JPH08218115A - Carbon roll having high strength and high wear resistance and excellent in copying property and its production - Google Patents

Abstract

PURPOSE: To produce a carbon roll with a long service life having high strength and high wear resistance, furthermore excellent in copying properties and excellent in steel sheet conveying properties at the time of high temp. or electric heating. CONSTITUTION: The outer circumference of a roll in which the barrel part is formed of carbon 3 is provided with a metallic layer 4 of 1 to 5mm thickness formed by thermal spraying or the shrinkage fitting of a metallic sleeve, and moreover, the surface of the metallic layer 4 is provided with a topmost surface layer 6 of 0.1 to 0.5mm thickness constituted of ceramics or cermet. By using this for a conveying roll for a steel sheet continuous heat treating furnace, the prevention of deterioration in the sheet shape, the prevention of the generation of meandering are made possible, and, as for a roll for energizing, the generation of sparks caused by deterioration in the contact can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon roll used as a carrying roll used in a heat treatment furnace, an energizing roll for energizing heating, or a pressing roll, and a method for producing the same.

[0002]

2. Description of the Related Art In a furnace-conveying roll used for annealing a metal, for example, continuous annealing of a cold-rolled steel sheet, when the temperature of the contacting steel sheet is lower than the ambient temperature, the temperature of the central portion of the roll contacting the steel sheet is The temperature distribution is low because the temperature is low and the edge portion has a high temperature. Depending on this temperature distribution, a concave crown having a dent in the center of the roll is produced. On the contrary, when the temperature of the contacting steel plate is higher than the ambient temperature, the temperature of the central part of the roll contacting the steel plate is high and the temperature of the edge part is low, so that a convex crown is formed.

In such a state where the roll is crowned, the steel sheet is subject to temperature distribution and tension distribution, and the shape is deteriorated, so that seismic waves and diaphragms are likely to occur. Further, when the width of the steel sheet changes, the profile of the roll also changes, and the shape of the steel sheet is likely to become unstable. Therefore, there is a problem that it is necessary to operate at a low speed until the profile of the roll becomes stable.

Further, in the energizing roll or the pressing roll in the nipping type energization, when the roll has a crown, the contact pressure on the steel plate is partially reduced, and as a result, a spark is generated between the steel plate and the roll. There is a problem that melting marks are generated on both rolls, resulting in deterioration of product quality and roll life.

As described above, when the profile of the roll changes, various inconveniences occur. Therefore, measures for making the roll surface temperature uniform or application of a material having a high thermal conductivity and a low thermal expansion coefficient have been studied.

In Japanese Unexamined Patent Publication No. 57-136793, a conductive magnetic film is formed on the roll surface so that the resistance value of the portion where the magnetic flux density becomes high becomes large, and a uniform temperature distribution is obtained by induction heating. The method of obtaining is described. Further, Japanese Patent Application Laid-Open No. 61-79733 discloses a transport roll whose surface is made of a conductive ceramic and which can be electrically heated. When this roll is used, the temperature distribution in the roll width direction can be made uniform by resistance heating when the conductive ceramic is energized, and the roll profile is said to be constant.

However, even if only the roll surface temperature is made uniform by these conventional methods, when a substance having a large temperature difference comes into contact with the roll surface, the roll surface temperature distribution becomes non-uniform, and the roll surface bearing It is difficult to make the roll profile uniform because heat moves in the direction and the temperature inside the roll becomes non-uniform.

[0008]

On the other hand, if carbon having a high thermal conductivity, a low thermal expansion coefficient, a high flexibility, and a property that easily follows a steel sheet (hereinafter, this property is referred to as a profile) is used, It is possible to keep the profile almost constant regardless of the temperature. However, carbon has a problem that it is soft and wears severely, has low strength, and is easily broken by mechanical impact.

The object of the present invention is to make use of the properties of carbon such as high thermal conductivity, low thermal expansion and conformability,
It has the characteristics of high strength and high wear resistance, the roll profile does not change, and therefore does not produce a crown,
It is an object of the present invention to provide a carbon roll having excellent long-life carbon roll which is excellent in transportability of a steel plate at high temperature or when electrically heated and is not damaged even when used for a long time, and a method for producing the same.

[0010]

According to a first aspect of the present invention, a body portion is formed on the outer peripheral surface of a roll by thermal spraying or shrink fitting of a metal sleeve and has a thickness of 1 to 5 mm.
Of the metal layer, and a thickness of 0.1 on the surface of the metal layer.
A carbon roll excellent in high strength, high wear resistance, and conformability, which is characterized in that an outermost layer composed of ceramics of 0.5 mm or cermet is provided, and a method for producing the same.

A second aspect of the present invention is to provide a metal layer having a thickness of 1 to 5 mm, which is formed by thermal spraying or shrink fitting of a metal sleeve, on the outer peripheral surface of the roll whose body is made of carbon.
Further, the outermost surface layer made of ceramics or cermet having a thickness of 0.1 to 0.5 mm is provided on the surface of the metal layer through a metal layer for bonding formed by thermal spraying, which has a high strength. A carbon roll excellent in high wear resistance and conformability, and a method for producing the same.

