JPH01119616A - Roller for conveying stainless steel - Google Patents

Abstract

PURPOSE:To manufacture a roller for conveying stainless steel in which internal progress of cracks is prevented by constituting the surface layer of a nontreated layer and also constituting the inside of an inorganic colloid-treated layer in a disk roll prepared by compressively laminating many sheets of annular formed plate with a specific composition on a shaft made of metal. CONSTITUTION:As a heat-resisting roller for conveying stainless steel in a high-heat treatment furnace, a disk roll prepared by compressively laminating many sheets of annular formed plate composed of inorganic fibers, inorganic fillers, inorganic binding materials, and organic binding materials on a shaft made of metal is used. The side face of the above annular molded plates is turned upward and the surface layer part of the roll is coated with aluminum sheet, etc., and then an inorganic colloid solution is applied to the above, by which the disk roll has a nontreated layer on the surface and an inorganic colloid-treated layer inside. Moreover, as the inorganic colloid, one or >=2 kinds among silica, aluminum, and zirconia sols are used and formed into a solution in which solid content is regulated to about 0.5-20wt.% and pH is properly adjusted. By this method, roll life can be prolonged.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a heat treatment line (annealing line, or annealing line) that continuously anneals high-temperature stainless steel plates.
This relates to conveyor rollers used in the annealing furnace and cooling zone of pickling lines.

(Prior art and its fFi issues) Heating furnace (annealing furnace) that continuously heat-treats stainless steel
A large number of rolls are arranged perpendicular to the direction of movement of the stainless steel strip for loading and unloading the stainless steel strip. In particular, the rolls that come into contact with high-temperature stainless steel strips are heat resistant, wear resistant, smooth, non-adhesive to stainless steel plates,
In addition, non-face-to-face aggression against stainless steel plates is also required.

Conventionally, this type of roll is made of natural asbestos! Taking advantage of the properties of asbestos I, asbestos fibers are formed into a sheet using a rubber binder, this sheet is cut into donut shapes, and the asbestos fibers are compressed and laminated onto a metal shaft to give a surface finish. It was used as a disk roll.

However, asbestos fibers are natural magnesium fibers that have large variations in fiber length, fiber diameter, chemical composition, etc., and contain 14 to 15 wt% of crystal water, so they can be exposed to high temperatures exceeding 1000℃. If the fibers are used under the same conditions, the volume shrinks due to variations in the fibers themselves and the separation of crystallized water, resulting in cracks on the roll surface, which may damage the surface of the stainless steel being conveyed or cause continuous use. In front of the bottom. There was a problem in that the crack progressed and the roll fell off the metal shaft, making it unusable in a short period of time.

Furthermore, since conventional asbestos disc rolls use at least asbestos F11fa, asbestos fibers may be scattered not only from the process of manufacturing the rolls but also from the equipment used, causing health problems.

In other words, Japan signed the International Convention on Cancer in 1970, and domestically, the handling of asbestos has been regulated by various ministerial ordinances, but from April 1, 1975, the "Ordinance on the Prevention of Hazards Due to Specified Chemical Substances" was enacted. Furthermore, the Enforcement Regulations of the Labor Standards Act were partially amended on March 30, 1971, and the Labor Standards Act Enforcement Regulations were partially amended to provide for "work that is exposed to asbestos" during illness caused by work in carcinogenic substances, carcinogenic factors, or carcinogenic processes. lung cancer or mesothelioma.

This ministerial ordinance has brought the issue of asbestos pollution into the spotlight in our country as well.

On the other hand, silica/alumina am
Ceramic fibers are formed into a sheet using an inorganic filler, an inorganic binder, and an organic binder if necessary, and are then compressed onto a metal shaft with a layer of surface finish, similar to asbestos disc rolls. ! A high quality roll is used.

