JPH0763748B2 - High heat resistance roll - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disk roll for conveying a steel material in a high temperature heat treatment furnace, and particularly to a disk roll having a very low reactivity with a scale of the steel material (iron oxide). Regarding heat resistant rolls.

[Prior art and its problems] The material to be treated is loaded into the heating furnace that continuously heat-treats,
Many are equipped with a large number of heat-resistant rolls for carrying out or moving in the furnace.

Heat resistance is required for this roll, and metal rolls mainly made of heat-resistant steel, ceramic rolls, and asbestos rolls have been widely used, but the scale of the heat-treated material reacts on the roll surface, causing adhesion and deposition ( Hereinafter, this is referred to as build-up), and has a drawback of scratching the surface of the material to be heat treated.

Therefore, in a catenary furnace that heat-treats steel sheets that require good quality, especially stainless steel sheets, use a heat-resistant roll in which an asbestos sheet is assembled at a low density on a metal shaft provided with a water cooling jacket, and the asbestos sheet surface is covered. It has been used while being rubbed with a heat-treated material. For this reason, the roll has a short life, and it has been necessary to replace the roll in one week at a place where the scale is most generated.

Furthermore, asbestos contains 37 to 42% by weight of SiO ₂ , 39 to 42% by weight of MgO and 14% by weight of H ₂ O as a typical composition. There is a defect that ₂ O molecules are released and cracking occurs due to remarkable thermal shrinkage.

On the other hand, according to Japanese Examined Patent Publication No. 57-61806, a mixed material in which asbestos is mixed with 3 to 50% by weight of crystalline alumina fiber or 3 to 50% by weight of mirica fiber is pre-compressed and mounted on a metal shaft. Alternatively, a heat-resistant roll that can be used even at high temperature is proposed, which can be used or compressed after being mounted and stored in the compressed state.

By the way, the applicant of the present application has previously filed Japanese Patent Application No. 59-253092, "a raw material composed of silica / alumina fiber, an inorganic filler, an organic binder and a sintering aid (clay) having a bulk specific gravity of 0.5 g.
We have filed a patent application for a "high heat-resistant roll in which a doughnut-shaped sheet molded to a size of / cm ³ or more is fitted and fixed to a metal shaft."

[Problems to be Solved by the Invention] In the heat-resistant roll proposed in Japanese Patent Publication No. 57-61806, which is a conventional technique, it is possible to reduce heat shrinkage by compounding highly heat-resistant fibers such as alumina fibers and silica fibers. Although it is possible, asbestos, which is the main component, contains many impurities and has a high reaction product (wetting property) with scale, and it is impossible to suppress buildup.

On the other hand, in the roll obtained by the invention proposed in Japanese Patent Application No. 59-253092, the high heat resistant ceramic fiber and the inorganic filler are sinter-bonded with a clay-based sintering aid to improve wear resistance. However, this clay-based sintering aid contains a large amount of alkali oxides and alkaline earth oxides, which increases the reactivity with the scale and has the drawback of promoting the scale build-up phenomenon. Had.

[Means for Solving Problems] In view of the situation of the prior art as described above, in the present invention, the surface of the material to be heat treated is not used while rubbing the surface with the material to be heat treated like the asbestos roll of the prior art. It is an object of the present invention to provide a transport roll that can be used for a long period of time by suppressing the reaction with the scale. In order to achieve this object, the present inventor has selected an inorganic material having low reactivity (wettability) with the scale, and has newly found that alumina and ceramic fibers are the best, and completed the present invention. Came to do. Further, it has been found that a composite having a high heat-resistant composition is desirable also from the viewpoint of improving roll moldability and thermal shock resistance. However, at the operating temperature of 1200 ° C, the alumina and ceramic fibers did not sinter, and sufficient wear resistance was not obtained.

Therefore, in the experiment of the present inventor, by impregnating and impregnating a polymer electrolyte solution composed of a polynuclear complex in which aluminum hydroxide ion is polymerized from the roll surface, the sintering at a low temperature of alumina is promoted and sufficient wear resistance is obtained. Could be a roll having.

In addition, a heat-resistant roll made of only ceramic fibers was surface-coated with a mixed solution of alumina fine powder and the above-mentioned polymer electrolyte, whereby a desired high heat-resistant roll could be obtained.

Next, the most typical embodiment of the present invention will be specifically described.

