JPH0570915A - Roll device for hot-dip plating bath - Google Patents

Abstract

PURPOSE:To highly extend the service life of a roll device in bath by constituting a bearing of the roll and the surface layer of the roll shaft used by dipping in the hot-dip plating bath with a ring-like graphite series single material. CONSTITUTION:The roll shafts 8 at both ends of the roll 3 are supported with roll hangers 7 through the bearings 9 and dipped into the hot-dip plating bath to guide a strip. In the above roll device for hot-dip plating bath, the bearing 9 and desirably, the surface layer of the roll shaft 8 are constituted with the ring-like graphite series single material. Further, clearance between the roll shaft 8 and the bearing 9 is preferable to be 0.5mm in the max. By using a material having excellent wettability resistance and self-lubricity to this hot-dip plating bath, corrosion of the roll shaft 8 is restrained and damage of the bearing 9 is prevented, and the service life of the roll device is extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll device such as a sink roll and a support roll which is used by immersing it in a molten zinc or aluminum bath.

[0002]

2. Description of the Related Art As typical prior art of a bearing structure in a device of this type, there are JP-A-1-316443 and JP-A-2-
No. 101150 is disclosed in each of these publications. FIGS. 6 and 7 relate to the former example and are cross-sectional views of the case where an integrated ceramic ring is mounted and the case where half-block ceramics are mounted. In addition, FIG. 8 is a partial cross-sectional front view of the latter example. 6 and 7, in a molten metal plating apparatus provided with a roll which is supported by a bearing in metal melt and rotates, a bearing made of a ceramic ring 11 or a bearing made of a ceramic block 13 is placed between the roll shaft and the shaft. A ceramic sintered body is mounted on the surface of the metal bearing shell 12 so as to be rotatable through the molten metal, and this is intended to prolong the service life.

On the other hand, the example of FIG. 8 is characterized by a structure in which the bearing 18 is made of a carbon-based material which is a complex with a metal.

[0004]

In each of the examples shown in FIGS. 6 and 7, the conventional bearing is made of a metal of chromium-based heat-resistant steel, which causes play due to corrosion and wear in the metal plating bath, which adversely affects the surface quality of the product. It was made in order to solve the problem that it had a life of about 10 days for that reason,
As shown in the diagram of the sliding wear test results for various bearing materials in FIG. 9, the service life has not been significantly extended. In addition to these, there are those using a thermal spray material such as tungsten, tungsten carbide, and cobalt, but the results are the same.

On the other hand, the example of FIG. 8 takes advantage of the excellent corrosion resistance, heat resistance, self-lubricating property, and wettability with metal of carbon, and can withstand continuous use for 30 days. It is clear that even if each of the above performances is excellent, it is not possible to achieve a long life unless the corrosion resistance of the roll shaft or the gap between the roll shaft and the bearing is carefully considered. There is.

Usually, since it is used in a molten metal, the surface pressure is applied only to the upper side of the bearing, so that a large clearance is generally taken between the roll shaft and the bearing. However, in that case, the dross in the bath is caught in the gap to cause uneven wear of the roll shaft, which damages the ceramic sintered body or the carbon-based composite material, resulting in a short life. Further, in the case of a sprayed bearing, the sprayed layer peels off, which is a serious problem. An object of the present invention is to extend the life of the in-bath roll device by improving the material and structure of the roll shaft and bearing of the roll device for hot dip bath.

[0007]

In order to achieve the above-mentioned object, the present invention has the constitution described below. That is, in a roll device for a hot dip bath in which roll shafts at both ends of the roll are rotatably supported via bearings and are immersed in a hot dip bath, the bearing is made of a ring-shaped graphite-based simple substance. It is a roll device for a hot dip bath.

Further, in the present invention, in a roll apparatus for a hot dip bath in which roll shafts at both ends of a roll are rotatably supported via bearings and are immersed in a hot dip bath, the bearing and the surface layer of the roll shaft are rings. It is a roll device for a hot dip bath, which is made of a simple graphite-based simple material.

The present invention is also a roll device for a hot dip bath, characterized in that the clearance between the roll shaft and the bearing is at most 0.5 mm.

[0010]

According to the present invention, by using a graphite-based simple substance as the bearing material, C0 and C0 ₂ are generated immediately after immersion in the bath, but thereafter stabilize in a short time. Although pores are generated also at this time, the bath metal does not penetrate because it has excellent wettability with respect to the zinc or aluminum alloy. Further, by using a graphite-based simple material for the roll shaft, it is possible to suppress corrosion of the roll shaft, and it is possible to prevent damage to the bearing material.
Specifically, by providing a graphite sleeve on the metal shaft, there is no problem in terms of surface pressure even if the width is the same as the conventional one.

Further, by combining the bearing shape with a ring and using a graphite material having excellent wettability with the molten metal, the molten metal is prevented from entering the contact surface between the bearing and the roll shaft. Therefore, it is possible to suppress wear and play of the bearing and the roll shaft.

Further, due to the self-lubricating property of graphite, there is no problem even if the clearance is strictly controlled to prevent the molten metal from entering, and the slip of the roll can be suppressed.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic structural view of a continuous hot-dip metal plating apparatus according to an embodiment of the present invention. The hot-dip galvanized strip 6 was immersed in a plating bath 2 through an annealing furnace (not shown), a snout 1, was vertically changed by a sink roll 3, passed through a support roll 4, and provided directly above the bath surface. The amount of adhesion is controlled by the wiping nozzle 4.

