KR101643167B1

KR101643167B1 - Disk roll for heat treatment furnace and method for manufacturing the disk roll

Info

Publication number: KR101643167B1
Application number: KR1020160019094A
Authority: KR
Inventors: 송호진
Original assignee: 대한동방 주식회사
Priority date: 2016-02-18
Filing date: 2016-02-18
Publication date: 2016-08-10

Abstract

The present invention relates to a disc roll, and a disc roll manufacturing method capable of improving a performance of a lifespan and suppressing an abrasion of a roll surface by forming an elaborate and hard roll surface layer in a temperature condition such as a heating treating furnace using the disc roll. According to the present invention, the method comprises: a material mixing step of mixing raw materials, including a ceramic fiber, an aluminum oxide, and an inorganic filler with each other; an additive mixing step of adding and mixing a first material, selected from among a boric oxide (B_2O_3), a boron nitride (BN), boric acid (H_3BO_3), and boric acid aluminum, with the raw materials; a disc manufacturing step of manufacturing the raw materials which have passed through the material mixing step and the additive mixing step into a disc having a center hole; a disc stacking step of stacking the disc in a longitudinal direction of a shaft to insert the shaft into a center hole; a roll shape completing step of compressing a plurality of stacked discs on the shaft, and installing flanges on both ends of the shaft to form the disc roll; and an initial surface hardening step of initially hardening a surface of the disc roll in a heat treating furnace due to heat by installing the disc roll in the heat treating furnace at 800-1250C to make a bottom supported by a steel sheet.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a disk roll for use in a heat treatment furnace,

The present invention relates to a disk roll installed in a heat treatment furnace and a method of manufacturing the disk roll, and more particularly, to a disk roll performing a role of conveying a steel sheet in a heat treatment furnace such as an annealing furnace in a steel sheet manufacturing process and a manufacturing method of such disk roll do.

BACKGROUND ART [0002] Conventionally, in a conveying roll used in an annealing furnace in an annealing process of a stainless steel sheet or the like, a roll using a mill board composed mainly of ceramic fibers and an inorganic filler has been used.

Since the annealing temperature condition of the stainless steel sheet varies depending on the type and thickness of the material to be treated and the ceramic fiber and the inorganic filler are fixed to each other due to the temperature condition of about 1200 ° C at the highest place, There is a problem that the strength is low and the roll surface is easily damaged by abrasion.

Accordingly, it is necessary to regularly separate the rolls from the annealing furnace, re-roll the roll surface, smooth it, and reuse it. After this reuse is performed 2 to 3 times, a new roll is used.

Therefore, increasing the service life by suppressing the abrasion of the roll remains a great challenge in the production of stainless steel sheets.

Japanese Unexamined Patent Publication No. 63-111118 discloses a method of impregnating the surface of a disk roll with an inorganic colloid solution as a measure against such abrasion.

However, in such a method, since the inorganic colloid is hardly impregnated sufficiently into the inside of the disk and only the roll surface is cured, when the surface layer is worn, it returns to the state before the treatment.

Japanese Patent Application Laid-Open No. 04-59322 discloses a method in which an inorganic colloid is impregnated in a disk before the disk is inserted into a shaft, and the disk is inserted into a shaft, followed by drying and polishing.

However, this method also has a problem that when the inorganic colloidal material dries to the roll surface along with the progress of drying, the hardness of the surface becomes high and gradually becomes lower as it goes inward. In addition, when the surface is polished to complete the roll, the portion having the highest hardness is removed during the smooth processing, which is economically wasteful.

From such a viewpoint, the present invention is directed to a disk roll and a disk roll manufacturing method in which a roll surface layer having a high density and a high hardness is formed under a temperature condition such as a heat treatment furnace in which a disk roll is used, And to provide the above objects.

