JP2000034552A - Hot dip metal coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot dip metal coating device capable of driving for a long time, by which the productivity of plated products is high and capable of executing plating with high quality. SOLUTION: As for a sink roll 5 and a support roll, all surfaces in contact with molten metal are coated with iron silicide layers. As for a bearing, a carbon-carbon fiber composite material is lined to a holder made of heat resistant steel. The surface of the holder is coated with an Fe3Si layer 13 similarly to the case of the sink roll 5. The Fe3Si layer 13 lines on the surface of a shaft part 11, is brought into contact with the carbon-carbon fiber composite material and is slid.

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 for immersing a workpiece in a molten metal to perform plating.
In particular, the present invention relates to a hot metal plating apparatus using a component having excellent corrosion resistance and wear resistance to molten metal.

[0002]

2. Description of the Related Art Heretofore, steel components such as cast iron, stainless steel, and high chromium steel having corrosion resistance have been used as components disposed in a molten metal of a hot metal plating apparatus. However, since the molten metal is highly corrosive, sink rolls, support rolls and the like using these materials cannot withstand long-term use. Further, when the roll bearing portion and the like are corroded and worn, the steel plate vibrates, and the plating layer is not formed uniformly, which may impair the quality of plating.

Further, when an iron component in the molten metal is corroded by the molten metal, a compound (impurity) of iron and the molten metal, called dross, is generated in the molten metal, and not only deteriorates the quality of the plating film. The life of the molten metal itself is also shortened.

For this reason, in the hot-dip metal plating apparatus, the rolls must be replaced in a short cycle, and the operation is stopped each time, so that the productivity of the plated product is poor.

[0005] In order to improve this, it is known that cermets and ceramics having corrosion resistance to molten metal are coated on the components in the molten metal, and the entire components in the molten metal are made of cermet and ceramics. .

For example, Japanese Patent Application Laid-Open No. 61-37955 discloses a method for producing a roll for a molten metal bath having excellent corrosion resistance, heat resistance, abrasion resistance, etc. by plasma spraying ceramics on the surface of an iron base material. Is described. JP 4-1
No. 24254 describes that the entire bearing is made of cermet or ceramics. JP-A-5-44002 describes that the roll shaft is made of cermet and the entire bearing is made of ceramics.

[0007]

However, in the surface treatment technique by the plasma spraying method, a pinhole is formed in the sprayed film, and the molten metal penetrates through the pinhole and corrodes the base material. Easy to peel, poor reliability. In addition, since components placed in molten metal are generally large, it is technically and economically difficult to make the entire component from cermet or ceramics.

An object of the present invention is to enable long-time operation,
An object of the present invention is to provide a hot-dip metal plating apparatus capable of performing plating with good productivity and high quality of plated products.

[0009]

A feature of the present invention to achieve the above object is that a hot-dip metal plating apparatus includes an iron part having an iron silicide layer on a surface. Fe ₃ silicide layer
Si or FeSi is preferred.

The inventors of the present invention have investigated the corrosion resistance of various materials in a molten Zn-Al alloy, and have found that iron silicide has excellent corrosion resistance.

[0011] Iron silicide includes Fe ₃ Si, Fe ₅ Si ₃ , Fe
Si, FeSi _{2 and the} like. The Fe ₃ Si layer can be formed by a silicon permeation method in which silicon permeates the surface of iron. For example,
A method in which silicon powder or silicon carbide powder and a steel member are put in a container and heated at a temperature of 930 to 1000 ° C. while introducing chlorine gas (Metal Progress, 33 (1938) 367).
), A method of heating at 1200 ° C. for about 20 minutes in a mixed gas flow of 10% SiCl ₄ + 90% N ₂ (see Journal of the Japan Institute of Metals, 26 (1962) 157), molten Mg—S
A method in which a steel member is put in an i-alloy bath and heated at 800 to 900 ° C. for several minutes (see Iron and Steel, 83 (1997) 25).
And so on.

