JPH0772291B2 - Walking hearth type upper heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a walking hearth-type upper heating furnace for heating a steel slab using an upper-burning heating furnace including a walking hearth including a fixed hearth and a movable hearth. The present invention relates to a fired heating furnace.

(Prior Art) In this type of upper-burning heating furnace, a steel slab is conveyed using a walking hearth arranged below the steel slab to be transferred. Therefore, the billet is heated from above, but the walking hearth has the advantage that it is not exposed to relatively high heat. This has the effect of reducing the degree of water cooling of the walking hearth and reducing the fuel consumption rate in the reactor.

(Problems to be solved by the invention) On the other hand, in a walking hearth type upper heating furnace, when heating a steel slab, the steel slab is heated from above and not from below. The temperature rises faster than the side.
Then, as shown in FIGS. 11 and 12, the steel piece may bend upward in an arcuate shape and may roll in the conveying direction. Due to this rolling, the billets are in a disordered state different from the aligned state at the time of charging, and there is a problem that the automatic extraction work at the outlet becomes difficult.

This invention makes it a technical subject to eliminate the above-mentioned conventional problems. That is, while maintaining the features of the upper firing type, the billet heads toward the outlet in an orderly state close to the aligned state at the time of charging, and a walking hearth type configured to facilitate automatic extraction work at the billet outlet. It is intended to provide an upper heating furnace.

(Means for Solving Problems) The present invention provides a steel slab charged from the above-mentioned inlet in an upper heating furnace having a steel slab inlet on one side and a steel slab outlet on the other side. A walking hearth configured to be conveyed toward the outlet is provided and provided, and the steel piece transferred from the inlet toward the outlet heats the steel piece from above in the conveying process to raise the temperature of the steel piece. In the above-mentioned walking hearth type heating furnace, in the above walking hearth, each of the walking hearths is provided with a plurality of billet reversal positioning portions for reversing the billet during conveyance by 180 degrees. In addition, the set position of each of the steel slab reversal positioning portions is set to a position where the temperature difference between the front and back of the steel slab reaches about 60 ° C during the process of successively raising the temperature while moving the steel slab in the transfer direction. So as to correct the warp bend One in which the.

(Operation) In walking hearth, the temperature difference between the top and bottom of the steel billet during transportation is about 60 ° C.
Flip over. Therefore, each steel slab is inverted by the upward warp before rolling from itself, the upper and lower temperature differences are corrected, and the bow-like upward warp does not occur.

(Example) Hereinafter, drawings showing an example of the present application will be described. The members denoted by reference numerals 1 to 14 in FIG. 1 are well known in this type of walking hearth type heating furnace, but will be briefly described. Reference numeral 1 indicates a heating furnace, 2, 3, 4 indicate in order a pre-tropical zone, a heating zone, a soaking zone, 5 indicates a burner position in the upper heating type, 6 indicates an outlet, and 7 indicates an inlet of a steel slab 14. 8 is a shift pusher, 9 is a charging roller, 10 is a billet outlet, and 11 is an extraction roller. Reference numeral 12 denotes a walking hearth, which is composed of a fixed hearth 16 and a movable hearth 17, which are shown in the following figures, arranged side by side. Reference numeral 13 indicates the existing positions of a member that supports the fixed hearth and a member that supports and drives the movable hearth. The walking hearth type heating furnace described above is a simplified example, but in the present case, a walking hearth type heating furnace having another configuration can be implemented if a walking hearth exists.

Next 15 should be part of the walking hearth,
The setting place of a billet reversal positioning part is illustrated. This place should be set in consideration of the following circumstances, but the number is 2
~ 6 places are good. First, the relationship between the furnace temperature in the heating furnace shown in FIG. 1 and the temperature difference between the upper and lower parts of the steel slab 14 is the relationship shown in FIG. 2 shown in the lower part of FIG. Note the positional relationship between the figure and FIG. That is, the furnace temperature in the heating furnace changes from the inlet 7 to the outlet 10 as shown in FIG. The difference between the upper and lower temperatures of the steel slab is as shown in Fig. 2 in relation to the heating time. In the above case, assuming that the billet is not reversed in the billet reversal positioning portion 15, the temperature relationship shown by the broken line in FIG. 2 is obtained, and if the temperature difference between the top and bottom of the billet becomes large, the warp bends as shown in FIGS. 11 and 12. ,
May rotate on its own axis. However, as shown in the figure, when the billet reversal positioning part is placed at a position where the temperature difference between the front and back sides of the billet is approximately 60 ° C and the billet is inverted there, the temperature relationship shown by the solid line in Fig. 2 results, and the vertical temperature difference There is little warpage and there is no danger of rotation. In addition, the phenomenon of the above warp is
It varies depending on the sectional area, length, and material of the billet. Some steel sheets do not roll even if the temperature difference between the top and bottom of the steel is 100 ° C, but if the temperature difference is kept at 60 ° C, rolling does not occur.

