JPS645964B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Field of Application" The present invention relates to a device for heating the end of a slab, and more particularly to a device for heating slabs, billets, etc. continuously cast in continuous casting equipment. When the slab is subsequently transferred to a hot rolling facility for rolling, the end portion of the slab where the temperature tends to drop is heated during the transfer to the hot rolling facility, and the temperature is re-heated to a temperature suitable for hot rolling. The present invention relates to an end heating device for a slab having good thermal efficiency and configured to raise the temperature.

``Prior art'' In continuous casting equipment, slabs, billets, etc. that are continuously cast directly from molten metal are transferred to hot rolling equipment while the high temperature during casting is still maintained. From the viewpoint of energy saving, it is desirable to hot-roll the cast slab after the continuous casting process, and a continuous rolling method in which the slab is hot-rolled following the continuous casting process has recently been widely adopted.

"Problem to be Solved by the Invention" By the way, in order to hot-roll a slab, the material temperature of the slab in the hot rolling equipment is generally
It is required that the slab be uniformly heated to over 1000℃, but while the slab is transported from the continuous casting equipment to this hot rolling equipment, it partially loses heat and the temperature drops, and if it is not heated as it is, Direct hot rolling is not possible. For example, as shown in Figure 1, the thickness is 200mm,
Assuming a continuously cast slab with a width of 1600 mm, the slab 10
The temperature distribution of the slab at the time when it is transported from the continuous casting equipment and reaches the hot rolling equipment is as shown in the figure, and the temperature at the end a and corner b in the width direction is
Ta, Tb, and the temperature Tc at the center of the upper surface of the slab are lower than the center temperature Td, and the temperature conditions are unsuitable for direct hot rolling as it is. Conventionally, therefore, a gas heating device or an induction heating device was installed between the continuous casting equipment and the hot rolling equipment to reheat the ends of the slab, where the temperature tends to drop, to a temperature suitable for hot rolling. Methods for raising the temperature are used, but the former often has a structure in which the burner simply faces the end face of the slab, resulting in poor heat transfer efficiency and high fuel costs, while the latter has relatively good thermal efficiency but requires very high equipment costs. The problem was that it was expensive.

``Object of the Invention'' The end heating device for a slab according to the present invention has been devised to overcome the above-mentioned difficulties, and is capable of easily reducing the temperature of a slab even with extremely good thermal efficiency. To provide an energy saving oriented slab end heating device capable of rapidly raising the temperature of the slab to a temperature suitable for hot rolling by intensively heating the end region, and requiring only a small equipment area. With the goal.

"Means for Solving the Problem" In order to achieve this object, the end heating device for a slab according to the present invention is provided in the longitudinal direction where the temperature of a long slab that is conveyed on a large number of rollers is likely to drop. The longitudinal edges of the slab are placed in a pair of heating blocks which can surround both ends so as to be freely movable and are arranged facing each other so as to be able to approach and move away from each other in order to match the width dimension of the slab. A pair of combustion heating chambers are formed by arranging burners oriented toward the respective combustion heating chambers, and above and below the traveling areas of the slab at both ends where the temperature of the slab tends to drop in each combustion heating chamber is made of a breathable solid material. A feature is that a radiation promoting plate is provided respectively.

In this case, if a flame distribution plate made of a fire-resistant material is arranged in the area defined by the upper and lower radiation promoting plates of the combustion heating chamber, the heating of the corners of the slab can be further promoted. suitable.

Embodiments Next, a preferred embodiment of the slab end heating device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a perspective view showing a schematic overall structure of an end heating device according to the present invention, and this heating device is installed between a cutting device and hot rolling equipment installed after continuous casting equipment (not shown). installed on the slab conveyance line. That is, a slab 10 (slab here) continuously produced in a continuous casting facility is carried in the direction of the arrow by a roller 14 whose both ends are supported by bearings 12 and which is rotationally driven by an appropriate power source. There is. A device of the present invention consisting of a pair of heating blocks 16, 16 configured to be able to approach and move away from each other is disposed in the width direction of the slab 10, and a plurality of this device are sequentially installed in the conveying direction of the slab 10. is preferable. As clearly shown in FIG. 3, the heating block 16 is a trolley 2 movable via wheels 20 on rails 18 laid at right angles to the direction of conveyance of the slab 10.
2, and a burner panel 24 mounted on this trolley 22.
It basically consists of. This burner panel 2
Reference numeral 4 consists of a steel shell with appropriate reinforcement, and inside the shell is lined with a refractory furnace wall 26 forming a cavity with a substantially U-shaped cross section. The cavity of the refractory furnace wall 26 is configured as a combustion heating chamber 28.
A radiant burner 32 is disposed on one side of the furnace wall. A plurality of burners 32 (three in this embodiment) are provided as shown in FIGS. 2 and 4.

