JP4453417B2 - Material transfer control method in heating furnace - Google Patents

Description

  The present invention relates to a method for optimally controlling the conveyance of material in a furnace in a walking beam type heating furnace equipped with a moving beam, a fixed beam, and an extractor.

  The material charged into the walking beam heating furnace is sequentially extracted after being heated to a predetermined temperature through the pre-tropical zone, the heating zone, and the soaking zone. In this walking beam type heating furnace, the material is transported at a constant pitch until it is extracted after being charged into the furnace, so that the residence time of the material in each band is constant. Of course, the staying time at the extraction end is the same.

  At the extraction end of such a walking beam type heating furnace, the extraction door opens and closes every time the material is extracted, so that it is easily affected by outside air. According to the investigation by the present inventors, as shown in FIG. 4, it has been found that as the in-furnace time at the extraction end becomes longer, the uneven thickness at the time of rolling generated due to the uneven heat increases. Accordingly, when transporting the inside of the furnace at a constant pitch, the closer to the extraction end, the more likely the uneven heat is generated.

However, conventionally, in the walking beam type heating furnace provided with a burner only in the upper part of the furnace, as a method for reducing the heat deviation generated in the vertical direction of the material,
1) A method of heating while rotating the material during conveyance,
2) The heating zone and the soaking zone transport mechanism are made independent. In the heating zone, the material interval is narrowed to increase the hearth load (heating capacity per unit time and unit hearth area). Only a method to increase the material spacing was described.
JP-A-53-37115 JP-A-11-302722

  Although the above method is considered to have an effect on reducing the heat deviation generated in the vertical direction of the material, each method has a constant transport pitch in the soaking zone, and therefore the present invention is intended. It is not possible to eliminate the uneven heat generated near the extraction end.

  The problem to be solved by the present invention is that there is no method for reducing the uneven heat generated near the extraction end of the walking beam heating furnace.

The material conveyance control method in the heating furnace of the present invention is:
In order to reduce the uneven heat generated near the extraction end of the walking beam furnace,
In the furnace inner position near the extraction end of the walking beam heating furnace,
Idling by moving the moving beam up and down and calculating the time for this idling,
If this time subjected to idling is less than a predetermined idling time, as the most important feature to perform an idling until the idling time a predetermined in-furnace side position location of the extracted near-edge of the heating furnace Yes.

The material conveying control method in a heating furnace of the present invention, in a furnace inside position of the extracted near-edge of the heating furnace, without conveying the material until the idling time predetermined to extraction end, extraction end near the furnace is performed at the side position location vertical movement only, temperature deviation is less likely to occur standing furnace time in an easy extraction end influenced by the outside air is shortened. In addition, since the material is transferred to the moving beam and the fixed beam every time it moves up and down, the support position of the material changes, so that the amount of heat removed at the support position is equalized, recuperation is promoted, and uneven heat is reduced.

In the material transport control method in the heating furnace of the present invention,
Upon extracting the material after completion of the idle,
From the end of the idling, a residence time t1 of the material until activation time only before the time of the extractor from the extraction scheduled time, walking beam from extraction end immediately before the pocket of the furnace up to pocket extraction end of a heating furnace Calculate the time t2 required for transport by
After the idling is completed , if the conveyance by the walking beam is not performed during the period of t1 to t2, the in-furnace time at the extraction end that is easily affected by the outside air becomes shorter, and it is difficult for the heat to be generated. Become.
At this time, the heat deviation is further reduced by performing idling during the time t1-t2 during which no conveyance is performed.

In the present invention, at the furnace inner position in the vicinity of the extraction end of the heating furnace, only the vertical movement is performed without conveying the material to the extraction end until a predetermined idling time is reached. Furnace time is shortened and uneven heat is less likely to occur.

  In addition, when the material is extracted after completion of idling, if the walking beam is not transported as much as possible until just before the extraction, the in-furnace time at the extraction end is shortened and it is difficult for heat to be generated.

Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS.
FIG. 1 is a schematic view of the extraction end of a walking beam heating furnace as viewed from the longitudinal section direction, and FIG. 2 is a schematic view of FIG. 1 as viewed from the transverse section direction.

  As shown in FIGS. 1 and 2, in the walking beam type heating furnace, the moving beam 1 has a longitudinal section of the heating furnace such as ascending, advancing, descending, and retreating as indicated by arrows in FIG. When driven in a U-shape when viewed from the direction, a large number of pockets 3a provided in the fixed beam 3 are addressed to one, and the material 2 is advanced to the extraction side. Needless to say, the moving beam 1 is also provided with a pocket 1 a similar to the fixed beam 3.

  In such a walking beam type heating furnace, in the conventional conveyance, as shown in FIG. 3A, when the material 2-1 located at the extraction end is extracted outside the furnace, the time set by the timer is set. When X (seconds) elapses, the moving beam 1 is driven to move the material 2-2 located in the pocket 3a immediately before the extraction end to the extraction end.

