JPH11293435A - Hot dip metal coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or suppress the formation of intermetallic compds. by the reaction between a retainer made of steel in a hot dip metal coating bath and hot dip metal and to enable long-term stable plating for a steel sheet. SOLUTION: On the contact face (the part in contact with a plating soln.) of a retainer 12 made of steel arranged in a hot dip metal coating bath and a member 11 on the fixed side, with WC-Co sprayed coating interposed, or without interposing sprayed coating, TiAlN coating 14 is formed, and this coating has a compsn. expressed by Ti1-x Alx N, where (x) lies in the range of 0.4 to 0.9 and has 0.5 to 10 μm thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot dip metal plating apparatus used in a continuous hot metal plating bath in which a steel sheet is immersed in a molten metal such as zinc or aluminum for plating.

[0002]

2. Description of the Related Art FIG. 1 shows a configuration of a known continuous molten metal plating apparatus. This apparatus guides a steel sheet 1 heated and annealed in a heating furnace (not shown) to a molten metal tank 2, plating the steel sheet 1 with a molten metal 3, and pulling up the same via a sink roll 4 and a support roll 5. Continuously metal-plated steel plate 6
Is what you get.

FIG. 2 shows the structure of the sink roll 4. The sink roll bearing 7 of the sink roll 4 is a cylindrical sleeve in which the rotation-side member 10 is fitted to a roll shaft or a roll shaft. On the other hand, the fixed side member 11 of the sink roll 4
Has a flat or half-cylindrical shape, and is held by a steel retainer 12. FIG. 3 shows an example of the structure.

FIG. 4 shows a structural example of a support roll bearing 8. The rotation side member 10 of the support roll bearing 8
A roll sleeve or a cylindrical sleeve fitted to the roll shaft. The fixed-side member 11 has a half-cylindrical shape, and is held by a steel retainer 12.

The above-mentioned sink roll 4 is rotated by the movement of the steel plate 1 as power. The rotation of the support roll 5 may be driven by the movement of the steel plate 1 or by a dedicated motor.

[0006] Incidentally, steel equipment such as the above-mentioned rolls, bearings, retainers, support fittings, and snouts are used in a plating bath. For the roll used in the bath, a material having excellent corrosion resistance to molten metal such as stainless steel and high chromium steel is applied. Zn, Al, S constituting plating bath
i is the steel equipment in the bath, for example F to achieve a roll matrix
reacts with e to form an intermetallic compound, which grows on the roll surface and hinders smooth passing of the sheet, or falls off to become a foreign substance and floats in the bath to cause a product defect. For this reason, it is also known to apply a material sprayed with a self-fluxing cobalt alloy or a cemented carbide to the roll surface and various members supporting the roll to prevent a reaction with the molten metal. However, since the component Co contained in the sprayed film is also eluted into the plating bath, C
When the elution of o is completed, it reacts with the base material, so that it is difficult to cut off the contact between the base material and the plating bath. Also,
It has been proposed to form various ceramic films (TiC, SiC, Si ₃ N ₄ , BN films) by the CVD method or the PVD method (JP-A-6-346208).

On the other hand, the rotating side member 10 and the fixed side member 11 of the bearing are made of a material having relatively excellent corrosion resistance to the molten metal constituting the plating bath in the sliding portion, for example, stainless steel, high chromium steel, stellite, Cemented carbide and the like are used. Since the fixed-side member comes into sliding contact with the rotating-side member at a local portion, the amount of wear is greater than that of the rotating-side member. When wear progresses and backlash occurs between the fixed side member and the rotating side member,
The rolls vibrate and significantly impair the plating properties of the steel sheet. Therefore, after 10 to 20 days of operation, even if the bearing member reaches the end of its life and there is no abnormality in the roll, production must be stopped and the entire part immersed in the molten metal plating bath must be replaced. Operational losses are very high.
It is difficult to eliminate corrosion by molten metal even with relatively high corrosion resistance metals such as the above stainless steel, high chromium steel, stellite, cemented carbide, etc., and corrosion wear occurs in parallel with mechanical wear. increase. That is, when corrosion proceeds to some extent, corrosion pits are formed on the sliding surface, which increases friction and accelerates wear. Therefore, the roll bearing in the molten metal plating bath has high corrosion resistance,
Low wear is required. From such a thing,
It is important to select a material having excellent corrosion resistance for the fixed-side member and the rotating-side member, and to combine a material having a low friction coefficient.

