JPS6034016Y2 - Intermediate charging type walking type heating furnace - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intermediate charging type walking type heating furnace having a heating material charging port also in the middle of the furnace.

In general, a continuous heating furnace heats the steel billet that has been turned into a cold billet in order to hot-roll the slab-rolled billet (slab, bloom, billet) or the billet extracted from the continuous casting machine. The steel slabs are charged from the bottom of the furnace and transported to the extraction side while being alternately replaced between the movable hearth and the fixed hearth by the conveyance cycle of the movable hearth arranged in the longitudinal direction of the furnace. The steel billet is then reheated to the desired temperature and transported from the extraction port to the subsequent rolling mill.

If the steel slabs to be charged into the heating furnace have been heated in the previous step, it is desirable from the viewpoint of energy saving to charge them into the heating furnace as hot slabs without cooling them once.

Hot billets do not require sufficient heating like cold billets, so they are charged from the middle of the furnace rather than from the bottom of the furnace. An intermediate-charging type heating furnace has been proposed in which the cold steel billet may be charged from the middle part at a temperature equal to the temperature that the cold steel billet takes on while being conveyed from the bottom of the furnace to the middle part.

Figures 1 and 2 show an overview of the heating furnace.

In these figures, 1 indicates the heating furnace main body, 1a is the ceiling of the furnace, 2 is the furnace bottom charging port, 5 is the intermediate charging port, and 12 is the extraction port.

4 represents a fixed hearth surface, and 8°9 represents a movable hearth divided into two in the longitudinal direction of the furnace.

The movable hearth reciprocates in parallel and up and down directions with respect to the fixed hearth, and if we focus on one point on the hearth surface, it forms a rectangular loop, but the intermediate charging port 5 is located at the tip of the movable hearth 8 on the butt side. It is installed at a central position on the furnace side wall that is perpendicular to the reciprocating locus.

Further, a roller table 6 and a charging calf that can move forward and backward on the roller table are provided on the outside of the furnace wall of the intermediate charging port 5, and roller tables 15 and 16 are also provided at the furnace bottom charging port 2 and the extraction port 12.

Reference numeral 3 denotes a billet charging device installed at the bottom of the furnace, which includes a plurality of protruding rods that penetrate the furnace wall and protrude into the furnace.

A discharger 11 is provided opposite to an opening 12a provided in the furnace wall on the opposite side of the furnace head from the extraction port 12.

The cold steel billet is sent through the roller table 15 in the direction of the arrow and charged from the furnace bottom charging port 2 to the tail end of the fixed hearth in the furnace as shown by Ml.

In this example, the cold steel billets are billets, and two billets are charged at the same time.

After charging the cold steel billets to the tail end of the fixed hearth, the charging device 3 is activated, and the projecting rod of the device pushes the cold steel billets M toward the head of the column and moves them onto the tail end of the movable hearth 8.

This state is shown in FIG. 3 by a dotted line M1'.

In this state, the movable hearth 8 is lowered, moved laterally to the left in the drawing, raised (at this time, the cold steel billet M' is lifted up on the movable hearth 8), and moved laterally to the right ( At this time M1'
The cold steel pieces M□' are conveyed to the furnace head side by repeating the process of lowering (M1' is lowered onto the fixed hearth 4).

If the steel pieces are charged from the furnace bottom charging port, the split movable hearth 8,
9 perform the reciprocating motion as a unit to transport the steel pieces from the bottom of the furnace to the top of the furnace, during which time they are heated by the burner.

The heated steel pieces conveyed to the furnace head are pushed out by a discharger 11 and are carried out from an extraction port 12 through a table roller 16 to the next process.

The hot steel billets are charged into the furnace through the intermediate charging port 5.

The pigeons are loaded into the furnace with the hot billet on a roller table 6 and pushed by a charging calf, sliding over a fixed hearth.

At this time, the hearth surfaces of the movable hearths 8 and 9 are slightly smaller than the fixed hearth surface, for example, by 10 to 15 Trr! It stops at a position that is about n downwards and closer to the reactor head in its reciprocating locus.

The charging billet M2 and the movable hearth 8 are placed in a slightly lower position.
9 does not collide, and this position also exists when the reciprocating locus is closer to the bottom of the hearth, but in this case, the tip gap G1 of the movable hearth on the head side is different from that in Fig. 2. On the contrary, it is larger than the tail end gap G2 of the movable hearth on the tail side,
Since the temperature inside the furnace is higher on the furnace head side than on the furnace bottom side, this has the disadvantage of causing a large heat loss.

With the movable hearths 8 and 9 greatly lowered, and/or with the movable hearth 8 on the bottom side moved toward the bottom side to create a large gap between the hearths 8 and 9, the steel pieces are loaded from the intermediate charging port. It is for the same reason that it is not charged.

A walking-type heating furnace with a split hearth and an intermediate charging port is
Hot steel pieces are charged from the intermediate charging port. When charging, conveying, and heating the hot steel pieces from the intermediate charging port, the movable hearth on the bottom side of the furnace can be stopped.

However, the position and state of the intermediately charged steel slabs can be adjusted as desired, that is, in FIG. .4,8.
4... It is not easy to place them correctly orthogonally on top of each other.

That is, as shown in FIG. 4, the charging path 20 from the charging port 5 of the steel billet to the fixed and movable hearths in the furnace is such that the fixed and movable hearths 4.8 are arranged alternately, with gaps between them. The movable hearth has an uneven path that is slightly lower than the fixed hearth.

In addition, the intermediately charged steel billet is, for example, a hot steel billet extracted from the above-mentioned continuous casting machine, and because it is not cooled evenly during transportation, it may be placed upward or downward, or to the left or right. This may cause significant bending.

