JPH0254716A - Roll for transportation - Google Patents

Abstract

PURPOSE:To form the transporting roll which does not flaw the steel sheet to be transported by crimping doughnut-shaped metallic plates between the arbitrary layers of the laminated molding in the disk roll formed by laminating many doughnut-shaped moldings made of zeolite to a metallic shaft. CONSTITUTION:The doughnut-shaped metallic plates are properly crimped between the arbitrary layers of the laminated molding in the disk roll formed by laminating the many doughnut-shaped moldings essentially consisting of the zeolite onto the metallic shaft. Iron plates are preferably used for the metallic plates in terms of heat resistance and cost and copper plates are preferably used in terms of hardness and thermal conductivity. The outside diameter of the metallic plates is set smaller by >=5mm than the finish diameter of the disk roll and the thickness thereof is confined to <=1mm. The spacing between the metallic plates and the metallic plates is confined to <=15mm. The disk roll adequate as the transporting roll in a heat treatment furnace for stainless steels is obtd. in this way.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a conveying roll used in a heat treatment line (annealing line or annealing/pinching line) that continuously heats high-temperature stainless steel plates, etc. Among these, it particularly relates to conveying rolls used in heat treatment furnaces.

(Prior Art and its Problems) A heat treatment line that continuously heat-treats stainless steel plates and the like has a large number of rolls arranged perpendicular to the direction of movement of the steel plates for loading and unloading the sheets.

By the way, among the above-mentioned rolls, rolls that come into contact with a steel plate in a high temperature state are required to have heat resistance, abrasion resistance, smoothness, non-adherence to the steel plate, and non-face-to-face attack resistance against the steel plate. Taking advantage of the properties of natural asbestos fibers, the rolls are made by forming asbestos fibers into sheets using a rubber binder, cutting these sheets into donut shapes, and compressing and laminating them onto a metal shaft. It was used as an asbestos disk roll with a surface finish.

However, asbestos fibers are natural magnesium silicate mineral fibers, and have large variations in fiber length, fiber diameter, chemical composition, etc., and contain water of crystallization, so they cannot be heated to 1000°C.
When used in a high temperature range exceeding
A crack occurs on the roll surface, and this crack causes
There are problems in that the surface of the steel plate being transported is damaged, the crank expands during use, and the roll falls off the metal shaft.

Furthermore, since conventional asbestos disc rolls use asbestos fibers, asbestos fibers are scattered not only from the process of manufacturing the rolls but also from the equipment used, posing a risk of 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, 1978,
Implemented the Regulations for Prevention of Hazards Due to Specified Chemical Substances, and
On March 30, 2017, the Labor Standards Act Enforcement Regulations were partially amended, stating that ``lung cancer or mesothelial cancer due to work involving exposure to cancer-causing substances, cancer-causing factors, or asbestos''"tumor" is specified.

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

On the other hand, instead of asbestos disc rolls, sheets are formed using inorganic fibers such as silica and alumina fibers, which are artificial heat-resistant fibers, inorganic fillers, and inorganic and organic binders added as necessary. A conveyor roll has been proposed in which materials are compressed and laminated onto a metal shaft and the surface is finished. The conveyor roll uses artificial heat-resistant fibers, so there is less variation in fiber length and fiber diameter than asbestos, and the chemical composition is very stable with few impurities, and it does not absorb crystallized water. Because of this, the roll has little shrinkage and can be operated stably even when used at high temperatures exceeding 1000°C.

However, since inorganic fibers such as silica/alumina fibers are amorphous, they undergo mullite recrystallization at temperatures around 980° C., causing slight thermal contraction. Furthermore, since it is amorphous, iron oxide generated on the steel plate tends to adhere to it at high temperatures.

Therefore, in a heat treatment line for steel sheets, the conveying roll cools the metal shaft of the roll with water in places where the temperature conditions are relatively low, such as the exit and inlet sides of a heat treatment furnace, or the rolls between furnaces of a split heat treatment furnace. It can be used without problems depending on the temperature, but the ambient temperature is 1200°C.
The rolls in the furnace used in the soaking zone or heating zone of the heat treatment furnace, which reach the front and back of the furnace, have a metal shaft that is water-cooled, but the temperature of the roll surface is almost equal to the ambient temperature. A slight rank may occur.

The width of the fine cracks is so small that the crank itself will not leave any scratches on the surface of the steel plate being conveyed. There was a problem in that the roll gradually expanded to reach the metal shaft, and the roll fell off from the metal shaft, making it unusable.