Accordingly, a method of manufacturing a disk roll according to the present invention includes: a raw material mixing step of blending raw materials including ceramic fibers, aluminum oxide and an inorganic filler; An additive mixing step of adding and mixing a first material selected from among boron oxide (B 2 O 3), boron nitride (BN), boric acid (H 3 BO 3) and aluminum borate to the raw material; A disk manufacturing step of fabricating the raw material through the raw material mixing step and the additive mixing step with a disk having a center hole; A disk stacking step of stacking the disk in the longitudinal direction of the shaft so that the shaft is inserted into the center hole; A roll-shaped finishing step of compressing a plurality of stacked disks on the shaft and providing flanges at both ends of the shaft to form a disk roll; And a surface initial curing step in which the disk roll is installed so as to support the lower portion of the steel sheet in a heat treatment furnace at 800 ° C to 1250 ° C so that the surface of the disk roll is first cured by heat in the heat treatment furnace do.

In the method of manufacturing a disk roll according to the present invention, the raw material may further include cellulose pulp and starch, and the inorganic filler may be sepiolite. In the raw material mixing step, the raw material may be 25 to 35 weight Wherein the first material added in the additive mixing step is a mixture of 20 to 30% by weight of aluminum oxide, 35 to 45% by weight of sepiolite, 1.5 to 4% by weight of cellulose pulp and 1.5 to 4% And 0.1 to 3.0 parts by weight based on 100 parts by weight of the raw material. The first material is pulverized to a particle size of 10 mu m or less in the slurry state of the raw material.

In the method of manufacturing a disk roll according to the present invention, the second material selected from calcium stearate and magnesium stearate is added and mixed in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the raw material in the additive mixing step, .

According to another aspect of the present invention, there is provided a disk roll for being installed in a heat treatment furnace of a steel plate, the disk roll including a shaft, a center hole formed in a longitudinal direction of the shaft so that the shaft is inserted into the center hole, Wherein the disc comprises a raw material consisting of ceramic fibers, aluminum oxide, sepiolite, cellulose pulp and starch, wherein the disc comprises boron oxide (B 2 O 3), boron nitride (BN), boric acid (H 3 BO 3) And a first material selected from aluminum borate is added.

The disk roll according to the present invention is characterized in that the raw material comprises 25 to 35% by weight of ceramic fibers, 20 to 30% by weight of aluminum oxide, 35 to 45% by weight of sepiolite, 1.5 to 4% by weight of cellulose pulp, The first substance is added in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the raw material, and the second substance selected from calcium stearate and magnesium stearate is further added in an amount of 0.01 to 2.0 parts by weight, As shown in Fig.

According to the present invention described above, it is possible to improve the hardness of the surface in the annealing furnace such as the annealing furnace to improve the service life of the steel sheet as the conveying roll.

Particularly, since the time when the production of the disk roll is completed is installed and used in the heat treatment furnace, the present invention does not require a separate firing process before use, thereby reducing the work process. In addition, since the surface of the roll is cured at the high temperature inside the heat treatment furnace and the inside of the roll can be maintained in the elastic state, the service life can be improved compared with the disk roll which is previously cured and cured as a whole.

Further, since the surface of the disk roll is fired to improve the hardness due to the temperature in the heat treatment furnace, even when the surface is worn, the new surface appearing in the worn position is fired again, resulting in higher hardness. Therefore, The ability to withstand wear and tear can be maintained constantly despite wear.

