JPS6237091B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is used by being attached to a direct rolling equipment for slab materials, in which continuously cast slabs are kept in a coiled state and kept on standby in a heat-retaining state. This relates to a coil heat retention furnace that discharges according to requests for plate width products.

[Prior art]

BACKGROUND ART Conventionally, a technique for obtaining wide thin plate products by direct rolling after continuous casting is known. In this case, the cast material is cut into lengths of 5 to 12 meters (weighing 5 to 45 tons), then heated and soaked, and then rolled in hot rolling equipment according to the width of the product dimensions. ing. By the way, in continuous casting equipment, generally the slab thickness is 200 to 250 mm and the width is 900 to 2000 mm.
A slab with a cross section of mm is produced. This slab is cut into lengths of 5 to 12 m on a continuous casting line. The cut slabs are heated again in the heating furnace of the hot rolling equipment to a temperature suitable for hot rolling (1200°C for ordinary steel), then reduced to a thickness of 30 to 60 mm in a rough rolling mill, and further heated. 1 to 25 on finishing tandem rolling mill
Roll to a thickness of about mm. Then, after winding it into a coil shape with a down coiler, it is supplied to the next process.

On the other hand, since the slab material after continuous casting is cut into a large number of slabs, the surface area of the cut slabs becomes enormous, and the sensible heat of the slabs is taken away by the atmosphere. As a result, the temperature of the cast slab, which was about 1200℃ when it was cut, drops to about 900℃, and in this low temperature state it is inserted into the heating furnace and heated again. Become. Therefore, in the heating furnace, the slab must be reheated from around 900°C to around 1200°C to make it ready for hot rolling.

However, the heat loss from the exhaust gas and furnace wall increases as the high-temperature section is heated, so as mentioned above, the slab is
30 per ton to raise the temperature from 900℃ to 1200℃
10,000 Kcal of heat is required. Therefore, equipment that employs the above-mentioned mold cutting method has the disadvantage that the amount of heat lost is enormous.

Therefore, in order to eliminate the above-mentioned conventional drawbacks, the applicant maintains the slab temperature as much as possible at a temperature suitable for the next process of hot rolling, and eliminates or minimizes the need for reheating the slab. We proposed continuous rolling equipment (patent application 1984-40952) that could significantly save energy. In this proposal, the casting material is directly rolled to a certain thinness and then wound into a coil shape so that it can be kept warm in this state. There was a problem when taking it out.

In other words, the width and quantity of the final product of wide thin sheets vary depending on demand. Therefore, a production plan corresponding to this is required even in continuous casting at the material stage.
Slab width changes are made. Therefore, even in the step of hot rolling from the coil, it is desirable to roll the slabs in the order in which they are continuously cast, in order to suppress the drop in slab temperature. By the way, the purpose of providing a coil heat retention furnace is to temporarily store hot slab material in case of discrepancies in operating timing between the continuous casting machine and the hot rolling mill. It is desirable to be able to carry out hot rolling operations even when the hot rolling mill is temporarily stopped, and conversely to be able to continue production in the continuous casting machine even if the hot rolling mill is temporarily stopped.

For this reason, the coil heat retention furnace needs an accumulator function and a heating function to prevent the temperature of the coil from decreasing due to excessive waiting time. Therefore, if a new high-temperature coil is inserted into the heat retention furnace while another coil is being heated, energy savings can be improved by supplying this high-temperature coil to the hot rolling mill by skipping over the coil currently being heated. However, in the above proposal, a so-called walking beam method is adopted, and the coils to be rolled are delivered in a continuous manner, so it is difficult to select and extract the necessary coils in this coil heat retention furnace. There was a drawback. In addition, so-called walking bar type heat retention furnaces that perform sequential discharging require a complicated mechanism for skipping, and furthermore, such a mechanism has a short lifespan in a high-temperature atmosphere, resulting in low equipment costs. The disadvantage was that running costs increased.

[Purpose of the invention]

An object of the present invention is to provide an economical coil heat retention furnace for direct rolling equipment that can unload loaded coils in any order.