As clearly shown in FIG. 3, the end of the slab 10 where the temperature tends to drop horizontally enters the opening of the combustion heating chamber 28 by an appropriate distance and is held by the heating zone of the heating chamber 28. It's starting to get pinched.
Therefore, at the opening periphery of this combustion heating chamber 28,
In order to reduce the gap between the slab 10 and the combustion heating chamber 28 as much as possible, it is desirable to provide a taper to form a constricted portion. Furthermore, the combustion heating chamber 28
An upper radiation promoting plate 34 and a lower radiation promoting plate 36 made of a so-called breathable solid are horizontally arranged and fixed above and below the slab 10 facing into the chamber, respectively. Between the ends of the plates 34 and 36 are heat-resistant insulating plates 38 and 38 as shown in FIG.
Make sure to connect it with That is, in the combustion zone where the end of the slab 10 of the combustion heating chamber 28 faces, two radiation promoting plates 34 and 36 are horizontally located close to each other so as to embrace the end of the slab. become.

Note that in this specification, the radiation promoting plate 34,
The breathable solid used as the material in 36 refers to a solid of appropriate thickness made by molding a heat-resistant material such as metal or ceramics into a net shape, honeycomb shape, fiber shape, or porous shape to give it breathability. This is thought to be composed of a large number of thin wires or fine grains, so its substantial surface area is extremely large. Since the radiation emission capacity of a solid is sufficiently higher than that of a gas, when high-temperature combustion gas is passed through the air-permeable solid as described later, the sensible heat of the combustion gas is transferred to the air-permeable gas, which has an extremely large surface area. A highly efficient heat exchange is performed by contacting with a solid solid, and a large amount of solid radiant heat is injected to the upstream side of the combustion gas. In the case of this example, the wire diameter is 1.0 mm,
Six layers of 16-mesh heat-resistant steel wire mesh are laminated to a thickness of approx.
12 mm plates were used as the radiation accelerator plates 34 and 36.

A duct 40 communicating with the combustion heating chamber 28 is provided at the top of the combustion heating chamber 28 to serve as an outlet for combustion waste gas, and a space defined between the top of the chamber and the upper radiation promotion plate 34 is provided with a duct 40 for supplying burner gas. A heat exchanger 42 for preheating the air for use is provided, and the pipe body led out from the heat exchanger 42 is passed through the duct 40 to the burner 32.
Connect to. Above the opening of the duct 40,
An exhaust hood 44 is provided, and the dimensions of the hood 44 are set in advance so as to open on the trajectory of movement of the duct 40 when the heating block 16 moves on the rail 18.

Furthermore, as shown in FIG.
Covering plate 4 whose base is fixed to the opposite sides of 6 and 16
6 and 46 are provided with a step and project horizontally, and are supported by a suitable support member (not shown) so as to cover the upper part of the slab 10 in a non-contact manner. This covering plate 4
6 and 46 are made of a heat-resistant heat insulating material because they are intended to prevent as much as possible the escape of thermal energy from the surface of the slab 10, but they may also be made of the above-mentioned air-permeable solid material. In this case, the radiant heat radiated from the slab 10 is returned to the slab 10 as a large amount of solid radiant heat in the air-permeable solid, which is more preferable. In addition, a highly flexible heat-resistant seal 48 made of asbestos, ceramic fiber, etc. is attached to the overlapping ends of the two covering plates 46, 46 arranged with a step difference, so that the covering space can be removed from the covered space. Prevents heat escape. In addition, in order to prevent air from entering from the surroundings, prevent combustion gas from randomly blowing out into the surroundings, and increase the temperature of the gas passing through the breathable solid, the opening periphery of the combustion heating chamber 28 has a As shown in FIGS. 2 and 3, a heat-resistant seal 50 is extended. Instead of this heat-resistant seal, a frame curtain may be used to blow out the combustion gas of the burner, as shown in FIG. In addition,
In FIG. 3, reference numeral 52 indicates a stainless steel reflector plate extending below the slab 10 along the conveyance direction, thereby preventing loss of thermal energy from the bottom surface of the slab 10 as much as possible. It is set as.