Therefore, in order to extend the life of a local bearing used in a hot-dip metal plating bath, Japanese Utility Model Application Laid-Open No.
No. 571 discloses that WC 50 wt% or TiC 50 wt%
% Of a roll for molten metal plating having a shaft and a bearing incorporating a cemented carbide having a composition of at least
No. 43 proposes a roll bearing in which a ceramic sintered body is mounted on the surface of a metal bearing shell. In Japanese Patent Application Laid-Open No. 5-44002, the fixed side member is made of ceramic,
We propose a roll bearing with the rotating side member as cermet,
The ceramics include alumina, silicon nitride or sialon, and the cermets include corrosion-resistant alloys containing high-hardness carbides. Japanese Patent Application Laid-Open No. H5-222499 proposes a roll bearing in which one of a fixed member and a rotating member is a ceramic sintered body and the other is a combination of a solid lubricating material, and as ceramics, alumina, zirconia,
Examples include hard ceramics such as silicon carbide, silicon nitride, and sialon, and ceramics including graphite, boron nitride, molybdenum disulfide, and tungsten sulfide as solid lubricating materials.

However, as described above, since hard foreign matter floats in the plating bath, it enters between the fixed-side member and the rotating-side member, and if the sliding surface is damaged, the friction increases, causing wear. There is a phenomenon that increases. For this reason, graphite and boron nitride are excellent lubricating materials, but because of their low hardness and strength, they are cut by such foreign matter and low wear cannot be achieved.

"Academic Journal of the Ceramic Society of Japan, vol.
105, No2, (1997), p.
_2- SiAlON material, and the rotating member is SiAlO
As N, the coefficient of friction was measured in a zinc bath, and it was found that the coefficient of friction decreased as the amount of TiB ₂ increased, reaching a very low value of about 0.1 at 80 wt%.

However, on the other hand, the TiB ₂ -SiAl
In the case of ON, it is pointed out that the strength of the material is reduced when the content of TiB ₂ is increased, and that the hardness is reduced when the content exceeds 60 wt%.

As described above, if a hard ceramic sintered body having good corrosion resistance in molten metal is applied to the fixed member of the sliding bearing of the roll used in the molten metal plating bath, the fixed member becomes smooth. As a result, wear of both the fixed side member and the rotating side member is reduced, and the life of the bearing can be extended.

However, when a hard ceramic sintered body having good corrosion resistance in molten metal is applied to the fixed side member of the sliding bearing of the roll, the following problems arise. As shown in FIGS. 3 and 4, when a hard ceramic sintered body is applied to the fixed side member 11 of the sliding bearing, the fixed side member 11 of the ceramic sintered body is generally supported by a steel retainer 12. It is a target. In this structure, the fixed side member 11 and the retainer 1
The molten metal enters the gap 2. The intruded molten metal comes into contact with the retainer 12 and gradually becomes Fe—Al or Fe
-Al-Zn intermetallic compound is generated, and the fixed-side member 11
Is pushed up from the back, and the ceramic sintered body is damaged. This phenomenon determines the life of the roll bearing.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a steel device in a molten metal plating bath, particularly a hard metal having good corrosion resistance in a molten metal. In a steel retainer that supports a fixed side member of a sliding bearing of a roll to which a ceramic sintered body is applied, a reaction between Fe and Zn, Al, Si and other molten metal components, which are main components thereof, is prevented, and the It is to extend the life.

[0015]

That is, the present invention provides: (1) A molten metal plating apparatus characterized in that a TiAlN film is formed on a portion of a device placed in a molten metal plating bath which is in contact with the plating bath.

(2) The TiAlN film is made of Ti _1-x Al _x N
Is a composition in which x is in the range of 0.4 to 0.9 and has a thickness of 0.1.
The molten metal plating apparatus according to (1), wherein the thickness is 5 to 10 μm.

(3) A WC-Co sprayed film is formed on a portion of the equipment placed in the molten metal plating bath which comes into contact with the plating solution, and the sprayed film described in (1) or (2) above. T
This is a molten metal plating apparatus characterized by forming an iAlN film.

(4) The equipment placed in the molten metal plating bath is a bearing of a sink roll provided with a stationary member made of a hard ceramic sintered body and a steel retainer.
The AlN film is formed at least on the contact surface between the stationary member and the steel retainer (1) or (2) or (3).
2. The molten metal plating apparatus according to 1.

(5) The equipment placed in the molten metal plating bath is a bearing of a support roll provided with a stationary member made of a hard ceramic sintered body and a steel retainer.
The iAlN film is the molten metal plating apparatus according to (1) or (2) or (3), which is formed on at least a contact surface between the fixed member and the steel retainer.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, the equipment placed in the hot-dip metal plating bath of interest is applicable to all steel equipment such as rolls, bearings, retainers, support fittings, and snouts used in the bath. A sink roll provided with a stationary member made of a hard ceramic sintered body and a steel retainer,
Valid for support roles. The specific configuration is shown in FIGS.