Because the ceramic am-based roll uses artificial heat-resistant fibers, there is less variation in fiber length and fiber diameter than asbestos, and the chemical composition is extremely stable with very few impurities, and has crystallization water. Therefore, when used at high temperatures exceeding 1000°C, we provide a roll that shrinks little and can operate stably.

However, since silica/alumina fibers are amorphous, mullite crystallization occurs at temperatures around 980°C, and a slight amount of heat shrinkage occurs, resulting in the formation of fine racks on the roll surface. be.

Furthermore, said ceramic fiber! Ik rolls have excellent heat insulation properties, so it is difficult to pre-sinter them.

During actual use, a significant temperature gradient occurs in the thickness direction of the doughnut-shaped molded plate.

Said ceramic fiber! Since Iga roll contains inorganic fillers, inorganic binders, and organic binders, it has strength in high temperature parts of 800℃ or higher due to sintering of the inorganic fillers and inorganic binders.
In addition, in the low-temperature part below 400°C, the organic binder remains and is strong, but the strength in the middle-temperature part of 400"C to 800"C is significantly inferior, so the width of the fine racks generated on the roll surface is It easily reaches the small but strong recessive mesotemperature part and even the remaining layer of the organic binder.

Since the width of the microscopic rack is very small, the crack itself will not damage the stainless steel plate being transported, but like asbestos disc rolls, the cracks will progress under continuous use. There was a problem that the roll could fall off the metal shaft, making it unusable.

(Means and operations for solving the problems) The present invention aims to eliminate and solve the drawbacks of the above-mentioned prior art, and as a means to achieve this purpose, the stainless steel conveying roller described in the claims is provided. This is what we provide.

That is, 1 the present invention is a heat-resistant roll for conveying stainless steel in a high-temperature heat treatment furnace, in which a doughnut-shaped molded plate formed of inorganic fibers, an inorganic filler, an inorganic binder, and an organic binder is made of metal. A disc roll in which multiple layers are compressed at one layer on the shaft is characterized by having an untreated layer on the surface layer and a treated layer of inorganic colloid inside, which reduces the occurrence of trough on the roll surface over time. This process is stopped by the inorganic colloid treatment layer, preventing the roll from falling off the metal shaft,
The present invention provides a stainless steel conveying roller that is highly durable and effective.

As the inorganic colloid, one or more of silica sol, alumina sol, and zirconia sol can be used, and a solution whose solid content is adjusted to a range of 0.5 to 20% by weight may be used. is preferred.

To form the inorganic colloid-treated layer, specifically, the side surface of the donut-shaped molded plate constituting the disc roll is facing upward, and the inorganic colloid-untreated layer on the surface layer of the roll (the outer periphery of the donut-shaped molded plate) is formed. may be coated with an aluminum plate or the like, and the inorganic colloid solution may be applied with a brush or sprayed with a spray gun.

In order to easily infiltrate the donut-shaped molded plate with the inorganic colloid solution, the inorganic colloid solution can be easily infiltrated by adjusting the pH of the inorganic colloid solution, even if the inorganic colloid solution is not particularly impregnated under reduced pressure.

In addition, by adjusting the pH appropriately, it is possible to prevent the permeated inorganic colloid solution from seeping out to the surface layer of the disc roll (outer peripheral part of the doughnut-shaped molded plate).

According to the method described above, the production of the transport roll is extremely easy. Of course, the inorganic colloid treated layer may be formed by impregnation treatment under reduced pressure.

After infiltrating the inorganic colloid solution in this manner, the donut-shaped molded plate is dried using a microwave dryer or the like.

Next, in the conveyance roll of the present invention, the inorganic colloid treatment layer is formed inside the disc roll, and the surface layer of the disc roll is provided with a donut-shaped molded plate with a depth of 0.5 mm or more. It is preferable that the untreated layer be formed in a proportion of up to 70% of the total. This is because when the inorganic colloid treated layer is present on the roll surface, impurities in the inorganic colloid, such as Na, 01K20, alkali content, etc. reacts with stainless steel plates or stainless steel oxides (Fe203, Fez 04), etc. that are transported under high temperatures,
This is because the roll surface becomes extremely hard, which may damage the stainless steel plate being conveyed, and furthermore, if the amount of impregnation is large, the heat shrinkage due to sintering will increase.