The carbon roll of the present invention has high thermal conductivity,
It does not impair the properties of carbon such as low thermal expansion and conformability, and has high strength because there is a metal layer with a thickness of 1 to 5 mm on the surface of carbon, and because there is a ceramic or cermet layer on the surface of the metal layer. Excellent wear resistance.

The carbon used in the present invention is in contact with the steel sheet uniformly, has a strength enough to hold the metal layer formed on the surface of the steel sheet, and minimizes a change in roll profile due to a temperature difference. Therefore, it is preferable that the Young's modulus is 2000 kg / mm ² or less, the compressive strength is 3 kg / mm ² or more, and the thermal expansion coefficient is 7 × 10 ⁻⁶ / ° C. or less.

In the carbon roll of the present invention, a metal layer is provided on the surface of the carbon in order to prevent the carbon from being destroyed by mechanical impact caused by passing through a welded portion when passing the steel sheet. The thickness of this metal layer needs to be in the range of 1 to 5 mm. If the thickness of the metal layer is less than 1 mm,
The carbon cannot be protected from the mechanical impact caused by passing through the welded portion during passing, and the carbon is damaged. Further, if the thickness of the metal layer is thicker than 5 mm, the conformity of carbon is impaired and the contact with the steel sheet becomes uneven.

When the metal layer is formed of a metal having a thermal expansion coefficient difference of 5 × 10 ⁻⁶ / ° C. or less from that of the carbon of the body, the metal layer does not rise due to the thermal expansion coefficient difference and can be used at higher temperatures. . For example, for carbon having a thermal expansion coefficient of 5 × 10 ⁻⁶ / ° C., it is preferable to use a metal such as Mo, Cr, or Ti for the metal layer.

In particular, the main components are Fe and Ni, and the respective weight ratios are Fe; 55-70%, Ni; 45-30.
% Low thermal expansion alloy, or the main component is Fe,
Ni and Co, the weight ratio of each of which is Fe; 50 to
The low thermal expansion alloy in the range of 60%, Ni; 29 to 31%, Co; 16 to 17% has high strength and excellent characteristics as a metal layer.

The metal layer is jet coated, plasma sprayed,
It can be formed by a thermal spraying method such as explosive thermal spraying or a shrink fitting method of a metal sleeve. In shrink fitting of a metal sleeve, in order to maintain strength as a metal sleeve, a sleeve thicker than a target thickness, for example, a sleeve having a thickness of 10 mm is manufactured, and after shrink fitting to carbon, a predetermined thickness, for example, 2 mm It is possible to form a metal layer having a desired thickness by shaving.

In the second carbon roll of the present invention, a bonding metal layer is provided between the two layers in order to improve the adhesion between the metal layer and the outermost layer. The bonding metal layer can be formed by a spraying method such as jet coating, plasma spraying, and explosion spraying. When powder is used as the thermal spray material, the particle size is 10 to 50
It is preferably μm. The thickness of the bonding metal layer is 50
The range is up to 300 μm.

The material is Ni-Cr, CoNiCrA.
heat resistant alloys such as 1Y, CoCrAlY, NiCrAlY,
Alternatively, a cermet material such as Al ₂ O ₃ —CoCrAlY is preferable.

In the carbon roll of the present invention, the outermost layer composed of ceramics or cermet can be formed by a spraying method such as jet coating, plasma spraying, explosive spraying and the like.

The thickness of the outermost layer needs to be in the range of 0.1 to 0.5 mm. This is because if the thickness of the metal layer is less than 0.1 mm, the outermost layer will be easily peeled off due to mechanical shock, thermal shock, etc. If it is more than 0.5 mm, it will be easily peeled off after coating. This is because

The chemical composition of the outermost layer is ZrO ₂ in oxide ceramics among ceramics and cermet materials,
_{Al 2 O 3 -Cr 2 O 3} , ZrSiO 4, in the non-oxide ceramics, TiN, TiC, ZrN, ZrC , Al 2 O 3 cermet cermet, ZrO ₂ cermet, ZrSiO ₄ cermet, WC cermet, the steel plate A material that is excellent in wear resistance under contact and has low reactivity with Fe is preferable.

When the carbon roll of the present invention is used as a current-carrying roll, the outermost layer has a specific resistance of 1 × 1.
It is preferably composed of ceramics of 0 ⁻³ Ω · cm or less, or cermet. Specifically, for example, Ti
There are non-oxide ceramics such as N, TiC, ZrN and ZrC, and cermets such as WC cermet.

When a material having a thermal conductivity of 2 Wm ^-1 K ^-1 or less is used, heat transfer from the steel sheet to the surface of the roll is small and the roll profile is large even when the difference between the roll temperature and the steel sheet temperature is large. Can be kept constant and the state of contact with the steel plate can be made uniform. As the material, for example,
There are oxide ceramics such as ZrO ₂ and SiO ₂ having a thermal conductivity of about ¹ Wm ^-1 K ^-1 .

The outermost layer has a very low reactivity with Fe,
When it is mainly composed of ZrO ₂ and SiO ₂ , it is judged to be ZrO ₂ or ZrSiO ₄ consisting of a cubic or tetragonal phase, or a mixed phase thereof, at least by X-ray diffraction. It is preferable that the substance contains a substance. This is because these minerals do not undergo crystal transformation in the temperature change from room temperature to high temperature and are stable. Furthermore, 60 wt% or more of the mineral composition of ZrO ₂ contained in the outermost layer is a cubic or tetragonal phase,
Or, when they are a mixed phase thereof, they are particularly stable against temperature change.