FIG. 2 is a front view of the sink roll 3 shown in FIG. 1, showing the bearing portion in section. In the sink roll 3, the roll shafts 8 at both ends are fixed to the roll hanger 7 via bearings 9. The bearing 9 is entirely made of a graphite-based single material. Although not shown, the bearing 9 is positioned and fixed by using the roll hanger 7 and the roll shaft 8. The clearance between the roll shaft 8 and the bearing 9 is controlled to 0.5 mm or less in order to prevent molten metal from entering or floating dross to be caught. This value takes into account the thermal expansion at the bath temperature used. Alternatively, the rotational movement of the sink roll may be confirmed during the offline preheating.

Since the graphite-based material has excellent wettability with respect to the zinc alloy and the aluminum alloy of this embodiment, if the clearance is controlled to an appropriate value, the molten metal does not enter the contact surface. When soaking in the bath,
It is important to manage the clearance and perform sufficient preheating before immersion.

FIG. 3 is a front view of the sink roll 3 of the continuous hot-dip galvanizing apparatus according to another embodiment of the present invention, showing a bearing in partial cross section. This example is characterized by a structure in which the roll shaft 8 is covered with a graphite sleeve 10 similar to the bearing 9. As the material of the conventional roll shaft 8, chrome heat-resistant steel or stellite build-up, thermal spraying, etc. have been adopted, but they end up causing unhealthy wear due to corrosion by molten metal or biting of dross. This causes damage to the bearings, resulting in backlash and problems in sheet passing, and transfer of the groove pattern of the sink roll to the product surface. As a result, they had to replace it in 10 to 15 days.

On the other hand, in this embodiment, by providing the graphite sleeve 10, it is possible to prevent the roll shaft 8 from being corroded and worn, and to achieve a long service life. That is, specifically, the apparatus of the present embodiment was set to 0.16% Al at 460 ° C
When installed and operated in a Zn alloy bath, no problems occurred even after continuous use for 40 days.

FIGS. 4 and 5 are enlarged sectional views showing a sink roll bearing portion of the continuous hot-dip metal plating apparatus according to each embodiment of the present invention. FIG. 4 shows an example in which the shape of the bearing 9 is improved, and shows a method of mounting the bearing 9 and the roll hanger 7. The bearing 9 is of a screw-in type. The bearing 9 is screwed to fix it to the roll hanger 7. In addition, a protective cover 11 is provided to further extend the life.

FIG. 5 shows an example in which the shape of the graphite sleeve 10 is improved, and the contact area between the sleeve 10 and the bearing 9 is increased. Further, the sleeve 10 is of a screw type like the bearing 9 described above. If the clearance between the roll shaft 8, the bearing 9 and the sleeve 10 is too large, damage will occur due to the inclusion of dross or the like. On the other hand, if the roll is made so small as to be driven by the roll, slipping with the strip 6 will occur and adversely affect the surface quality of the product.

Although the sink roll 3 has been described above, the bearing of the support roll has the same structure.

[0021]

As described above, according to the present invention, since the bearing 9 is made of a graphite-based single material, it has excellent wettability with molten metal, so that there is no penetration of bath metal. It is possible to dramatically extend the life of the roll device in the bath. In addition, since the surface of the roll shaft 8 is also made of a graphite-based simple material, it is possible to prevent molten metal from entering the contact surface between the bearing 9 and the roll shaft 8 and suppress wear and backlash of the bearing portion. In addition, the clearance can be strictly controlled and smooth rotation without slips can be guaranteed.

[Brief description of drawings]

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

FIG. 2 is a front view showing a cross section of a bearing portion of the sink roll 3 in FIG.

FIG. 3 is a front view showing a cross section of a bearing portion of a sink roll 3 of a continuous molten metal plating apparatus according to another embodiment of the present invention.

FIG. 4 is an enlarged sectional view showing a sink roll bearing portion of a continuous molten metal plating apparatus according to another embodiment of the present invention.

FIG. 5 is an enlarged sectional view showing a sink roll bearing portion of a continuous hot-dip metal plating apparatus according to another embodiment of the present invention.

FIG. 6 is an enlarged sectional view showing a sink roll bearing portion of an example of a conventional continuous molten metal plating apparatus.

FIG. 7 is an enlarged sectional view showing a sink roll bearing portion of an example of a conventional continuous molten metal plating apparatus.

FIG. 8 is a front view showing a cross section of a bearing portion of a sink roll 3 of an example of a conventional continuous molten metal plating apparatus.

FIG. 9 is a diagram showing the results of a sliding wear test for each material in a sink roll bearing of an example of a continuous hot metal plating apparatus.

[Explanation of symbols]

1: Snout, 2: Plating bath, 3: Sink roll,
4: Support roll 5: Wiping nozzle, 6: Strip, 7: Roll hanger, 8: Roll shaft, 9: Bearing, 10: Sleeve.

Claims (3)

[Claims] 1. A roll apparatus for a hot dip bath, in which roll shafts at both ends of the roll are rotatably supported via bearings and are immersed in a hot dip bath, wherein the bearing is made of a ring-shaped graphite-based simple substance. A roll device for a hot dip bath, which is characterized in that 2. A roll apparatus for a hot dip plating bath in which roll shafts at both ends of the roll are rotatably supported via bearings and are immersed in a hot dip bath, wherein the bearing and the roll shaft surface layer are ring-shaped graphite. A roll device for a hot dipping bath, which is made of a simple substance of a system. 3. The roll apparatus for a hot dip bath according to claim 1, wherein the clearance between the roll shaft and the bearing is at most 0.5 mm.