Further, the depth of the treated layer is 0.5 mm or less.

This is because the inorganic colloid treated layer may affect the stainless steel being transported, and it is virtually impossible to provide a uniform inorganic colloid treated layer with an accuracy of 0.5 mm or less.

Furthermore, it is unnecessary for the inorganic treatment layer to account for 70% or more of the total wall thickness of the doughnut-shaped molded plate, as this would strengthen the strong organic binder residual layer near the metal axis. .

The stainless steel conveying roller according to the present invention has the following effects.

First, the untreated layer formed on the surface of the transport roll does not contain impurities, does not react with or fuse with the stainless steel plate being transported, stainless steel oxides (Fe201.Fez O4), etc., and has an appropriate hardness. Because it has a stainless steel plate, it will not damage the stainless steel plate being transported.

In addition, the inorganic colloid layer formed inside the conveyor roll forms a strong layer in a medium humidity region where the organic binder is burned away and the inorganic filler and binder do not sinter. It is possible to stop the rack due to minute particles generated in the layer, and prevent the roll from falling off the metal shaft.

The present invention will be explained by examples.

(Example) Example 1 60wt% of commercially available silica/alumina fiber (trade name Ibiwool) and 32w of commercially available fine grain low soda alumina
t% and 8 wt% of modified acrylic acid ester emulsion latex were stirred and mixed in water to form a slurry, and then flocculated with a polyacrylamide flocculant,
A sheet with a thickness of 18 mm was made using a paper machine.

Next, bulk density 1.0 (g/crn
), was press-molded to a thickness of 5 mm, dried, and cut to prepare a test piece measuring 6" x 30" x 130 mm.

Example 2 The test piece of Example 1 was impregnated with commercially available silica sol (trade name Snowtex-AK) at a solid content ratio of 2.5 wt%, and then dried in a microwave. °C, 800 °C, 1ooo °C, 120
After heat treatment at 0° C. for 2 hours each, three-point bending strength was measured at a span of 100 mm and a bending speed of 10 mm/min.

Figure 1 shows the relationship between temperature and bending strength.

Example 3 The press-formed sheet of Example 1 was made into an outer diameter of 110 mm and an inner diameter of 2.
After punching out a disc plate of 2 mm (thickness: 6 mm), it is dried, and the outer circumferential portion is
Leaving 20 mm of the inner circumference, commercially available silica sol (trade name Snowtex-AK) was used at a solid content ratio of 2.5 w.
The inorganic colloid-treated disk plate impregnated with t% and dried was press-dried onto a metal shaft with an outer diameter of 22 mmφ and an effective surface length of 100 mm, and then the roll surface was polished with a metal lathe to an outer diameter of 105 mmφ. After treating the fibrous disc roll with water in a metal pipe at 1100°C for 2 hours in an electric furnace, we observed the occurrence of cracks and found that three fine cracks had appeared on the roll surface. When the roll was removed from the shaft and the internal progress of cracks was checked, all cracks had stopped at the inorganic colloid-impregnated layer.

Figures 2 and 3 show the occurrence of cracks.

Comparative Example 1 The test piece of Example 1 was left untreated at room temperature and at 40°C.
0℃, 600℃, 800'C11000℃, 1200
After each heat treatment for 2 hours at C, the bending strength was measured in the same manner as in Example 2.

Figure 1 shows the relationship between temperature and bending strength.

Comparative Example 2 Commercially available asbestos board for disc rolls was 6” x 30 (w)
After cutting to l40 (l>mm), the bending strength was measured in the same manner as in Example 2 and Comparative Example 1.