The outermost layer satisfying such characteristics is Ca
A ZrO ₂ powder containing ₂ to 20 wt% of at least one oxide selected from the group consisting of O, Y ₂ O ₃ , MgO, CeO ₂ , HfO ₂ , and rare earth element oxides is prepared by a conventional thermal spraying method. It can be obtained by applying.

Thus, ZrO ₂ is added to CaO, Y
_At least one oxide particle selected from the group consisting of ₂ O ₃ , MgO, CeO ₂ , HfO ₂ , and rare earth element oxides; and CaO, Y ₂ O ₃ , MgO, CeO ₂ , HfO.
₂ and the powder having a mixture of ZrO ₂ particles containing ₂ to 20 wt% of at least one oxide selected from the group consisting of rare earth element oxides can be applied by explosive spraying to obtain the above-mentioned characteristics. The outermost layer that satisfies the requirement can be constructed.

The powder contains CaO, Y ₂ O ₃ , MgO and Ce.
The addition of at least one kind of oxide particles selected from the group consisting of O ₂ , HfO ₂ and rare earth element oxides is
ZrO ₂ particles formed by decomposition of ZrSiO ₄ particles during thermal spraying
For stabilizing the cubic phase or the tetragonal phase, or a mixed phase thereof.

CaO, Y ₂ O ₃ , MgO, CeO ₂ , H
The amount of at least one kind of oxide particles selected from the group consisting of fO ₂ and rare earth element oxides stabilizes ZrO ₂ in a cubic or tetragonal phase or a mixed phase thereof. Therefore, when ZrSiO ₄ is decomposed and formed, it reacts with ZrO ₂ to obtain ₂ wt% of oxide-containing ZrO ₂ .
% Or more, and in order to suppress the reactivity of ZrO ₂ and Fe to a very low level, it is preferably in the range of 20 wt% or less. If it is less than 2 wt%, ZrO ₂ is not stable, and if it exceeds 20 wt%, the reactivity of Fe increases, which is not preferable.

[0030]

The operation of the present invention will be described with reference to the drawings. FIG.
FIG. 3 is a cross-sectional view of the first carbon roll of the present invention. Figure 2
FIG. 6 is a cross-sectional view of a second carbon roll of the present invention.

The carbon 3 is provided in close contact with the heat insulating layer 2 provided on the shaft 1 of the roll. Heat insulation layer 2
From the outermost layer 6 to the metal layer 5 for bonding (the second invention of FIG.
(Provided only on the carbon roll of the above) and the heat transferred to the carbon 3 through the metal layer 4 is reduced directly to the shaft 1, and the thermal expansion of the shaft 1 and its thermal stress due to the transferred heat are reduced. It is also responsible for absorbing.

With this structure, the temperature distribution in the roll is made uniform. Further, the metal layer prevents the carbon from being destroyed by a mechanical shock generated by passing through a welded portion when passing the steel sheet.

On the metal layer 4, an outermost surface layer 6 made of ceramics or cermet and having excellent wear resistance with a steel plate is provided, and the wear resistance is excellent. In addition, in the second carbon roll of the present invention, the bonding metal layer 5 is provided in order to improve the adhesion of the outermost layer 6 to the metal layer 4.

Since the carbon roll of the present invention has a small coefficient of thermal expansion of carbon of about 1 to 7 × 10 ^-6 / ° C., it has a small roll crown even in a high temperature furnace and a large thermal conductivity. Therefore, it has an excellent characteristic that the profile can always be kept almost constant even if the width of the steel sheet changes.

When the carbon roll of the present invention is used as an energizing roll or a pressing roll in a nipping type energization, the Young's modulus is as small as 2000 kg / mm ² or less, so that it has a high elasticity even during hot and is easily heated. The material can be pressed between the energizing rolls. Further, by forming the outermost layer of ceramics having a specific resistance of 1 × 10 ⁻³ Ω · cm or less, or cermet, it can be used as an energizing roll.

[0036]

EXAMPLES First, an example of the method for producing the first carbon roll of the present invention will be described. (Examples 1 and 2) Young's modulus of 6 was added to the carbon portion of the roll.
00kg / mm ^2, compression strength 4.8 kg / mm ^2, a thermal expansion coefficient 1.5 × 10 ^-6 / ℃, thermal conductivity 140Wm ^-1 K ^-1, an outer diameter of 300 mm, was used a cylinder of length 1300mm .

First, a caster having a thermal conductivity of 0.86 Wm ^-1 K ^-1 was formed on a roll shaft made of S45C having a diameter of 100 mm to have a thickness of 3
Construction was carried out at 0 mm, and this carbon cylinder was shrink-fitted on it at 400 ° C. Next, Mo having a thermal expansion coefficient of 6.4 × 10 ⁻⁶ / ° C. was applied by plasma spraying to form a metal layer. Furthermore, by jet coating on this, the specific resistance is 1 × 10.
A WC-27NiCr sprayed layer of ^-4 Ω · cm was formed as the outermost layer.

