JPH05287475A - Continuous hot dip metal coating device and method therefor - Google Patents

Abstract

PURPOSE:To hold a roll still in a molten metal and to enable uniform plating of a steel sheet by forming the part of the rolls which comes into contact with the steel sheet of ceramics which is not wet with the molten metal. CONSTITUTION:The roll to be used by being immersed in the molten metal is disposed in the continuous hot dip metal coating device for the steel sheet. At least the part of such roll which comes into contact with the steel sheet is formed of the ceramics which is not wetted with the molten metal. The steel sheet is plated while the roll is held still in the molten metal. The ceramics is formed to >=90 deg. contact angle with the molten metal and is formed of an oxide, carbide, nitride or boride. The ceramics is formed to a circular cylindrical shape and one or plural pieces of the circular cylindrical bodies are fixedly built axially into the roll. As a result, the plating device which withstands the use of the long-term continuous operation is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous hot dip metal plating apparatus and a plating method using the hot dip metal plating apparatus, and particularly to a roll such as a sink roll or a support roll used in the hot melt metal against corrosion and wear by the hot metal. The present invention relates to a continuous molten metal plating apparatus in which a roll mounting structure is simplified by using a material having excellent performance, and a plating method using the apparatus.

[0002]

2. Description of the Related Art In a method of producing a plated steel sheet by a continuous hot dip metal plating method, a steel sheet whose surface has been cleaned and activated is inserted as a pretreatment into a hot metal bath and the direction is changed by a sink roll in the going bath. After that, in order to suppress the warp of the steel sheet in the width direction, it is passed between two support rolls, further pulled up, and extra zinc adhering to the surface of the steel sheet is squeezed by means such as blowing high-pressure gas, The plating thickness is adjusted.

[0003]

In this plating method, the sink roll in the bath has its support shaft rotatably supported by the bearing of the support located in the bath, while its body is always made of steel plate. It is in contact. Since the steel sheet is continuously wound, it travels at a constant speed. Therefore, the sink roll always rotates while receiving a force biased in a fixed direction. Similarly, the support roll is rotatably supported by its support shaft, and the body of the support roll is forcibly pressed against the flat surface of the steel plate to prevent warping of the steel plate and a load is applied outside the bath. It is rotated through a shaft by driving a motor.

The roll as described above is made of a metallic material, and the roll support shaft and the bearing at both ends are rotating in the molten metal. Further, during the operation time, the molten metal is eroded between the roll support shaft and the bearing surface, and the tension applied to the steel plate to wind the steel plate causes a biasing force in a certain direction to be constantly generated in the bearing part. Therefore, in the conventional continuous hot-dip galvanizing apparatus, many improvements have been made to the structure between the roll support shaft and the bearing so as to enable stable operation for a long time (Japanese Patent Laid-Open No. 49-135829). Japanese Patent Laid-Open No. 1-316443, Japanese Patent Laid-Open No. 3-79746, etc.).

Although these improved techniques have reduced the occurrence of erosion or wear in the bearing portion to some extent, they have a complicated structure and use a special material for the support shaft and the bearing portion. Not only did this lead to higher costs, but the occurrence of wear and erosion could not be avoided at all.Therefore, when the operation was continued for a certain period of time, the rattling between the roll support shaft and the bearing increased, and as a result, the running It is unavoidable that vibration occurs in the steel sheet inside and the plating characteristics deteriorate significantly. Therefore, in the equipment operated today, in order to prevent the occurrence of defective steel sheets due to the deterioration of the plating characteristics, the line was stopped after a relatively short period of operation, the plating operation was stopped, and the rolls were replaced. It is the current situation. This line stop has a problem that productivity is remarkably reduced and roll replacement cost causes high cost.

As another means for solving the above problems of the roll bearing portion, the sink roll is fixed in a bath, and a plurality of small-diameter rotating bodies are provided at predetermined intervals within a predetermined range on the surface of the sink roll. One that is rotatably embedded is proposed (Japanese Patent Laid-Open No. 2-310349). This proposal solves the problem of wear and erosion that occurs in the bearing part of the sink roll because the sink roll is fixed, but the small-diameter rotating body rotatably embedded in the surface of the sink roll does not However, the problems of erosion and wear in the bearing portion are also present, and the problems of shortening the roll life and vibration of the steel sheet are unavoidable. ..