Since the iron silicide layer of Fe ₅ Si ₃ , FeSi, and FeSi ₂ cannot be formed by the silicon infiltration method, it is formed by the plasma spraying method. However, Fe ₅ Si ₃ and Fe ₅
Using Si ₂ , these are 1193 ° C., 120
Since it decomposes at 4 ° C. to generate Si, it is not suitable as a raw material powder for forming an iron silicide layer. FeSi powder has a melting point of 1
Since it is stable at 410 ° C, to form an iron silicide layer, Fe
It is preferable to form a sprayed FeSi film by a plasma spraying method using Si powder.

In the present invention, the Fe ₃ Si layer is formed by the Si infiltration method using an Mg—Si alloy bath, and the FeSi layer is formed by the FeSi layer.
It is formed by a plasma spraying method using powder as a raw material. By these methods, a dense iron silicide film can be formed relatively easily, and the formed iron silicide layer has good adhesion to iron as a base material. Therefore, since iron parts having an iron silicide layer on the surface have a long life without being corroded even in molten metal, a molten metal plating apparatus using such iron parts can be operated for a long time, and the production of plated products can be performed. Efficiency is improved.

Further, between the base material iron and the iron silicide layer,
An intermediate layer made of iron, silicon and cobalt, for example, FeS
An i-12Co layer may be provided. By providing an intermediate layer made of iron, silicon and cobalt between the base material iron and the iron silicide layer, even if a thermal shock is applied, the iron silicide layer is prevented from peeling from the base material iron. it can.

Another feature of the present invention resides in that an iron rotating body which rotates in contact with a solid metal has an iron silicide layer on a surface. In a hot-dip metal plating apparatus in which an iron silicide layer is provided on the surface of a rotating body such as a sink roll and a support roll, the sink roll and the support roll are excellent in corrosion resistance and abrasion resistance. Productivity is improved. In addition, since the generation of dross is small, plating defects are reduced, the quality of plating can be improved, and the life of the molten metal itself can be prolonged.

Another feature of the present invention resides in that the bearing for supporting the rotating shaft of the rotating body has a member made of carbon fiber in contact with the rotating shaft having an iron silicide layer on the surface. The rotating shaft with the Fe ₃ Si layer formed on the surface of the iron base material and the carbon
In a hot-dip metal plating system that uses a combination of carbon fiber bearings such as carbon fiber composite materials, corrosion and wear on the rotating shaft are extremely small, so that even when the machine is operated for a long time, the steel plate does not vibrate and the plating quality is low. Can be maintained for a long time.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various tests were conducted on test pieces simulating iron parts used in the hot-dip metal plating apparatus of the present invention. The test piece was formed by forming a layer of iron silicide on the surface of a cylindrical base material made of carbon steel (S45C) having a diameter of 10 mm and a length of 20 mm. Two types of test pieces were prepared: test piece A in which iron silicide was Fe ₃ Si and test piece B in which FeSi was used.

In the test piece A, a Fe ₃ Si layer was formed on the surface of a columnar base material made of carbon steel by a Si infiltration method. More specifically, a carbon-based cylindrical base material is made of an Mg-3% Si alloy bath (in which an Mg-3% Si alloy obtained by adding 3% by weight of high-purity silicon to industrial magnesium is melted).
At 850 ° C. for 15 minutes to a thickness of about 10
An Fe ₃ Si layer of 0 μm was formed.

In the test piece B, an FeSi layer is formed on the surface of a columnar base material made of carbon steel by a plasma spraying method.
Specifically, FeSi powder having an average diameter of 5 μm was injected into a plasma jet, and FeSi was sprayed on the surface of a columnar base material made of carbon steel to form a FeSi layer having a thickness of about 250 μm.

