JPH0215809A - Ceramic roll for high temperature use - Google Patents

Abstract

PURPOSE:To obtain a ceramic roll which does not break even if the roll expands at high temps. by symmetrically forming a tapered face at both ends of the inside periphery of a ceramic annular body, supporting the body on the roll shaft by fixing means, and forming a gap between the periphery and fixing means. CONSTITUTION:Tapered faces 1a, 1b are symmetrically formed on both sides of the inside periphery of a ceramic annular body 1 at respectively equal angles thetafrom a cross-point P of the central axis Q of the body 1 and of the central cross section of the body 1. Then, the body 1 is fixed on a roll shaft 2 by a fixing means 4 of the shaft 2 and a gap delta, by which the inside periphery and the fixing means 4 are not brought into contact with each other at high temps., is formed between the periphery and the means 4. Therefore, a contacting condition is unchanged even the body 1 and the fixing means 4 are expanded at high temps., so that stresses are not generated in the annular body 1.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a wear-resistant roll that has a ceramic annular body as a surface member and can be used at high temperatures without fear of breakage. .

(Prior Art) Metal rolls are generally used as rolling rolls or guide rolls because they are used at high temperatures, but they have the drawback of insufficient wear resistance and relatively short lifespan.

In order to eliminate this drawback, it is possible to use ceramics such as Si3N4 (including SiAlON), which is corrosion resistant at high temperatures, lightweight, and has high hardness and wear resistance, as the surface material of the roll, and this has been carried out on a trial basis. has been done.

However, ceramics such as 5ilN4 have a different coefficient of thermal expansion from the metal forming the shaft or boss member of the roll, so they have the disadvantage of being easily damaged during use at high temperatures.

That is, the difference in thermal expansion between metal and ceramic material at high temperatures is about I x 10-5/''C, and a ceramic annular roll surface member fitted or incorporated at room temperature will not expand when used at high temperatures. Thermal expansion causes tensile stress on the inner part of the annular body, causing it to break.

(Purpose) The present invention provides a ceramic roll with high hardness, abrasion resistance, and a support structure that absorbs the difference in thermal expansion between metal and ceramic, which causes damage to ceramic annular bodies, and which is stable even when used at high temperatures. It provides:

(Solution) In order to achieve the above objective, we researched various support structures taking into account that the amount of thermal expansion of metal is larger than that of ceramic.As a result, we developed a structure for symmetrical clamping on both sides of the inner circumference of the ceramic annular body. It has been found that it is effective to form a tapered surface and to provide a gap between the internal circumferential surface of the annular body and the surface of the metal supporting member facing thereto to allow expansion of the supporting member for fixation.

The taper angle θ is 5° or more, preferably 10 degrees, from the intersection point P on the central axis of the annular body (i.e., the rotational axis of the roll) with the central cross section of the annular body.
The angle is at least .degree. and is the angle at which the necessary clamping force for the annular body can be obtained.

Moreover, the gap distance δ is a distance at which the re-facing parts can maintain a non-contact state at the roll usage temperature.

The material of the ceramic constituting the annular body may be 5j3N4, SIC, etc. depending on the object to be processed by the roll, for example, the metal to be rolled.
, ZrB2, Cr3C2, AIN, etc., and the molding method thereof is arbitrary.

The roll clamping and supporting means includes a fixing member having a tapered surface in contact with one of the tapered surfaces, and a fastening ring in contact with the other tapered surface and screwed onto the fixing member, and the fixing member is connected to the roll axis. It may be formed integrally with the roll shaft, or it may be a ring body fitted to the roll shaft.

(Example 1) FIG. 1 shows an example of a rolling roll.

(1) is a ceramic annular body (inner diameter 35 mm), Si3N4 (thermal expansion coefficient 4xlO-'/'C)
It is molded in.

(2) is the roll shaft (5KS3, thermal expansion coefficient 17
(3) is a flange that is integrally formed with the shaft and serves as a fixing means, (4) is a movable member that is screwed (5) to the shaft at a position opposite to the flange of the fixed member. This is a fastening ring that serves as a member, and supports a ceramic annular body (1) sandwiched between it and the flange.

(la>(lb) is a tapered surface formed on both sides of the inner peripheral side of the annular body, and (6)<7) is a tapered surface that is in contact with each side.

The taper angle θ is approximately 15° with respect to the perpendicular Q to the point P on the central axis of the shaft.

The gap distance δ was set to 0.20 mm.

The above rolling roll was assembled at room temperature and used as a noble metal rolling roll at 400° C., but it did not break due to thermal expansion and could not sufficiently withstand the rolling load and thermal shock during use.

(Example 2) FIG. 2 shows an embodiment of the guide roll.

(1) is a ceramic annular body (inner diameter = 150mm)
This is the same material as in Example 1.

(13) is a fixing ring that is pivotally attached to the roll shaft (2), and a fitting tightening ring (14) is screwed onto the fixing ring on the opposite surface (13b) side of the tapered part (13a). (15
), and the annular body is supported under pressure between the two.

The gap distance is 0.70 mm.

No damage was observed even when the guide roll was used in a copper wire rolling process at 500°C.

(Effects) The roll of the present invention has the above-described configuration, and the pinching taper angle of the ceramic annular body and its fixing member is formed symmetrically with respect to the point P on the roll center axis, so that both can be used under high temperatures. Even if each expands, the contact state between the two does not change, and the entire surface of the tapered surface always contacts and simply slides against each other, so that stress due to thermal deformation is not generated in the annular body.

Further, since a necessary and sufficient gap is provided, even if the metal member expands to a large extent, the metal member does not come into contact with the annular body, so there is an effect that no external force is applied to the annular body.

As a result, the life of the roll of the present invention is greatly improved and can be used semi-permanently under normal use.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are half-sectional views of the example roll, respectively. (1) is a ceramic annular body, (2) is a roll shaft (l
a) (lb) is a tapered surface. Patent applicant: Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] In a roll in which a ceramic annular body is supported by metal fixing means, the same diameter is applied to both sides of the inner peripheral side of the ceramic annular body from the intersection of the central axis of the annular body and the central cross section of the annular body. An angularly symmetrical tapered surface is formed and supported by the fixing means of the roll shaft, and a gap is provided between the inner circumferential surface of the annular body and the fixing means to the extent that they do not come into contact at high temperatures during use. High temperature ceramic roll.