The object of the present invention is to roll the roll used in a metal bath by using a ceramic that does not wet the molten metal and plate the roll in the metal bath while the roll is stationary.
It solves the problems of the conventional technology and enables uniform plating.
Furthermore, the corrosion resistance and wear resistance of the roll are improved, the life of the roll is extended, the productivity is improved, the number of poorly plated steel sheets is reduced,
It is an object of the present invention to provide a continuous hot-dip metal plating apparatus and a plating method capable of reducing the total cost of products by reducing roll replacement costs.

[0008]

In order to solve the above-mentioned problems and to achieve the object, in the present invention, in a continuous hot-dip metal plating apparatus, various rolls used in a metal bath do not get wet with the hot metal. By using ceramics to prevent corrosion by the metal bath, and to reduce the friction coefficient of the contact area between the roll and the steel plate to make the steel plate easier to slip, plating is performed while the entire roll is stationary without rotating. I decided.

The ceramics that are not wet with the molten metal are, for example, ceramics having a contact angle with the molten metal of 90 degrees or more, and oxides, carbides, nitrides and borides are preferable. Since the erosion due to the metal bath is particularly remarkable in the portion that comes into contact with the steel plate, a preferred embodiment for carrying out the present invention is to use ceramics that is not wet with the molten metal in at least the portion that comes into contact with the steel plate of the roll. It is possible to achieve the purpose sufficiently.

For example, a structure in which the shape of ceramics is a cylindrical body and one or more cylindrical bodies are fixedly incorporated in the axial direction of the roll, or the shape of the ceramics is spherical and the spherical body is formed. One or more in the axial direction of the roll, the structure is fixedly incorporated, and the shape of the ceramic is formed into a columnar body having one end surface having a curved surface, and the columnar body is oriented with its curved end surface facing outward. A plurality of in the circumferential direction of the roll, a structure that is fixedly incorporated, also, the shape of the ceramic is a cylindrical body,
The structure may be such that one or more rolls are fixedly incorporated in the axial direction of the roll by being fitted to a core material made of metal or ceramics. In any case, the shape of the ceramic is hollow. May be

The roll in the molten metal plating bath to which the present invention is applied is not particularly limited, and may be one or a plurality of various rolls such as a sink roll, a support roll, and a drawing roll. Considering the corrosion resistance, it is generally considered that the erosion caused by the molten metal depends on the degree of wetting of the ceramics by the melt to affect the erosion rate, and a material that is hard to wet has a high corrosion resistance. Since the contact angle between the melt and the ceramics varies depending on the type of metal and the plating conditions, it is necessary to select an appropriate material from the materials having a large contact angle. Ceramic materials include MgO and Al ₂
O ₃ , oxides such as ZrO ₂ , nitrides such as TiN and Si ₃ N ₄ , carbides such as SiC and TiC, BN and ZrB
Many ceramic materials such as borides such as ₂ TiB ₂ are possible.

In general, aluminum or zinc is used as a metal to be plated, and the magnitude of the contact angle between these molten metals and the ceramics has a great influence, but this contact angle differs depending on the type of ceramics. There is. For example, a melt of zinc at 600 ° C and aluminum at 1000 ° C, alumina (Al ₂ O ₃ ), zirconia (Zr
O ₂ ), titanium nitride (TiN), silicon nitride (Si
₃ N _4), sialon (Si _{5. 5} Al _0.5 O
_0.5 N _7.5 ), silicon carbide (SiC), boron nitride (BN)
When the contact angle with each ceramic was measured in an argon atmosphere, it was in the range of 120 to 180 degrees in any of the zinc melts, almost no wetting, and the erosion depth was as shallow as 2 μm or less in 1 hour. , I found that it hardly responded. Therefore, it was found that these ceramics have excellent corrosion resistance and can be used for a long time when used in a zinc bath.

On the other hand, the maximum contact angle between the aluminum melt and the ceramic is 160 degrees of BN and the minimum is Si.
At 40 degrees C, it varies greatly depending on the type of ceramics. Further, the erosion depth becomes shallower as the contact angle becomes larger, and becomes deeper as the contact angle becomes smaller. FIG. 1 is a diagram showing a wet state of a 1000 ° C. aluminum melt and the ceramics. The contact angle is plotted on the vertical axis and the erosion depth is plotted on the horizontal axis. From this figure, it can be seen that the type of ceramics, the contact angle, and the erosion depth are on a single line. From this, the contact angle of BN, Si ₃ N ₄ , sialon, and TiN is considerably larger than 90 degrees, and the erosion depth is shallow, so that wetting of these ceramics and aluminum melt is small,
It has been found that when these boride and nitride ceramics are used, they have excellent corrosion resistance and can be used for a long time.

