JP2607630B2 - Sleeve assembly type roll and equipment using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sleeve-assembled roll, and more particularly to a sleeve-assembled roll suitable for use at high temperatures and equipment using the same.

[Conventional technology]

It is well known that it is effective to use a material having excellent corrosion resistance and friction resistance for the body and shaft of a roll used in a high-temperature and corrosive environment. For example, a ceramic sleeve is fitted to a roll shaft used in an electrolytic plating tank (Japanese Patent Application Laid-Open No. 60-208626), and a ceramic sleeve is fitted to a roll body for transporting a high-temperature material. (Japanese Patent Laid-Open No. 61-55409).

[Problems to be solved by the invention]

When assembling the sleeve to the arbor,
No. 208626 describes that the sleeve is loosely fitted to the arbor, but there is no quantitative description, and how the dimensional relationship between the sleeve and the arbor is in use,
Unknown. Japanese Patent Application Laid-Open No. 61-55409 discloses that when a sleeve is cracked due to a difference in thermal expansion coefficient between the sleeve and the arbor, a different material such as metal is interposed between the sleeve and the arbor as an expansion allowance absorbing material. However, the stress generated in the sleeve is not mentioned, and the quantitative effect is unknown.

On the other hand, in order to prevent the sleeve from cracking, a structure in which the sleeve and the sleeve are separated from each other without being formed as a single body has been proposed (Japanese Utility Model Application Laid-Open Nos. 58-170156, 58-170157, 59-10958, and 59-10958). 59
-25360). Further, rolls in which a part of the surface is made of ceramics have been proposed (Japanese Utility Model Application Laid-Open Nos. 58-152356 and 59-58560). However, if the sleeve is divided or a material such as ceramics is used which has high abrasion resistance and corrosion resistance, the gap is corroded and the purpose cannot be sufficiently achieved. In addition, discontinuity may occur and smooth rotation may not be obtained, which may adversely affect the product.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sleeve-assembled roll having a long life without stress being applied to the sleeve when not in use.

[Means for Solving the Problems] In order to achieve the above object, according to the first aspect of the present invention, in a sleeve-assembled roll having a sleeve mounted on an arbor, a gap is formed between the sleeve and the arbor at normal temperature. The circumferential stress generated on the inner peripheral surface of the sleeve at the operating temperature is smaller than the tensile strength of the sleeve material, and the sliding force generated between the sleeve and the arbor by driving the roll is smaller than the sliding force generated between the sleeve and the arbor. A sleeve assembly type roll characterized in that radial dimensions of the sleeve and the arbor are set so as to increase the slip resistance of the sleeve.

According to the second aspect of the present invention, in a sleeve-assembled roll in which a sleeve is mounted on an arbor, a gap is provided between the sleeve and the arbor at normal temperature, and ((R ₃ ² + R ₀ ² ) /
(R ₃ ² −R ₀ ² )) · p <σ _B (R ₃ : outer radius of the sleeve at room temperature, R ₀ : outer radius of the arbor when the arbor contacts the sleeve, or inner radius of the sleeve, p: used Radial stress at the contact surface of the arbor and sleeve at temperature,
σ _B : tensile strength of the sleeve) and p> T / (2πμ · R ₀ ²
(L) (T: torque applied to the arbor; μ: coefficient of sliding friction between the arbor and the sleeve; L: length of the sleeve).

It is preferable that the sleeve of the first or second invention is fixed to a flexible structure so as not to move in the axial direction of the arbor.

As the method of fixing the flexible structure, at least one hole is provided in the radial direction of the sleeve, a method of fixing to the arbor via a bolt, a groove is provided on an end face of the sleeve,
A method of fixing the sleeve to the arbor using a block, and a method of holding both ends of the sleeve by a flange having a diameter larger than the diameter of the arbor can be applied.

The sleeve-assembled roll of the present invention can be used as a roll for rolling of a rolling mill, a roll for transporting an object to be heat-treated in a heat treatment furnace, a sink roll in a continuous molten metal plating facility, and the like.

[Action]

FIG. 1 is a sectional view for explaining the present invention. That is, there is a gap 3 between the arbor 1 and the sleeve 2 at normal temperature. In the present invention, by controlling the gap 3, cracks do not occur in the sleeve, and slippage does not occur between the sleeve and the arbor during operation of the roll.

Hereinafter, a method of determining an appropriate gap will be described.

