EP1751319A1

EP1751319A1 - Adiabatic roll

Info

Publication number: EP1751319A1
Application number: EP05764922A
Authority: EP
Inventors: Hwa Woong Song; Kanji c/o Ask Technica Corporation HIRAKURI
Original assignee: Ask Technica Corp; Korea Toho Co Ltd
Current assignee: Ask Technica Corp; Korea Toho Co Ltd
Priority date: 2004-05-20
Filing date: 2005-04-26
Publication date: 2007-02-14
Also published as: KR100578468B1; CN1989260A; EP1751319A4; US20070232471A1; WO2005113843A1; KR20050110979A

Abstract

The object of this invention is to fit heat-resistant rings and disks around a metal tub shaft without welding so as to assure excellent deformability in accordance with thermal expansion and shrinkage due to changes in temperature. An adiabatic roll of this invention comprises a metal tub shaft (1). A plurality of heat-resistant rings (2) is axially arranged at predetermined intervals between a fixed flange (5) and a movable flange (6) provided on a circumference of the metal tub shaft (1). A plurality of disks (7) is arranged between the heat-resistant rings (2). The heat-resistant rings (2) and the disks (7) are fitted around the metal tub shaft (1) without welding.

Description

ADIABATIC ROLL

[Technical Field]

The present invention relates, in general, to an adiabatic roll and, more particularly, to

an adiabatic roll which has low thermal conductivity, prevents reduction of the atmospheric

temperature of a furnace, and has excellent deformability according to thermal expansion and

shrinkage due to changes in temperature when the furnace is operated or stopped.

[Background Art]

A conventional adiabatic roll is exemplified by a carrier roll in a furnace for preheating

a slab before hot rolling, and an example is shown in FIG. 7. A plurality of heat-resistant rings

2 for supporting the load of a slab is welded into a water-cooled metal tub shaft 1. Studs 3 ,

made of heat-resistant steel are welded into a portion of a surface of the metal tub shaft 1 other

than ring-welded portions, and the resulting structure is coated with heat-resistant mortar 4,

thereby achieving adiabatic construction of the adiabatic roll 6A. However, the above-

mentioned constitution is not disclosed in patent documents.

[Detailed Description of Invention ]

[Technical Problem]

The conventional adiabatic roll having the above-mentioned constitution has the following problems.

In other words, since rings made of heat-resistant steel are directly welded into a metal

tub shaft in the conventional adiabatic roll, heat loss through the water-cooled metal tub shaft is

high, and the atmospheric temperature of a furnace is reduced or fuel consumption increases. Furthermore, the temperature difference between surfaces of the heat-resistant rings

and welded parts of the water-cooled metal tub shaft is high, thus resulting in high heat stress.

Additionally, because the heat-resistant rings or the metal tub shaft are frequently separated from

the welded parts, operation of the furnace must be stopped in order to change the roll.

Also, since an adiabatic structure is formed by applying a heat-resistant mortar, gaps

are formed at interfaces of the heat-resistant rings and the mortar due to shrinkage that occurs

when the mortar is dried and cured and due to thennal shrinkage caused by heating during

operation of the structure. Heat permeates through the cracks into the water-cooled metal tub

shaft, thus increasing fuel consumption and deteriorating the metal tub shaft, resulting in the

reduced life of the roll. Additionally, the heat-resistant mortar is easily removed due to a heating cycle

associated with operation and stoppage of the furnace, thus making it necessary to renovate the

mortar every three or four months.

Therefore, an object of the present invention is to provide an adiabatic roll in which

heat-resistant rings and disks are not welded into a metal tub shaft but are fitted around the metal

tub shaft, so that thermal conductivity is low, the adiabatic roll deforms in accordance with thermal expansion and shrinkage of the heat-resistant rings and thus prevents the formation of

cracks and heat loss, the atmospheric temperature of a furnace is not lowered, fuel consumption

is not increased, and resistance to impact is excellent.

[Technical Solution] The present invention provides an adiabatic roll. The adiabatic roll comprises a metal

tub shaft 1 which has a through hole 1 A for passing cooling water 20 therethrough, a plurality of

heat-resistant rings 2 which is fitted around the metal tub shaft 1 and axially arranged at

predetermined intervals between a fixed flange 5 and a movable flange 6 provided on a

circumference of the metal tub shaft 1, and a plurality of disks 7 which is axially arranged

between the heat-resistant rings 2. The heat-resistant rings 2 and the disks 7 are fitted around

the metal tub shaft 1 without welding.

