EP2050829B1

EP2050829B1 - Continuous annealing apparatus

Info

Publication number: EP2050829B1
Application number: EP20080010476
Authority: EP
Inventors: Hiroo Nakagawa
Original assignee: Chugai Ro Co Ltd
Current assignee: Chugai Ro Co Ltd
Priority date: 2007-10-12
Filing date: 2008-06-09
Publication date: 2010-04-21
Anticipated expiration: 2028-06-09
Also published as: ES2341502T3; JP4999631B2; JP2009091642A; EP2050829A1; CN101407856B; CN101407856A

Description

This application is based on application No. 266014/2007 filed in Japan.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a continuous annealing apparatus for continuously annealing a steel strip moved through an annealing furnace from an inlet side toward an outlet side thereof. Particularly, the invention relates to a continuous annealing apparatus employing a guiding member for inserting the steel strip through the annealing furnace. The apparatus is designed to prevent the heat deterioration of the guiding member and to facilitate an operation of inserting the steel strip through the annealing furnace or particularly the operation of inserting the steel strip through the annealing furnace in the event that the steel strip being annealed breaks off in the annealing furnace.

Description of the Related Art

In the continuous annealing apparatus for continuously annealing the steel strip moved through the annealing furnace from the inlet side toward the outlet side thereof, the steel strip must be inserted through the annealing furnace and hence, a worker is allowed to enter the annealing furnace to do his job when the temperature in the furnace is lowered nearly to room temperatures.
However, the following problem exists in a case where the steel strip breaks off in the annealing furnace in the course of continuously annealing the steel strip moved through the annealing furnace. In this case, the furnace temperature is extremely high so that the worker cannot enter the annealing furnace to insert the steel strip through the annealing furnace again. If the worker waits for the furnace temperature to be lowered nearly to the room temperatures, the worker is bound to have quite a long waiting time, which results in a serious decrease of working efficiency.
In this connection, the following apparatus such as disclosed in Japanese Unexamined Patent Publication No.S57 (1982 )- 3735 ( JP-A-53046416 ) has been proposed in the art. The apparatus is provided with a hook-shaped heat resistant retaining member in the annealing furnace. The retaining member stretchingly retains a guiding member formed from a heat resistant material such as nichrome wire so as to insert the guiding member through the annealing furnace. The guiding member is reeled in by means of a reeling device such as a winch whereby the steel strip is inserted through the annealing furnace.
However, the use of the heat resistant material such as the nichrome wire as the guiding member involves a problem of cost increase. Even the guiding member formed from such a heat resistant material is prone to break off as gradually deteriorated while it is maintained in the annealing furnace under high temperature conditions. This leads to the need for frequently replacing the guiding member. The frequent replacing operations take much time so that the working efficiency is seriously decreased and a significant cost increase results.
More recently, there is a demand for increasing the length of the annealing furnace to about 300m, a three time increase from the conventional furnace length (about 100m), to cope with increase in the amount of throughput of the steel strip. The annealing furnace increased in length dictates the need for increasing the length of the guiding member.
However, the guiding member increased in length entails the following problem. When the stretched guiding member is retained by the retaining member, the guiding member is subjected to such a great load. If this guiding member is maintained in the annealing furnace under high temperature conditions, as described above, the guiding member becomes more susceptible to breakage. It is practically impossible to apply the guiding member to the annealing furnace having the length on the order of 300m.
Another proposal has been made in the art as disclosed in Japanese Unexamined Patent Publication No. H7(1995)-91591 ( JP-A-63111130 ). An endless wire rope adapted for circulative movement is stretched between the inlet and outlet sides of the annealing furnace. One end of the steel strip is connected to the endless wire rope by means of a tow rope so as to insert the steel strip through the annealing furnace.
However, the arrangement wherein the endless wire rope adapted for circulative movement is stretched between the inlet and outlet sides of the annealing furnace requires a long wire rope having a length at least twice the length of the annealing furnace, which results in cost increase. In addition, the most part of the endless wire rope resides in the annealing furnace. Hence, the problem still exists that the endless wire rope suffers deterioration as maintained in the annealing furnace under high temperature conditions.
Furthermore, a great power is required for driving the long endless wire rope into circulative movement and hence, running cost is increased. What is more, load is exerted on the endless wire rope during the circulative movement so that the endless wire rope is prone to breakage.
In the case where the annealing furnace is increased in length as described above, it is required to form the wire rope longer than twice the length of the annealing furnace into the continuous loop shape and to move the looped wire rope circulatively. This involves not only a significant cost increase but also the difficulty of circulatively moving the endless wire rope. It is therefore impossible to apply the endless wire rope to the annealing furnace having the length on the order of 300m.