On the other hand, regarding wear resistance, rolls and steel plates
The coefficient of friction on the sliding surface in contact with
Therefore, a friction / wear test was conducted in a metal bath. Experiment melted
Rotate the disk in metal and press the test piece to the side of the disk
The sliding wear test method was used. The test conditions are as follows
It is as below. Dimensions of rotating disk: outer diameter 100 mm, thickness 10 mm Specimen dimensions: outer diameter 5 mm, length 25 mm Surface pressure: 15 kg / cm² Sliding speed: 45m / min Molten metal: Al (670 ℃), Zn (460 ℃) Test time: 5h SS41 (J
IS). As the material of the test piece, SUH
309 (JIS), Al for ceramics₂O₃, ZrO ₂, Ti
N, Si₃N_Four, Sialon and SiC were selected. Friction clerk
The number was continuously determined from the beginning of sliding. The amount of wear is before the test
Was calculated as the difference in length after the test.

The above test results are summarized in Table 1, which shows the coefficient of wear at the initial stage of sliding, and Table 2 shows the amount of wear. A combination with a small coefficient of friction and less wear is desirable, but the coefficient of friction is 0.1 to 0.2 in both Zn and Al baths.
The value was in the range of, and thereafter, it was stable at a lower value. The wear is different between the Zn bath and the Al bath. Looking at the case of SiC, wear of 0.05 mm in the Zn bath and 0.7 mm in the Al bath was observed.
Greater wear in the bath. It was found that TiN, Si ₃ N ₄ and sialon ceramics hardly wear even in Zn and Al baths. From the above test results, ceramics with a contact angle of more than 90 degrees and hard to be wetted by molten metal have a small friction coefficient in combination with a metal material in a metal bath, little wear, and excellent corrosion resistance and wear resistance. ..

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

The roll for continuous hot-dip galvanizing of the present invention is made of ceramics which is not wetted by the hot-dip metal, so that it is hardly eroded by the hot-dip metal and has a small friction coefficient at the contact portion between the roll and the steel plate. Less wear. Therefore, the plating operation can be continuously performed for a long time with the entire roll stationary, and the roll bearing structure can be simplified.

[0019]

The present invention will be described in more detail based on the following examples.

[0020]

Example 1 First, an example in which the present invention is applied to a support roll will be described. FIG. 2 shows a schematic cross section of an example of a continuous hot-dip metal plating apparatus suitable for carrying out the present invention. The steel plate (strip) 1 is fed into the bath through the snout 2. In the plating tank 3, the direction is changed by the sink roll 4 and the movement of the strip is stabilized by the support roll 5. Further, the strip drawn out from the plating bath 6 is adjusted in plating thickness by the squeeze roll 7.

In this embodiment, the support roll 5 is made by using sialon as a ceramic as described later, and as shown in FIG. 3, its shaft support 51 is machined from SUH309 (JIS) which is a heat-resistant steel plate material. It is fixedly assembled to the end portion of the support body 9 created as described above. Support roll 5
In the preparation of, first, a small amount of binder was added to sialon powder, then wet kneading was performed in methanol, and granulation was performed by a spray dry method. Then, using a cold isostatic press, it was formed into an outer diameter of 125 mm and a length of 1200 mm. After calcination of the molded body, the dimensional change due to the main calcination and the finishing machining allowance were taken into consideration, and the molded body was machined to a predetermined size. Main firing is 1750
C. and performed in nitrogen gas. The dimensions after finishing are
Two cylinders with an outer diameter of 100 mm and a length of 1000 mm were manufactured. The surface roughness of the roll was Ra 0.05 μm.

The shaft support portion 51 of the support roll 5 produced as described above was assembled as follows. After inserting a ring-shaped high thermal expansion metal 10 (brass, JIS 2600), which has been machined to a predetermined dimension, into the end surface of the support 9 made by machining SUH309 (JIS), which is a heat-resistant steel, after heating the whole,
The shaft support was inserted. (FIG. 4) As a result of using the support roll having the above structure for continuous plating in a Zn plating bath at 460 ° C., the life of the conventional steel support roll was 7 days, whereas that of this example Even after 20 days of use, no abnormal wear was found on the sliding surface of the ceramic steel plate, and uniform plating could be performed.