The thickness of each layer is as follows in Examples 1 and 2. Mo (metal layer) WC-27NiCr (outermost layer) Example 1 1 mm 0.1 mm Example 2 5 mm 0.5 mm

Next, an example of a method for manufacturing the second carbon roll of the present invention will be described. (Examples 3, 4, and 5) The shaft, castable, and carbon configurations were the same as in Example 1. First, the coefficient of thermal expansion 4 × 10
^A metal sleeve made of Fe-Ni-Co low thermal expansion alloy having a thickness of ^-6 / ° C and a thickness of 10 mm was prepared, and after shrink-fitting on carbon at 400 ° C, it was ground to a thickness of 2 mm to form a metal layer. next,
A 100 μm thick bonding metal layer (Ni—Cr) was formed on this metal layer by plasma spraying. Furthermore, plasma spraying raw material powder of the following components from above,
The outermost layer was formed to a predetermined thickness.

The components of the thermal spraying raw material powder and the thickness of the outermost layer are as follows in Examples 3, 4, and 5, respectively. Outermost layer spraying raw material powder component Outermost layer thickness Example 3 8 wt% Y ₂ O ₃ stabilized ZrO ₂ 0.1 mm Example 4 20 wt% Y ₂ O ₃ stabilized ZrO ₂ 0.2 mm Example 5 2 wt% CaO stabilized ZrO ₂ 0.5 mm

(Examples 6 and 7) The carbon portion of the roll had a Young's modulus of 1350 kg / mm ² and a compressive strength of 17.5 kg /
mm ² , thermal expansion coefficient 4.8 × 10 ^-6 / ° C, thermal conductivity 70W
A cylinder having an outer diameter of 300 mm and a length of 1300 mm with m ⁻¹ K ⁻¹ was used.

First, an S45C roll shaft having a diameter of 100 mm was coated with Al ₂ O ₃ —SiO ₂ fiber having a thermal conductivity of 4 Wm ⁻¹ K ⁻¹ to a thickness of 8 mm, and this carbon cylinder was baked at 400 ° C. I messed up. Next, the coefficient of thermal expansion 4 × 10
A metal sleeve made of a Fe-Ni-Co low thermal expansion alloy having a thickness of ^-6 / ° C and a thickness of 10 mm was produced, shrink-fitted on carbon at 400 ° C, and then ground to a predetermined thickness to form a metal layer.

A metal layer for bonding (Al ₂ O ₃ --CoCrAl) having a thickness of 100 μm was formed on the metal layer by explosive spraying.
Y) was formed, and the thermal spraying raw material powder having the following components was explosively sprayed thereon to form an outermost layer having a thickness of 0.2 mm. Example 6 Metal sleeve thickness 1 mm Outermost layer thermal spraying raw material powder component 20 wt% CeO ₂ stabilized ZrO ₂ (50 wt%) +3 wt%
Gd ₂ O ₃ +6 wt% CeO ₂ +41 wt% ZrSiO ₄ Example 7 Metal sleeve thickness 5 mm Outermost layer thermal spraying raw material powder component (6 wt% Gd ₂ O ₃ -12 wt% CeO ₂ stabilized ZrO ₂
(50 wt%) + 5 wt% Y ₂ O ₃ +45 wt% ZrSiO
_Four

(Embodiment 8) The structure of the shaft, castables and carbon was the same as that of the embodiment 6. Next, the coefficient of thermal expansion 4 ×
A metal sleeve made of Fe-Ni-Co low thermal expansion alloy having a thickness of 10 ^-6 / ° C and a thickness of 10 mm was prepared, and after shrink-fitting on carbon at 400 ° C, it was ground to a predetermined thickness to form a metal layer.

Furthermore, a metal layer for bonding (Al ₂ O ₃ --CoCr) having a thickness of 100 μm was formed on the metal layer by explosive spraying.
AlY) formed, and then 8 wt% Y ₂ O ₃ -2 wt% H
fO ₂ stabilized ZrO ₂ and 10 wt% Y ₂ O ₃ added ZrSi
A powder obtained by mixing O ₄ powder at a weight ratio of 1: 1 was explosion-sprayed to form an outermost layer having a thickness of 0.1 mm.

(Examples 9, 10, 11, 12, 13, 1)
4) The configurations of the shaft, castable, carbon, metal layer sleeve, and coupling metal layer were the same as in Example 8. Thermal spraying raw material powder having the following components was explosively sprayed on the bonding metal layer to form an outermost layer having a thickness of 0.2 mm. Outermost layer thermal spraying raw material powder component Example 9 20 wt% CeO ₂ stabilized ZrO ₂ (50 wt%) + 3 wt%
Y ₂ O ₃ +2 wt% MgO +45 wt% ZrSiO ₄ Example 10 10 wt% MgO stabilized ZrO ₂ (50 wt%) +5 wt% C
aO + 5 wt% HfO ₂ +40 wt% ZrSiO ₄ Example 11 14 wt% Y ₂ O ₃ stabilized ZrO ₂ (50 wt%) +5 wt%
Y ₂ O ₃ +45 wt% ZrSiO ₄ Example 12 6 wt% CaO-stabilized ZrO ₂ (50 wt%) +5 wt% Y ₂
O ₃ +45 wt% ZrSiO ₄ Example 13 20 wt% CaO-stabilized ZrO ₂ (50 wt%) +5 wt% Y
₂ O ₃ +45 wt% ZrSiO ₄ Example 14 4 wt% CaO-stabilized ZrO ₂ (50 wt%) +4 wt% Y ₂
O ₃ +1 wt% HfO ₂ +45 wt% ZrSiO ₄

(Example 15) The structure of the shaft, castable, carbon, metal layer sleeve, and metal layer for coupling was the same as in Example 8. A powder of 10 wt% CaO-stabilized ZrO ₂ and 10 wt% Y ₂ O ₃ -added ZrSiO ₄ was mixed at a weight ratio of 1: 1 from the top of the bonding metal layer, and an explosive spray was applied to form a 0.5 mm thick outermost layer. Formed.