(Means and effects for solving the problems) The present invention aims to eliminate and solve the drawbacks of the above-mentioned prior art, and as a means for achieving this purpose, the conveying roll described in the claims It provides:

That is, the present invention provides a disc roll in which a large number of donut-shaped molded bodies mainly made of Seviolite are laminated on a metal shaft, and a donut-shaped metal plate is sandwiched between the eyebrows of the laminated molded bodies. This is a conveying roll characterized by the following.

Note that the donut-shaped molded body mainly made of Seviolite of the present invention is made of Seviolite, an organic binder, and an inorganic binder added as necessary.

Next, the present invention will be explained in detail.

The conveying roll of the present invention requires that a donut-shaped metal plate be sandwiched between arbitrary eyebrows of the laminated molded bodies. The reason for this is that the metal plate sandwiched between the eyebrows of the molded body allows the water cooling effect of the metal shaft to reach not only the vicinity of the metal shaft but also the surface layer of the disc roll, which allows the ambient temperature to reach around 1200℃. This is because even in the soaking zone or heating zone of a heat treatment furnace where the roll reaches 300 degrees, cracks can be prevented from occurring on the roll surface and falling off from the metal shaft, resulting in extremely excellent durability.

According to the present invention, sepiolite is preferable for the donut-shaped molded body because it has high compressive strength when fitted onto a metal shaft and is low cost.

The reason is that sepiolite is a naturally crystalline form of hydrated magnesium silicate, and although it undergoes thermal contraction due to separation of crystal water and mineral transition in hot conditions, it remains crystalline.
This is because there is significantly less iron oxide adhesion during hot heating. Furthermore, unlike asbestos, sepiolite is not carcinogenic.

Further, as the organic binder, emuldigon latex such as NBR, 5BR1 acrylic acid ester type, paper strength enhancer represented by polyacrylamide, etc. can be used. Among these, it is preferable to use modified acrylic ester-based emulsion latex to provide wet strength when producing the donut-shaped molded product, and polyacrylamide to provide strength after drying. is more effective.

According to the present invention, the inner diameter of the metal plate is preferably in close contact with the metal shaft in order to function as a cooling fin to make the water cooling of the metal shaft more effective. In terms of workability during installation, a slight clearance with the metal shaft is required, and the clearance is 50111 mm.
If it is below, there will be little effect on the necessary cooling effect.
Desirably, IIIl or less is more preferable.

Originally, it is desirable that the outer diameter of the metal plate be equal to the outer diameter of the disc roll in order to make the cooling effect of the metal shaft more effective, but according to the present invention, the outer diameter of the metal plate must be 51 or more smaller than the finished diameter of the disc roll. The reason for this is that when a metal plate is exposed on the roll surface, not only does it cause scratches on the steel plate being conveyed, but the metal plate itself becomes an oxide, and the oxides generated on the steel plate surface are layered on top of this oxide, causing buildup. This is because a phenomenon called up (or pink-up) occurs, causing indentation scratches on the surface of the steel sheet being transported.

In addition, since there is a slight clearance between the inner diameter of the metal plate and the metal shaft as described above, when processing the roll surface to a predetermined dimension after fitting it to the metal shaft, the metal plate may be uneven on the disk roll surface due to the eccentricity of the metal plate. This is to prevent exposure to

Furthermore, since the heat treatment temperature, conveyance speed, etc. differ depending on the material, thickness, etc. of the steel plate to be conveyed, even if there is no metal or metal oxide on the roll surface or roll surface layer, the physical voids of the roll or alkali metal etc. Due to the presence of impurities, oxides generated on the surface of the steel sheet being transported are successively pushed and deposited on the surface layer of the roll by the weight of the steel sheet being transported, resulting in a phenomenon called build-up (or pick-up). This may cause indentation scratches on the surface of the steel plate. As a countermeasure to this, the steel oxides pushed into the roll surface are removed by using rolls that have a certain wear rate, but at this time the metal plate is exposed on the roll surface. Otherwise, build-up (or pick amp) will be promoted for the reason mentioned above.

That is, a doughnut-shaped molded plate is attached to the metal shaft.

In order to prevent build-up (or pickup) due to exposure of the metal plate to the roll surface during compression lamination and exposure of the metal plate to the roll surface due to abrasion of the roll surface during use, the outside of the metal plate is The diameter must be smaller than the finished diameter of the disc roll (both 51 or more smaller).