[0023]

Second Embodiment A support roll 5 having the same structure as that of the first embodiment is used.
As a result of using it for continuous plating work in an Al plating bath at 670 ° C, the wear of the sliding surface of the conventional steel support roll shaft and bearing was about 15 mm in 4 days, and the wear of the sliding surface with the steel plate of the body part Was about 10 mm, and no further plating work could be performed. On the other hand, when the present embodiment was used for continuous plating work for 10 days, the wear of the sliding surface with the steel plate was about 0.1 mm. Of goods
Less than 1/100, and without changing ceramics
Although it was used for continuous plating for 10 days, uniform plating could be performed, and the wear of the sliding surface with the steel plate was about 0.3 mm. Furthermore, when used for continuous plating for 30 days, the wear of the sliding surface became about 1 mm, so take it out of the bath, change the position of the sliding surface with the ceramic steel plate, and perform the same continuous plating as above. I was able to work and I was able to confirm the effect.

[0024]

Embodiment 3 FIG. 5 shows another embodiment of the shape of the roll according to the present invention. In this embodiment, the roll 60 comprises a support member 11 made of steel and a cylindrical ceramic body 8 fixedly assembled to the support member 11. The support member 11 includes a hollow cylindrical portion 12, a flange portion 13 having a larger diameter on both end sides thereof, and a shaft support portion 14 integrally formed with the flange portion 13, and the flange portion 13 on one end side is a separate body. It is preferable that the roll 60 is made as a single piece and integrated by means such as welding when the roll 60 is assembled.

As shown in FIG. 6, at least a portion of the cylindrical portion 12 that is in sliding contact with the steel plate is provided with a hole 15 having a size into which the columnar ceramic body 8 can be inserted with its cylindrical peripheral surface partially exposed. It is formed over the entire length in the axial direction,
Further, a concave hole portion 16 having the same shape as the hole 15 is formed in a portion of the flange portion 13 facing the hole 15. More specifically, the support member 11 was made by casting method using steel SCH13 (JIS) and finished by machining. After the ceramic body 8 is fixedly assembled to the support member 11 as described later to form the roll 60, the shaft support portion 14 of the roll 60 is inserted into the support body 9 made of heat-resistant steel plate material (SUH309 JIS) and welded. ..

The columnar ceramics 8 were prepared by first adding a small amount of binder to sialon powder, then wet kneading in methanol, and granulating by spray drying.
Then, using a cold isostatic press, outer diameter 100 mm, length
Molded to 1200 mm. After calcination of the molded body, the dimensional change due to the main calcination and the finishing machining allowance were taken into consideration, and the molded body was machined to a predetermined size. The main calcination was performed at 1750 ° C. in nitrogen gas. The dimensions after finishing are 80 mm in diameter and 10 in length for the sliding surface.
It is a 00 mm cylinder. The surface roughness of the sliding surface with the steel plate is R
a 0.03 μm.

A high thermal expansion metal 10 (duralumin, JIS-) which is processed into a ring shape in the concave hole portion 16 of the flange portion 13 of the support member 11.
(A2017), the columnar ceramics 8 was inserted into the hole 15 of the supporting member 11, and finally the other flange portion 13 formed as a separate member was joined to the supporting member 11 to form the roll 60. An experiment was conducted by applying the roll 60 thus created to a sink roll. As a result of using the sink roll having the above structure for continuous plating in a Zn plating bath at 460 ° C., the life of the conventional steel sink roll was 7 days, while that of the present embodiment was 20 days. Even when used, no abnormal wear was observed on the sliding surface of any ceramic with the steel plate, and uniform plating could be performed.

[0028]

Example 4 A sink roll having the same structure as in Example 3
As a result of using it for continuous plating work in an Al plating bath at ℃, the wear depth of the sliding surface of the shaft and bearing of the conventional steel sink roll was about 25 mm in 4 days, Wear is about 10
mm, and no further work was possible, whereas the one of this example was used for continuous plating work for 10 days, and the wear of the sliding surface with the steel plate was about 0.1 for any of the ceramics.
mm, which is one-hundredth of that of conventional products, and even if ceramics were used for continuous plating for 10 days without replacement, uniform plating could be performed.

[0029]

Fifth Embodiment FIG. 7 shows still another embodiment of the shape of the roll according to the present invention. In this embodiment, the roll 70 is composed of a steel support member 71 and a columnar ceramic body 81 fixedly assembled to the support member 71. The support member 71 is a steel cylindrical body, and the shaft support portions 72 are integrally formed on both sides as in the other embodiments. Further, a plurality of openings 73 are formed in the direction of the central axis in at least the portion of the cylindrical surface that is in sliding contact with the steel plate (FIG. 8).