FIG. 5 shows another embodiment of the slab end heating device according to the present invention, in which a jet burner in which combustion gas is injected in a substantially convergent manner is used as the burner 54. In addition, a flame distribution plate 5 made of a heat-resistant material such as ceramic is provided in the area defined by the upper radiation promotion plate 34 and the lower radiation promotion plate 36 in the combustion heating chamber 28.
6 by appropriate means. Here, "defined" by the upper radiation promoting plate 34 and the lower radiation promoting plate 36 means that the inside of the combustion heating chamber 28 is partitioned into upper and lower parts by the upper radiation promoting plate 34 and the lower radiation promoting plate 36. It means "internally partitioned". The flame distribution plate 56 deflects the flame of the combustion gas that is injected from the jet burner 54 toward the end of the slab 10 in a substantially convergent manner, and directs it toward the corner end of the slab where heat input is particularly required. Since this assists uniform heating, it is preferable to dispose it in the direction of combustion gas injection from the jet burner 54 and close to the end of the slab 10, as shown in FIG.

There are no particular formal restrictions on the burner used in the present invention, and a so-called burning wall that allows air and fuel to pass through porous bricks to cause combustion near the surface of the bricks may be used. For example, FIG. 6 shows still another embodiment of the slab end heating device according to the present invention, in which the combustion heating chamber 28 is used instead of the radiant burner 32 and the jet burner 54.
A porous brick 58 is placed in front of the porous brick 58, and a mixed gas of combustion gas and air is forcibly supplied to the back of the porous brick 58, so that the gas permeates into the front of the porous brick 58, and the hot combustion gas is brought into the room. It is of the burning wall type that was obtained during the 28th century. In this case, the porous brick 58 itself can be regarded as a collection of countless burners, and an extremely homogeneous flame can be obtained. Further, the heat shield between the opening edge of the combustion heating chamber 28 and the slab 10 facing into the chamber may be a heat-resistant seal 50 shown in FIG. 3, but a porous brick 60 may be used as shown in FIG. It is preferable to employ a so-called frame curtain which is disposed at the edge of the opening and, as before, is configured to forcibly supply a mixture of combustion gas and air to radiate flame. In the figure, reference numeral 62 indicates a combustion gas supply pipe, 64 indicates an air supply pipe (preferably connected to the heat exchanger 42), and 66 indicates a mixer for mixing combustion gas and air at a predetermined ratio. .

"Operations of the Embodiment" The operations of the slab end heating device according to the present embodiment configured as described above will be described below, mainly in relation to the device shown in FIG. 3. First, roller 14
The carts 22, 22 are moved onto the rail 18 and their positions are adjusted appropriately according to the width dimension of the slab 10 being conveyed thereon. 16 combustion heating chambers 28
(See Figure 3). In this state, burner 3
2, 32 are ignited to radiate high-temperature combustion gas toward the combustion heating chamber 28, while the rollers 14 are rotationally driven to convey the slab 10. The combustion gas radiated into the combustion heating chamber 28 is throttled by the constriction formed at the periphery of the opening of the chamber, and the combustion gas is radiated into the combustion heating chamber 28.
The end portion of the slab 10 facing freely into the slab 8 is heated primarily by convective heat transfer. Further, a part of the high temperature combustion gas in the heating combustion chamber 28 passes through an upper radiation accelerating plate 34 and a lower radiation accelerating plate 36 disposed above and below the slab 10, and passes through the top and bottom of the combustion heating chamber 28, respectively. It flows out towards the bottom. At this time, as mentioned earlier, the high-temperature combustion gas is absorbed by the radiation promoting plate 3, which is made of an air-permeable solid with an extremely large surface area.
4, 36, highly efficient heat exchange of sensible heat is performed, and the radiation promoting plates 34, 36 inject a large amount of radiant heat to the upstream side of the combustion gas (that is, the side facing the slab 10). As a result, the vicinity of the end of the slab 10 is additionally heated from both the upper and lower directions, and the temperature is again raised to a temperature suitable for the next step of hot rolling. Furthermore, by operating the burner 32, the radiation promoting plates 34, 3
6 is heated to a high temperature, even if the combustion gas contains unburned components, they will be re-burned when passing through the high-temperature radiation promotion plates 34 and 36, further improving combustion efficiency.

