JPH0310685B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for extracting steel billets in a continuous heating furnace, in which steel billets are charged in double rows in the furnace, heated efficiently, and steel billets are efficiently extracted at regular intervals. This is intended to provide a method that can be used.

Extracting steel slabs by heating in a continuous heating furnace has been widely practiced in the past, and as is generally known, the method is to use a walking beam consisting of a fixed beam and a moving beam (walking beam). In a type continuous heating furnace, the moving beam is raised or lowered by an eccentric cam or diagonal rail installed at the bottom of the furnace body, and is also moved forward or backward by hydraulic or electric power provided independently of these mechanisms. , 1st
By repeating the rectangular movements of ascending a, advancing b, descending c, and reversing d as shown in the figure with respect to the fixed beam path lines e...e, the steel material is sequentially advanced toward the extraction side. By the way, in the forward and backward movement of such a moving beam, there is a limit to the amount of movement that can be made in one operation (one cycle in Figure 1) due to constraints such as cylinder stroke. The maximum amount of advancement per cycle in a beam furnace is about 700 mm. In addition, the dimensions of the steel billets charged into the heating furnace vary; for example, in large steel factories that roll H-beams of various sizes, steel billets with a width of about 1400 mm are cut from blooms, which are about 200 mm wide. In order to efficiently heat not only the top and bottom surfaces but also the side surfaces, these steel slabs are charged and heated at appropriate intervals smaller than the width of the steel slabs. This interval varies depending on the effective length of the heating furnace, the number of heated tubes per hour, the heating temperature, etc., but is generally about 50 to 200 mm.

For example, in Fig. 2, a 500mm width (W) steel piece 11
When charged with a spacing (s) of 150 mm, the charging pitch (P) is 650 mm (hereinafter, in this specification, the charging pitch (P) is the billet width (W)).
Assume that the steel slab spacing (s) is added to: P=W+
s) Yes. Furthermore, the length of the steel slab 11 is also variable; for example, in a heating furnace with an effective furnace length of 10 m, a steel slab of approximately 3.5 m to 10 m is appropriately selected depending on the desired length of the final rolled product. (Since the moving beams and fixed beams are both arranged at fixed intervals, objects shorter than a certain length cannot move forward due to the rectangular movement of the moving beams.) Here, conventionally, the length of the steel slab is less than 1/2 of the effective furnace length (in a heating furnace with the above-mentioned effective furnace length, it is 5 m or less, but in reality, it is about 4.8 m or less due to some safety considerations). As shown in FIG. 3, charging is carried out in double rows in the width direction of the furnace, that is,
By increasing the number of steel slabs 11 charged into the heating furnace and increasing the time each steel slab spends in the furnace, the aim is to utilize the heating furnace more efficiently and to reduce the fuel consumption rate. However, in order to extract the steel billet as described above, conventionally the steel billet is first advanced to an appropriate position as shown in FIG. 4 (as shown in FIG. 4-A), and then the steel billet 2 is
1 is extracted, and then a steel piece 22 is extracted as shown in FIG.
The operation of the moving beam (specifically, the advancement of the steel piece) is controlled by turning ON and OFF. In other words, detector 1
In the 2ON state, there is a piece of steel at the extraction position, so there is no need to operate the moving beam, and the moving beam moves forward with the detector 12 OFF, and repeats the operation until the tip of the piece of steel turns the detector 12 ON. It is something. That is, at the stage when the steel piece 21 is extracted, the steel piece 22 is still at the extraction position, so the moving beam is not activated, and at the stage when the steel piece 22 is extracted, the detector 12 is turned off and the moving beam is moved to the position shown in FIG. Start like C. By the way, in order for the next steel billet 23 (or 24) to reach the position of the detector 12 due to such operation of the moving beam, in the case of the charging pitch P as described above, a forward movement of 650 mm is required.
Now, assuming that the maximum amount of movement per operation of the moving beam, which is generally operated based on the width of the steel piece, is 500 mm, in one cycle of operation by the moving beam, as shown in Fig. 4D, the detector 12 is turned OFF. It remains as it is and one more cycle of operation is required. In other words, since the moving beam moves the steel piece forward by 500 mm in the first operation, the detector 12 turns ON when the steel piece moves forward by 150 mm in the second operation, and at this stage, the steel piece 23 is extracted as shown in Figure 4E. This makes it possible to extract the steel piece 24 next time without requiring the moving beam to advance the steel piece 24.

However, as shown in Fig. 1, when the moving beam operates in the cycle of ascending a → forward b → descending c → backward moving d, it usually takes about 40 to 70 seconds. Now here's an example of rising 20
If it takes 10 seconds to move forward, 20 seconds to descend, and 10 seconds to move backward, then one cycle is 60 seconds, and from the time when the steel piece 21 is extracted until the time when the steel piece 22 is extracted. No operation is required, and the required extraction time is usually about 50 seconds, depending on the cycle time of incidental equipment such as extractors and rolling equipment used in the next process. On the other hand, in order to start extracting the steel pieces 23 after extracting the steel pieces 22, it is necessary to operate the moving beam twice, so a time of 60 seconds x 2 (times) = 120 seconds is required. Therefore, the extraction time cycle for each billet is 50 seconds → 120 seconds → 50 seconds → 120 seconds, but generally speaking, considering the capacity of the rolling equipment after the heating furnace, The variation in the extraction time cycle for each billet is extremely unreasonable, and for this reason, a uniform speed must be adopted for the operation of the rolling equipment, so in the end, the extraction time cycle of the heating furnace is 120 seconds. You will be forced to choose. However, it is clear that such a situation significantly lowers the working efficiency of the continuous heating furnace and is also undesirable in terms of fuel consumption, and it goes without saying that it is preferable to equalize the extractable time cycle for each billet.