(1) The diameter of the arbor when the temperature rises by ΔT is 2R ₁ ′ = (1 + α ₁ · ΔT) 2R ₁ (1) where α _{1 is} the linear expansion coefficient of the arbor R _{1 is} the radius of the arbor at room temperature ( 2) The diameter of the inner surface of the sleeve when the temperature rises by ΔT is 2R ₂ ′ = (1 + α ₁ · ΔT) 2R ₂ (2) where α ₂ : linear expansion coefficient of the sleeve R ₂ : sleeve at room temperature Inner radius (3) Gap (arrangement) between arbor and sleeve when temperature rises by ΔT δ = (2R ₁ ′ −2R ₂ ′) −δ ₀ = 2 (α ₁ R ₁ −α ₂ R ₂ ) ΔT −δ ₀ … (3) where δ ₀ : gap between the arbor and the sleeve at room temperature. (4) The radial stress generated at the contact surface between the arbor and the sleeve is obtained from the official collection of material mechanics (Corona, September 1963) From here, issued on March 15) Here, the radius of the arbor when the arbor comes into contact with the sleeve (diameter of the inner surface of the sleeve) As 2R _0, if put a 2R ₀ = 2R ₂ for simplicity of calculation Where E ₁ : Young's modulus of the arbor ν ₁ : Poissonization of the arbor E ₂ : Young's modulus of the sleeve ν ₂ : Poisson's ratio of the sleeve R ₃ : Outer radius of the sleeve at room temperature (5) Generated on the inner periphery of the sleeve Circumferential stress can be obtained from the official collection of material mechanics (Corona, published September 15, 1963) (6) Conditions for preventing the sleeve from cracking σ _ti <σ _B ... (6) where σ _B : tensile strength of the sleeve (7) Conditions for preventing slippage between the sleeve and the arbor T <μp · 2πR ₀ · LR ₀ Where T: Torque μ: Sliding coefficient of friction between arbor and sleeve L: Length of sleeve That is, the gap δ between the sleeve and arbor at normal temperature to satisfy Equations (6) and (7) at normal operating temperature. ₀
By determining = 2 (R ₁ -R ₂ ), a sleeve-assembled roll that does not crack in the sleeve and does not slip between the sleeve and the arbor can be obtained.

〔Example〕

Example 1 FIG. 2 shows a sleeve-assembled roll manufactured according to the present invention. Arbor 1 is made of JIS SCM 440H steel (chromium molybdenum steel) heated to 850 ° C and then oil quenched. Was. Further, the sleeve Si ₆ - Using β sialon ceramic try sintered body _{Z - Z Al Z O Z N} 8. z is 0 to 4.2. The material has a Vickers hardness of 1800, excellent wear resistance, and does not decrease in hardness up to about 1000 ° C.

This roll is used for rolling difficult-to-machine materials such as W and Mo at a temperature of about 450 ° C.

Hereinafter, the method for assembling the sleeve according to the present invention will be described quantitatively.

The dimensions of Arbor 160mm outside diameter (2R _1), 550 mm overall length,
The dimensions of the sleeve are 160.5 mm for the inner diameter (2R ₂ ) and the outer diameter (2R ₃ ).
The length (L) was 200 mm and the length (L) was 300 mm. The linear expansion coefficient, Young's modulus, and Poisson's ratio of the arbor and the sleeve are as follows.

α ₁ = 12 × 10 ⁻⁶ / ° C. α ₂ = 3.2 × 10 ⁻⁶ / ° C. E ₁ = 2.1 × 10 ⁴ kg / mm ² E ₂ = 3.1 × 10 ⁴ kg / mm ² ν ₁ = ν ₂ = 0.28 The coefficient of sliding friction (μ) between the arbor and the sleeve is 0.15 from experimental results. The tensile strength (σ _B ) of Sialon Ceramics used for the sleeve is 40 kg / mm ² . From the use conditions, ΔT is 450 ° C at the use temperature of the roll,
The torque (T) is 2.5 × 10 ⁴ kg-mm.

Substituting these values into equations (3) ', (4), and (5), the gap (δ ₀ ) between the arbor and the sleeve at normal temperature and the radial stress generated on the contact surface between the arbor and the sleeve generated during roll operation The relationship between (φ) and the circumferential stress (σ _ti ) generated at the inner peripheral edge of the sleeve was calculated and is shown in FIG. Further, FIG. 3 shows the range of δ ₀ according to the present invention under the conditions shown in Expressions (6) and (7). From FIG. 3, δ ₀ may be selected within the range of 0.363 <δ ₀ <0.6296 mm, but in the present embodiment, δ _{0 was set to} 0.5 mm. Substituting δ ₀ = 0.5 mm into equation (3) ′, the interference at the time of operation is δ = 0.13 mm
From equation (4), the contact stress between the arbor and the sleeve is p = 4.28 kg / mm ² , and the circumferential stress on the inner peripheral edge of the sleeve is σ _ti = 19.5 kg / mm ² from equation (5). Therefore,
The slip resistance is sufficiently large for p> 0.014 kg / mm ² obtained from equation (7), and the sleeve has a crack limit σ _ti <
For σ _B = 40 kg / mm ² , σ _ti is about one-half, and both are safe values.