[Summary of the Invention] The present invention provides a coil heat retention furnace in which a plurality of coils are temporarily loaded and heat-retained. The above object is achieved by rotating and discharging any one of the coils to the discharge port.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an embodiment of a thin plate direct rolling facility having a coil heat retention furnace according to the present invention.
The continuous casting equipment 1 turns the obtained thin slab material into a coil shape, and once loads this coil into a coil heat retention furnace 2. The coils loaded in the coil heat retention furnace 2 are supplied to the entry side of the finishing tandem rolling mill 4 of the hot rolling equipment 3 as required. In the hot rolling equipment 3 in this example, a rough rolling mill 5 is installed upstream of the finishing tandem rolling mill 4. FIG. 2 is a schematic side view of the continuous casting equipment 1 shown in FIG. 1 above. Molten steel is once appropriately poured from a ladle 6 into a tundish 7, and then continuously poured into a continuous casting machine 8 below, whereby a slab material shaped into a predetermined mold cross section is drawn out. The dimensions of the mold of continuous casting machine 8 are 60 to 100 mm thick.
The dimensions are such that a slab material having a cross section with a width of about 900 to 2000 mm is formed, and a synchronous mold, for example, capable of high-speed casting is used. In this case, if high-speed casting of thin slab material is possible,
Any type of casting machine is acceptable.

Molten steel poured into the continuous casting machine 8 is cooled and shaped by a mold, and the inside is drawn out as an unsolidified slab 9. In this case, the solidified thickness of the slab 9 on the exit side of the mold is approximately 10 to 20 mm. For this purpose, the slab 9 is passed through a spray cooling body 10 in order to completely solidify the slab 9. The spray cooling body 10 supports and cools the slab 9. The slab 9, which has solidified almost to its internal center, then enters an adiabatic furnace 11 to uniformize its temperature. Next, the slab 9 is horizontally rolled in an in-line mill 12 to adjust the thickness and to compress center porosity that often occurs inside the slab.
The thickness of the slab 9 after horizontal rolling is 40 mm, which is suitable for winding.
Good condition. The slab 9 that has come out of the in-line mill 12 passes through a running shearer 13 and an adiabatic furnace 14, is bent by bending rollers 16, and is then wound into a coil by a winder 17. The slab 9 is divided by the running shearing machine 13 so that the weight of the coil wound in this way is about 5 to 45 tons,
After dividing, the coiling speed is increased and further coiling is performed by a winder 17 to minimize the temperature drop of the slab 9 due to heat radiation. Incidentally, the adiabatic furnace 14 serves to prevent the temperature from decreasing when the slab 9 is wound up.

Thin slab coil 1 manufactured as above
8 is loaded into the coil heat retention furnace 2 and temporarily stored there. Note that illustration and description of a device for transporting and loading the coil 18 into the coil heat retention furnace 2 will be omitted.

FIG. 3 shows details of an embodiment of the coil heat retention furnace of the present invention. Rail laid in a circle 1
An annular trolley 20 serving as a coil holding section is movably mounted on 9 via wheels 21 . This cart 20 is connected via a beam 24 to a turning center shaft 23 that is rotated by a motor 22.
The truck 20 is moved to the rail 19 by the driving force of the motor 22.
The top can be manipulated. The rotation center shaft 23 is rotatably supported by a bearing 25. Further, a V-shaped pedestal 26 for supporting the coil 18 is provided on the upper part of the truck 20. Furthermore, trolley 2
The upper part of 0 is covered by an annular heat retaining wall 27, and this heat retaining wall 27 is provided with a coil inlet 28 and a coil outlet 29 as shown in FIG. In the coil heat retention furnace 2 having such a structure, only the cart 20 on which the coils 18 are loaded rotates to select the coils 18 of desired strip width to be supplied to the finishing tandem rolling mill 4 and move them to the coil outlet 29. The pedestal 2 is unloaded and the coil 18 is not loaded.
6 is placed on the coil loading port 28 side to load a new coil 18. Such a coil heat retention furnace 2 is used to raise the temperature inside the furnace and to keep the coil 18 warm for a long time. A heater (not shown), for example a heavy oil burner, is installed. Also, the size of the coil heat retention furnace 2 can be set in any way depending on the specifications of the rolling equipment, but if it is, for example, about 20 m in diameter and 2 m in height, it will normally store about 30 coils. This makes it possible to sufficiently absorb production volume discrepancies and troubles between the continuous casting equipment 1 and the hot rolling equipment 3. In addition, the hot rolling equipment 1 generally has a capacity of 200,000 to 300,000 tons/month, whereas the conventional continuous casting equipment 1 has a capacity of 50,000 tons/month.
Since the production capacity is approximately 100,000 tons/month, two to four continuous casting facilities are normally installed to balance production capacity. On the other hand, high-speed continuous casting of thin slabs
Since a casting speed of 10 to 15 m/min is possible, if the slab size is 80 mm thick x 1200 mm wide, it has a production capacity of 200,000 to 300,000 tons/month, which is sufficient even with one continuous casting machine. I can do it.