The present invention also provides an adiabatic roll characterized in that each of the

heat-resistant rings 2 comprises first and second heat-resistant ring parts 2A, 2B which have

different diameters and are concentrically arranged on the same vertical axis. The present invention also provides an adiabatic roll characterized in that the first and

second heat-resistant ring parts 2A, 2B of the heat-resistant rings 2 are joined together using a

pair of ring-shaped plates 2D and round head screws 2E axially threaded into the ring-shaped

plates 2D at a joint 2M thereof

The present invention also provide an adiabatic roll characterized in that metal tub shaft key grooves Id are formed on an external wall of the metal tub shaft 1, key grooves 2C are

formed on internal walls of the heat-resistant rings 2, and the heat-resistant rings 2 are fitted

around the metal tub shaft 1 by keys 10 which engage with the metal tub shaft key grooves Id

and the key grooves 2C. The present invention also provides an adiabatic roll characterized in that metal tub

shaft key grooves Id are formed on an external wall of the metal tub shaft 1, key grooves 2C are

formed on internal walls of the second heat-resistant ring parts 2B having relatively smaller

diameters among the heat-resistant rings 2, and the second heat-resistant ring parts 2B are fitted

and the key grooves 2C.

The present invention also provides an adiabatic roll characterized in that the heat-

resistant rings 2 are partially or entirely made of ceramic.

The present invention also provides an adiabatic roll characterized in that the external

first heat-resistant ring part 2 A of each of the heat-resistant rings 2 is made of nickel ^• cobalt or

stainless steel, and the internal second heat-resistant ring part 2B of each of the heat-resistant

rings 2 is made of ceramic.

[Effects of Invention]

An adiabatic roll of the present invention having the above-mentioned structure

provides the following effects. In the adiabatic roll of the present invention, heat-resistant rings which constitute an

external surface part of the roll have excellent resistance to abrasion and impact, and can endure a

load occurring in the course of carrying a slab during a hot rolling process and also endure

abrasion and impact. Furthermore, the heat-resistant rings are fitted around a water-cooled

metal tub shaft, thereby reducing heat loss through the metal tub shaft due to heat conduction and

preventing separation of the heat-resistant rings from the metal tub shaft due to heat stress.

Additionally, heat-resistant rings having larger and smaller diameters are used in example 2, thus

reducing thermal conductivity. SUS310S, instead of only using costly nickel ^• cobalt-based

heat-resistant steel, is used to manufacture the rings, thus minimizing cost. Furthermore, heat-resistant ceramic rings are used, thereby preventing heat loss due to

heat conduction.

Furthermore, since disks made of inorganic material are used in an adiabatic part, no

gaps or cracks occur at the interfaces of the heat-resistant rings with the adiabatic disks because

of the cushiony disks, and direct inflow of heat to the water-cooled metal tub shaft is prevented.

In addition, if nuts tightening the disks are loosened after the adiabatic roll is tested in example 1 ,

the disks made of inorganic material are axially restored by 15 mm (25 %) so as to sufficiently

absorb 1.5 mm (calculated when the entire ring is at 1200 ^°C: linear expansion coefficient 17.8 X 10^"6) which corresponds to the change in axial thermal expansion of the rings made of

nickel • cobalt-based heat-resistant steel, thereby preventing the occurrence of gaps. The present invention can be applied to an adiabatic roll for manufacturing iron and other carrier equipment at high temperatures.

[Brief Description of Drawings]

FIG. 1 is a longitudinal sectional view of an adiabatic roll according to the present

invention;

FIG. 2 is a longitudinal sectional view of the roll of FIG. 1, which is to be tested; FIG. 3 is a sectional view taken in the direction of arrows along the line Y-Y of FIG 2;

FIG. 4 is a sectional view of a main part of FIG. 2;

FIG. 5 is a transverse sectional view of another type of ring, which is different from

that of FIG. 3;

FIG. 6 is a longitudinal sectional view of FIG. 5; and

FIG. 7 is a longitudinal sectional view of a conventional adiabatic roll.

1 : metal tub shaft 1 A: through hole for passing cooling water therethrough la: end lb: the other end lc: threaded part Id: metal tub shaft key groove 2: heat-resistant ring 2C: key groove 5: fixed flange 6: movable flange 7: disk 8: nut 10: key 6A: adiabatic roll

2A: first heat-resistant ring part 2B : second heat-resistant ring part

2D: ring-shaped plate 2E: round head screw

[Mode for Carrying Out Invention] A description will now be provided for an adiabatic roll of the present invention with

reference to the accompanying drawings. Furthermore, the same reference numerals are used

throughout the different drawings to designate the same or similar components.