As a comparative example, the following rolls were manufactured. (Comparative Example 1) The structure of the shaft, castable, and carbon was the same as that of Example 1, and a pure carbon roll in which nothing was applied on the carbon surface was produced.

(Comparative Examples 2 and 3) The structure of the shaft, castable, and carbon was the same as in Example 1. Mo having a thermal expansion coefficient of 6.4 × 10 ⁻⁶ / ° C. was applied on carbon by plasma spraying to form a metal layer. The thickness of each of Comparative Examples 2 and 3 is as follows. Comparative Example 2 Mo metal layer coating thickness: 0.5 mm Comparative Example 3 Mo metal layer coating thickness: 6 mm Further, a thickness of 100 μ was formed on the metal layer by plasma spraying.
forming a Ni-Cr bonding metal layer of m, and
wt% Y ₂ O ₃ stabilized ZrO ₂ powder is plasma sprayed,
An outermost layer having a thickness of 0.2 mm was formed.

(Comparative Examples 4 and 5) The structure of the shaft, castable and carbon was the same as in Example 6. Next, a metal sleeve made of Fe—Ni having a coefficient of thermal expansion of 4 × 10 ⁻⁶ / ° C. and a thickness of 10 mm was prepared, shrink fitted into carbon at 400 ° C., and then ground to form a metal layer. The thickness of each of Comparative Examples 4 and 5 is as follows. Comparative Example 4 Metal layer sleeve thickness; 0.5 mm Comparative Example 5 Metal layer sleeve thickness; 6 mm Further, a thickness of 100 was obtained by plasma spraying on the metal layer.
A Ni—Cr bonding metal layer having a thickness of μm was formed, and 8 wt% Y ₂ O ₃ -stabilized ZrO ₂ powder was plasma-sprayed thereon to form an outermost layer having a thickness of 0.2 mm.

(Comparative Examples 6 and 7) The structure of the shaft, castables and carbon was the same as in Example 6. Next, Mo with a thermal expansion coefficient of 6.4 × 10 ⁻⁶ / ° C. was formed by plasma spraying to a thickness of 2
The metal layer was constructed with a thickness of mm. A 100 μm thick Ni—Cr bonding metal layer was formed on this metal layer by plasma spraying, and an outermost layer was formed by plasma spraying 8 wt% Y ₂ O ₃ -stabilized ZrO ₂ powder on it. The thickness of this outermost layer is as follows in Comparative Examples 6 and 7. Comparative Example 6 Outermost layer sprayed coating thickness: 0.05 mm Comparative Example 7 Outermost layer sprayed coating thickness: 0.6 mm

(Comparative Example 8) The structure of the shaft, castables and carbon was the same as in Example 6. Thermal expansion coefficient 4 × 10 ^-6
/ C, thickness 10mm, thermal conductivity 13Wm ^-1 K ^-1 Fe-N
A metal sleeve made of i was produced, shrink-fitted on carbon at 400 ° C., and then ground to a thickness of 2 mm to form a metal layer. However, no treatment was applied to the surface of this metal layer.

With respect to the test rolls processed as described above, the wear resistance and strength were evaluated by a hot rolling wear tester, and the flatness was evaluated by a rolling down test on a steel sheet having an edge drop.

The wear resistance was measured by heating a cast iron roll (diameter: 300 mm) with a width of 100 mm to 700 ° C. by induction heating, and pressing it against a test roll with a linear pressure of 3 kg / mm, which is a rolling force that does not cause carbon to collapse. Rotating, test roll 300
It was evaluated by the amount of wear after running 0 km. Wear amount is 10
If it is more than μm, it is ×, if it is less than 10 μm and 2 μm or more,
When it was less than μm, it was marked as ◎.

As for strength, a cast iron roll with a width of 100 mm (diameter 30
0 mm) in the axial direction of the surface 1 mm wide x 1 mm high x 100 mm long
Paste the steel plate of, and heat to 700 ℃ by induction heating,
The test roll was pressed at a linear pressure of 3 kg / mm while being rotated to give an impact, and the number of revolutions until carbon destruction was evaluated. Those that broke less than 500 times were rated as X, those that broke less than 500 times and less than 1000 times were rated as ◯, and those that withstood the impact of 1,000 times or more were rated as ◎.

The conformability was evaluated by placing a steel plate having an edge drop of 40 mm in width and 25 μm on a surface plate, applying a rolling force of 3 kg / mm of linear pressure, and evaluating whether the edge drop portion comes into contact with the surface plate. To judge contact with the surface plate, apply a colorant to the steel plate,
It was performed depending on whether the colorant was transferred to the platen.