To assemble the sleeve to the arbor, form a flange with an outer diameter larger than the body at one end of the body of the arbor, fit the sleeve at room temperature, and then use the hollow disk with the outer diameter larger than the body at the other end. The flexible structure was fixed by bolting to the arbor. Although a hollow disk is used in this embodiment, a block may be partially fixed to the arbor using a block instead of the hollow disk.

The roll assembled at room temperature in this manner was incorporated into a rolling mill, and the entire rolling mill was heated to 450 ° C. while keeping the roll horizontal. Heating time for both arbor and sleeve
It was long enough to reach 450 ° C. Then roll the whole roll 4
While maintaining the temperature at 50 ° C., the tungsten was rolled. As a result, there was no crack in the sleeve and no slippage between the arbor and the sleeve, and it was possible to achieve a service life 200 times or more longer than that of a conventional roll using high-speed steel.

[Example 2] In Example 1, sialon ceramics was used as a sleeve material. In this example, one kind of cemented carbide, WC-TiC, was used.
-The result of applying a TaC-Co sintered alloy (JIS K10 equivalent) is described. The linear expansion coefficient, Young's modulus and Poisson's ratio of this material are as follows.

α ₂ = 5.5 × 10 ⁻⁶ / ° C. E ₂ = 5.7 × 10 ⁴ kg / mm ² ν ₂ = 0.22 Further, the coefficient of sliding friction with steel was experimentally determined to be μ = 0.17. The tensile strength (σ _B ) of the sleeve material was 125 kg / mm ² . The working temperature and the rolling torque are the same as in the first embodiment.

The dimensions of Arbor 160mm outside diameter (2R _1), 550m full length
m, sleeve dimensions are 160.3 mm for inner diameter (2R ₂ ) and outer diameter (2R
R ₃ ) was 200 mm, and the length (L) was 300 mm.

Substituting these values into Equations (3) ', (4), and (5), the interference during operation is δ = 0.17 mm, the contact stress between the arbor and the sleeve is p = 9.0 kg / mm ² , and the inner peripheral edge of the sleeve Is σ _ti = 41.7 kg / mm ² . Therefore, the slip resistance is about 650 times the slip force generated by the torque, which is sufficiently large, and the safety factor against cracking of the sleeve is about 3.

To assemble the sleeve to the arbor, a flange is machined at one end of the body of the arbor, and the other end of the sleeve is spaced apart by 180 degrees to a size of 20 mm in the circumferential direction and 5 mm in the axial direction.
This was carried out by the same flexible structure assembly as in Example 1 in which the block was bolted using the groove processed.

The roll assembled at room temperature in this manner was incorporated into a rolling mill, and the entire rolling mill was heated to 450 ° C. while keeping the roll horizontal. Heating time for both arbor and sleeve
It was long enough to reach 450 ° C. Then roll the whole roll 4
The tungsten was rolled while keeping the temperature at 50 ° C. As a result, no cracks occurred in the sleeve and no slippage occurred between the arbor and the sleeve, and a service life approximately four times as long as that of a conventional roll using high-speed steel was obtained.

Example 3 Various heat treatments are performed on a metal during its manufacturing process to give required dimensions and characteristics. The temperature can be adjusted to 10
It covers a wide range from a high temperature of 00 ° C or higher to a subzero treatment of 0 ° C or lower. As a third embodiment of the present invention, the result of applying the present invention to a roll used in a high-temperature heat treatment furnace will be described.

The roll has a body diameter of 160 mm and a length of 700 mm. The roll is driven by a chain and is used in a continuous bright annealing furnace in which products are fed on the roll. The roll temperature during operation is 920 ° C. Conventionally, the roll material is C
r Heat-resistant steel such as steel, Ni-Cr steel or Ni-Cr-Co alloy was used, but conversion was often required due to oxidation, corrosion, deformation, and alteration. Accordingly, an attempt was made to assemble and use a ceramic sleeve on a steel arbor by the method of the present invention. Sleeve outer diameter (2R ₃ ) is 160mm, inner diameter (2R ₃ )
₂ ) is 141.0 mm, the length (L) is 700 mm, the outer diameter of the arbor (2R ₁ ) is 140 mm, and the total length is 1000 mm. The Sialon ceramics sintered body described in Example 1 was used as the material of the sleeve, and Ni-Cr steel was used as the material of the arbor.