1 is a block flow diagram showing a method of manufacturing a disk roll according to an embodiment of the present invention;
2 is a perspective view of a disk for manufacturing a disk roll according to an embodiment of the present invention.
FIG. 3 is an explanatory view showing a process of sequentially laminating disks to produce a disk roll according to an embodiment of the present invention.
4 is an explanatory view showing a state after the completion of the roll shape finishing step in the process of manufacturing the disk roll according to the embodiment of the present invention
5 is a view illustrating a state in which a disk roll is used in a heat treatment furnace to complete the production of a disk roll according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, a method of manufacturing a disk roll according to an embodiment of the present invention includes a raw material mixing step of blending raw materials including ceramic fibers, aluminum oxide, and an inorganic filler with each other, a boron oxide (B 2 O 3) A method for producing a raw material, comprising the steps of: adding a first material selected from boron (BN), boric acid (H3BO3) and aluminum borate to the raw material and mixing the raw material; A disk stacking step of stacking the disk in the longitudinal direction of the shaft so that the shaft is inserted into the center hole; compressing the plurality of stacked disks on the shaft to form flanges 31 and 32 at both ends of the shaft; And the disk roll is installed so as to support the lower portion of the steel plate 60 in the heat treatment furnace 50 at 800 ° C to 1250 ° C, And a surface initial curing step in which the surface of the disk roll is first cured by heat in the heat treatment furnace (50).

First, the raw material blending step (step S10) is a step of blending raw materials at a set ratio. The raw materials include ceramic fibers, aluminum oxide, and inorganic fillers. Herein, the inorganic filler uses sepiolite, and it is preferable that a small amount of cellulose pulp, starch and the like are further blended.

In the raw material mixing step, the mixing ratio of the raw material is 25 to 35% by weight of ceramic fiber, 20 to 30% by weight of aluminum oxide, 35 to 45% by weight of sepiolite, 1.5 to 4% by weight of cellulose pulp, . The blend ratio of the raw materials is most preferably 30% by weight of ceramic fibers, 25% by weight of aluminum oxide, 40% by weight of sepiolite, 2.5% by weight of cellulose pulp and 2.5% by weight of starch.

The sepiolite has the largest compounding ratio and forms a cushioning filler. The ceramic fibers are uniformly mixed according to the characteristics of the fibers to prevent cracking of the ceramic rolls and have abrasion resistance.

Aluminum oxide (Al2O3), aluminum hydroxide, aluminum sulfate, and the like can be mentioned, but it is preferable to use thermally stable alumina in consideration of use at a high temperature, and aluminum oxide is used at a high temperature To form a dense roll surface layer and to prevent abrasion of the roll surface.

The additive mixing step (S20) is a step of adding and mixing a first material selected from among boron oxide (B 2 O 3), boron nitride (BN), boric acid (H 3 BO 3) and aluminum borate to the raw material. Since the method of forming a disk to be described later is an edging method, it is preferable to use boron nitride which is insoluble in water in consideration of the outflow of boron by drainage.

The first material is added in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the raw material, and the first material is pulverized to a particle size of 10 mu m or less in a slurry state of the raw material And more preferably 1 mu m is preferable), so that it can be mixed so as to be evenly distributed as a whole. It is most preferable that the additive-mixing step is performed in a slurry state of the raw material, but the raw material blending step (step S10) and the additive blending step (step S20) may be simultaneously performed if necessary. The first material reacts with the aluminum oxide at the use temperature of the disc roll to produce aluminum borate or the aluminum borate itself added as the first material binds the raw material to form a dense surface layer.

When the addition amount of the first substance is 0.1 parts by weight or less, the effect is insufficient because the amount is too small. When the addition amount is 3.0 parts by weight or more, the degree of curing is too large to be suitable as a disk roll. Therefore, 2.5 parts by weight or less is more preferable.

The slurrying step of the raw material is a step of making a raw material compounded with a predetermined blending ratio into a slurry. The blended raw material is put into a solvent such as distilled water and stirred to prepare a slurry. It is more preferable that the starch in the raw material is mixed with other raw materials in a slurrying step so that the starch can be well mixed and act as a binder.

The disc making step S30 is a step of manufacturing the raw material having the center hole 12 from the mixing step (step S10) and the additive mixing step (step S20). In the disk manufacturing step, the disk 11 may be manufactured by forming a plate-shaped millboard and then punching it, or may be directly manufactured in the form of a disk using a die when forming a mill board.

The mill board is formed by drying the slurry that has been loosened in a solvent to form a thin plate by a papermaking method like a method of making paper.