In this test, assuming that the steel sheet is at room temperature and there is a temperature difference between the steel sheet and the roll, the steel sheet is subjected to 40
It was carried out with heating to 0 ° C. 400 ℃ even at room temperature
Even when heated to 0, those not in contact with each other were marked with X, those in contact with only one were marked with ◯, and those in contact with both were marked with ◎.

The mineral composition of the outermost layer was analyzed by X-ray diffraction, and the proportion of cubic (c), tetragonal (t) and monoclinic (m) crystal phases of ZrO ₂ was determined by X-ray analysis. It was calculated from the peak height I by the following formula. The numbers in parentheses indicate the crystal orientation.

[Equation 1] Further, regarding ZrSiO ₄ , the case where it was detected was marked with ◯.

Table 1 summarizes the test results of the examples and comparative examples of the present invention. It can be seen that all of the carbon rolls of the present invention are excellent in wear resistance, strength and conformability. However, in Examples 1 and 2, since the thermal conductivity of the outermost layer was as high as 7 Wm ^-1 K ^-1 , the roll was crowned by the contact with the high temperature steel plate, and the conformability was poor. If all tests were evaluated as ◎, the overall evaluation is also ◎.

On the other hand, in Comparative Example 1, nothing was applied to the surface, so that the wear was severe, and in Comparative Example 6, the thickness of the ceramic sprayed layer was thin and the ceramic sprayed layer was peeled off during the test. Further, Comparative Example 8 in which the outermost layer was not provided resulted in inferior wear resistance and conformability to the high temperature steel plate.

On the other hand, in Comparative Examples 2 and 4, the metal layer is thin and the strength is poor. In Comparative Examples 3 and 5, the metal layer was too thick and was poor in conformity, and in Comparative Example 7, the ceramic sprayed layer was thick, and the ceramic sprayed layer was peeled off during the test.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

EFFECTS OF THE INVENTION The carbon roll of the present invention has characteristics such as high strength and high abrasion resistance while utilizing the properties of carbon such as high thermal conductivity, low thermal expansion and conformability, so that the roll profile does not change. Therefore, a crown is not generated, the steel sheet is easily transported at high temperatures or when electrically heated, and the life is long. For example, if it is used as a carrier roll for a continuous heat treatment furnace for metals that are subjected to a heat load, due to the high thermal conductivity of carbon, it is difficult to have a temperature distribution even when it comes into contact with a high-temperature material to be heated, and the coefficient of thermal expansion of carbon. The small value makes it possible to suppress the generation of a thermal crown, and prevent deformation due to poor contact with the steel sheet and uneven temperature.

Further, even when the plate width is changed, the profile of the roll is stable, so that the deterioration of the plate shape can be prevented and the occurrence of meandering can be prevented. As a result, production can be performed without slowing down the line speed, and high-speed transportation is also possible. On the other hand, when applied to a current-carrying roll, the profile is stable even if it comes in contact with metal heated to high temperature,
Since the conformability of carbon is not impaired, the occurrence of sparks due to poor contact can be prevented.

With respect to wear, which is a drawback of carbon, since this roll has an outermost surface layer made of hard ceramics or cermet, it can be stably used for a long time, and even if wear occurs, It is economical because the base metal can be used many times if only the surface layer is reprocessed even if it goes on.

[Brief description of drawings]

FIG. 1 shows the structure of a first carbon roll of the present invention.

FIG. 2 shows a structure of a second carbon roll of the present invention.

[Explanation of symbols]

1 axis 2 heat insulation layer 3 carbon 4 metal layer 5 metal layer for bonding 6 outermost layer made of ceramics or cermet

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[Procedure amendment]

[Submission date] March 10, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 10

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

When the metal layer is formed of a metal having a thermal expansion coefficient difference of 5 × 10 ⁻⁶ / ° C. or less from that of the carbon of the body, the metal layer does not rise due to the thermal expansion coefficient difference and can be used at higher temperatures. . For example, for carbon having a thermal expansion coefficient of 5 × 10 ⁻⁶ / ° C., it is preferable to use a metal such as Mo, Cr, or Ti for the metal layer.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Further , ZrSiO ₄ particles and CaO, Y ₂ O
₃ , MgO, CeO ₂ , HfO ₂ , and at least one kind of oxide particles selected from the group consisting of rare earth element oxides, CaO, Y ₂ O ₃ , MgO, CeO ₂ , HfO ₂ ,
Also, the above properties can be satisfied by applying a powder by mixing with ZrO ₂ particles containing ₂ to 20 wt% of at least one oxide selected from the group consisting of oxides of rare earth elements by explosive spraying. The outermost layer can be constructed.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

CaO, Y ₂ O ₃ , MgO, CeO ₂ , H
The amount of at least one kind of oxide particles selected from the group consisting of fO ₂ and rare earth element oxides stabilizes ZrO ₂ in a cubic or tetragonal phase or a mixed phase thereof. Therefore , 2 wt% or more is required, and ZrO ₂ and Fe are required.
In order to suppress the reactivity with the extremely low, it is preferable to set it in the range of 20 wt% or less. If less than 2 wt%,
ZrO ₂ is not stable, and if it exceeds 20 wt%, the reactivity of Fe increases, which is not preferable.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