FIG. 5 shows an example of a sink roll bearing. The TiAlN film 1 is formed by ion plating on the entire steel retainer including the entire contact surface between the fixed side member 11 made of a hard ceramic sintered body and the steel retainer 12.
3 is given.

FIG. 6 shows an example of a support roll bearing. The TiAlN film 1 is formed by ion plating on the entire steel retainer including the entire contact surface between the fixed side member 11 made of a hard ceramic sintered body and the steel retainer 12.
Apply 3. After the WC-Co sprayed film is formed on the rotation side 10 of the bearing, for example, Ti _0.5 Al is formed by ion plating.
_{A 0.5} N film 14 is provided.

Various stainless steels, heat-resistant steels, and heat-resistant cast steels can be used as materials for steel equipment. For example, SUS3
16L. These materials have stable mechanical properties, are not severely damaged, and have high reliability. As shown in Japanese Patent Publication No. 55555/1990, stellite overlay welding, C
o-based self-fluxing alloy, WC-Co
A reaction with a plating bath such as n or Al may be suppressed to prevent wear.

When applied to a sink roll or a support roll, a steel retainer or the like is made of stainless steel, high carbon steel.
It can be made of a conventionally known material having excellent corrosion resistance to a molten metal such as steel, stellite, and cemented carbide. On the other hand, high-quality ceramics applied to the fixed-side member include alumina, zirconia, silicon carbide, silicon nitride,
A conventionally known material such as sialon can be applied.

The portion where the TiAlN film is formed is at least the contact surface between the stationary member and the steel retainer. TiAl
The N film is represented by Ti _1-x Al _x N, where x in this chemical formula is a parameter represented by an atomic ratio.
And the atomic ratio of Al to 1-x and x, respectively. In the present invention, the x is 0.4 to 0.9, i.e., the nitride is in the range of _{Ti 0.6 Al 0.4 N~Ti 0.1 Al 0.9} N. The larger x is, the better the corrosion resistance to the molten metal, but the lower the hardness. Conversely, the smaller x is, the higher the hardness is and the higher the wear resistance is, but the corrosion resistance tends to decrease. If x is less than 0.4, the corrosion resistance is low and the film is inevitably eluted in the molten metal. If it exceeds 0.9, the hardness decreases, so that it cannot be applied to equipment requiring abrasion resistance, in particular, to the contact surface between the roll and the steel plate, the contact portion between the rotating side of the bearing and the rotating side of the fixed side. Therefore, x is set to 0.4 to 0.9 in consideration of these characteristics. However, those exceeding 0.9 have good corrosion resistance and are therefore suitable for retainers and support fittings that do not require abrasion resistance.

There is no particular limitation on the method of forming the TiAlN film, but ion plating is preferred because a uniform thin film having good adhesion can be easily obtained. 0.5 to 1 thickness
0 μm. This is because if the thickness is less than 0.5 μm, the service life becomes short, and if it exceeds 10 μm, the film is easily peeled.

The TiAlN film may be made of WC-Co
It can be formed through a thermal spray coating to further extend the service life. A conventionally known method can be applied to the formation of the WC-Co thermal spray coating.

As described above, the TiAlN film is disposed on the support surface of the steel retainer on the back surface of the hard ceramic sintered body at the portion that comes into contact with the plating solution of the equipment placed in the plating bath, particularly at the ceramic bearing. Thereby, generation of an intermetallic compound on the back surface can be prevented. The intermetallic compound prevents the hard ceramic sintered body from being damaged by pushing from the back.

[0029]

(Embodiment 1) This embodiment is an embodiment of a bearing for a sink roll. 140mm × 26
0 mm, length 180 mm steel retainer 12 made of material S
Made with US316L. Then, semicircular fixed member 11 shown in FIG. 5 (internal diameter 140 mm, outer diameter 200 mm, length 140 mm) of _{80wt% TiB 2, 20wt% B} 4
C, made of a material having a theoretical density ratio of 100%.

A 2 μm thick Ti _0.1 Al _0.9 N film 13 was formed by ion plating on the entire inner and outer surfaces including the contact surface of the steel retainer 12 with the fixed member 11. This slide bearing was applied to a sink roll bearing of a continuous galvanizing apparatus. The rotation side member 10 is made of SUS
316L was overlaid and welded with a stellite alloy to a thickness of 3 mm. The bearing has been usable without breakage for the stated 200 days. The maximum wear amount of the fixed side member was 0.4 mm.