During actual operation, troubles in the continuous casting equipment 1 often occur and production is temporarily stopped.
Further, in the hot rolling equipment 3 that follows this, it is necessary to rearrange the rolling rolls every few hours, and production is temporarily stopped. Furthermore, these production suspension periods do not necessarily coincide due to their nature. For this reason, it is essential to provide the above-mentioned coil heat retention furnace 2 to temporarily store the coil 18.

Now, the coil 18 temporarily stored in the coil heat retention furnace 2 is transferred to the finishing tandem rolling mill 4 as shown in FIG.
The down coiler 32 shown in FIG. It is wound up again into a coil shape and transported to the next process. As mentioned above, the thickness of the product plate at this time is about 1 to 10 mm.

According to this embodiment, the heat retention furnace 2 has a circular rail 1
The coil 18 can be loaded onto a trolley 20 that rotates on the top of the coil 18, and if necessary, the trolley 20 can be rotated to move any coil 18 to the coil exit 29 and unload it. Mouth 2
8, it has the effect that it can be dispensed in any order, regardless of the order in which it was loaded. Therefore, the heat retention furnace 2 can retain the heat of the coil 18 and supply the desired coil 18 to the finishing tandem rolling mill 4 without heating it, which of course has an energy saving effect. As described above, since any coil 18 can be supplied to the finishing tandem rolling mill 4, it is possible to discharge the high temperature coil 18 as needed, thereby achieving further energy saving effect. Moreover, as shown in FIG. 3, the coil heat retention furnace 2 has a simple structure including the rail 19, the trolley 20, the heat retention wall 27 of the motor 22, etc., so that the above effects can be realized economically. can be,
It also has the effect of being highly reliable. Furthermore, as a matter of course, the coil heat retention furnace 2 of this embodiment temporarily stores the coils 18 depending on the operating status of the continuous casting equipment 1 side and the hot rolling equipment 3 side, so the operating rate of the entire equipment can be reduced. It has the effect of improving

In addition, in the above example, the case where one continuous casting machine is used was explained, but since troubles in continuous casting machines are often sudden such as solidification, breakage, and outflow of molten steel, it is necessary to obtain stable production capacity. The present invention can also be applied to equipment equipped with a plurality of continuous casting machines. Further, the same effect can be obtained by using a plurality of coil heat retention furnaces depending on the number of storage units and ensuring the coil movement of each heat retention furnace by appropriate means.

〔Effect of the invention〕

As described above, according to the coil heat retention furnace of the direct rolling equipment of the present invention, by making the heat retention furnace a rotating type, loaded coils can be taken out in any order, resulting in an economical energy saving effect. can be realized.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an embodiment of direct rolling equipment equipped with a coil heat retention furnace of the direct rolling equipment of the present invention, and Fig. 2 shows a detailed example of the continuous casting equipment shown in Fig. 1. 3 is a block diagram showing an embodiment of the coil heat retention furnace of the present invention, and FIG. 4 is a block diagram showing a detailed example of the finishing tandem rolling mill shown in FIG. 1. 1... Continuous casting equipment, 2... Coil heat retention furnace, 3
...hot rolling equipment, 4...finishing tandem rolling mill,
9...Slab, 18... Slab coil, 19...Rail, 20...Dolly, 22...Motor, 23...Swivel center axis, 24...Beam, 27...Heat retaining wall, 2
8...Carry-in entrance, 29...Carry-in exit.

Claims (1)

[Scope of Claims] 1. In a coil heat retention furnace where a plurality of slab coils produced by continuous casting equipment are temporarily loaded and heat-retained and then supplied to hot rolling equipment, the periphery is covered with a heat-retaining wall. A rotatable annular coil holding part is provided,
A coil maintenance device characterized in that a slab coil inlet and an outlet are formed in the heat retaining wall, and a sending means for delivering the slab coil to the outside of the heat retaining wall is provided in correspondence with the outlet. Heat furnace. 2. The coil heat retention furnace according to claim 1, wherein the coil holding section is comprised of a truck movably supported on a circular rail.