A metal layer for bonding (Al ₂ O ₃ --CoCrAl) having a thickness of 100 μm was formed on the metal layer by explosive spraying.
Y) was formed, and the thermal spraying raw material powder having the following components was explosively sprayed thereon to form an outermost layer having a thickness of 0.2 mm. Example 6 Metal layer thickness 1 mm Outermost layer thermal spraying raw material powder component 20 wt% CeO ₂ stabilized ZrO ₂ (50 wt%) +3 wt%
Gd ₂ O ₃ +6 wt% CeO ₂ +41 wt% ZrSiO ₄ Example 7 Metal layer thickness 5 mm Outermost layer thermal spraying raw material powder component (6 wt% Gd ₂ O ₃ -12 wt% CeO ₂ stabilized ZrO ₂
(50 wt%) + 5 wt% Y ₂ O ₃ +45 wt% ZrSiO
_Four

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

(Embodiment 8) The structure of the shaft, castables and carbon was the same as that of the embodiment 6. Next, the coefficient of thermal expansion 4 ×
A metal sleeve made of Fe-Ni-Co low thermal expansion alloy having a thickness of 10 ^-6 / ° C and a thickness of 10 mm was prepared, and after shrink-fitting on carbon at 400 ° C, it was ground to a predetermined thickness of 2 mm to form a metal layer.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

Furthermore, a metal layer for bonding (Al ₂ O ₃ --CoCr) having a thickness of 100 μm was formed on the metal layer by explosive spraying.
AlY) is formed, and 8 wt% Y ₂ O ₃ -2 wt%
HfO ₂ stabilized ZrO ₂ and 10 wt% Y ₂ O ₃ added ZrS
A powder obtained by mixing powders of iO _{4 at} a weight ratio of 1: 1 was explosion-sprayed to form an outermost layer having a thickness of 0.1 mm.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

(Examples 9, 10, 11, 12, 13, 1)
4) The configurations of the shaft, castable, carbon, metal layer, and bonding metal layer were the same as in Example 8. Thermal spraying raw material powder having the following components was explosively sprayed on the bonding metal layer to form an outermost layer having a thickness of 0.2 mm. Outermost layer thermal spraying raw material powder component Example 9 20 wt% CeO ₂ stabilized ZrO ₂ (50 wt%) + 3 wt%
Y ₂ O ₃ +2 wt% MgO +45 wt% ZrSiO ₄ Example 10 10 wt% MgO stabilized ZrO ₂ (50 wt%) +5 wt% C
aO + 5 wt% HfO ₂ +40 wt% ZrSiO ₄ Example 11 14 wt% Y ₂ O ₃ stabilized ZrO ₂ (50 wt%) +5 wt%
Y ₂ O ₃ +45 wt% ZrSiO ₄ Example 12 6 wt% CaO-stabilized ZrO ₂ (50 wt%) +5 wt% Y ₂
O ₃ +45 wt% ZrSiO ₄ Example 13 20 wt% CaO-stabilized ZrO ₂ (50 wt%) +5 wt% Y
₂ O ₃ +45 wt% ZrSiO ₄ Example 14 4 wt% CaO-stabilized ZrO ₂ (50 wt%) +4 wt% Y ₂
O ₃ +1 wt% HfO ₂ +45 wt% ZrSiO ₄

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

(Example 15) The structure of the shaft, castable, carbon, metal layer, and metal layer for bonding was the same as in Example 8. 10 wt% CaO-stabilized ZrO from above the binding metal layer
A powder obtained by mixing ₂ and 10 wt% Y ₂ O ₃ -added ZrSiO ₄ powder at a weight ratio of 1: 1 was explosion-sprayed to form a 0.5 mm thick outermost layer.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Change

[Correction content]

(Comparative Examples 4 and 5) The structure of the shaft, castable and carbon was the same as in Example 6. Next, a metal sleeve made of Fe—Ni having a coefficient of thermal expansion of 4 × 10 ⁻⁶ / ° C. and a thickness of 10 mm was prepared, shrink fitted into carbon at 400 ° C., and then ground to form a metal layer. The thickness of each of Comparative Examples 4 and 5 is as follows. Comparative Example 4 metal thickness only; 0.5 mm Comparative Example 5 Metal layer thickness only; 6 mm Furthermore, the thickness by plasma spraying onto the metal layer 100
A Ni—Cr bonding metal layer having a thickness of μm was formed, and 8 wt% Y ₂ O ₃ -stabilized ZrO ₂ powder was plasma-sprayed thereon to form an outermost layer having a thickness of 0.2 mm.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction content]

[0063]

[Table 2]

Front Page Continuation (72) Inventor Yoshiaki Hirota 20-1 Shintomi, Futtsu City, Chiba Nippon Steel Co., Ltd.Technology Development Division (72) Inventor Shoji Yamagata 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd. Technology Development Division (72) Inventor Takao Nagase 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Co., Ltd. (72) Inventor Masaru Fukuyama 20-1 Shintomi, Futtsu City, Chiba Nippon Steel Corporation Technology Development Division

Claims (17)