When the specimens A and B were observed with an optical microscope, the iron silicide layer was dense. The tests consisted of (1) a melting test, (2) a sliding test, and (3) a thermal shock resistance test. (1) Dissolution test The test piece A and the test piece B were placed in a zinc-aluminum alloy bath, and the degree of dissolution of the iron silicide layer was examined. The zinc-aluminum alloy bath is obtained by melting an alloy of aluminum and zinc. A zinc-aluminum alloy bath at 460 ° C. to 620 ° C. was prepared by changing the composition ratio of aluminum and zinc. After holding the test piece in these zinc-aluminum alloy baths at a peripheral speed of 20 m / min for 100 hours, the test piece was cut, and the Fe-Si-based compound layer was observed with an optical microscope.

As a comparative example, an Fe—C-based compound, an Fe—S-based compound, and an Fe—P
Specimens on which a layer of a base compound, iron nitride (mainly Fe ₄ N containing Fe ₂ to ₃ N) and iron boride (FeB and Fe ₂ B) were formed, respectively, were prepared. Tested.

Table 1 shows the test results.

[0023]

[Table 1]

The test piece A (Fe ₃ Si) had an Al concentration of 6
Up to 0%, no erosion of the Fe ₃ Si layer was observed, and 100%
Some erosion was observed. For test piece B (FeSi),
Almost no erosion of the Fe ₃ Si layer was observed up to an Al concentration of 100%.

In the test piece having the Fe—C compound layer, the Fe—C compound layer disappears in the alloy bath containing 5% or more of aluminum in zinc.

The test piece having the layer of the Fe—S compound is
When the aluminum concentration is 1% or more, the layer of the Fe-S-based compound disappears.

The test piece having the Fe-P compound layer is
Even pure zinc causes erosion, and the film disappears regardless of the aluminum content.

Specimens having a layer of iron nitride (main component Fe ₄ N) were eroded in both baths.

In the test piece having the iron boride layer (FeB and Fe ₂ B), no erosion was observed up to an aluminum concentration of 1%, but some erosion was observed at 10%, and no erosion was observed at 55% or more. Lost.

From the above results, it was found that the iron silicide layer formed on the surface of the carbon steel base material had excellent corrosion resistance and was stable even at an aluminum concentration of 55% or more.

Further, FeS formed by the plasma spraying method is used.
The film of i-silicide was not peeled off from the base material.

In general, other ceramic films (Al ₂ O ₃ , Z) formed on the surface of a carbon steel base material by a plasma spraying method.
(rO ₂ , TiC, WC-12Co, TiB _2, etc.) does not melt itself in the Zn-55% Al molten metal, but peels off from the base material. This is presumably because there are many pinholes in other ceramic films formed by the plasma spraying method, and the molten metal passing through the pinholes reaches the base material and corrodes the base material. On the other hand, the FeSi iron silicide film formed by the plasma spraying method was not peeled off because the melting point of FeSi was 1410 ° C. and Al ₂ O ₃ , Zr
2000 of O ₂ , TiC, WC-12Co, TiB ₂
Since the temperature is much lower than 3100 ° C., it is considered that the diameter of the pinhole formed during the film formation is very small or no pinhole is generated.

Therefore, Fe formed by the plasma spraying method
It can be said that a film made of Si iron silicide has a higher performance of coating a carbon steel base material than other ceramic films formed by the plasma spraying method.

Next, the test pieces A (Fe ₃ Si) and the test pieces B (FeSi) having different thicknesses were subjected to a melting test.

For the test piece A, the carbon steel base material was M
0.5, 1, 3, 5, at 850 ° C. in a g-3% Si alloy bath.
After immersion for 10 minutes, the average film thickness was 4, 8, 20, 40,
A thing of 70 μm was prepared. With respect to the test piece B, the average film thickness was changed to 20, 45, 60, by changing the scanning speed of plasma spraying using FeSi powder having an average diameter of 5 μm.
95,135 μm were prepared.

In the erosion test, a Zn-55% Al bath was used.
The test was performed under the conditions of a bath temperature of 600 ° C., no rotation, and an immersion time of 100 hours. After the erosion test, the test piece was taken out, immersed in an HCL aqueous solution until the generation of bubbles (H ₂ ) disappeared, and the surface was observed visually and with an optical microscope to check for corrosion.