Figure 1 shows the relationship between temperature and bending strength.

Comparative Example 3 The press-formed sheet of Example 1 was not treated with an inorganic colloid solution. When the test of Example 3 was conducted and the occurrence of cracks was examined, fine cracks and cracks were observed on the roll surface. When the roll was removed from the shaft and the internal progress of the crack was checked, the crack had reached the remaining organic binder layer.

FIG. 4, No. 5F211 shows the occurrence of cracks.

Comparative Example 4 When conducted using a commercially available asbestos board for disc rolls,
Numerous cracks measuring 111,611 mm to 3 mm were generated on the surface of the roll, and when the roll was removed from the shaft and the internal progress of the cracks was observed, the cracks had progressed to 1/2 of the thickness of the disk plate.

Figures 6 and 7 show the occurrence of cracks.

As a result, the conveyance roller shown in the example is: ■Comparative example 1
, the bending strength is higher than that of Comparative Example 2.

(2) Compared to Comparative Example 3, the number of cracks occurring is the same, but the cracks have not progressed inside the roll.

(2) Compared to Comparative Example 4, the number of cracks generated was smaller, and the cracks did not progress inside the roll.

(Effects of the invention) As described above, the stainless steel conveying roller according to the present invention achieves
By using commercially available low-cost materials, it has become possible to prevent cracks caused by heat shrinkage from progressing inside the roll and extend the life of the roll.

[Brief explanation of the drawing]

FIG. 1 shows Example 2. It is a graph showing the three-point bending strength of each test piece of Comparative Example 1 and Comparative Example 2 after being treated at each temperature for 2 hours. FIG. 2 is a front view of the roll showing the occurrence of cracks in the roll of Example 3. FIG. 3 is a cross-sectional view of FIG. 2 in which the progress of cracks was observed after the roll of Example 3 was disassembled. FIG. 4 is a front view of a roll showing the occurrence of cracks in the roll of Comparative Example 3. FIG. 5 is a cross-sectional view of FIG. 4 showing the progress of cracks after the roll of Comparative Example 3 was disassembled. FIG. 6 is a front view of a roll showing the occurrence of cracks in the roll of Comparative Example 4. FIG. 7 is a cross-sectional view of FIG. 6 in which the progress of cracks was observed after the roll of Comparative Example 4 was disassembled. Explanation of symbols 1...Test piece of Comparative Example 1, 2...Test piece of Comparative Example 2. 3... Test piece of Example 2, 4... Metal pipe, 5... Metal collar, 6...
Ceramic fibrous disk roll of Example 3, 7...
- Generated surface crack, 8... Inorganic colloid treated layer, 9-... Organic residual layer,
10-... Sintered layer, ll-... Stopped crack, 12
- Ceramic fiber laga disk roll of Comparative Example 3,
lco...Crack that has occurred on the surface, 14-...Crack that has reached the organic layer. 15... Asbestos disc roll of Comparative Example 4, 16
-...Crack that occurred on the surface, 17...-Crack that reached the middle of the disk plate. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1) A heat-resistant roll for conveying stainless steel in a high-temperature heat treatment furnace, which comprises a doughnut-shaped molded plate formed of inorganic fibers, inorganic fillers, inorganic binders, and organic binders. A stainless steel conveying roller comprising a large number of disc rolls compressed and laminated on a metal shaft, the disc roll having an untreated layer on its surface layer and having an inorganic colloid solution impregnated inside and fitted therein. . 2) The untreated layer has a depth of 0 from the surface of the disc roll.
．． The stainless steel conveying roller according to claim 1, characterized in that the stainless steel conveying roller contains up to 70% of the total wall thickness of the doughnut-shaped molded plate up to 5 mm or more. 3) The stainless steel conveying roller according to claim 1, wherein the inorganic colloid solution is one or more of silica sol, alumina sol, and zirconia sol.