Example 1 In a container with a stirrer having a volume of 1 m ³ , 800 water and 8 kg of commercially available ceramic fiber having a shot content of 50% were charged and stirred for 15 minutes to prepare a slurry solution. On the other hand, capacity
170 / min from the side wall of 25 cylindrical container, water pressure 1.5kg / cm ²
Pressurized water is sent to the center of the vortex from the upper part of the cylindrical container at a flow rate of 80 / min to loosen the flocs, and the slurry is discharged from the center of the vortex to a mesh of 30 mesh. Collected. Next, 309 g of the ceramic fiber that has been processed, and alumina fine powder 13
2g and 60ml of Nitosol butadieny latex (solid content 40
%) In 25 water and thoroughly stirred and mixed to form a slurry. In this slurry, 118 ml of a 7.5% polyacrylamide flocculant solution and 400 ml of a 10% sulfuric acid band solution are added.
Was added, and a sheet having a wet thickness of 18 mm was made into paper by a paper machine. Then, dehydration press molding was performed to a thickness of 6 mm in the wet state, dried and punched into a donut-shaped annular body to obtain a disk having concentric circles. As shown in FIG. 1, a predetermined number of the discs are fitted onto the metal shaft of the annular body,
After laminating, both ends were fixed with a metal washer (3) and a nut (4), and the surface of the roll was ground smoothly to obtain a high heat resistant roll. Then, a basic aluminum lactate aqueous solution (solid content 40%) was applied to the high heat resistant roll at 1 K per roll surface area.
It was applied with a g / m ² brush and dried at a temperature of 100 ° C. The physical properties of the rolls thus obtained are shown in Table 1.

In addition, the reactivity with the scale is that the water-cooled prototype roll and stainless steel roll (SUS3
04) was contacted for 5 hours while rotating, and after cooling, the adhered state of the scale was visually observed and judged. In addition, the abrasion test of the roll is performed by firing at 1200 ° C. for 12 hours, and then using the tester shown in FIG. 2, a friction rotor plate (6) that rotates the forming roll (5) (sandpaper is attached to a steel plate). The above was brought into contact with a constant load, and the frictional weight loss rate of the molding roll was measured.

Example 2 441 g of ceramic fibers treated in the same manner as in Example 1 and 60 ml of nitrile butadiene latex (40% solids) were added to 25 water and sufficiently stirred and mixed to form a slurry. 118 ml of 7.5% polyacrylamide flocculant solution and 400 m of 10% sulfuric acid band solution in the slurry
l and were added, and a sheet having a wet thickness of 18 mm was made into paper by a paper machine. Then, dehydration press molding was performed to a thickness of 6 mm in the wet state, dried and punched into a donut-shaped annular body to obtain a disk having concentric circles. As shown in FIG. 1, a predetermined number of the discs are fitted on the metal shaft of the annular body, the discs are laminated, and both ends thereof are fixed with a metal washer (3) and a nut (4). Was ground smoothly to obtain a high heat resistant roll. Then, a mixed solution prepared by dispersing 2% of cationized starch and 20% of alumina fine powder having an average particle diameter of 1 μm in a basic aluminum acetate aqueous solution (solid content: 20%) was applied to the high heat-resistant roll at 2 Kg / m ² per roll surface area. Apply with a brush,
It was dried at a temperature of 100 ° C. The physical properties of the roll are also shown in Table 1.

Comparative Example 1 Similarly, Table 1 shows the results of measuring the physical properties of the asbestos roll of the prior art.

Comparative Example 2 Further, various physical properties of the high heat resistant roll disclosed in Japanese Patent Application No. 59-253092 were measured, and the results are shown in Table 1.

[Effects of the Invention] As is clear from the above, the high heat-resistant roll of the present invention has various excellent effects as shown below as compared with the prior art.

1) Scale generated on the surface of the heat-treated material (FeO, Fe
The chemical reactivity with ₂ O ₃ ) is extremely low, and face-to-face attack due to deposition of scale on rolls does not occur. (Ie,
(It does not damage the material to be heat treated.) 2) It became possible to increase the roll assembly density, and the durability of the roll was greatly improved.

3) Since the high heat resistant fiber is used as the material, the opening of the joint between layers due to heat shrinkage does not occur.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the main part of a disk roll using the high heat resistant roll of the present invention. FIG. 2 is a perspective view of an abrasion tester for measuring the roll friction reduction rate. Explanation of code 1 …… Pipe 2 …… Doughnut shaped molding plate 3 …… Washer 4 …… Nut 5 …… Molding roll 6 …… Wear disc (sandpaper) 7 …… Supporting base 8 …… Weight mounting jig.

Claims (4)

[Claims] 1. A heat-resistant roll for transporting a material to be heat-treated in a high-temperature heat treatment furnace, comprising: a disk roll in which a large number of donut-shaped compacts are compression-fitted onto a metal shaft. A high heat resistant roll comprising 60% or more of ceramic fiber, and at least alumina and a sintering aid of alumina as main components, which are press-molded. 2. The molded body is a mixed composition containing a ceramic fiber, alumina and a sintering aid of alumina as main components, or sintering of alumina and alumina through a binder on the surface of the ceramic fiber. The high heat-resistant roll according to claim 1, wherein the auxiliary heat-resisting roll is one type or two types containing an auxiliary agent as a main component. 3. The alumina sintering aid is at least one selected from a basic organic acid, aluminum, and alkyl aluminate, and the sintering aid according to claim 1 or 2. High heat resistant roll. 4. The molded body comprises ceramic fibers, alumina, and a sintering aid of alumina as main components, and at least one of inorganic fibers other than ceramic fibers, an inorganic filler, and an inorganic binder, and if necessary. A high heat-resistant roll according to any one of claims 1 to 3, characterized in that it contains an organic binder.