In addition, in the case of a heating device having a structure in which a flame distribution plate 56 shown in FIG. The flow direction of the slab 10 is deflected, and heat is input intensively to the corner ends where the temperature drop of the slab 10 is particularly significant, thereby making it possible to increase the temperature distribution of the slab 10 substantially uniformly. Also,
The apparatus shown in FIG. 6 can similarly suitably achieve end heating of the slab.

Next, the combustion waste gas, which has passed through the radiation promoting plates 34 and 36 and whose temperature has been lowered by being deprived of sensible heat, reaches the top of the combustion heating chamber 28 and comes into contact with the heat exchanger 42 disposed at the top. After preheating the burner supply air, the air is collected in a hood 44 via a duct 40. Further, the covering plates 46, 46 and the reflecting plate 52
blocks heat escape from the upper and lower surfaces of the slab 10 and prevents the temperature of the slab 10 from dropping. In addition,
When the dimensions of the slab 10 to be transported to the hot rolling equipment are changed, the carts 22 and 22 are moved closer and further apart to adjust the dimensions in order to match the dimensions of the new slab whose specifications have been changed. be exposed.

"Effects of the Invention" As explained in detail above, according to the slab end heating device according to the present invention, a combustion heating chamber in which a burner faces the heating block is defined, and a slab is heated in the combustion heating chamber. By allowing the end portion where the temperature tends to drop to be freely exposed, and by arranging radiation promoting plates made of air-permeable solid above and below the combustion heating chamber, radiation from the burner into the combustion heating chamber is provided. The combustion gas heated heats the end of the slab facing into the chamber by convection and radiation heat transfer, and when the still hot combustion gas passes through the radiation promotion plate and comes into contact with it, highly efficient heat exchange is performed. By doing so, a large amount of radiant heat is injected into the end of the slab, and the temperature of the slab can be raised with good thermal efficiency to a temperature suitable for hot rolling.

Furthermore, the entire device has a simple structure and is extremely compact, so it can be incorporated as a part of a slab conveying device, contributing to a reduction in installation area and energy savings.

The preferred embodiments of the slab end heating device according to the present invention have been described above, but the present invention is not limited to these embodiments, and many improvements and improvements can be made within the spirit of the invention. Of course, changes can be made.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the temperature distribution of a slab manufactured in a continuous casting facility and subsequently transported to a hot rolling facility, and FIG. 2 is an overall structure of the end heating device for a slab according to the present invention. A perspective view schematically illustrating the third
The figures are a sectional view taken along the - line in Fig. 2, Fig. 4 is a sectional view taken along the - line in Fig. 3, Fig. 5 is a partial sectional view showing another embodiment in which a flow dividing plate is provided in the device of the present invention, and Fig. 6 is a sectional view taken along the - line in Fig. 2.
The figure shows a partial sectional view of another embodiment of the apparatus according to the invention, in which porous bricks are provided as burners and frame curtains are used instead of heat-resistant seals. 10... Slab, 12... Bearing, 14... Roller, 16... Heating block, 18... Rail, 2
0...Wheel, 22...Dolly, 24...Burner panel, 26...Furnace wall, 28...Combustion heating chamber, 32...
...Burner, 34, 36...Radiation promotion plate, 38...
Insulating plate, 40...Duct, 42...Heat exchanger, 4
4...Exhaust hood, 46...Covering plate, 48,50
... Heat-resistant seal, 52 ... Reflector, 54 ... Jet burner, 56 ... Flame distribution plate, 58, 60
... Porous brick, 62 ... Combustion gas supply pipe, 6
4...Air supply pipe, 66...Mixer.

Claims (1)

[Scope of Claims] 1. A long slab 10 that is conveyed on a large number of rollers 14 and can be freely wrapped around both ends in the longitudinal direction where the temperature tends to drop, and that the slab 10 is A burner 32 directed toward the longitudinal edge of the slab 10 is disposed in a pair of heating blocks 16, 16, which are arranged facing each other so as to be able to approach and separate from each other in order to match the width dimension of the slab. Combustion heating chamber 28, 28
Radiation promoting plates 34 and 36 made of air-permeable solid are respectively disposed above and below the running area of both ends of the slab 10 where the temperature tends to drop in each combustion heating chamber 28. An end heating device for slabs. 2. A flame distribution plate 56 made of a fire-resistant material is disposed in a region defined by the upper and lower radiation promoting plates 34 and 36 of each combustion heating chamber 28. Slab end heating device.