According to the present invention, the thickness of the metal plate needs to be less than 1 mm. The reason why the thickness of the metal plate is thinner than 11 mm is that if it is 1 mm or more, the weight of the roll will increase significantly and cause trouble in idle rotation, and the metal plate should be sandwiched between the eyebrows of the doughnut-shaped molded plate made of Seviolite. When the molded plate made of doughnut-shaped Seviolite is compressed and fitted onto a metal shaft, a significant difference occurs in the bulk density of the molded plate made of doughnut-shaped Seviolite between the surface layer of the roll without the metal plate and the inside of the roll where the metal plate is adjacent. This is because a significant difference in strength occurs at the interface at the outer periphery.

Note that the intervals between the metal plates do not necessarily have to be equal, and may be changed as appropriate depending on the roll surface temperature distribution when the rolls are used in an actual furnace.

However, according to the present invention, the cooling effect can be sufficiently exhibited, and in view of the increase in weight of the roll itself, it is appropriate that the distance between the metal plates be in a range of 1511I11 or less. Particularly in areas where the temperature is high, it is preferable to make the interval smaller than 5 cm.

Further, the metal plate used in the present invention may be an iron plate, a zinc-coated steel plate, a stainless steel plate, a copper plate, etc., but an iron plate is more preferable in terms of heat resistance and cost, and a copper plate is more preferable in terms of hardness and thermal conductivity.

The transport roll according to the present invention has the following effects.

First, the area from the surface layer of the conveyor roll to the part where the metal plate is fitted has a moderate hardness that does not react with or fuse with the steel plate or steel oxides being conveyed during hot temperatures around 1200℃. Because it has a high strength, it does not cause scratches on the steel plate being transported. Furthermore, by appropriately setting the average particle diameter and bulk density of the inorganic filler, the build amplifier (
It is possible to prevent indentation scratches on the steel plate that is the object to be conveyed due to (or pink-up).

Further, since the metal plate sandwiched inside the transport roll effectively exhibits the water cooling effect of the metal shaft up to the vicinity of the roll surface, it is possible to prevent cranks occurring on the roll surface due to thermal contraction.

The present invention will be explained by examples.

(Example 1) 90% by weight of commercially available Seviolite and 7% by weight of modified acrylic acid ester emulsion latex were stirred and mixed in water to form a slurry, and then 3% by weight of a polyacrylamide paper strength enhancer was added. After that, the mixture was flocculated using sulfuric acid clay and a polyacrylamide-based polymer flocculant, and then a continuous wet sheet having a width of 30 mm and a thickness of 1 mm was formed using a wet machine.

Then, the bulk density of the wet sheet after drying is 0.8 g.
/crl, which was dehydrated and pressed to a thickness of 1 mm, was punched in a wet state into a donut shape with an inner diameter of 22.05+ nm and an outer diameter of 1101 m, and then dried to produce a molded body for a disc roll.

Next, after fitting two of the molded plates to a metal shaft with an outer diameter of 22 mm and a wall thickness of 21111 mm and having a metal collar welded to one side,
Outer diameter 80mm, inner diameter 22.05++n, thickness 0.2m
Insert one copper plate of size m. After repeating this process sequentially, a metal collar was fitted, compressed and then welded to form a roll with an outer diameter of 110a+m and an effective roll surface length of 30011mm.
The roll had a bulk density of 1.4 g/cd in the I111 molded plate portion. Further, the spacing between the metal plates was approximately 3.4+ui.

Furthermore, the outer diameter of this roll is changed to Lomm using a metal lathe.
A disc roll for testing was created using a lathe.

Next, water cooling pipes were connected to both ends of the metal pipe via rotary joints, and the cooling water (15
°C) is 51! ,/Roll 20rp while flushing in the stomach.
While rotating at I11, the temperature was raised to 1200°C in 30 minutes, held at 1200°C for 2 hours, and then the electric furnace lid was opened and forced cooling was performed to reach room temperature in 30 minutes. When observed, no crank was observed at all.

(Example 2) Thickness 1m+1, outer diameter 265vs by the same method as Example 1
A molded body having an inner diameter of 150111I was prepared. In addition, an iron plate with a thickness of 0.2-1 is made with an inner diameter of 150.05 mm and an outer diameter of 230 mm.
A metal plate was prepared by processing it into a donut shape of mm.

Next, nine of the molded bodies were fitted onto a water-cooled metal shaft having an outer diameter of 150+*m and a wall thickness of 25 mm and a metal collar was welded to one side, and then one of the doughnut-shaped graphite sheets was fitted.

After repeating this operation, a metal collar was fitted and compressed, and the metal collar was fixed with double nuts to form a disc roll having a bulk density of 1.5 g/cd and an effective surface length of 1800 mm. The spacing between the iron plates is approximately 4. It was ha. Further, the outer diameter of this roll was lathed to a diameter of 250 mm to produce a roll for a stainless steel catenary furnace.

