JPH05239558A - Traveling furnace hearth type continuous heat treatment apparatus - Google Patents

Abstract

PURPOSE:To continuously change plural heat patterns in good controllability by arranging a parting door in each of parts between sections in a shifting furnace hearth and controlling the furnace temp. and the atmosphere in the each section. CONSTITUTION:In the traveling furnace hearth 2, parting doors 5 for dividing the furnace are arranged as the furnace length units having integral times that of a section unit treating a charging/ejecting lot of materials to be heat- treated as one unit, and in each of parts between the sections, convection and radiation heat are shut off. Further, an gas exhaust device 6 for exhausting the gas generated by directly firing a gas fuel to the each section unit is arranged so as to be possible to execute the settings of plural heat patterns by executing the furnace temp. setting independently in the section unit. By closing the connecting line in each of the parts between the sections in the shifting furnace hearth 2 at the lower end of the parting door 5, sealing near the parting door 5 is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous heat treatment apparatus such as a metal strip coil.

[0002]

2. Description of the Prior Art For annealing a steel plate coil for a long time,
As a furnace for batch annealing, a box furnace is available, but the moving hearth furnace is currently the main product because of poor production efficiency. For example, when annealing a grain-oriented silicon steel sheet, since the heat pattern differs depending on the steel type, it is necessary to have an annealing furnace for each heat pattern. For steel types with low production, annealing in a moving hearth furnace is uneconomical for the reasons described below, and it is unavoidable to use box furnaces with poor productivity as described above, but steel types with high production are continuous furnaces. That is, a moving hearth type furnace is used. A coil annealing method using a moving hearth type heating furnace is widely known, and a steel plate coil having an inner cover is placed on a moving hearth that rotates in a plane,
While supplying an atmosphere gas such as H ₂ into the inner cover, the material is continuously transferred and passed through the rotary furnace composed of a heating chamber, a soaking zone, and a cooling zone one pitch at a time, and continuously passed through a predetermined heat cycle. Annealing is performed.

Therefore, in the moving hearth type furnace, it is necessary to increase the length of the furnace in order to improve productivity, and for example, a plurality of sections such as 10 heating zones and 3 soaking zones are distributed. Therefore, as long as it is annealed continuously, it is affected by the furnace temperature of the adjacent section, so that only one heat pattern can be set, and the annealing is limited to the specific steel type. When it is unavoidable to process different heat patterns, in order to prevent the trailing coil (leading coil) from being affected by the furnace temperature of the leading coil (subsequent coil), the leading coil is heated, and the furnace is heated after leaving the soaking zone. After changing the temperature setting, there is a method in which a trailing coil is charged and annealed, but there is a problem that the production efficiency is lowered because heating and soaking is once made into an empty furnace.

As the demand for quality improvement of products has increased in recent years, it has become more and more necessary to precisely control the heat pattern during heat treatment of coils and the like. As a method therefor, JP-A-57-76122 discloses a method of providing a separation zone for interrupting the circulation of the atmosphere between the soaking zone and the cooling zone, and JP-A-60-67628 discloses each zone. Although a method of providing a heat source that can be controlled independently is disclosed in
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 is disclosed in, for example, Japanese Utility Model Laid-Open No. 60-177953, but there is a problem in that sufficient control cannot be expected because it merely interrupts the circulation of the atmosphere.

[0005]

SUMMARY OF THE INVENTION The present invention provides a technique capable of continuously changing a heat pattern with good controllability even in a moving hearth type continuous heat treatment apparatus.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention uses a partition door for shielding convection, radiant heat between a heating zone and soaking zones, and exhaust gas generated by a gas-fired direct fire. By providing an exhaust device for exhausting gas in units of compartments, it is possible to set the furnace temperature independently in units of compartments and to set a plurality of heat patterns.
That is, the present invention is a moving hearth-type continuous heat treatment furnace, in which a moving hearth length with one unit of charging / extracting lot of a heat-treated product as a unit is a unit of an integral multiple of this unit. , A moving hearth-type continuous heat treatment apparatus that can control the furnace temperature and atmosphere for each of the divided compartments by providing a partition door for partitioning the furnace. It is a moving hearth type continuous heat treatment device that is closed at the lower end, in which a groove is formed in the lower part of the partition door so that the seam heat insulating material of each hearth is integrated, and the groove is fitted to the partition wall. Also, a groove is provided so as to fit with the partition door, a sealing eave with a T-shaped cross section in the length direction is provided at the upper end of the partition door, and the partition door is descending together with the receiving part of the furnace ceiling. Then, the moving hearth where each section is sealed In the continuous heat treatment device, a door casing is provided on the upper part of the partition door, a joint heat insulating material of each hearth is integrated structure, and a groove is provided on the lower part of the partition door so as to fit with the partition door. A moving hearth-type continuous heat treatment device in which a groove was provided so as to fit with a partition door so that each compartment was always sealed, and in which a heat source such as an electric heater that did not generate exhaust gas was used. It is a moving hearth-type continuous heat treatment apparatus consisting of multiple sections.

