JP2774011B2 - Moving hearth type continuous heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving hearth type continuous heat treatment apparatus, and more particularly to a moving hearth type continuous heat treatment apparatus used for metal strip coils and the like.

[0002]

2. Description of the Related Art When a steel sheet coil is annealed for a long time,
At present, a moving hearth type continuous heating furnace is mainly used. This moving hearth type continuous heating furnace is such that a steel coil with an inner cover mounted thereon is placed on a moving hearth rotating in a plane, and an atmosphere gas such as H ₂ is supplied into the inner cover while the heating band is being heated. , And is passed through a rotary furnace consisting of a soaking zone and a cooling zone sequentially and intermittently one pitch at a time, and continuously annealed through a predetermined heat cycle. And it is more productive than conventional box furnaces.

However, as long as continuous annealing is performed, the temperature of the furnace in the adjacent section is affected, so that only one heat pattern can be set, and the annealing is limited to annealing of a specific steel type.
If it is unavoidable to process different heat patterns, the heating of the preceding coil (leaving coil) and leaving the furnace to prevent the following coil (leading coil) from being affected by the furnace temperature of the leading coil (leading coil) After changing the temperature setting, the subsequent coil is inserted and annealed. This has the problem that the production efficiency is reduced because the heating and soaking zone is once made into an empty furnace.

[0004] Further, as the demand for improving the quality of products has increased in recent years, it has become increasingly necessary to precisely control the heat pattern during heat treatment of coils and the like.
As a method for solving these problems, Japanese Patent Application Laid-Open No. 57-76122
Japanese Patent Application Laid-Open No. 60-67628 discloses a method of providing a separately controllable heat source for each zone, and the like. It has been disclosed. However, in the former case, the band is too wide, and in the latter case, the cutoff between the bands is not perfect, so that the heat pattern of the coil itself cannot be controlled with sufficient accuracy. A method of further dividing each band into smaller bands is disclosed, for example, in Japanese Utility Model Laid-Open No. 60-177953, but there is a problem that sufficient control cannot be expected because the flow of the atmosphere is only cut off.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique capable of continuously changing a heat pattern and atmosphere in a moving hearth type continuous heat treatment apparatus with good controllability.

[0006]

In order to solve this problem, the present invention solves this problem by providing a highly sealed partition door for sufficiently shielding convection and radiant heat between the heating zone and the solitary zone, and a gas-fired open flame. By providing an exhaust device that exhausts exhaust gas generated by, for example, sections, the furnace temperature and atmosphere can be controlled independently for each section, and a plurality of heat patterns can be set. .

[0007] That is, the invention according to claim 1 is a moving hearth type continuous heat treatment furnace, wherein charging / extracting lots of articles to be heat-treated are extracted in sections in which a heat pattern differs according to steel type in a heating / soaking zone. A moving hearth type continuous heat treatment apparatus characterized in that a partition door for dividing a furnace is provided with a moving hearth length of one unit as a section unit, and the furnace temperature and atmosphere can be controlled for each of the divided sections.

According to a second aspect of the present invention, there is provided the moving hearth type continuous heat treatment apparatus according to the first aspect, wherein a seam line between each section of the moving hearth is closed by a lower end of the partition door. According to a third aspect of the present invention, the joint heat insulating material of each hearth is formed as an integrated structure, and a groove is provided in the lower part of the partition door and the furnace side wall so as to be fitted with the partition door, and a longitudinal section is provided at an upper end of the partition door. Is provided with a T-shaped sealing eave, and the T-shaped ends of the eave are received by receiving portions provided on the furnace ceiling so that each section is sealed when the partition door is lowered. Item 4. A moving hearth type continuous heat treatment apparatus according to item 1.

According to a fourth aspect of the present invention, a door casing is provided at an upper portion of the partition door, and a joint heat insulating material of each hearth is formed as an integral structure, and a groove is formed at a lower portion of the partition door and a furnace side wall so as to be fitted with the partition door. The moving hearth-type continuous heat treatment apparatus according to claim 1, wherein each section is always sealed. The invention according to claim 5 is the moving hearth type continuous heat treatment apparatus according to claim 1, comprising a plurality of sections using a heat source that does not generate exhaust gas in the furnace.

A sixth aspect of the present invention is the moving hearth type continuous heat treatment apparatus according to any one of the first to fourth aspects, further comprising an exhaust device capable of controlling the atmosphere for each section. According to a seventh aspect of the present invention, the exhaust device includes an exhaust port, an exhaust duct, a damper, a heat exchanger, a furnace pressure adjusting valve, and an exhaust fan.
It is a moving hearth type continuous heat treatment apparatus described in the above.

[0011]

According to the present invention, a partition door and an exhaust device are provided in each of the heating and soaking zones, and the degree of sealing of the partition doors is increased. Without this, independent furnace temperature setting and atmosphere control can be performed, and a plurality of heat patterns can be set.

1 and 2 show a plan view and a sectional view of a moving bed type continuous heat treatment apparatus according to the present invention. In FIG. 1, 1 is a furnace structure, 2 is a rotary moving hearth (hereinafter referred to as a rotary hearth), 3 is a heating and soaking zone composed of a plurality of sections, 4 is a cooling zone, 5 is a partition door, 6 Is an exhaust device. The S1 to S3 sections having a low coil temperature have the same heat pattern even when the steel type is changed, and the partition door is not necessarily required.

The exhaust system 6 has three exhaust systems: a low temperature range, a medium temperature range, and a high temperature range. These require not only the controllability of the furnace pressure but also the heat resistance of the equipment. 6b is an exhaust duct, 6c
Is a damper, 6d is a heat exchanger, 6e is a furnace pressure regulating valve, 6f
Is an exhaust fan. In FIG. 2, 7 is a coil, 8 is an inner case, 9 is a burner, 6a is an exhaust port, 2 is a rotary hearth, and 2a is a rotary hearth support roll.