The prepared mill board needs to be dried before punching to remove the solvent such as water. A plurality of mill boards are stacked and then punched to form the disk 11 as shown in FIG. The disk 11 formed by punching has a center hole 12 formed therein.

3, in order to manufacture a disk roll, the disk is stacked in the longitudinal direction of the shaft 20 so that the shaft 20 is inserted into the center hole 12, The roll body can be formed.

The shaft 20 has a cooling water passage through which cooling water flows to cool the shaft and the inside of the disk stack 10 in the heat treatment furnace.

The roll shape finishing step (S50) compresses the plurality of stacked disks on the shaft 20 and tightens the flanges 31 and 32 so as to maintain the compressed state, thereby completing the shape of the disk roll as shown in FIG. . The plurality of stacked discs can be integrated with each other by being compressed using a jig, and flanges (31, 32) are provided at both ends of the disc stack body (10) in a compressed state to manufacture a disc roll . The outer peripheral surface of the roll body made of the disc laminate 10 is polished and smoothed.

When the shape of the disk roll is completed, a disk roll which is not baked without firing the disk stack body 10 is installed in the heat treatment furnace 50 in accordance with the original use and the surface initial hardening step .

The surface hardening step (step S60) is a step of hardening the laminated disk before the disk roll is delivered to the site, As shown in FIG. 5, and is immediately started to be used.

The disk roll installed and used to support the lower portion of the steel plate 60 conveyed in the heat treatment furnace 50 at an environment of 800 ° C. to 1250 ° C. is a disk roll which is used for the first time The hardness of the surface is increased. On the other hand, on the inner side of the stacked disk, firing is not performed or incompletely progressed, so that the elasticity is maintained.

Usually, the heat treatment furnace 50 of the steel plate 60 forms a temperature state of about 1000 캜 or higher.

Thus, the production of the disk roll of the present embodiment is characterized in that the disk laminate 10 constituting the roll body is subjected to firing during use in the heat treatment furnace 50 without performing a firing process in advance . Therefore, the disk roll of the present invention is finally manufactured by using the disk roll in the heat treatment furnace 50 in which the heat treatment of the steel plate 60 is performed. The heat treatment furnace 50, As the production stage.

When the disk roll is completed by performing the firing process before the field use, the disk roll is hardened as a whole and is easily broken by the impact with the steel plate 60. Therefore, the manufacturing method according to the present invention can solve such a problem . That is, the surface on which the laminated disk not subjected to the firing process comes into contact with the steel plate 60 due to contact with the steel plate 60 or the portions to be directly heated are mainly fired, so that they are not fired in the disk laminate 10 with high hardness, Thereby maintaining elasticity.

Particularly, a cooling water passage through which cooling water flows in the shaft 20 of the disk roll is formed so that the inside of the disk stack body 10 can retain the elasticity without being fired by cooling.

Further, even when a part of the surface of the disk roll is worn due to friction with the steel plate 60 during use of the disk roll in the heat treatment furnace 50, if the worn portion is newly exposed, the surface can be hardened by heat Therefore, even if abrasion or thin layer falls off, the surface can maintain a high hardness and maintain the elasticity inside.

The surface temperature of the disk roll in the initial curing step is more preferably 1000 to 1200 ° C.

In the surface initial curing step (S60), the surface is cured in this temperature environment because an aluminum oxide component such as aluminum oxide reacts with a boric anhydride component such as boric acid and boron oxide to act as a binder.

The aluminum borate which acts as a binder is obtained by reacting an aluminum oxide component such as aluminum oxide, aluminum hydroxide or aluminum sulfate with an anhydrous boric acid component such as boric acid and boron oxide at a temperature of 800 to 1200 DEG C to form a reaction product of Al2O32B2O3 or 2Al2O3B2O3 .

Meanwhile, the following Table 1 shows evaluation results according to blending or addition ratio and presence or absence of discs produced by the raw materials and additives according to the present embodiment.