As a result, the average thickness of the test piece A was 4
And 8 μm test pieces showed defects due to corrosion, but no defects due to corrosion when the average film thickness was 20 μm or more. Regarding the test piece B, a defect due to corrosion was observed in the test piece having an average film thickness of 20 μm, but no defect was found due to corrosion when the average film thickness was 45 μm or more.

The difference between the film thickness of the test piece A and the test piece B that resists corrosion is that the film formed by the plasma spraying method is made of Si.
It is considered that the roughness of the film is larger than that of the film formed by the infiltration method, so that the area in contact with the zinc-aluminum alloy is large, and the film is easily corroded. From the above results, when the Fe ₃ Si film is formed by the Si infiltration method, the film thickness is set to 20 μm or more.
When forming the FeSi film by the plasma spraying method, the thickness is 4
It is preferable that the thickness be 5 μm or more.

(2) Sliding Test First, a sliding test was performed using the test piece A and a test piece made of mild steel in order to examine the coefficient of friction between the roll and the steel sheet and the amount of friction of the roll. The test piece made of mild steel simulates a steel plate to be plated.

Test piece A was prepared by immersing a base material made of carbon steel in an Mg-5% Si alloy bath at 800 ° C. for 1 hour. A relatively porous layer of about 150 μm exists on the surface of the test piece A, and a dense Fe layer of about 350 μm exists between the layer and the base material.
₃ Si layer was present. When the composition was analyzed by the X-ray diffraction method, FeSi ₂ excessive in silicon was slightly detected on the very surface, but the other generated layers were Fe ₃ Si.
The test piece A was brought into contact with a mild steel test piece at a surface pressure of 5 MPa, the test piece A was rotated at a rotation speed of 16 m / min, the composition ratio of the zinc-aluminum alloy bath was changed, and the continuous operation was performed for 10 hours. went.

FIG. 1 shows the results. For comparison, about 10
FIG. 1 also shows the test results using a test piece having a 0 μm FeB film.
Shown in

In FIG. 1, a test piece A (Fe ₃ S
In case i), in all zinc-aluminum alloy baths,
There was almost no erosion or wear, and the friction coefficient was about 0.1. This is a sufficiently low wear coefficient. Therefore, a component having a Fe ₃ Si layer on the surface of a carbon steel base material is excellent in corrosion resistance and abrasion resistance, so that it is suitable as a component in a molten metal and a steel plate such as a sink roll and a support roll. It is also suitable as a part that comes into contact with

On the other hand, in the test piece having the FeB film indicated by ●, abrasion appeared in a zinc-aluminum bath having an aluminum concentration of 10%, and melting was caused. As the aluminum content further increases, the wear caused by the erosion greatly increases. At an aluminum concentration of 60% or more, the FeB film disappeared. Therefore, components having an FeB film are ineligible as components in the molten metal.

Next, in order to examine the coefficient of friction between the roll and the bearing and the amount of friction of the roll, test pieces A and B were tested.
And a carbon / carbon fiber test piece were subjected to a sliding test. The carbon and carbon fiber specimens simulate bearings that support shafts such as sink rolls and support rolls.

The test piece A has a base material made of carbon steel on its surface.
It has an Fe ₃ Si layer of about 180 μm formed by immersing in a Mg-3% Si alloy bath at 0 ° C. for 20 hours. Test piece B
Is approximately 100% formed on the surface by plasma spraying.
It has a FeSi layer of μm. A test piece made of carbon / carbon fiber is formed by hot press forming a fiber bundle having a diameter of 80 to 120 μm in which a matrix (pitch-based carbon) component is previously contained on the surface of a carbon fiber (5 to 7 μm), and then firing (in vacuum) , 2300 ° C).
Carbon / carbon fiber composite materials have been used as sliding members since they have high corrosion resistance to molten metal and solid lubricity.