SUMMARY OF THE INVENTION

The invention seeks to offer solution to the aforementioned problems encountered by the continuous annealing apparatus when the steel strip is inserted through the annealing furnace, the apparatus arranged to continuously anneal the steel strip moved through the annealing furnace from the inlet side toward the outlet side thereof.
Specifically, the object of the invention is to prevent the heat deterioration of the guiding member used for inserting the steel strip through the annealing furnace and to facilitate the operation of inserting the steel strip through the annealing furnace or particularly, the operation of inserting the steel strip through the annealing furnace in the event that the steel strip being annealed breaks off in the annealing furnace.
According to the invention, a continuous annealing apparatus for continuously annealing a steel strip moved through an annealing furnace from an inlet side toward an outlet side thereof, comprises: a guiding member which guides the steel strip in insertion through the annealing furnace and which is disposed externally of the annealing furnace as extending along the annealing furnace from the inlet side toward the outlet side thereof; an introducing slit which introduces the guiding member into the annealing furnace and which is extended along the annealing furnace from the inlet side toward the outlet side thereof; and seal means for closing the introducing slit.
According to the continuous annealing apparatus of the invention, the introducing slit extended along the annealing furnace from the inlet side toward the outlet side thereof may be formed at a roof or a side wall of the annealing furnace.
Further, the introducing slit may be extended in the overall length of the annealing furnace.
Further, it is preferred that the introducing slit is formed to incline toward the interior of the annealing furnace.
A variety of seal methods may be used as the seal means for closing the introducing slit. For instance, a seal member extending along the introducing slit may be slidably disposed at place outside the annealing furnace such that the seal member may be slidably moved to close or open the introducing slit. Alternatively, a roller member extending along the introducing slit may be rotatably disposed at place outside the annealing furnace in a manner to close the introducing slit, while a retaining portion for retaining the guiding member may be axially formed in an outer periphery of the roller member.
In the case where the seal member extending along the introducing slit is slidably disposed at place outside the annealing furnace, the introducing slit is normally closed with the seal member. On the other hand, the seal member may be slidably moved to open the introducing slit when the guiding member is introduced into the annealing furnace through the introducing slit.
In the case where the roller member extending along the introducing slit is rotatably disposed at place outside the annealing furnace in the manner to close the introducing slit while the retaining portion for retaining the guiding member is axially formed in the outer periphery of the roller member, the roller member may be rotated so as to position the guiding member retained by the retaining portion at the introducing slit when the guiding member is introduced into the annealing furnace through the introducing slit.
In the continuous annealing apparatus of the invention wherein the introducing slit is formed at the roof or the side wall of the annealing furnace as described above, it is preferred that support means for supporting the roof or the side wall of the annealing furnace is provided externally of the annealing furnace for the purpose of maintaining the strength of the annealing furnace.
According to the continuous annealing apparatus of the invention, the guiding member for guiding the steel strip in insertion through the annealing furnace is disposed externally of the annealing furnace as extending along the annealing furnace from the inlet side toward the outlet side thereof. The apparatus solves the prior-art problem that the guiding member is maintained in the annealing furnace under high temperature conditions. Hence, the guiding member is prevented from being deteriorated by heat.
This negates the need for using the heat resistant material such as the nichrome wire for forming the guiding member but permits the use of an inexpensive material such as stainless steel. Furthermore, the guiding member can provide a long-term service so that the number of operations of replacing the guiding member is reduced. What is more, a notable cost reduction is achieved.
Since the heat deterioration of the guiding member is prevented as described above, even the guiding member, which is increased in length, does not break off easily. Even in the annealing furnace increased in length, the guiding member may be used for properly inserting the steel strip through the annealing furnace.
When the guiding member is used for inserting the steel strip through the annealing furnace, the guiding member disposed externally of the annealing furnace as extending along the annealing furnace from the inlet side toward the outlet side thereof, as described above, can be inserted through the annealing furnace via the introducing slit extended along the annealing furnace from the inlet side toward the outlet side thereof. The operation of inserting the guiding member through the annealing furnace can be easily accomplished.
Except when the guiding member is introduced into the annealing furnace, the introducing slit is closed with the seal means so that the leakage of heat or gas in the annealing furnace is prevented.
The introducing slit so formed as to incline toward the interior of the annealing furnace affords an advantage of allowing less radiation heat from the annealing furnace to leak therethrough when the guiding member is introduced into the annealing furnace through the introducing slit as described above.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate specific embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1 is a schematic sectional view of a continuous annealing apparatus according to one embodiment of the invention for showing how a steel strip is annealed as moved through an annealing furnance with an introducing slit closed with seal means comprising a transversely slidable seal member, the introducing slit formed at a roof of the annealing furnace;