Then, when the extraction schedule at time of material 2-2 of the extracted edge, extractor is started, the material 2-2 is extracted out of the furnace. After the extraction of the material 2-2, when the time X (seconds) set by the timer has elapsed, the moving beam 1 is driven, and the material 2-3 located in the pocket 3a immediately before the extraction end reaches the extraction end. Moved.

  As described above, in the conventional conveyance, the material 2 is conveyed at a constant pitch regardless of the position of the material 2, and therefore the in-furnace time α of the material 2 at the extraction end is always constant, and the extraction of the material 2 is performed. As the extraction door opens and closes every time, it approaches the extraction end that is susceptible to the influence of outside air.

  Therefore, in the present invention, in such a walking beam type heating furnace, in order to reduce the uneven heat generated near the extraction end, the conveyance of the material is controlled as follows.

  That is, in the present invention, when the material 2-1 located at the extraction end is extracted outside the furnace, the material 2 located in the pocket 3a immediately before the extraction end immediately after the time X (seconds) set by the timer elapses. -2 is not moved to the extraction end, but the moving beam 1 is moved up and down to perform idling. Due to this vertical movement, the material 2 is alternately transferred to the moving beam 1 and the fixed beam 3 and the support position of the material 2 is changed, so that the amount of heat removal at the support position is equalized, recuperation is promoted, and uneven heat is reduced. .

  Then, the idling time is calculated, and when the idling time is less than the predetermined idling time β, idling is performed until the idling time β is reached at the position. It is.

The pitch of the vertical movement when performing the idling is not particularly limited, but it is needless to say that the vertical movement is desirably performed at a fast pitch within a range that is possible in the driving structure of the moving beam 1. Also, advance idling time β to be determined, after the extraction end material 2 is extracted, set within the time obtained by subtracting the material transport time by the mobile beam 1 from until extraction scheduled during time of the next material 2 To do.

After the idling time β reaches a predetermined idling time β, the moving beam 1 is driven to move the material 2-2 to the extraction end. Then, when the extraction schedule at time of material 2-2 of the extracted edge, activates the extractor to extract the material 2-2. In addition, after extraction of this material 2-2, the next material 2-3 is moved to an extraction end similarly. FIG. 3B illustrates the above conveyance control pattern.

  By performing such transport control, in the present invention, the in-furnace time at the extraction end, which is easily affected by outside air, becomes α ′ shorter than the conventional idling time β compared to the prior art, and it is difficult for heat deviation to occur. Become.

  In the above example, description has been given of performing idling while transporting from the pocket immediately before the extraction end to the extraction end. However, if the idling position is in the vicinity of the extraction end, not only the position of this example. The idling may also be performed at other positions.

Further, in the above method of the present invention, when extracting the material 2 after the idling completion, from said idling the end of the dwell time t1 of the material until activation time only before the time of the extractor from the extraction scheduled time, by walking beam from the pocket immediately before the extraction end of the furnace up to the pocket of the extraction end of the furnace (moved by driving the beam 1) the time t2 required for the transport is calculated respectively, after the end of the idling, this t1-t2 If the conveyance by driving the moving beam 1 is not performed, the in-furnace time α at the extraction end that is easily affected by outside air can be shortened.

  Needless to say, the idling described above may be performed during the time t1-t2 during which no conveyance is performed.

  The above example is merely an example, and the present invention is not limited to the above example, and it goes without saying that the embodiment may be appropriately changed within the scope of the technical idea described in each claim.

  The present invention described above can be applied not only to a heating furnace but also to a supplementary heating furnace or any furnace as long as it is a walking beam type furnace.

It is the schematic seen from the longitudinal cross-sectional direction explaining the extraction end part in a walking beam type heating furnace. FIGS. 1A and 1B are schematic views of the transverse cross-sectional direction of FIG. 1, in which FIG. 1A shows a moving beam descending, and FIG. 1B shows a moving beam rising. It is a figure explaining the material conveyance control method in a heating furnace, (a) is the conventional material conveyance control method, (b) is the figure which showed the material conveyance control method in invention of Claim 1. It is the figure which showed the relationship between the in-furnace time in a heating furnace extraction end, and the amount of uneven thickness resulting from a heating furnace partial heat.

Explanation of symbols

1 Fixed Beam 1a Pocket 2 Material 3 Fixed Beam 3a Pocket

Claims (2)

A method for controlling the transfer of material in a furnace in a walking beam type heating furnace,
In the furnace inner position near the extraction end of the heating furnace,
Idling by moving the moving beam up and down and calculating the time for this idling,
If this time subjected to idling is less than a predetermined idling time, the heating furnace and performing idling until the idling time a predetermined in-furnace side position location of the extracted near-edge of the heating furnace Material transport control method inside. In the material conveyance control method in the heating furnace of Claim 1,
Upon extracting the material after completion of the idle,
From the end of the idling, a residence time t1 of the material until activation time only before the time of the extractor from the extraction scheduled time, walking beam from extraction end immediately before the pocket of the furnace up to pocket extraction end of a heating furnace Calculate the time t2 required for transport by
The material conveyance control method in a heating furnace, wherein the conveyance by the walking beam is not performed for the time t1 to t2 after completion of the idling .

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