[0007]

According to the present invention, since the partition door and the exhaust device are provided in each of the heating and soaking zones, the furnace temperature of the section adjacent to each section unit is not affected and the furnace temperature is independently set. Can be set, 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 is a furnace hearth, 2 is a rotary moving hearth (hereinafter referred to as a rotary hearth), 3 is heating composed of a plurality of sections, a soaking zone, 4 is a cooling zone, 5 is a partition door, and 6 is an exhaust device. is there. The S1 to S3 sections where the coil temperature is low do not need to be provided because the heat pattern is common even if the steel type is changed and a partition door is not required. Exhaust device 6 has a low temperature range, a medium temperature range, and a high temperature range.
The system exhaust will be manufactured in consideration of the controllability of the furnace pressure and 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, and 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.

Regarding the sealing near the partition door, the following method has been proposed. 1) When the integrated structure is not used at the joint of each section of the moving hearth, as shown in FIG. 3, this joint is simply closed by the lower end of the partition door. 2) When the integrated structure is used at the joint of each section of the moving hearth, as shown in FIG. 4, the side wall in contact with the partition door and the grooves 5f, 5e for fitting with the partition wall are provided in the hearth. .. Therefore, the degree of airtightness is better than that of 1). 3) In 2), the ceiling of the furnace is simply sealed,
As shown in FIG. 5, an eaves having a T-shaped cross section in the lengthwise direction is provided on the partition door, and a receiving portion 5g made of, for example, ceramic fiber is provided on the ceiling of the furnace to seal when the partition door is lowered. It is a structure to be. In this case, when the partition door is raised, the seal deteriorates. This method can be manufactured at a lower cost than the next more complete sealing method, and is preferably used when the temperature control does not require so much accuracy as in a heating zone of 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 seal the compartment more completely. The tightness can be increased by adjusting the opening length 1 and the opening width w by the drop arch shown in FIG. This method is suitable for use in the soaking zone where it is necessary to precisely control the temperature.

FIG. 7 shows a method of setting the furnace temperature in the moving hearth type heat treatment apparatus manufactured according to the present invention and a change in coil temperature corresponding thereto. FIG. 7A is a graph in which the horizontal axis is expanded into sections and the vertical axis furnace temperature is set, and a plurality of furnace temperature settings such as a, b, and c can be set. FIG. 7B shows the coil temperature corresponding to the furnace temperature setting, that is, the heat treatment diagrams a ′ and b ′.
c'is shown. By applying the above method in the moving hearth type heat treatment equipment, it is easy to change the heat pattern for each section, and the change can be done continuously without time, and the temperature and atmosphere can be changed. The controllability is extremely good. Now, in the moving hearth type heat treatment equipment 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, the annealing of the steel sheet coil has been mainly described, but the heat-treated product is not limited to the steel sheet coil.

[0010]

As described above, according to the present invention, in heating and soaking, it is possible to set the furnace temperature independently for each section, so that a plurality of heat patterns can be continuously changed.
Can flexibly respond to production.

[Brief description of drawings]

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

2 is a cross-sectional view of FIG.

FIG. 3 is an example of the partition door of FIG.

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

5 is an example of the partition door of FIG.

FIG. 6 is a cross-sectional view showing a partition door and a groove of a furnace side wall of the present invention.

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

[Explanation of symbols]

 1 Furnace Structure 1a Furnace Ceiling 1b Furnace Side Wall 1c Drop Arch 2 Moving Hearth 2a Moving Hearth Support Roll 3 Heating and Soaking 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 floor 5f Groove provided on furnace side wall 5g Receiver 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 fan 7 Coil 8 Inner case 9 Burner l Opening length by drop arch w Opening width by drop arch

Claims (5)

[Claims] 1. A moving hearth type continuous heat treatment furnace, wherein a moving hearth length with one unit of the charging / extracting lot of the heat-treated product as a unit is a unit of an integral multiple of this unit. A moving hearth-type continuous heat treatment apparatus in which a partition door for partitioning the furnace is provided, and the furnace temperature and atmosphere can be controlled for each partitioned section. 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 a partition door. 3. The structure according to claim 1, wherein the seam heat insulating material of each hearth is formed as an integrated structure, and a groove is provided in a lower portion of the partition door so as to be fitted with the partition door, and the furnace side wall is also fitted with the partition door. A groove is provided so that the partition door is provided with a T-shaped sealing eaves having a T-shaped cross section in the longitudinal direction at the upper end of the partition door. Moving hearth type continuous heat treatment equipment. 4. The furnace according to claim 1, wherein a door casing is provided on 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 on a lower part of the partition door so as to be fitted with the partition door. A moving hearth-type continuous heat treatment device in which a groove is also provided on the side wall so as to fit with the partition door so that each section is always sealed. 5. The moving hearth type continuous heat treatment apparatus according to claim 1, comprising a plurality of compartments using a heat source such as an electric heater that does not generate exhaust gas in the furnace.