Fig. 2 is a schematic perspective view of the continuous annealing apparatus according to the above embodiment for showing how the steel strip is annealed as moved through the annealing furnace as described above;
Fig.3 is a schematic sectional view of the continuous annealing apparatus according to the above embodiment for showing how a guiding member is introduced into the annealing furnace through the introducing slit opened by slidably moving the above seal member;
Fig. 4 is a schematic perspective view of the continuous annealing apparatus according to the above embodiment for showing a state where the introducing slit formed at the roof of the annealing furnace is closed with the seal member and the guiding member is laid in the annealing furnace to extend from the inlet side toward the outlet side thereof;
Fig.5 is a schematic sectional view of the continuous annealing apparatus according to the above embodiment for illustrating a modification of the seal means for closing the introducing slit formed at the roof of the annealing furnace and for showing how the introducing slit is closed with a roller member which is retained by a roller retainer disposed on the roof of the annealing furnace and has an outer periphery formed with a retaining portion for retaining the guiding member;
Fig.6 is a schematic sectional view of the above modification of the seal means comprising the roller member for showing how the roller member is rotated to introduce the guiding member retained by the retaining portion into the annealing furnace through the introducing slit; and
Fig.7 is a schematic sectional view of the continuous annealing apparatus according to the above embodiment for illustrating a modification thereof wherein the introducing slit for introducing the guiding member into the annealing furnace is extended through a side wall of the annealing furnace and for showing how the introducing slit is closed with the seal means comprising a vertically slidable seal member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A continuous annealing apparatus according to a preferred embodiment of the invention will hereinbelow be described in detail with reference the accompanying drawings. It is to be noted that the continuous annealing apparatus of the invention is not limited to the following embodiments and changes or modifications may be made thereto as needed so long as such changes or modifications do not depart from the scope of the invention.
As shown in Fig.1 and Fig.2, the continuous annealing apparatus according to the embodiment includes a plurality of support rolls 11 longitudinally arranged in an annealing furnace 10 at required space intervals. A steel strip 1 to be treated is introduced into the annealing furnace 10 from an inlet thereof and is annealed as moved on the support rolls 11. The steel strip 1 thus annealed is led out of the annealing furnace 10 via an outlet thereof.
In the continuous annealing apparatus of the embodiment, the annealing furnace 10 is formed with an introducing slit 12 which is extended through a roof 10a thereof and includes an inclined portion 12a inclined toward the interior of the annealing furnace 10. The introducing slit is extended in the overall longitudinal length of the annealing furnace 10.
The apparatus further includes a heat resistant seal member 21 as seal means for closing the introducing slit 12. The seal member 21 is extended along the introducing slit 12 and is transversely slidably provided on the roof 10a of the annealing furnace 10 formed with the introducing slit 12. The seal member 21 is slidably moved to close or open the introducing slit 12.
The apparatus further includes a rope-like guiding member 13 which is introduced into the annealing furnace 10 through the introducing slit 12. The guiding member 13 is disposed on the roof 10a of the annealing furnace 10 at place proximal to the introducing slit 12. The guiding member 13 is extended along the introducing slit 12 from the inlet side toward the outlet side of the annealing furnace 10.
The continuous annealing apparatus of the embodiment further includes a support frame 30 external to the annealing furnace 10 such as to support the roof 10a of the annealing furnace 10 which is formed with the introducing slit 12 extended in the overall longitudinal length of the furnace. The support frame 30 is provided with a plurality of retaining members 31 at an upper frame 30a thereof for retaining the roof 10a.
In the continuous annealing apparatus of the embodiment, the steel strip 1 is inserted through the annealing furnace 10 as follows. As shown in Fig. 3, the seal member 21 disposed on the roof 10a of the annealing furnace 10 is slidably moved to open the introducing slit 12. The guiding member 13 is introduced into the annealing furnace 10 through the introducing slit 12 thus opened.
Subsequently, the seal member 21 is slidably moved back to close the introducing slit 12, as shown in Fig.4. The guiding member 13 is so laid in the annealing furnace 10 as to extend from the inlet side toward the outlet side thereof.
Subsequently, an end of the steel strip 1 is attached directly to an inlet-side end of the guiding member 13 thus laid in the annealing furnace 10 to extend from the inlet side toward the outlet side of thereof. Otherwise, the end of the steel strip 1 may be attached to the inlet-side end of the guiding member by means of a connecting member such as an auxiliary wire (not shown). In this state, the guiding member 13 is reeled in by means of a reeling device such as a winch (not shown) so that the guiding member 13 together with the steel strip 1 are moved to the outlet side of the annealing furnace 10 whereby the steel strip is inserted through the annealing furnace 10.
In a case where the steel strip 1 being annealed breaks off in the annealing furnace 10, it is a common practice to draw out the individual steel strips 1 remaining in the annealing furnace 10 from the inlet side and outlet side of the annealing furnace 10.