(Embodiment 2) This embodiment is an embodiment of a bearing for a support roll. A steel retainer 12 having an outer diameter of 170 mm, an innermost diameter of 120 mm, and a length of 120 mm in FIG.
Is made of SUS316L and the whole surface is 0.1mm thick
Sprayed WC-12 wt% Co. On the other hand, the semicircular fixed side member 11 (inner diameter 120 mm, outer diameter 148
mm, length 80 mm) to 80 wt% TiB ₂ , 20 wt
% TiC, a material having a theoretical density ratio of 100%.

A 2 μm thick Ti _0.1 Al _0.9 N film was formed by ion plating on the entire inner and outer surfaces including the contact surface between the steel retainer 12 and the fixed member 11. On the other hand, a Ti _0.5 Al _0.5 N film 14 having a thickness of 4 μm was formed on the surface of the rotating member 10 by ion plating.

This slide bearing was applied to a bearing of a support roll of a continuous galvanizing apparatus. The working side member was build-up welded to SUS316L with a 3 mm thick stellite alloy. The bearing was able to be used without stopping rotation for the stated 200 days. The maximum wear amount of the fixed side member 11 is 0.8 mm, and the wear amount of the rotating side member 10 is 0.2 mm.
Met. (Comparative Example) This comparative example is an example of a support roll bearing. 4 outer diameter 170mm, innermost diameter 120m in FIG.
m, 120 mm long steel retainer 12 made of SUS
316L, WC-12 with 0.1mm thickness
wt% Co was sprayed. On the other hand, the semicircular fixed side member 11 (inner diameter 120 mm, outer diameter 148 mm, length 8
0 mm) was manufactured using 80 wt% TiB ₂ , 20 wt% TiC, and a material having a theoretical density ratio of 100%.

This slide bearing was applied to a support roll bearing of a continuous galvanizing apparatus. The working side member was build-up welded to SUS316L with a 3 mm thick stellite alloy. When this bearing was used, 12
It could be used without stopping rotation for days, but then became unrotatable. Inspection revealed that the fixed-side member 11 was broken at the center in the length direction. The cause of the fracture was found to be that the intermetallic compound generated on the back surface locally pushed up the fixed-side member. In addition, no abrasion of the fixed side member was observed.

[0035]

As described above, according to the present invention, it is possible to prevent or suppress the formation of intermetallic compounds due to the reaction between the steel equipment and the molten metal in the molten metal plating bath. It becomes possible.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a configuration of a continuous hot-dip metal plating apparatus.

FIG. 2 is an explanatory diagram showing a configuration of a sink roll.

FIG. 3 is an explanatory view showing a structural example of a fixed side member.

FIG. 4 is an explanatory view showing a structural example of a support roll bearing.

FIG. 5 relates to a bearing for a sink roll according to the present invention.
FIG. 4 illustrates an embodiment.

FIG. 6 is a diagram showing an embodiment of a support roll bearing according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Steel plate, 2 ... molten metal tank, 3 ... molten metal, 4 ... sink roll, 5 ... support roll, 6 ... metal plating steel plate, 7
... Sink roll bearing, 8 ... Support roll bearing, 1
0 ... rotary member, 11 ... fixing member, 12 ... steel retainer, 13 ... TiAlN film, 14 ... Ti _0.5 Al _0.5 N
film

Claims (5)

[Claims] 1. A hot-dip metal plating apparatus, wherein a TiAlN film is formed on a portion of a device disposed in a hot-dip metal plating bath, which is in contact with a plating bath. 2. The TiAlN film has a composition in which x is in the range of 0.4 to 0.9 as represented by Ti _1-x Al _x N and a thickness of 0.5 to 0.9.
The molten metal plating apparatus according to claim 1, wherein the thickness is 10 µm. 3. The TiAlN film according to claim 1 or 2, wherein the TiAlN film according to claim 1 or 2 is formed via a WC-Co sprayed film on a portion of the equipment placed in the molten metal plating bath that comes into contact with the plating solution. Molten metal plating equipment. 4. An apparatus arranged in a hot-dip metal plating bath is a bearing of a sink roll provided with a fixed side member made of a hard ceramic sintered body and a steel retainer.
The molten metal plating apparatus according to claim 1, wherein the N film is formed on at least a contact surface between the fixed member and the steel retainer. 5. An apparatus arranged in a hot-dip metal plating bath is a bearing of a support roll provided with a fixed member made of a hard ceramic sintered body and a steel retainer, and is made of TiA.
The molten metal plating apparatus according to claim 1, wherein the 1N film is formed at least on a contact surface between the fixed-side member and the steel retainer.