In FIG. 1, reference numeral 1 denotes a tub-shaped metal tub shaft which has a

through hole 1A for guiding cooling water therethrough. A fixed flange 5 is welded into a

circumference of an end la of the metal tub shaft 1, and a movable flange 6 is provided at the

other end lb thereof The movable flange 6 is axially and elastically supported by a nut 8,

which is screwed around an externally threaded part lc of the other end lb.

Disks 7 made of a predetermined material (for example, plural sheets of ring-shaped

inorganic material which includes a non-asbestos containing ASK#2057 manufactured by ASK

Technika Co. in Japan) and nickel • cobalt-based heat-resistant rings 2 are axially fitted around

the metal tub shaft 1 between the flanges 5, 6. When the nut 8 is screwed to be moved toward

to press the fixed flange 5, the disks 7 and the heat-resistant rings 2 are pressed and elastically and

firmly supported, thereby creating an adiabatic roll 6A.

Furthermore, the heat-resistant rings 2 and the disks 7 are fitted around the metal tub shaft 1 without welding.

When the adiabatic roll 6A having a structure shown in FIG. 1 is subjected to a

characteristic test, the roll may be as shown in FIGS. 2 to 4. However, with respect to the basic

principle, all of the structures shown in FIGS. 1 to 4 constitute the same adiabatic roll 6A

according to the present invention.

A pair of metal tub shaft key grooves Id is formed with a 180° interval on an external

wall of the metal tub shaft 1 shown in FIGS. 1 to 4 so that they are opposite to each other. A

pair of key grooves 2C is formed on an internal wall of each heat-resistant ring 2, and keys 10 are

inserted into spaces formed by the key grooves Id, 2C. Accordingly, it is impossible to

circumferentially rotate the heat-resistant rings 2 with respect to the metal tub shaft 1, but the

rings can axially move.

In other words, the heat-resistant rings 2 are not axially fixed, but can axially move

while they are interposed between the disks 7 made of inorganic material when thermal

expansion and shrinkage occur. Furthermore, a design is conducted so as to sufficiently compensate for circumferential

thermal expansion and shrinkage, thus preventing idling of the heat-resistant rings 2 caused by

impact applied in a rotational direction (circumferential direction) in the course of carrying a slab.

In other words, if axial thermal expansion and shrinkage of the heat-resistant rings 2 occurs, the

disks 7, which act as a spring, prevent gaps from occurring, and the heat-resistant rings 2 are not

fixed. Accordingly, the generation of heat stress is reduced and it is possible to prevent separation.

With respect to heat loss of the water-cooled metal tub shaft 1 due to heat conduction

of the heat-resistant rings 2, unlike a conventional structure in which the rings are welded into the

metal tub shaft, the heat-resistant rings 2 are fitted around the water-cooled metal tub shaft 1, thus

providing resistance to heat transfer at interfaces of the rings and the shaft, thereby decreasing the

amount of heat transferred.

A better understanding of the present invention may be obtained through the following

examples, which are set forth to illustrate, but are not to be construed as the limit of the present

invention.

EXAMPLE 1

An adiabatic roll (6 A) having the size shown in FIGS. 2 to 4 was manufactured, and

heated at 1200 °C in a siliconit furnace 11, indicated by a dotted line. Temperatures of portions

of nickel • cobalt-based heat-resistant rings (xA to xD portions in FIGS. 3 and 4) were measured,

and inlet and outlet temperatures of cooling water 20 were measured, so that the amount of heat

loss was compared with that of a conventional welding structure or heat-resistant mortar

adiabatic structure. Furthermore, whether gaps were formed at interfaces of the heat-resistant

rings 2 and adiabatic material was visually confirmed. In the conventional welding structure or heat-resistant mortar adiabatic structure, heat- resistant rings 2 were welded into a water-cooled metal tub shaft 1 in an adiabatic roll 6A shown

in FIG. 7, and Y members 3 were welded into a portion of the metal tub shaft 1, at which disks 7

made of inorganic material were provided. Asahi light caster- 13 (LC-13) manufactured by

Asahi Glass Co., Ltd. was mixed therewith to produce a structure 4 which contained 35 wt%

heat-resistant mortar and had an external diameter of 280 φ, and comparison tests were

conducted. The amount of cooling water used was 3 L/min.