Subsequently, the guiding member 13 is introduced into the annealing furnace 10 in the same way as described above. An end of the steel strip 1 drawn out from the inlet side is attached to the inlet-side end of the guiding member 13. Thereafter, the guiding member 13 together with the steel strip 1 drawn out from the inlet side are led to the outlet side of the annealing furnace 10 whereby the steel strip 1 is inserted through the annealing furnace 10. Using the above connecting member or the like, the steel strip 1 thus inserted through the annealing furnace 10 is connected with the steel strip 1 previously drawn out from the outlet side of the annealing furnace 10.
According to the continuous annealing apparatus of the embodiment, the guiding member 13 is disposed on the roof 10a of the annealing furnace 10 so as to be maintained at place outside the annealing furnace 10 unless the operation of inserting the steel strip 1 through the annealing furnace 10 is carried out. Hence, the guiding member 13 is not maintained in the annealing furnace 10 under high temperature conditions for long hours. The guiding member 13 is prevented from suffering the heat deterioration.
This allows for the use of an inexpensive material such as stainless steel as the material of the guiding member 13, negating the need for using a heat resistant material such as nichrome wire. What is more, this guiding member 13 can provide a long-term service so that a notable cost reduction may be achieved.
When the steel strip 1 is inserted through the annealing furnace 10, the guiding member 13 can be easily and quickly laid in the annealing furnace and extended from the inlet side toward the outlet side thereof by merely taking the steps of slidably moving the seal member 21 for opening the introducing slit 12 as described above, and introducing the guiding member 13 into the annealing furnace 10 through the introducing slit 12 thus opened. The operation of inserting the steel strip 1 through the annealing furnace 10 is dramatically increased in efficiency.
The introducing slit 12 is normally sealed with the abovementioned seal member 21 except when the guiding member 13 is introduced into the annealing furnace 10. Therefore, leakage of heat or gas in the annealing furnace 10 is prevented.
Since the introducing slit 12 is provided with the inclined portion 12a inclined toward the interior of the annealing furnace 10, less radiation heat from the inside of the annealing furnace 10 is allowed to leak through the introducing slit 12 when the guiding member 13 is introduced into the annealing furnace 10 through the introducing slit 12. This leads to the prevention of the decrease of temperature in the annealing furnace 10. Hence, the operation of annealing the steel strip 1 is increased in efficiency.
According to the continuous annealing apparatus of the embodiment, the seal means for closing the introducing slit 12 comprises the heat resistant seal member 21 which is slidably disposed in proximity of the introducing slit 12 and which is slidably moved to guide the guiding member 13 into the introducing slit 12 when the guiding member 13 is introduced into the annealing furnace 10. However, the seal means for closing the introducing slit 12 is not limited to this.
An alternative arrangement may be made as shown in Fig. 5, for example. A roller retainer 14 for retaining a heat resistant roller member 22 is provided on the roof 10a of the annealing furnace 10 formed with the introducing slit 12. The heat resistant roller member 22 is rotatably retained by the roller retainer 14 such that the introducing slit 12 may be closed with the roller member 22 . A recessed retaining portion 22a is axially formed in an outer periphery of the roller member 22 such that the guiding member 13 may be retained in the retaining portion 22a.
The guiding member 13 retained in the retaining portion 22a formed in the roller member 22 may be introduced into the annealing furnace 10 through the introducing slit 12 as follows. As shown in Fig. 6, the roller member 22 is rotated to position the guiding member 13 retained in the retaining portion 22a at the introducing slit 12 so as to introduce the guiding member 13 into the annealing furnace 10 through the introducing slit 12.
This arrangement is also adapted to suppress the leakage of the heat or gas in the annealing furnace 10 through the introducing slit 12 when the guiding member 13 is introduced into the annealing furnace 10 through the introducing slit 12. Hence, the temperature decrease of the annealing furnace 10 is even further suppressed so that the operation of annealing the steel strip 1 is further increased in efficiency.
While the continuous annealing apparatus of the above embodiment is provided with the introducing slit 12 extended through the roof 10a of the annealing furnace 10, the introducing slit 12 may also be formed to extend through a side wall 10b of the annealing furnace 10 as inclined toward the interior thereof, as shown in Fig.7. In this case, it is preferred that besides the upper frame 30a of the support frame 30, a side frame 30b thereof is also provided with a plurality of retaining members 31 for retaining the side wall 10b, as shown in Fig.7.
In the case where the introducing slit 12 is extended through the side wall 10b of the annealing furnace 10, the heat resistant seal member 21 extended along the introducing slit 12 is vertically slidably mounted to an outside portion of the side wall 10b of the annealing furnace 10 formed with the introducing slit 12. A retaining portion 21a for retaining the guiding member 13 is provided on a top of the seal member 21 and is inclined toward the introducing slit 12.
According to this arrangement, the guiding member 13 retained by the retaining portion 21a is guided into the introducing slit 12 so as to be introduced into the annealing furnace 10 through the introducing slit 12 when the seal member 21 is slidably moved down to open the introducing slit 12.
According to the continuous annealing apparatus of the foregoing embodiments, the introducing slit 12 for introducing the guiding member 13 into the annealing furnace 10 is formed in the overall length of the annealing furnace 10 so as to extend from the inlet side to the outlet side of the annealing furnace 10. Alternatively, the introducing slit 12 may also be extended to place proximal to the inlet or outlet side of the annealing furnace 10 rather than extended in the overall length thereof. The end of the guiding member 13 introduced into the annealing furnace 10 through this introducing slit 12 can be drawn out from the inlet or outlet of the annealing furnace 10.