Table 1

Examples 1 to 3 were prepared by adding 0.3, 1.0, and 2.5 parts by weight of a slurry of aluminum borate obtained by wet-pulverizing a slurry of ceramic fiber, alumina, sepiolite, cellulose pulp, After that, a test piece was prepared through an aging process and a drying process.

In Examples 4 to 6, 0.3, 1.0, and 2.5 parts by weight of boron nitride were added as solid components to a slurry of a mill board mixed with ceramic fibers, alumina, sepiolite, cellulose pulp, and starch, And alumina were reacted to produce aluminum borate. The test pieces were prepared through an aging process and a drying process.

In Comparative Example 1, aluminum borate or boron nitride was not added, and the raw material was compounded into a disk mill board to prepare a test piece.

(1) Compression

The compression ratios of the respective disk-use test pieces were determined on a press material tester with a thickness of T1 when a compressive load of 0.05 MPa was applied at a rate of 1 mm / min., And a thickness of T1 when the load was 10 MPa.

Compression ratio (%) = ((T0 - T1) / T0) * 100

(2) Hardness

A disk material having an outer diameter of 120 mm and an inner diameter of 50 mm was punched out from each of the disk mills for remolding the disk and set at a filling density of 1.46 (g / cm 3) by tightening the stainless steel shaft 20 to a face length of 200 mm. , The hardness (Shore D) of the roll surface was measured after polishing to an outer diameter of 115 mm. After heating at 1150 DEG C for 24 hours, the same measurement was carried out.

(3) Wear rate

A disk material having an outer diameter of 120 mm and an inner diameter of 50 mm was punched out from each of the disk mills for remelting disks and set when the packing density was 1.46 (g / cm < 3 >) by tightening the surface of the stent shaft 20 with a surface of 200 mm. The disk roll was rotated (11RPM) while applying a line pressure of 6.0 kg / cm to a SUS310 load roll in an 1150 ° C atmosphere in a disk roll test furnace, and after heating for 24 hours, And the outer diameter of the unloaded part were measured to determine the wear rate according to the diameter difference.

Wear rate (%) = ((No load part outer diameter - Load part outer diameter) / No load part outer diameter) * 100

(4) Crack resistance

After the heating test of the wear rate measuring roll in (3) above. The appearance of cracks was visually observed, and ○ indicates no problem in use of the roll due to cracking. ? Indicates that the cracks are somewhat grown but there is no problem in using the roll. X is a crack, and there is a fear that the roll surface may fall off. Were classified into three stages.

As shown in Examples 1 to 6, as the addition amount of aluminum borate or boron nitride increased, the discs prepared by the raw materials and the additives according to the present Example were evaluated according to blending or addition ratio and presence or absence thereof The hardness after heating increases, the wear rate of the roll is also reduced, and the wear resistance is improved.

In the comparative example, the hardness after heating is relatively largely lower than that before heating, and the wear rate is also increased.

Hereinafter, a method of manufacturing a disk roll and a disk roll according to another embodiment of the present invention will be described.

In this embodiment, to prevent cracks, abrasion, and dropouts on the surface of the disk roll, it is proposed to prevent the destruction of the ceramic fibers during the manufacturing process.

In the present embodiment, the second material selected from calcium stearate and magnesium stearate is further blended in an amount of 0.01 to 2.0% by weight in the raw material blending step or the slurrying step.

The second material is a material adopted in the present embodiment in order to prevent the ceramic fibers contained in the disc from being broken due to the compressive force in the process of compressing a plurality of discs stacked in the roll-form finishing step.

In the case of the disk roll in which the ceramic fiber is broken, cracks, abrasion and detachment of the surface of the disk roll are promoted under conditions of use in contact with the steel plate 60. Therefore, until the disk roll is installed in the heat treatment furnace 50, It is necessary to maintain the fiber state, thereby preventing wear and tear of the disk roll surface.