The following method has been proposed for sealing around the partition door. 1) When the joint of each section of the moving hearth is not an integrated structure, a method of closing this joint with the lower end of the partition door as shown in FIG. 3 is adopted. 2) In the case where the joint of each section of the moving hearth has an integrated structure, as shown in FIGS. 4 to 6, grooves 5 f and 5 e to be fitted to the side wall in contact with the partition door and the hearth with the partition wall. Is provided. For this reason, the degree of sealing is better than the case of 1).

3) In 2), the ceiling of the furnace is simply sealed, and as shown in FIG. 5, an eave having a T-shaped cross section in the longitudinal direction is provided on the partition door. A receiving portion 5g made of fiber or the like is provided so as to be sealed when the partition door is lowered.
In this case, the sealing performance during the raising of the partition door is reduced. This method can be manufactured at a lower cost than the following more complete sealing method, and is preferably used when the temperature control and atmosphere control do not require much precision, such as a heating zone at a relatively low temperature.

4) In 3), a door casing 5b is provided on the ceiling corresponding to the partition door as shown in FIG. 4 to more completely seal the compartment. The degree of sealing can be increased by adjusting the opening length l and the opening width w of the drop arch 1C shown in FIG. This method is preferably used in a tropical zone where temperature and atmosphere need to be controlled more precisely.

FIG. 7 shows a method of setting a furnace temperature in a moving hearth type heat treatment apparatus manufactured according to the present invention and a corresponding change in coil temperature. In FIG. 7A, the horizontal axis is defined as a section, and the vertical axis is a graph showing a set furnace temperature, indicating that a plurality of furnace temperatures such as a, b, and c can be set. FIG. 7B shows a coil temperature corresponding to the furnace temperature setting, that is, a heat treatment diagram a ′,
b ′ and c ′ are shown.

By applying the above-described method in the moving hearth type heat treatment apparatus, it is easy to change the heat pattern for each section, and the change can be performed continuously without requiring time. And the controllability of atmosphere is very good. Well, in the moving hearth type heat treatment apparatus as above,
If the heat source is gas, a complicated piping structure as shown in FIG. 1 is required, but if the heat source is electricity, this problem is greatly reduced.

In the detailed description of the present invention, mainly the annealing of the steel sheet coil has been described, but the article to be heat-treated is not limited to the steel sheet coil.

[0020]

According to the present invention, since the furnace temperature and the atmosphere can be independently controlled for each section in heating and soaking, the plurality of heat patterns can be changed continuously. Flexible for production.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is an example of a partition door of FIG. 1;

FIG. 4 is an example of the partition door of FIG. 1;

FIG. 5 is an example of the partition door of FIG. 1;

FIG. 6 is a sectional view showing a partition door and a groove in a furnace side wall according to the present invention.

FIG. 7 is a graph showing a relationship between each zone section, a furnace temperature setting, and a coil temperature according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace structure 1a Furnace ceiling 1b Furnace side wall 1c Drop arch 2 Moving hearth 2a Moving hearth supporting roll 3 Heating / heating zone 4 Cooling zone 5 Partition door 5a Partition door main body 5b Partition door casing 5c Partition door lifting device 5d Partition door Drive motor 5e Groove provided on hearth 5f Groove provided on furnace side wall 5g Receiving part provided on furnace ceiling 6 Exhaust device 6a Exhaust port 6b Exhaust duct 6c Damper 6d Heat exchanger 6e Furnace pressure control valve 6f Exhaust gas 7 Coil 8 Inner case 9 Burner l Opening length by drop arch w Opening width by drop arch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-119311 (JP, A) JP-A-63-315885 (JP, A) JP-A-1-157150 (JP, U) 32045 (JP, B1) (58) Field surveyed (Int. Cl. ⁶ , DB name) C21D 9/56 F27B 9/04 F27B 9/16 F27B 9/40 F27D 7/06

Claims (7)

(57) [Claims] 1. A moving hearth type continuous heat treatment furnace, wherein a heat pattern is different for each steel type in a heating / soaking zone.
A partitioning door is provided for partitioning a furnace in units of a moving hearth length in which a charging / extraction lot of a heat-treated product is defined as one unit, and the furnace temperature and atmosphere can be controlled for each of the partitioned sections. Hearth type continuous heat treatment equipment. 2. The moving hearth type continuous heat treatment apparatus according to claim 1, wherein a seam line between each section of the moving hearth is closed by a lower end of the partition door. 3. A joint heat insulating material of each hearth is formed as an integrated structure, and a groove is provided in a lower part of the partition door and a furnace side wall so as to be fitted with the partition door.
2. A shape-shaped sealing eave is provided so that both ends of the T-shape of the eave are received by receiving portions provided on the furnace ceiling so that each section is sealed when the partition door is lowered. The moving hearth type continuous heat treatment apparatus as described in the above. 4. A door casing is provided at an upper part of the partition door, and a joint heat insulating material of each hearth is formed as an integrated structure, and a groove is provided at a lower part of the partition door and a furnace side wall so as to be fitted with the partition door. The moving hearth type continuous heat treatment apparatus according to claim 1, wherein 5. The moving hearth type continuous heat treatment apparatus according to claim 1, comprising a plurality of sections using a heat source that does not generate exhaust gas in the furnace. 6. The moving hearth type continuous heat treatment apparatus according to claim 1, further comprising an exhaust device capable of controlling an atmosphere for each section. 7. The moving hearth type continuous heat treatment apparatus according to claim 6, wherein the exhaust device comprises an exhaust port, an exhaust duct, a damper, a heat exchanger, a furnace pressure regulating valve, and an exhaust fan.