In a Zn-55% Al alloy bath, the test pieces A and B were respectively brought into contact with carbon / carbon fiber test pieces at a surface pressure of 5 MPa, and the test pieces A and B were rotated at a rotational speed of 16 m / m. It was rotated at min and operated continuously for 10 hours.

FIG. 2 shows the results. For comparison, FIG. 2 also shows the test results using a stainless steel 304 test piece and a carbon / carbon fiber test piece.

For the combination of test piece A (Fe ₃ Si) and a test piece made of carbon / carbon fiber, and the combination of test piece B (FeSi) and a test piece made of carbon / carbon fiber, Until the passage of time, the coefficient of friction was about 0.1 and the amount of wear was small. Therefore, if a Fe ₃ Si layer is formed on the surface of a shaft such as a sink roll or a support roll and combined with a carbon / carbon fiber bearing, a highly reliable sliding part with excellent corrosion resistance and wear resistance can be obtained. Can be configured.

On the other hand, in the combination of the stainless steel test piece and the carbon / carbon fiber test piece, the friction coefficient is small, but the wear amount of the stainless steel test piece increases with time.

In the sliding test, both test pieces A and B
Since the iron silicide layer did not peel off from the base material, it can be said that the iron silicide layer has good adhesion to the base material.

(3) Thermal shock resistance test A test member C in which an iron silicide layer was formed on the surface of a carbon steel base material, and FeSi-12C on a surface of the carbon steel base material
The thermal shock resistance of the test member D in which the iron silicide layer was formed with the layer of o interposed therebetween was examined.

The test member C has an outer diameter of 250 mmΦ and an inner diameter of 21 mm.
0mmΦ, 300mm long S45C carbon steel hollow base metal, about 200μm thick FeS by plasma spraying
An i-layer is formed. Test member D is the same as test member C
About 70 μm of Fe by plasma spraying
An Si-12Co intermediate layer is formed and then about 200 μm F
An eSi layer is formed.

These test members were heated to 600 ° C.
After subjecting the members to thermal shock by a method of throwing them into an n-55% Al bath, each member was immersed in an aqueous HCl solution to attach Zn-A.
1 was removed and the surface was visually observed.

The peeling occurred at the edge of the test member C. This was thought to be due to stress generation based on the difference in thermal expansion due to thermal shock. On the other hand, the test member D did not peel.

Therefore, it is effective to provide an intermediate layer of FeSi-12Co between the base material made of carbon steel and the FeSi layer for thermal shock.

(Embodiment 1) A hot metal plating apparatus according to a first embodiment of the present invention will be described. The hot-dip metal plating apparatus of this embodiment uses a component in which an iron silicide layer is formed on the surface of a carbon steel base material. FIG. 3 shows an example of the hot-dip metal plating apparatus of the present embodiment.

The hot-dip metal plating apparatus of the present embodiment is provided with a plating bath 2 for filling a molten metal 1 therein, a snout 4 for guiding a strip-shaped steel plate 3 to the plating bath 2, and disposed in the plating bath 2. Roll 5, which is disposed in the plating bath 2 to suppress vibration of the steel plate 3, and removes excessive molten metal 1 adhering to the surface of the steel plate 3 drawn from the plating bath 2. And a gas wiping device 7 to be used. In this embodiment, the surfaces of the sink roll 5 and the support roll 6 that come into contact with the molten metal 1 are all covered with an iron silicide layer. The respective shafts of the sink roll 5 and the support roll 6 are supported by bearings 8 and 9 fixed in the plating bath 2. The diameter of the support roll 6 is one third of the diameter of the sink roll 5
It is about.