More specifically, the supporting member 71 is made of steel SCH13 (JIS) by a casting method and finished by machining. After the ceramic body 81 is fixedly assembled to the supporting member 71 to form the roll 70 as described later, the shaft support 72 of the roll 70 is attached to a heat-resistant steel plate material (SUH309 JI
It was inserted into a support 9 made of S) and welded.

The columnar ceramic body 81 was manufactured as follows. First, a small amount of binder was added to sialon powder, then wet kneaded in methanol, and granulated by a spray dry method. Then, using a cold isostatic press,
The outer diameter was 25 mm and the length was 50 mm. After calcination of the molded body, the dimensional change due to the main calcination and the finishing machining allowance were taken into consideration, and the molded body was machined to a predetermined size. The main calcination was performed at 1750 ° C. in nitrogen gas. The dimension after finishing is one tip
81 is a curved surface of R10, and the length is 35 mm. The surface roughness of the curved surface was Ra 0.05 μm.

A ring-shaped high thermal expansion metal 10 (brass, JIS-C2600) machined to a predetermined size is inserted into the outer peripheral portion of the columnar ceramic body 81 thus created at a high temperature, and after cooling, it is inserted. The assembly was carried out by inserting the curved end portion 81 into the opening 73 formed in the heated support member 71 so as to project the same distance. As a result of using the roll 70 having the above structure as a sink roll for continuous plating in a Zn plating bath at 460 ° C., the life of the conventional steel sink roll was 7 days, whereas that of the present example. Even when used for 20 days, no abnormal wear was observed on the sliding surface of the ceramic curved surface with the steel plate, and uniform plating could be performed.

[0033]

Example 6 A sink roll having the same structure as in Example 5
As a result of using it for continuous plating work in an Al plating bath at ℃, the wear depth of the sliding surface of the shaft and bearing of the conventional steel sink roll was about 25 mm in 4 days, Wear is about 10
mm, and no further work was possible, whereas the one of this example was used for continuous plating work for 10 days, and the wear of the sliding surface with the steel plate was about 0.1 for any of the ceramics.
mm, which is one-hundredth of that of conventional products, and even if ceramics were used for continuous plating for 10 days without replacement, uniform plating could be performed.

[0034]

Example 7 An experiment was conducted by arranging two rolls having the structure described in Example 1 so as to face each other and using them as squeezing rolls. The squeezing roll was soaked in a Zn plating bath at 460 ° C and used for continuous plating. As a result, the wear depth of the sliding surface of the shaft and bearing of the conventional steel squeezing roll was about 5 m in 7 days.
m, the wear of the sliding surface of the body on the steel plate was about 2 mm, and further work could not be performed, whereas the wear of the sliding surface of the present invention on the steel plate was about 0.05 mm, which was small. .. further,
Although it was used for continuous plating for 10 days without replacement, uniform plating could be performed, and the abrasion of the sliding surface with the steel sheet was about 0.3 mm or less, confirming sufficient effect. Furthermore, when it was used for continuous plating work for 30 days, the wear of the sliding surface with the steel plate became about 1 mm, so the position of the sliding surface with the steel plate of the ceramic part was changed and the same continuation as above was performed. After performing the plating work, the plating work could be continued without any trouble.

The above description is merely a description of some preferred embodiments, and the present invention has many other modifications. For example, in the first embodiment shown in FIG. 3, the entire roll 5 is made of sialon ceramics, but as in the third or fifth embodiment, a cylindrical support member is made of steel material to form a ceramic body. It may be formed as a tubular body having a size that fits into the support member.

Further, since the roll itself does not rotate, the cross-sectional shape of the roll does not necessarily have to be circular, and at least the outer peripheral surface portion in contact with the steel plate has a continuous smooth curved surface such as an elliptical shape. Any shape may be used as long as it is provided. Therefore, instead of the columnar ceramic body in the embodiment shown in FIGS. 7 and 8, a spherical or ellipsoidal ceramic body can be fixedly embedded in at least a portion of the supporting member that is in contact with the steel plate.

The fixing means of the roll to the support is not limited to fixing by thermal expansion metal or welding, but any fixing means that can withstand the temperature in the bath can be applied, and fixing and releasing can be selectively performed. It is also possible to use a means that can be used (for example, a means for inserting a detachable pin). In that case, as described in Example 7, by changing the position of the sliding surface between the ceramic portion and the steel plate, the same roll can be used a plurality of times in a new state, which is more economical. Further, in the case of a roll whose cross section is shown in FIG. 6 or FIG. 8, the same purpose can be achieved by fixedly assembling the ceramic body from the beginning on the entire circumferential surface of the supporting member. ..

