ceramic which is hard to be wetted by the hot metal is sialon ceramic. 6. A roll apparatus for hot metal plating according to claim 1, wherein the member having solid lubricity is a carbon composite material. 7. A roll bearing used by being immersed in a molten metal in a molten metal plating apparatus for immersing a thin metal plate in a molten metal and plating the surface of the thin metal plate with the molten metal. At least the sliding surface is made of a member having solid lubricity in which particles having a hardness lower than that of the roll member combined with the roll bearing and a hardness higher than that of the dross present in the molten metal are dispersed. Roll bearings for hot metal plating.