The strip-shaped steel sheet 3 whose surface has been activated by being reduced by hydrogen or the like outside is guided through the snout 4 into the molten metal 1 in the plating bath 2. The traveling direction of the steel sheet 3 is changed by the sink roll 5, and the steel sheet 3 is drawn out of the plating bath 2 through the support roll 6. Then, the excess molten metal 1 is removed by the gas wiping device 7, the plating thickness is adjusted, and the plating treatment is performed. It is sent out as a finished steel plate. The supply and winding of the steel sheet 3 are interlocked, and a constant tension is applied to the steel sheet 3. The feeding and winding speed is 10 to 200 m / min.

The sink roll 5 and the support roll 6 used in the hot-dip metal plating apparatus of this embodiment will be described in detail.

FIG. 4 shows the sink roll 5. The sink roll 5 includes a cylindrical body 10 made of S45C carbon steel,
And a shaft portion 11 made of C carbon steel. One end of the shaft portion 11 is processed into a flange shape, and the body portion 10 and the shaft portion 11 are connected by bolts 12. The support roll 6, like the sink roll 5, also includes a cylindrical body made of S45C carbon steel and a shaft made of S45C carbon steel.

FIG. 5 shows a cross section of the sink roll 5. The sink roll 5 has an Fe ₃ Si layer 13 formed on the surface of S45C carbon steel. A method for forming the Fe ₃ Si layer 13 on the sink roll 5 will be described below.

First, after preserving S45C carbon steel at a temperature of 900 ° C. for 10 hours, a pretreatment of gradually cooling in a furnace was performed.
The body 10 and the shaft 11 were machined from the pretreated S45C carbon steel and assembled into a roll.

Next, a silicidation treatment for forming the Fe ₃ Si layer 13 on the surface of the roll was performed by a Si infiltration method. In the silicification treatment, first, a roll is suspended in a cylindrical case made of stainless steel (SU316), and Mg-5% Si obtained by adding 5% high-purity silicon by weight to industrial magnesium is used.
The alloy ingot was put into a cylindrical case.

The cylindrical case was heated to 800 ° C. in an electric furnace in an argon atmosphere to melt the Mg-5% Si alloy,
The roll was kept in the molten metal for 3 hours.

After the silicidation treatment, the roll was taken out of the molten metal and transferred to an electric furnace heated to 800 ° C.
Cooled to room temperature at a cooling rate of h. The surface of the body 10 and the shaft 11 of the completed sink roll 5 has a thickness of 110
A Fe ₃ Si layer 13 of μm to 140 μm is formed,
There was no cracking or peeling. The support roll 6 was produced in the same manner as the sink roll 5.

Next, the bearing 8 fixed in the plating bath 2
And 9 will be described. The bearings 8 and 9 support the shafts of the sink roll 5 and the support roll 6, respectively.

FIG. 6 shows the bearing 8. Since the tension of the steel plate 3 is applied to the sink roll 5 from below, the bearing 8 of the sink roll 5 has an arc shape. A carbon / carbon fiber composite material 15 is lined in a heat-resistant steel holder 14.
The surface of the holder 14 is made of Fe ₃ S like the sink roll 5.
The i-layer 13 is covered. The bearing 9 of the support roll 6 may be the same as the bearing 8 of the sink roll 5,
As shown in FIG. 10, the carbon / carbon fiber composite material 15 and the holder 14 may be cylindrical.

FIG. 7 shows an axial section when the sink roll 5 and the bearing 8 are combined. An Fe ₃ Si layer 13 is provided on the side surface and the end surface of the shaft portion 11 and comes into contact with the carbon / carbon fiber composite material 15 and slides.

The sink roll 5 and the bearing 8 are placed in a Z
The n-55% Al alloy was put into a hot-dip metal plating apparatus filled in the plating bath 2 and used continuously for 100 hours. After use, the body 10 and the shaft 11 are not worn at all.
The sliding surface of the carbon / carbon fiber composite material 15 was smooth. In addition, dross and the like were not adhered to the body, and were good.