The present invention was devised after consideration to solve the above-mentioned problems with conventional products, and its gist is to install steel materials in double rows in a walking beam continuous heating furnace. The steel materials charged in double rows are heated with an interval smaller than the width of the steel materials, and the charging pitch of the steel materials is adjusted in each charging row to 1 of the maximum movement amount per moving beam in the heating furnace. The method is characterized in that the moving beam is operated once every time one steel piece is extracted, and the steel pieces are sequentially extracted.

That is, FIG. 5 shows one embodiment of the extraction method according to the present invention, and in this FIG.
Reference numeral 13 indicates a steel billet position detector (in this case, using gamma rays), and the most efficient mounting position is about 750 mm from the furnace wall in extracting the billet as described above. In this example, the effective reactor length is 10 m, and the moving beam is
Steel slabs with a width of 500 mm and a length of 4.8 m are placed in a walking beam continuous heating furnace with a maximum forward movement of 500 mm per cycle.
We will discuss the case of charging in double rows in the width direction with an interval of 150 mm (that is, a charging pitch of 650 mm). However, it is clear that the present invention can be applied without departing from its essential features, and for example, a walking hearth type furnace with a moving hearth similar to a walking beam type furnace may be used without any problem. Of course, each of the dimensional conditions described above can be modified as appropriate.
However, in the case shown in Fig. 5 above, as the steel billet moves forward, the detector 13 is turned on, and the forward movement of the moving beam stops at this point, and the steel billet enters the standby state as shown in Fig. 5A. . Next, the steel slab 31 is extracted out of the furnace as shown in Fig. When the extraction end signal of the steel piece 31 is detected, the moving beam moves forward at its maximum stroke amount (ie, 500 mm), and stops when the rear end detection signal of the steel piece 32 is detected, as shown in FIG. 5C. However, when the extraction of the subsequent steel pieces 32 is completed as shown in FIG.
(or 34) is stopped as shown in FIG. 5E when it advances to the ON state of the detector 13.

That is, according to the extraction method of the present invention, the moving beam operates only one cycle each time one steel piece is extracted, and the two-cycle operation as in the conventional method described above is eliminated. In other words, after extracting the steel piece 31,
The moving beam operates for one cycle (two cycles according to the conventional method) until the steel piece 33 is extracted.
Therefore, the extractable time cycle for each steel slab is also equalized, and it becomes possible to extract all pieces with a cycle pitch of 60 seconds.

FIG. 6 shows another embodiment according to the present invention, in which the steel billets are charged in a staggered manner in the width direction of the furnace as shown in the figure. It is recommended that the single-position detector be installed approximately 100mm from the furnace wall.

However, in FIG. 6A, the steel piece 41 moves forward and the detector 1
3 is turned ON, indicating that it is in a stopped state. From this state, as shown in Figure B, after extracting the steel piece 41, the detector 13 turns OFF, and the moving beam starts operating, and the steel It operates as shown in FIG. 6C until the piece 42 stops with the detector 13 ON. If the amount of displacement between the steel pieces 41 and the steel pieces 42 in this state is set to 325 mm as shown in Fig. 7, the amount of advance of the moving beam will be 325 mm, which is less than the maximum amount of movement, so the moving beam will move the specified amount in one cycle. It is possible to advance the billet into position.

Next, the moving beam starts operating again in response to the OFF signal of the detector 13 after extracting the steel piece 42 as shown in FIG. 6D, and the moving beam starts operating again as shown in FIG. However, in this case as well, the amount of advancement of the moving beam is 325 mm, which is less than the maximum amount of movement, so one cycle of operation is sufficient.
In the case of this embodiment as well, since the moving beam operation cycle for each piece of steel is one cycle, the possible extraction cycles are equalized and extraction can be made every 60 seconds.

According to the present invention as described above, the extraction time cycle of this type of continuous heating furnace, which conventionally required time for two cycles of the moving beam during double-row charging, can be reduced to one cycle. Because it can be carried out smoothly in an operating time of
This invention is industrially extremely effective because it improves work efficiency (and by extension, rolling efficiency) and also makes it possible to reduce the fuel consumption rate in this type of heating furnace.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, and FIG. 1 is an explanatory diagram showing the operational relationship of a moving beam in a continuous heating furnace, FIG. 2 is an explanatory diagram of the arrangement spacing of steel slabs, and FIG. Figure 4 is an explanatory diagram showing the relationship between charging multiple rows of steel slabs in a furnace according to the conventional method, Figure 4 is an explanatory diagram showing the operation cycle relationship of pitches or moving beams step by step, and Figure 5 is an explanatory diagram showing stepwise the relationship between the operation cycles of the pitch or moving beam. FIG. 6 is an explanatory diagram showing the same relationships as in FIG. 4 in stages for an embodiment; FIG. 6 is an explanatory diagram showing the same relationships as in FIGS. 4 and 5 for another embodiment of the present invention;
FIG. 7 is an explanatory diagram of a concrete arrangement pitch relationship of steel pieces in the case of FIG. 6. In these drawings, 12, 13 are detectors, 21-26, 31-36 and 41-46.
Both indicate steel pieces.

Claims (1)

[Claims] 1 Steel materials are charged in double rows into a walking beam type continuous heating furnace, and the steel materials charged in the double rows are heated with an interval smaller than the width of the steel materials, and the charging pitch of the steel materials is adjusted in each charging row. The maximum movement amount per movement of the moving beam in the heating furnace is more than 1 times and less than 2 times, and the moving beam is operated once every time one piece of steel is extracted to sequentially extract the pieces of steel. Method for extracting steel billets in a continuous heating furnace.