Next, an example of the configuration of the billet reversal positioning portion for reversing the billet will be described with reference to FIGS. 3 to 6. Reference numerals 161-169 indicate the upper surface of the fixed hearth 16, and 171-179 indicate the upper surface of the movable hearth 17. The movable hearth 17 is shown in FIG.
Is repeated as one cycle, and the steel pieces 14 (A to F materials) move one after another in the direction of the arrow 19 by the movement (the range of movement shown is, for example, the lift 18 is 20).
0mm and Travel 19 is 280mm). Therefore, the third
When the movable hearth is operated in the order from FIG. 6 to FIG. 6, for example, the C material rides on the slope 172 between FIGS. 3 to 4 and is positioned (corrected) by the presence of the stopper 173. Next, in FIG. 5, it is located above the corner 164 and descends in the direction of the arrow 20 to move to the slope 165 and tilt 90 degrees as shown to ride on the receiving surface 167. After that, it moves to the place of D material and E material in order.
Further ahead, if there is a structure similar to that of FIGS. 3 to 6, C
All slabs, including wood, will roll an additional 90 degrees and eventually flip 180 degrees.

Next, the example shown in FIGS. 7 to 10 shows another configuration in which the steel piece 14e is inverted by 180 degrees. That is, A material is 1 cycle
Roll 90 degrees. Then, in the next one cycle (position of the C material), it further rolls 90 degrees.

It is to be noted that the portions which are functionally considered to be the same as or equivalent to those in FIG. 3 to FIG.

(Effects of the Invention) As described above, according to the present invention, the above billet is heated with high thermal efficiency (low fuel consumption rate) while being transported by the walking hearth in the upper heating furnace. There is an effect that can be.

Moreover, even in a furnace that can raise the temperature of the billet in the state where the basic unit becomes low as described above, in a place where the temperature of the upper side of the billet is greatly increased compared to the lower side during transportation, It reverses at the provided billet reversal positioning part, and the temperature difference between the upper and lower sides is corrected each time, and as a result, there is an effect that the rolling of the billet due to the warp bending that has occurred conventionally is prevented. . This prevents the automatic extraction work at the extraction end of the upper-burning heating furnace from becoming difficult, and is effective in further improving the usability of the above-described upper-burning heating furnace having good thermal efficiency.

[Brief description of drawings]

The drawings show the embodiments of the present application. FIG. 1 is a vertical cross-sectional view showing the position of a steel bill reversal positioning portion using a walking hearth type heating furnace of a conventional example, and FIG. 2 shows temperature and heating time. A graph showing the relationship, FIGS. 3 to 6 are explanatory views showing the operation in the billet reversal positioning portion, FIGS. 7 to 10 are explanatory views showing other operation examples, and FIG. 11 and FIG. The front view and perspective view which show the warp bending of a steel piece. 1 …… Heating furnace, 12 …… Walking hearth, 14 …… Steel, 15 …… Steel reversal positioning part.

Claims (1)

[Claims] Claim: What is claimed is: 1. A steel slab charged from the inlet is conveyed to an outlet in an upper heating furnace having a steel slab inlet on one side and a steel slab outlet on the other side. A walking hearth is provided with a structured walking hearth, and the steel piece to be transferred from the inlet to the outlet is heated on the above-mentioned steel piece from above during the conveying process to raise the temperature of the steel piece. In the above-mentioned walking hearth in a heating furnace with a heating furnace, a plurality of billet reversal positioning portions are provided in the transport direction, each of which is designed to flip the billet during transport 180 degrees. The setting position of the positioning part is set so that the temperature difference between the front and back of the steel slab reaches approximately 60 ° C during the process of sequentially raising the temperature while moving the steel slab in the transfer direction so as to correct the upward warp. War that is characterized by焚式 heating furnace on the type Nguhasu.