Therefore, in the hot-dip metal plating apparatus of the present embodiment, since the sink roll, the support roll, and the like are excellent in corrosion resistance and wear resistance, a long-time plating operation can be performed, and the productivity of the plated steel sheet is improved. Further, since the corrosion and wear of the shaft portion 11 such as the sink roll and the support roll are extremely small, the steel plate does not vibrate even after a long operation,
Plating quality can be maintained for a long time. In addition, since the generation of dross is small, plating defects are reduced, the quality of plating can be improved, and the life of the molten metal itself can be prolonged.

In the bearing 8, the carbon / carbon fiber composite material 15 is lined with the holder 14. However, as shown in FIG. 8, a block-shaped carbon / carbon fiber composite material 15 may be embedded in the holder 14.

In the above description, the sink roll 5, the support roll 6, and the bearings 8 and 9 have been described in which the surfaces are covered with an iron silicide layer. May be provided.

For example, if the surfaces of the guide roll contacting the plated steel sheet, the nozzle portion of the gas wiping device 7, the snout 4, and the pipes, valves, pumps, etc. used for exchanging the molten metal are coated with iron silicide, Corrosion by molten metal can be prevented.

However, since iron silicide is corroded by molten metal in an environment where oxygen is present, it is necessary to avoid these atmospheres and provide a non-oxidizing atmosphere around these components. The snout 4 can also be coated with an iron silicide layer only on the inside of the snout 4 which is a hydrogen atmosphere.

According to the zinc-aluminum alloy molten metal plating apparatus of the present embodiment, components placed in the molten metal such as the sink roll 5, the support roll 6, and the bearings 8 and 9 have sufficient corrosion resistance and resistance. Since it has abrasion, long-time plating operation is possible.

In this embodiment, the entire surface of the roll is covered with the iron silicide layer. However, depending on the type of molten metal,
The body portion 10 of the sink roll 5 and the support roll 6 is a conventional one, and a shaft portion 11 to which high surface pressure and sliding are applied.
May be covered with an iron silicide layer.

(Embodiment 2) A hot metal plating apparatus according to a second embodiment will be described. The molten metal plating apparatus of the present embodiment is different from the first embodiment in the sink roll and the support roll, but is the same in other respects. The surface of the roll of this embodiment is covered with an intermediate layer of FeSi-12Co and a layer of FeSi iron silicide.

FIG. 9 shows a cross section of the sink roll 20.
An approximately 70 μm thick FeSi-12Co layer 16 is formed on the surface of the body portion 10 and the shaft portion 11 made of S45C carbon steel, and an approximately 200 μm FeSi layer 17 is formed thereon.

A method for forming the FeSi-12Co layer 16 and the FeSi layer 17 on the sink roll 20 will be described below. As with the sink roll 5, a roll prepared by pretreatment, machining, and assembling is used.

First, an FeSi-12Co layer 16 was formed on the surface of the roll by plasma spraying. Further, the FeSi layer 17 is changed to the FeSi-12Co layer 1 by plasma spraying.
6 was formed. The completed sink roll 20 did not crack or peel. Support roll also sink roll 2
0.

According to the hot-dip metal plating apparatus of this embodiment,
The same effect as the hot-dip metal plating apparatus described in the first embodiment can be obtained, and the sink roll 20 and the support roll are excellent in thermal shock resistance. Even if there is a temperature change, it is possible to prevent the sink roll 20 and the support roll from being cracked or peeled off, thereby improving the reliability of the molten metal plating apparatus.

In the above description, carbon steel is used as a base material of parts of a hot-dip metal plating apparatus. However, the present invention is not limited to carbon steel, and a material capable of forming an iron silicide layer by a Si infiltration method or a plasma spraying method. I just need.

[0083]

According to the present invention, an iron part having an iron silicide layer on its surface has a long life without being corroded even in molten metal. Therefore, a hot-dip metal plating apparatus using such an iron part requires a long time. Operation becomes possible, and the production efficiency of plated products is improved. The iron silicide layer is preferably made of Fe ₃ Si or FeSi.

Further, if an intermediate layer made of iron, silicon and cobalt is provided between the base material iron and the iron silicide layer, the iron silicide layer can be formed from the base material iron even if a thermal shock is applied. Peeling can be prevented.