EXAMPLE 2

The nickel • cobalt-based heat-resistant ring 2 was the same as described in example 1

except that it consisted of a first heat-resistant ring part 2A having a larger diameter and a second

heat-resistant ring part 2B having a smaller diameter so that they were concentrically arranged on

the same vertical axis as shown in FIGS. 5 and 6, and the second heat-resistant ring part 2B

constituting the internal ring part was made of SUS310S. Furthermore, ring-shaped plates 2D

and round head screws 2E were provided at a joint 2M so as to join the first and second heat-

resistant ring parts 2A, 2B together. The remaining test conditions were the same as those of

example 1.

EXAMPLE 3 The second heat-resistant ring part 2B, which constituted the internal ring part of the

first and second heat-resistant ring parts 2A, 2B of example 2, was made of an Al₂O₃ ceramic

sintered body instead of SUS310S. The remaining test conditions were the same as those of

example 1.

EXAMPLE 4

The heat-resistant ring 2 of example 1 was made of an Al₂O₃ ceramic sintered body instead of nickel-cobalt-based heat-resistant steel. The remaining test conditions were the same as those of example 1.

The results of examples 1, 2, 3, and 4, and a comparative example are described in

Table 1.

TABLE 1

of portions of B 1070 1100 1150 1155 1055

heat-resistant 921 921 1100 950 843 ring °C D 251 225 186 153 255

Heat loss amount of 3960 3240 2340 1440 5220 cooling water Kcal/Hr

No cracks

No cracks No cracks No cracks and no and no and no and no gaps were Cracks and gaps were gaps were gaps were formed at gaps (1.0 - formed at formed at formed at the 1.5mm) were the the the interface of formed at the Appearance of roll interface of interface of interface of the heat- interface of the after test the heat- the heat- the heat- resistant heat-resistant resistant resistant resistant ceramic steel ring and ring and ring and ring and ring the heat- the the the (Al₂O₃) resistant mortar adiabatic adiabatic adiabatic and the disk disk disk adiabatic disk

Claims

[CLAIMS]

[Claim 1]

An adiabatic roll, comprising: a metal tub shaft 1 which has a through hole 1A for passing cooling water 20

therethrough; a plurality of heat-resistant rings 2 which is fitted around the metal tub shaft 1 and

axially arranged at predetermined intervals between a fixed flange 5 and a movable flange 6

provided on a circumference of the metal tub shaft 1; and a plurality of disks 7 which is axially arranged between the heat-resistant rings 2, wherein the heat-resistant rings 2 and the disks 7 are fitted around the metal tub shaft 1

without welding.

[Claim 2]

The adiabatic roll as set forth in claim 1, wherein each of the heat-resistant rings 2

comprises first and second heat-resistant ring parts 2A, 2B which have different diameters and

are concentrically arranged on the same vertical axis.

[Claim 3]

The adiabatic roll as set forth in claim 2, wherein the first and second heat-resistant ring parts 2A, 2B of the heat-resistant rings 2 are joined together by using a pair of ring-shaped plates

2D and round head screws 2E axially threaded into the ring-shaped plates 2D at a joint 2M

thereof

[Claim 4] The adiabatic roll as set forth in claim 1, wherein metal tub shaft key grooves Id are

formed on an external wall of the metal tub shaft 1, key grooves 2C are formed on internal walls

of the heat-resistant rings 2, and the heat-resistant rings 2 are fitted around the metal tub shaft 1

by keys 10 which engage with the metal tub shaft key grooves Id and the key grooves 2C.

[Claim 5] The adiabatic roll as set forth in claim 2 or 3, wherein metal tub shaft key grooves Id

are formed on an external wall of the metal tub shaft 1, key grooves 2C are formed on internal

walls of the second heat-resistant ring parts 2B having relatively smaller diameters among the

heat-resistant rings 2, and the second heat-resistant ring parts 2B are fitted around the metal tub

shaft 1 by keys 10 which engage with the metal tub shaft key grooves Id and the key grooves

2C.

[Claim 6]

The adiabatic roll as set forth in claim 1, wherein the heat-resistant rings 2 are partially or entirely made of ceramic.

[Claim 7]

The adiabatic roll as set forth in claim 2 or 3, wherein the external first heat-resistant

ring part 2A of each of the heat-resistant rings 2 is made of nickel ^• cobalt or stainless steel, and

the internal second heat-resistant ring part 2B of each of the heat-resistant rings 2 is made of

ceramic.