Claims

A continuous annealing apparatus for continuously annealing a steel strip moved through an annealing furnace (10) from an inlet side toward an outlet side thereof, comprising:
a guiding member (13) which guides the steel strip in insertion through the annealing furnace said guiding member is disposed externally of the annealing furnace as extending along the annealing furnace from the inlet side toward the outlet side thereof; an introducing slit (12) which introduces the guiding member into the annealing furnace said slit is extended along the annealing furnace from the inlet side toward the outlet side thereof; and seal means for closing the introducing slit.
A continuous annealing apparatus according to Claim 1, wherein the introducing slit is extended in the overall length of the annealing furnace.
A continuous annealing apparatus according to Claim 1 or 2, wherein the introducing slit is formed at a roof or a side wall of the annealing furnace.
A continuous annealing apparatus according to any one of Claims 1 to 3, wherein the introducing slit is formed to incline toward the interior of the annealing furnace.
A continuous annealing apparatus according to any one of Claims 1 to 4, wherein a seal member (21), as the seal means, extended along the introducing slit is slidably mounted to an outside portion of the annealing furnace.
A continuous annealing apparatus according to any one of Claims 1 to 4, wherein a roller member (22), as the seal means, extended along the introducing slit is rotatably mounted to an outside portion of the annealing furnace in a manner to close the introducing slit and wherein a retaining portion (21a) for retaining the guiding member is axially formed in an outer periphery of the roller member.
A continuous annealing apparatus according to any one of Claims 1 to 6, wherein support means for supporting a roof or side wall of the annealing furnace is provided externally of the annealing furnace.