Further, in a hot-dip metal plating apparatus in which an iron silicide layer is provided on the surface of a rotating body such as a sink roll and a support roll, the sink roll and the support roll are excellent in corrosion resistance and wear resistance. And the productivity of plated products is improved. In addition, since the generation of dross is small, plating defects are reduced, the quality of plating can be improved, and the life of the molten metal itself can be prolonged.

The combination of the rotating shaft and the bearing is a combination of a rotating shaft having a Fe ₃ Si layer formed on the surface of an iron base material and a carbon fiber bearing such as a carbon / carbon fiber composite material. In the hot-dip metal plating apparatus, since the corrosion and wear of the rotating shaft are very small, even when the apparatus is operated for a long time, the steel sheet does not generate vibration and the plating quality can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram showing the results of a sliding test simulating sliding between a roll and a steel plate.

FIG. 2 is a diagram showing the results of a sliding test simulating sliding between a roll and a bearing.

FIG. 3 is a view showing a hot metal plating apparatus according to a first embodiment.

FIG. 4 is a view showing a sink roll 5;

FIG. 5 is a view showing a cross section of the sink roll 5;

FIG. 6 is a view showing a bearing 8;

FIG. 7 is a view showing an axial section when the sink roll 5 and the bearing 8 are combined.

FIG. 8 is a view showing another example of the bearing 8;

FIG. 9 is a view showing a cross section of the sink roll 20.

FIG. 10 is a view showing an example of a bearing 9;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Molten metal, 2 ... Plating bath, 3 ... Steel plate, 4 ... Snout, 5 ... Sink roll, 6 ... Support roll, 7 ... Gas wiping device, 8, 9 ... Bearing, 10 ... Body, 11 ... Shaft, 12 bolt, 13 Fe ₃ Si layer, 14 holder, 15 carbon / carbon fiber composite material, 16
... FeSi-12Co layer, 17 ... FeSi layer, 20 ... Sink roll.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Sakai 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Osamu Shimoyumura Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi 1-1, Hitachi, Ltd. 3-chome, Hitachi, Ltd. (72) Inventor Takehisa Kimura 3-1-1, Sakaimachi, Hitachi, Ibaraki, Japan Hitachi, Ltd. Hitachi, Ltd. (72) Inventor Yasushi Yoshimura, Ibaraki Hitachi 1-1, Yachimachi, Hitachi City Hitachi, Ltd. Hitachi Plant (72) Inventor Yasunori Kani 3-1-1, Yachimachi, Hitachi City, Ibaraki Prefecture Hitachi Plant Hitachi Plant, Ltd. (72) Invention Person Yoshio Takakura 3-1-1 Kochi-cho, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd.Hitachi Plant (72) Inventor Hironori Shimogama 3-1-1 Kochi-cho, Hitachi-shi, Hitachi, Ltd. In the Works Hitachi factory

Claims (5)

[Claims] 1. A molten metal plating apparatus for plating a solid metal by bringing the molten metal into contact with the solid metal, the apparatus comprising an iron component having an iron silicide layer on a surface thereof. 2. The iron silicide layer is made of Fe ₃ Si or FeSi.
2. The hot-dip metal plating apparatus according to claim 1, wherein: 3. Between the iron member and the iron silicide layer,
2. The hot metal plating apparatus according to claim 1, further comprising an intermediate layer made of iron, silicon and cobalt. 4. An iron rotator that rotates in contact with the solid metal to move the solid metal in the molten metal, the rotator having an iron silicide layer on a surface. The hot metal plating apparatus according to claim 1. 5. A bearing for supporting a rotating shaft of the rotating body for fixing a position of the rotating body, wherein the bearing has a member made of carbon fiber in contact with the rotating shaft, and the rotating body rotates. The hot-dip metal plating apparatus according to claim 4, further comprising an iron silicide layer on a surface of the shaft.