[0038]

As described above, since the roll for continuous hot metal plating of the present invention is a ceramic which is not wet with the hot metal, it is not eroded by the hot metal and has a small friction coefficient at the contact portion with the steel sheet. Therefore, since the steel sheet is slippery and wears less, even if the plating work is performed while keeping the contact portion with the steel plate in a non-rotating state, that is, in a stationary state, it can withstand the use of continuous plating work for a long time, and uniform plating can be achieved. It has a great effect that it can be done.

Therefore, not only the productivity is remarkably lowered and the roll replacement cost, which is one of the causes of the high cost, can be reduced, but the continuous hot-dip galvanizing apparatus according to the present invention has a big technical problem in the past. In addition, since it is possible to configure without using the rotary bearing portion that had to be complicated and complicated, it is possible to manufacture the device itself at low cost, which brings about a great economic effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a test result of wetting performance of ceramics in an aluminum melt.

FIG. 2 is a partial schematic explanatory view of a continuous molten metal plating apparatus.

FIG. 3 is a diagram when the present invention is applied to a support roll.

FIG. 4 is a sectional view taken along the line AA ′ of FIG.

FIG. 5 is a partially cutaway side view when the present invention is applied to a sink roll.

6 is a sectional view taken along the line BB ′ of FIG.

FIG. 7 is a side view of another embodiment when the present invention is applied to a sink roll.

FIG. 8 is a sectional view taken along the line DD ′ of FIG.

[Explanation of symbols]

1: Strip 2: Snout 3: Plating tank 4: Sink roll 5: Support roll 6: Plating bath 7: Drawing roll 8: Ceramics body 9: Support body 10: High thermal expansion metal 11: Support member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Taguchi 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Yoshio Takakura 3-1-1, Saiwaicho, Hitachi City, Ibaraki Stock Company Hitachi, Ltd., Hitachi Plant (72) Inventor, Norihiko Okochi, 2nd, 832, Horiguchi, Katsuta City, Ibaraki Prefecture Hitachi Ltd., Katsuta Plant

Claims (12)

[Claims] 1. A continuous molten metal plating apparatus for a steel sheet, comprising a roll for use by immersing in a molten metal, wherein at least a portion of the roll in contact with the steel plate is made of ceramics which is not wet with the molten metal, and the roll is in the molten metal. A continuous hot-dip metal plating apparatus characterized by performing stationary plating. 2. The continuous hot-dip metal plating apparatus according to claim 1, wherein the ceramics that are not wet with the molten metal have a contact angle with the molten metal of 90 degrees or more. 3. The continuous hot-dip metal plating apparatus according to claim 1, wherein the ceramics which are not wet with the molten metal are oxides, carbides, nitrides and borides. 4. The cylindrical shape of the ceramics,
One or a plurality of the cylinders in the axial direction of the roll,
A fixedly incorporated structure.
The continuous hot-dip metal plating apparatus described. 5. The ceramic has a spherical shape,
The continuous hot metal plating apparatus according to claim 1, wherein a plurality of the spherical bodies are fixedly incorporated in the circumferential direction of the roll. 6. The ceramic is formed into a columnar body having one end curved, and a plurality of the columnar bodies are fixedly incorporated in the circumferential direction of the roll with the curved end face facing outward. The continuous hot-dip metal plating apparatus according to claim 1, which is configured. 7. The shape of the ceramic is a cylindrical body,
The continuous hot-dip metal plating apparatus according to claim 1, wherein the core is made of metal or ceramics, and one or a plurality of the fittings are fixedly incorporated in the axial direction of the roll. .. 8. The continuous hot-dip galvanizing apparatus according to claim 4, wherein the shape of the ceramic is hollow. 9. A plating apparatus having one sink roll and at least one support roll in a molten metal plating bath, wherein the roll according to any one of claims 1 to 8 is used as the sink roll. Continuous molten metal plating equipment. 10. A plating apparatus having one sink roll and at least one support roll in a molten metal plating bath, wherein the roll according to any one of claims 1 to 8 is used as the support roll. Continuous molten metal plating equipment. 11. A roll according to claim 1, wherein in the plating apparatus having one sink roll, at least one support roll and two drawing rolls in the molten metal plating bath, the drawing rolls are used. A continuous hot-dip metal plating apparatus characterized by using. 12. A method for plating a steel sheet, wherein the continuous hot-dip metal plating apparatus according to any one of claims 1 to 11 is used.