When the disc roll was used as a conveyor roll in a catenary furnace (ambient temperature: 1200°C), it was approximately 60°C.
When a 00 ton stainless steel plate (SUS 304) was heat-treated, the outer diameter of the roll was worn down to about 1 mm, but no cracks were observed on the roll surface, and no indentation flaws due to build-up (pick-up) occurred. Ta.

(Example 3) A roll made in the same manner as in Example 2 was cold transported (ambient temperature 550'C) in a stainless steel catenary furnace.
) When approximately 3,500) tons of stainless steel sheets were transported, no effect on the quality of the transported stainless steel sheets was observed.

(Comparative Example 1) A molded body for a disc roll similar to that in Example 1 was created, and then a commercially available iron plate with a thickness of 0.3 m+a was molded with an inner diameter of 22.051 mm.
, an iron plate was created by processing it into a donut shape with an outer diameter of 801111. After fitting 18 molded bodies onto a metal shaft with an outer diameter of 22 and a rolled wall thickness of 2+u+, which had a metal collar welded on one side, the metal plate was made into a donut shape. Insert one sheet. After repeating this process, the metal collar is fitted and compressed, and then the metal collar is welded.
Outer diameter 110+wm, roll effective surface length 300Ill1
The roll had a bulk density of 1.4 g/ej per molded body portion.

The spacing between the iron plates is 30. It was hm. Furthermore, the outer diameter of this roll was lathed into 100 pieces to create a test disc roll, and a test was conducted under the same conditions in the same electric furnace as in Example 1, and the occurrence of cracks on the roll surface was observed. , Three fine lines were found on the surface.

(Comparative Example 2) A stainless steel catenary furnace roll without any metal plate was created using a molded body made in the same manner as in Example 2, and transported in the same furnace as in Example 2 under the same conditions. When used as a commercial roll, several fine cracks appeared on the roll surface after heat treating a stainless steel plate (StlS 304) weighing approximately 500 tons. Although this crank is narrow, it penetrates close to the water-cooled metal shaft, so we stopped reusing it because there was a concern that it might fall off the water-cooled metal shaft.

(Comparative Example 3) Same as Example 3, but using a copper plate as the metal plate,
A disc roll was prepared by punching a metal plate with an outer diameter of 250 mm and an inner diameter of 230 m. When used in the same furnace as in Example 3, marks from the metal plate were left on the surface of the stainless steel plate being transported immediately after the start of use.

(Comparative Example 4) Same as Example 2, but two metal plates with a thickness of 1.6 mm were laminated to have an apparent thickness of 3.2 mm to create a disk roll and used in the same furnace as in Example 2. When approximately 400 tons of stainless steel plates (SUS304) were heat-treated, a portion of the roll surface became defective, not only leaving marks on the stainless steel plates being transported, but also causing build-up (or pickup) in some areas. .

(Effects of the Invention) As described above, the conveying roll according to the present invention has a space between the disc body layers mainly made of sepiolite in the disc rolls conventionally used as the outer roll of catenary furnaces and the interfurnace roll of split catenary furnaces. By inserting a high thermal conductor, even when the roll is in a furnace with a high ambient temperature, the steel plate being conveyed will not be damaged, and there will be no cranking and there is no fear of it falling off the metal shaft. It has now become possible to provide highly durable conveyor rolls that do not cause scratches on steel plates.

In addition, since no asbestos fibers are used, the production or use of the rolls is subject to the "Specified Chemical Substance Hazard Prevention Regulations."
It has now become possible to provide a conveying roll that has no risk of causing asbestos pollution as specified in .

that's all

Claims (1)

[Scope of Claims] 1) A disc roll in which a large number of donut-shaped molded bodies mainly made of sepiolite are laminated on a metal shaft, and a donut-shaped metal plate is sandwiched between arbitrary layers of the laminated molded bodies. A transport roll that is characterized by its ability to 2) The transport roll according to claim 1, wherein an interval between the sandwiched metal plates is 15 mm or less. 3) The conveying roll according to claim 1, wherein the outer diameter of the metal plate is smaller than the outer diameter of the molded plate by 5 mm or more. 4) The transport roll according to claim 1, wherein the metal plate has a thickness of 1 mm or less. 5) The conveyance roll according to claim 1, wherein the conveyance roll is a conveyance roll used in a soaking zone or heating zone of a stainless steel heat treatment furnace.