Furthermore, when the hot steel billet is extracted and cut, the cut portion may be deformed, and the tip of the steel billet may be bent downward as shown in FIG.

Also, depending on the weight of the steel billet and the fulcrum that supports it, the tip of the steel billet will move up or down.

When a steel billet that is bent due to these various reasons, especially a steel billet with a downwardly bent tip as shown in Fig. 3, is inserted in the middle,
The tip of the steel piece hits the charging side end of the fixed hearth 4 that protrudes from the movable hearth 8, causing difficulty in charging and damage to the fixed hearth.

The present invention is an attempt to improve this point, and includes an intermediate device in which the material to be heated is also charged between the bottom of the furnace where the material to be heated is charged and the head of the furnace from which the heated material is extracted. In a walking type heating furnace equipped with an inlet, the fixed hearth portion forming a heating material charging path extending from the intermediate charging port into the furnace across the fixed hearth and the movable hearth of the heating furnace. It is characterized by a slope that rises from below the surface of the movable hearth when viewed from the material charging side.

In this way, even if the tip of the steel piece is slightly bent downward, it is possible to avoid colliding with the fixed hearth or digging into the gap between the fixed and movable hearth.

Embodiments of the present invention are shown in FIGS. 5 to 7. In FIG. 5, the surface of the fixed hearth 4, that is, the material support surface, is a relatively large slope S1 on the material charging side, and a slope S2 with a gentle slope following the slope S1.

The charging side end W31' of the slope S1 is below the surface of the movable hearth 8.

In this way, the material support surface of the fixed hearth 4 becomes an inclined surface that rises above the movable hearth surface from the same level as the movable hearth surface or an even lower level when viewed from the charging side, and the charged steel Even if the tip of piece M2 is slightly bent downward as shown in the figure, the tip rests on the inclined surface of the fixed hearth and does not collide with the side of the fixed hearth, and as it is pushed, the tip of the corner of the steel piece M2 The movable hearth slides on the fixed hearth surface while being lifted by the surface, and moves relatively smoothly to the next movable hearth and the fixed hearth beyond that.

A slope S3 is also formed at the charging side end of the fixed hearth 4 including the furnace side wall, which corresponds to the above-mentioned S1, and facilitates charging of the steel billet into the furnace from the table roller.

6 and 7 show other embodiments of the present invention, in which the charging side of the fixed hearth 4 is chamfered.

S. is the slope created by the chamfering, which corresponds to S1 in FIG.

That is, in this example, there is no slope S2 with a gentle slope following the slope S1 with a relatively large slope, but only a slope with a relatively large slope and formed only on the charging side of the surface of the fixed hearth.

In FIG. 7, the fixed hearth surface is an inclined plane S5 with a single slope.

The charging side end of this plane is also set below the surface of the movable hearth, and the opposite side is set higher than that, that is, the height is such that the above-mentioned step at the time of charging can be secured.

According to the experimental results, FIG. 5 shows the best results.

However, if the width of the hearth is narrow, it is not easy to process the two planes, so the chamfering method shown in FIG. 6 is advantageous.

Note that the corners formed at the beginning and end of the slope may be rounded, or the entire fixed hearth surface may be a curved surface similar to the shape shown.

In this way, it is possible to prevent the tip of the intermediately charged billet from getting caught in the fixed hearth, but the intermediately charged billet must be charged almost perpendicular to the conveying direction, and this perpendicularity must be maintained. The entrance path 20 is secured by a method such as making a depression.

Therefore, the fixed hearth surface shape of the present invention is that in the cross section in the width direction of the hearth, and three-dimensionally it is implemented in a form that is synthesized with the recess.

If the charged steel billet is bent downward as shown in Figure 4 or Figure 5, it will not get caught in the hearth if it is reversed, that is, charged with the tip bent upward.

Although this is given as a work instruction,
It is troublesome to observe the shape of the tip of the steel billets that are being conveyed one after another and then charge them as they are or inverted, so it is desirable to develop a method that does not cause any problems even if they are charged as they are. .

As explained above, according to the present invention, even if a material that is slightly bent downward is charged, its tip will be guided to the material support surface of the hearth, so it will not get caught on the hearth or get wedged between the hearths. This prevents damage to the hearth, and also avoids situations in which the material cannot be charged.

Although the above description has been made regarding a walking berth type heating furnace, the present invention can also be applied to a walking beam type heating furnace.

Furthermore, the movable hearth may not be of the two-divided type as shown in FIGS. 1 and 2, but may be of a non-divided type in which these two parts are integrated.

[Brief explanation of drawings]

Figures 1 and 2 are schematic vertical cross-sectional views of a split hearth type walking type heating furnace with an intermediate charging port, which is an embodiment of the present invention. Figure 3 is a diagram illustrating the charging state of billets, and Figure 4 is FIGS. 5 to 7 are explanatory diagrams of the problems that occur in the case of intermediate charging, and are explanatory diagrams of the main parts of the present invention. In the drawing, M19M2 is the material to be heated, 1 is the walking type heating furnace main body, 5 is the intermediate charging port, 20 is the material to be heated passage, 4
is a fixed hearth, 8 and 9 are movable hearths, and S1 to S5 are slopes.

Claims (1)

[Scope of utility model registration request] In a walking heating furnace equipped with an intermediate charging port for charging the material to be heated between the bottom of the furnace where the material to be heated is charged and the head of the furnace from which the heated material is extracted, there is no flow inside the furnace from the intermediate charging port. (f) a slope rising from below the surface of the movable hearth when viewed from the heated material charging side of the fixed hearth portion forming a heated material charging path extending across the fixed hearth and the movable hearth of the heating furnace; An intermediate charging type walking type heating furnace characterized by the following.