JPS60116714A - Heat-resistant roll - Google Patents

Abstract

PURPOSE:To prevent the generation of a defective product in the heat treatment of steel plates, etc., and to reduce the treating cost by piercing a roll shaft through the central part of a body consisting of plural annular bodies of sintered boron nitride which are put together, and fixing to form a heat resistant roll. CONSTITUTION:The powder of boron nitride is compression-molded, and sintered to obtain an annular body 4. A perforated part 5 is perforated at the central part of the annular body 4. The desired number of the annular bodies 4 are put together, and a roll shaft 2 is pierced through the perforated parts 5. Each annular body 4 is clamped by a fixture 6 to form a heat-resistant roll 1. In addition, a key way 7 is provided to the perforated part 5 of the annular body 4, and a key of the roll shaft 2 is pushed through the key way to prevent the rotation of the annular body 4 in the circumferential direction. When the drum part 3 of the roll is locally damaged, the heat-resistant roll can be easily repaired by exchanging only the damaged annular body. The surface of the roll possesses an excellent lubricating property even at high temps., and the surface of the steel plate is not flawed during the annealing treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-resistant roll that is disposed in a heat treatment furnace such as an annealing furnace and allows a steel plate or the like to pass through the furnace while supporting the roll.

Generally, when applying heat treatment such as annealing to improve the material quality of steel materials, the plate-shaped or band-shaped material to be treated is passed through a processing furnace, and in the process of passing through, a large amount of material is uniformly heat-treated. A heat treatment furnace that performs heat treatment using this method is equipped with rolls that support the material within the furnace and allow it to pass through the furnace.

For example, in the case of an annealing furnace, the rolls installed in this heat treatment furnace must be made of heat-resistant O-roll, as the furnace reaches a high temperature of 1000 to 1200°C. Heat-resistant alloys were used. However, materials called heat-resistant alloys are generally heat resistant and have high hardness, and when rolls made of such hard materials are placed in a heat treatment furnace for the above-mentioned purpose, pick-up occurs on the surface of the steel sheet that has passed through the treatment furnace. This tends to result in the formation of so-called flaws.

In recent years, heat-resistant rolls made of ceramic have been developed as a substitute for the above-mentioned heat-resistant rolls made of heat-resistant alloys, with advances in processing technology such as sintering technology, and their performance has been studied. However, S
Although ceramics such as '3N4.5iC1^Q203 have excellent heat resistance, their hardness is quite high, and they still have the disadvantage of causing scratches on steel plates.In addition, their tendency to react with scale adhering to the surface of steel plates makes them difficult to roll. It also had the disadvantage of causing cracks on its own surface. In addition, in the case of other asbestos discs and rolls that are actually used, although the problem of hardness has been resolved, scale that forms on the steel plate due to iron oxidation tends to adhere, and such scale The disadvantage is that the convex deposit layer formed on the roll causes pick-up on the steel plate passing through the processing furnace.

This invention has been made in view of the above-mentioned conventional circumstances, and provides a heat-resistant roll that can reduce the incidence of defective products and reduce heat treatment costs when continuously heat treating steel plates, etc. The purpose is to

That is, the heat-resistant roll of the present invention is characterized in that a roll shaft is fixed through the center of one or more annular bodies made of a compacted and sintered body of boron nitride.

Explain this invention in more detail to your subordinates.

FIG. 1 is a perspective view showing an example of a heat-resistant roll according to the present invention.
It is fixed through the hole. In this example, the roll body 3 includes an annular body 4 as shown in FIGS. 2 and 3.
are formed by overlapping a predetermined number corresponding to the length of.

That is, a hole 5 is bored in the center of the annular body 4, and with the required number of annular bodies 4 stacked one on top of the other, the roll shaft 2 is passed through the hole 5, and each The heat-resistant roll 1 is formed by tightening the annular bodies 4 together. Note that a keyway 7 is provided in the hole 5 of the annular body 4.
A key (not shown) of the roll shaft 2 is pushed through the key 17 to prevent the annular body 4 from rotating in the circumferential direction while attached to the roll shaft 2.

The annular body 4 is manufactured, in particular, by compression molding boron nitride powder and then sintering it. For compression molding and shaping of boron nitride, it is possible to use hot pressing or IIP method to sinter the boron nitride powder at once under high temperature and high pressure. It is also possible to sinter the compacted powder body.