[Claims] 1. A metal layer having a thickness of 1 to 5 mm, which is formed by thermal spraying or shrink fitting of a metal sleeve, is provided on the outer peripheral surface of a roll whose body portion is made of carbon, and further, on the surface of the metal layer. A carbon roll excellent in high strength, high wear resistance and conformability, which is characterized by having an outermost layer made of ceramics having a thickness of 0.1 to 0.5 mm or cermet. 2. A metal layer having a thickness of 1 to 5 mm, which is formed by thermal spraying or shrink fitting of a metal sleeve, is provided on the outer peripheral surface of the roll whose body portion is made of carbon, and further, on the surface of the metal layer. A high-strength, high wear resistance, and an outermost layer composed of ceramics or cermet having a thickness of 0.1 to 0.5 mm provided through a bonding metal layer formed by thermal spraying. Carbon roll with excellent conformability. 3. The high-strength, high abrasion resistance, and conformability according to claim 1 or 2, wherein the outermost layer made of ceramics or cermet is formed by thermal spraying. Excellent carbon roll. 4. The metal layer is formed of a metal having a difference in thermal expansion coefficient with carbon of the body of 5 × 10 ⁻⁶ / ° C. or less. A carbon roll excellent in high strength, high wear resistance and conformability according to item 1. 5. The metal forming the metal layer is mainly Fe and N.
Low thermal expansion alloy containing i as a component, or Fe, Ni and C
A carbon roll excellent in high strength, high wear resistance, and conformability according to claim 4, which is made of a low thermal expansion alloy containing o as a component. 6. The high strength, high strength according to claim 1, wherein the outermost layer is made of ceramics having a thermal conductivity of 2 Wm ⁻¹ K ⁻¹ or less. A carbon roll with excellent wear resistance and conformability. 7. A substance which is determined to be ZrO ₂ or ZrSiO ₄ substantially consisting of a cubic or tetragonal phase or a mixed phase thereof by at least X-ray diffraction is contained in the outermost layer. 7. A carbon roll excellent in high strength, high wear resistance and conformability according to claim 6. 8. 60% or more of the mineral composition of ZrO ₂ contained in the outermost layer obtained by X-ray diffraction is a cubic or tetragonal phase or a mixed phase thereof. A carbon roll excellent in high strength, high wear resistance, and conformability according to claim 7. 9. The ZrO ₂ contained in the outermost layer is Ca
ZrO ₂ containing ₂ to 20 wt% of at least one oxide selected from the group consisting of O, Y ₂ O ₃ , MgO, CeO ₂ , HfO ₂ , and rare earth element oxides. A carbon roll excellent in high strength, high abrasion resistance and conformability according to claim 7 or 8. 10. The high-strength material according to any one of claims 1 to 5, characterized in that an outermost layer made of ceramics or cermet having a specific resistance of 1 × 10 ⁻³ · cm or less is provided. , A carbon roll with high wear resistance and excellent conformability. 11. A metal layer having a thickness of 1 to 5 mm is provided on an outer peripheral surface of a body formed of carbon, and a ceramic having a thickness of 0.1 to 0.5 mm or a cermet is provided on the surface of the metal layer. A method for producing a carbon roll having high strength, high wear resistance, and conformability, which comprises forming a metal layer by thermal spraying when producing a carbon roll provided with a constituted outermost layer. 12. A metal layer having a thickness of 1 to 5 mm is provided on the outer peripheral surface of the body formed of carbon, and a ceramic having a thickness of 0.1 to 0.5 mm or cermet is further provided on the surface of the metal layer. When producing a carbon roll provided with the outermost layer configured, high strength, high wear resistance, characterized by forming a metal layer by shrinking the metal sleeve, carbon roll excellent in conformability Production method. 13. The outermost layer is formed by thermal spraying of ceramics or cermet.
A method for producing a carbon roll excellent in high strength, high wear resistance, and conformability according to item 1 or 12. 14. A metal layer having a thickness of 1 to 5 mm is provided on the outer peripheral surface of a body formed of carbon, and a thickness of 0.1 to 0 is further provided on the surface of the metal layer via a metal layer for bonding. When manufacturing a carbon roll having an outermost layer composed of 0.5 mm ceramics or cermet, a metal layer and a bonding metal layer are formed by thermal spraying. A method for producing a carbon roll having excellent easiness of production. 15. A metal layer having a thickness of 1 to 5 mm is provided on the outer peripheral surface of the body made of carbon, and the thickness of 0.1 to 0 is further provided on the surface of the metal layer via a metal layer for bonding. When manufacturing a carbon roll provided with an outermost layer composed of 0.5 mm ceramics or cermet, the metal sleeve is heat-shrinked to form a metal layer, and the bonding metal layer is formed by thermal spraying. A method for producing a carbon roll having high strength, high wear resistance, and excellent conformability. 16. The outermost layer is formed by thermal spraying of ceramics or cermet.
A method for producing a carbon roll excellent in high strength, high wear resistance, and conformability according to item 4 or 15. 17. ZrSiO ₄ particles and CaO, Y ₂ O
₃ , MgO, CeO ₂ , HfO ₂ , and at least one kind of oxide particles selected from the group consisting of rare earth element oxides, CaO, Y ₂ O ₃ , MgO, CeO ₂ , HfO ₂ ,
And a powder obtained by mixing ZrO ₂ particles containing ₂ to 20 wt% of at least one oxide selected from the group consisting of rare earth oxides to form an outermost layer by thermal spraying. A method for producing a carbon roll according to claim 13 or 16, which has excellent high strength, high wear resistance and conformability.