The performance characteristics of the present embodiment can be more specifically explained by the execution composition and evaluation results shown in the following Table 2. [

Table 2

In Examples 7 to 9 and Comparative Example 2, the test pieces were produced from the wheat mixed slurry containing the raw materials as in the previous case. Example 5 is the case of Example 5 in which the above evaluation results are presented.

In Examples 7 to 9 and Example 5, 1.0 part by weight of boron nitride was added to the millboard slurry in an amount of 1.0 part by weight based on 100 parts by weight of the raw material, 0.3 to 0.5 parts by weight of calcium stearate was added to each of Examples 7 to 9 And mixed evenly.

Comparative Example 2 shows a mill board formulation in which no boride such as aluminum borate or boron nitride was added and calcium stearate was not added.

In Table 2, it can be seen that the abrasion resistance of Examples 7 to 9 is improved as the addition amount of calcium stearate is higher than that of Example 5 containing only boron nitride and Comparative Example 2 in which boron nitride and calcium stearate are not added at all.

In Comparative Example 2, the hardness after heating is lowered relatively higher than that before heating, and the wear rate is also increased.

10; Disk stack 11; disk
12; Center hole 20; shaft
31, 32; Flange 50; Heat treatment furnace
60; Steel plate

Claims

A raw material mixing step of blending ceramic fibers, aluminum oxide and an inorganic filler together to prepare a raw material containing both the ceramic fiber, the aluminum oxide and the inorganic filler;
An additive mixing step of adding and mixing the first material selected from boron oxide (B 2 O 3), boron nitride (BN), boric acid (H 3 BO 3) and aluminum borate to the raw material;
A disk manufacturing step of fabricating the raw material through the raw material mixing step and the additive mixing step with a disk having a center hole;
A disk stacking step of stacking the disk in the longitudinal direction of the shaft (20) so that the shaft (20) is inserted into the center hole;
A roll-shaped completion step of compressing a plurality of stacked disks on the shaft (20) and providing flanges (31, 32) at both ends of the shaft (20) to form a disk roll; And
The disk roll is installed so as to support the lower portion of the steel plate 60 in the heat treatment furnace 50 at a temperature of 800 to 1250 DEG C so that the surface of the disk roll in the heat treatment furnace 50 is first cured A curing step,
In the additive mixing step
Calcium stearate and magnesium stearate are added and mixed in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the raw material,

The method according to claim 1,
In the raw material blending step, the raw material is further comprised of cellulose pulp and starch,
Wherein the inorganic filler is sepiolite,
In the raw material blending step, the raw material may include 25 to 35 wt% of the ceramic fiber, 20 to 30 wt% of the aluminum oxide, 35 to 45 wt% of the sepiolite, 1.5 to 4 wt% of the cellulose pulp, By weight, the starch is formulated in 1.5 to 4% by weight,
The first material added in the additive mixing step is added in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the raw material,
Wherein the first material is pulverized to a particle size of 10 mu m or less in a state where the raw material is slurried and added

delete

In the disk roll to be installed in the heat treatment furnace 50,
A shaft 20,
And a plurality of disks formed in the longitudinal direction of the shaft (20) so that the shaft (20) is inserted into the center hole,
The disk
A raw material containing both the ceramic fiber, the aluminum oxide, the sepiolite, the cellulose pulp and the starch are blended together with ceramic fiber, aluminum oxide, sepiolite, cellulose pulp and starch,
Wherein a first material selected from boron oxide (B 2 O 3), boron nitride (BN), boric acid (H 3 BO 3) and aluminum borate is added,
The shaft (20) is provided with a cooling water passage through which cooling water flows,
The raw material
Wherein the ceramic fiber is 25 to 35 wt%, the aluminum oxide is 20 to 30 wt%, the sepiolite is 35 to 45 wt%, the cellulose pulp is 1.5 to 4 wt% 4% by weight,
With respect to 100 parts by weight of the raw material,
The first material is included in an amount of 0.1 to 3.0 parts by weight,
Calcium stearate, and magnesium stearate is further contained in an amount of 0.01 to 2.0 parts by weight,