The interference at the operating temperature is δ = 0.137 mm, the contact stress between the arbor and the sleeve is p = 3.33 kg / mm ² , and the circumferential stress generated on the inner peripheral edge of the sleeve is σ _ti = 25.8 kg / mm ² . The slip force generated by the torque applied to this roll is sufficiently small and negligible compared to the slip resistance. Further, the stress generated in the sleeve is smaller than the strength of the sleeve, and there is no problem.

Next, a method of assembling the sleeve to the arbor will be described. After processing the sleeve to the specified dimensions, the processing required for assembly is not performed, and one side of the arbor has an outer diameter of 200 mm and a thickness of 30 m
After attaching a flange of m and thread-cutting the other side, assembling the sleeve into an arbor at room temperature, it was screwed with a female screw having an outer diameter of 200 mm and a thickness of 30 mm. The rolls thus assembled were put into the furnace, and after the temperature of the sleeve and the arbor reached 920 ° C., a continuous annealing operation was started. After one week of continuous operation, the rolls were extracted from the furnace and the surface condition was examined. As a result, no cracks were observed and there was no change from the assembled state. On the other hand, Ni-Cr steel rolls showed scratches and wear, confirming the effectiveness of the sleeve type roll assembled by the method of the present invention.

Further, the sleeve type roll according to the present invention can be used as a roll for continuous casting or various rolls for transporting a high-temperature material.

Example 4 Sink rolls and support rolls used in the continuous molten metal plating bath of FIG. 5, particularly in a zinc or aluminum bath, are required to have corrosion resistance and abrasion resistance. Conventionally, stainless steel, high chromium steel, and the like have been used in the form of overlays and sleeves. However, when these materials are used for a long period of time, corrosion and wear occur, and it is necessary to change the rolls. That is, the surface of the roll is roughened due to the erosion by the molten metal, and the uniformity of plating is impaired. Further, in the shaft portion, the roll shaft becomes thin due to the erosion action of the molten metal and the wear damage due to the load, causing looseness between the roll shaft and the bearing, which causes vibration and uneven thickness of the plating.

In this example, the results of applying the method of the present invention to a sink roll for continuous molten metal plating will be described.

FIG. 4 shows a cross section of a roll according to the invention. That is, the structure is such that sleeves 7 and 8 having excellent corrosion resistance and wear resistance are assembled on the surface of the roll shaft 4 and the body 5.

Hereinafter, a method for producing the roll will be described. The diameter of shaft 4 is
The shaft sleeve 7 has an outer diameter of 150 mm, an inner diameter of 130.6 mm, and a length of 180 mm. The diameter of the torso 5 is 42
0mm, length is 1160m except flange 6 and retaining ring 9
m, outer diameter of trunk sleeve 8 is 450mm, inner diameter is 422mm, length is 1
160 mm.

Material is shaft 4, copper 5, flange 6 and retaining ring 9 are Ni
-Cr-Mo steel, and the shaft sleeve 7 and the body sleeve 8 were the sialon ceramic sintered bodies shown in Example 1.

As the Ni-Cr-Mo steel, SNCM447 was selected by the JIS symbol. As the heat treatment, the steel was quenched in oil at 850 ° C and then tempered at 670 ° C to make the Brinell hardness (H _B ) 320.
Then, it was finished to predetermined dimensions by machining.

Sialon ceramics was formed into a compact by cold isostatic pressing, subjected to roughing while leaving firing shrinkage and finishing allowance, fired at 1750 ° C., and finished to predetermined dimensions.

In the assembly, first, a sleeve sleeve 8 was inserted into the body 5 at a room temperature by a clearance fit, and then the flexible structure was fixed with a screw 10 by a retaining ring 9. Next, after the shaft sleeve 7 was fitted into the shaft 5 with a clearance at room temperature, the shaft sleeve 7 was fixed to the shaft 5 with a flexible structure by using a bolt through an asperity hole 11 formed in the shaft sleeve 7.