Further, the density of the sintered body, that is, the annular body 4 is 1.7 to 2.2.
(It is desirable to set it to 1/Cm', and the corresponding hardness is preferably about 20 to 70 in Shore hardness. In other words, if the density exceeds 1.7o/cm', it is necessary to have sufficient strength as a heat-resistant roll. However, if it is less than 1.7g10-, sufficient strength as a heat-resistant roll cannot be obtained.

As described above, in this invention, the annular body 4 constituting the heat-resistant roll 1 is a powder sintered body of boron nitride, and the powder sintered body of boron nitride is soft. Because of this characteristic, processing of relatively complicated shapes such as the processing of the hole 5 and the key groove 7 can be easily performed. Therefore, the hole 5 and the keyway 7 may be provided during the powder sintering process of the annular body 4, but they may also be provided by drilling a hole in the center of the annular body 4 after the annular body 4 is powder sintered. Easy to do.

In addition, in the above example, the roll body 3 is made of a refined product made by overlapping the annular bodies 4, so even if the roll body 3 is partially damaged while the heat-resistant roll 1 is being used, the damaged part will be damaged. The butterfly can be easily fixed by replacing the annular body 4. However, in the heat-resistant roll of the present invention, the body 3 does not necessarily have to have a structure in which a plurality of annular bodies are stacked one on top of the other, and the heat-resistant roll may be constructed by attaching a single, integral annular body to the roll shaft. .

Next, an example in which the heat-resistant roll of the present invention was actually manufactured and used will be described.

Example A heat-resistant roll 1 having the shape shown in FIG.
The outer diameter of the annular body 4 was set to 3001 mm, and the length of the roll body 3 was set to 2500 mm. The density of each annular body 4 is about 1.97~2゜12g/C-,
The hardness was about 45 to 55 on Shore hardness. Also,
The coefficient of friction is about 0.1 to 0.15 at room temperature, and its value does not change even when the heat-resistant roll 1 is heated to a high temperature and measured.
From this, it was confirmed that the heat-resistant roll 1 had good 1ltllll properties not only at room temperature but also at high temperatures.

Next, the heat-resistant O-ru 1 was actually installed at the entrance of the heating furnace and scorching furnace of the thin plate heat treatment line, and the furnace temperature was set at 500 to 1200°C.
A 1000 t thin steel plate was annealed. After that, N
At the time when 1000 t of #l plate was treated, the heat-resistant roll 1 was taken out and its surface condition was examined, and the thin steel plate after the treatment was also examined for the occurrence of flaws. As a result, no damage such as cracks occurred in the heat-resistant roll 1, and there was no accumulation of foreign matter, and no flaws were observed in the thin steel sheet after rU processing.

As mentioned above, according to this invention, a heat-resistant roll is constructed by attaching an annular body formed by compacting and sintering boron nitride to a roll shaft, so that it has a soft surface and is particularly effective at high temperatures. Since it has good surface lubricity (chilling property), for example, it does not cause flaws in the steel plate to be processed in an annealing furnace or the like during annealing treatment.

Furthermore, heat-resistant rolls made of powdered sintered compacts of n-nitride have a tendency to have scale attached to the surface of the steel plate, such as diluted iron oxide. There is no possibility that the deposits will cause scratches on the steel plate being treated. Therefore, by using the heat-resistant 0-L of the present invention, it is possible to reduce the incidence of defective products during annealing treatment of steel plates, and also to reduce processing costs.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a heat-resistant roll according to an embodiment of the present invention, Fig. 2 is a plan view of an example of a disc body constituting Komei's heat-resistant roll, and Fig. 3 is a sectional view of Figs. It is. 1...Heat-resistant roll, 2...Roll shaft, 3...
Roll body, 4... Annular body, 5... Hole, 6
...Fixing bracket, 7...Keyway. Applicant Kawasaki Steel Co., Ltd. Agent Patent attorney Takehisa Toyota (and 1 other person)

Claims (1)

[Claims] A heat-resistant roll, characterized in that a roll shaft is fixed through the center of one or more annular bodies made of powdered sintered bodies of boron nitride.