The condition of use of this roll is that it is used continuously in an aluminum plating bath at 650 ° C, and the gap between the arbor and the sleeve at room temperature is when the arbor and the sleeve reach 650 ° C (3) ', (4) and (5) are determined so that the values obtained from the equations (6) and (7) are satisfied. That is, for the shaft sleeve, δ = 0.145m
m, p = 4.02 kg / mm ² , σ _ti = 29.2 kg / mm ² , and for the trunk sleeve, δ = 0.408 mm, p = 1.84 kg / mm ² , σ _ti = 27.7 kg / mm ² .

Hereinafter, the evaluation of the present invention will be described. As a result of using the sink roll manufactured according to the present invention in a continuous plating operation in an aluminum bath at 650 ° C., the conventional metal roll had severe shaft wear, and had to be replaced in four days.
The roll of the present invention did not have abnormal wear even after continuous use for two months, had a small amount of wear, and was able to perform a uniform fixing work. Also, it was confirmed that the assembly method according to the present invention can effectively utilize the ceramic sleeve without cracking or slippage of the sleeve.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, in the sleeve assembly type roll used at high temperature, even when the thermal expansion coefficient of a sleeve is smaller than the thermal expansion coefficient of an arbor, an appropriate interference can be provided at a use temperature. Accordingly, a sleeve made of ceramics, which is a brittle material weak against tensile stress, can be effectively used. Since ceramics has high-temperature strength, abrasion resistance, and corrosion resistance, it has a much longer life as a roll for hot rolling, a heat treatment furnace, and a molten metal plating than a conventional metal roll. Further, if the temperature is up to about 500 ° C., a sleeve made of cemented carbide, which is a cermet composed of metal and ceramics, can be used, and a long life can be obtained.

Therefore, the sleeve-assembled roll according to the present invention is effective in improving productivity, reducing the cost of products, and improving quality.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining the method of the present invention, FIG. 2 is a perspective view of a rolling roll showing one embodiment of the present invention, and FIG.
FIG. 4 is an explanatory view showing the scope of the present invention according to one embodiment, FIG. 4 is a cross-sectional view of a molten metal plating roll showing another embodiment of the present invention, and FIG. 5 is a continuous molten metal. 1 ... Arbor, 2 ... Sleeve, 3 ... Gear gap.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Osamu Shimomura 832 Horiguchi, Katsuta-shi, Ibaraki Pref. Hitachi, Ltd. Katsuta Plant (56) References JP-A-52-82658 (JP, A) JP-A-53-45654 (JP, A) JP-A-63-273505 (JP, A) JP-A-51-72953 (JP, A) JP-B-59-2561 (JP, B2)

Claims (7)

(57) [Claims] 1. A sleeve-assembled roll having a sleeve mounted on an arbor, wherein there is a gap between the sleeve and the arbor at room temperature, and a circumferential stress generated on the inner peripheral surface of the sleeve at a use temperature is reduced by the sleeve material. The radial dimension of the sleeve and arbor is set so that it is smaller than the tensile strength, and the slip resistance between the sleeve and the arbor is larger than the sliding force generated between the sleeve and the arbor by driving the roll. Sleeve assembly type roll. 2. A sleeve prefabricated roll made by mounting the sleeve on the arbor has a gap between the sleeve and the arbor at room ^{_{temperature, ((R 3 2 + R}} 0 2) / (R 3 2 -R 0 2) ) · P <σ _B (R ₃ : outer radius of the sleeve at room temperature, R ₀ : outer radius of the arbor when the arbor contacts the sleeve, or inner radius of the sleeve, p:
Radial stress generated on the contact surface of the arbor and the sleeve in the use temperature, sigma _B: tensile strength of the sleeve) and, p> T / (2πμ · R 0 2 · L) (T: torque on the arbor, mu: Arbor The coefficient of sliding friction between the sleeve and the sleeve, L: the length of the sleeve. 3. The sleeve-assembled roll according to claim 1, wherein the sleeve is fixed to a flexible structure so as not to move in the axial direction of the arbor. 4. A sleeve assembly type roll according to claim 3, wherein said flexible structure fixing method is characterized in that at least one hole is provided in a radial direction of said sleeve, and said sleeve is fixed to an arbor via a bolt. 5. A method for fixing a flexible structure according to claim 3, wherein a groove is formed in an end face of the sleeve, and the sleeve is fixed to an arbor using a block. 6. A sleeve assembling roll according to claim 3, wherein both ends of said sleeve are held by flanges having a diameter larger than the diameter of the arbor. 7. A hot-dip metal plating apparatus wherein the sleeve-assembled roll according to claim 1 is used as a roll in a bath for hot-dip metal plating.