JPH0519324Y2 - - Google Patents

Description

[Detailed explanation of the idea]

<Industrial Application Field> The present invention is applicable to long side end faces of slabs (i.e. bottom faces).
The present invention relates to a bottom-charging vertical slab induction heating furnace equipped with a rotary heat insulator that prevents heat dissipation from the furnace. <Prior Art> In vertical induction heating furnaces, a bottom charging type is generally used because the top charging type causes indentation flaws and falling slabs due to hangers such as tongs. In the case of a bottom-charging vertical induction heating furnace, the configuration of the device is as described in, for example, Japanese Utility Model Publication No. 15344/1983;
As also seen in Japanese Utility Model Publication No. 52-56336, and as shown in FIG. 6, after loading the slab 1 in a horizontal state onto the L-shaped turning lever 2 of the rotating device, The turning lever 2 is turned 90 degrees to raise the slab 1 to a vertical position. Then the seventh
As shown in the figure, the lifting device 3 is raised by a lifting drive device (not shown), and the slab 1 placed on the turning lever 2 is received in a vertical state and charged into the heating furnace 4 as it is. The relationship between the turning lever 2 and the lifting device is as shown in FIG.
The turning lever 2 is located in a position where it is pinched by the slab holder 5, and in order to prevent the turning lever 2 from interfering with the slab holder 5 during turning, either there is no slab holder 5 in the turning path or the interference range of the turning lever 2 is cut out. It has a traditional structure. Furthermore, a hearth 6 is provided below the pedestal 5 to seal the inside of the heating furnace. When the slab 1 is transferred vertically from the rotating lever 2 to the slab holder 5 of the lifting device 3 and loaded into the heating furnace 4, the rotating lever moves the slab 1 vertically as shown in Fig. 6. After raising and stopping the lifting device 3, the slab 1 is received from above the turning lever 2 onto the slab pedestal 5, and the hearth 6 is placed on the turning lever 2.
Just before it interferes with the lever, rotate the turning lever 2 and open it.
A passage is formed through which the hearth 6 passes. Of course, at this time, the height of the pedestal 5 is adjusted so that the turning lever 2 does not interfere with the slab 1 on the pedestal 5. Further, although not shown in this figure, a fall prevention device is appropriately provided to prevent the slab from falling when it stands up and rises. In this way, the slab 1 is charged into the heating furnace 4 and is heated, but the problem here is the non-uniformity of the temperature of the heated slab. As mentioned above, the shape of the slab pedestal 5 of the lifting device 3 is the eighth shape in order to avoid interference with the turning lever.
If the slab is supported and heated with such a pedestal as shown in Fig. 9 and Fig. 9, for example,
As seen in Publication No. 22111, the heat dissipation loss is large in the parts that do not touch the pedestal, and in the case of the slab pedestals shown in Figures 8 and 9, the temperature distribution at the bottom of the slab is as shown in Figure 10, respectively. , as shown in FIG.
That is, FIG. 10 shows the temperature distribution in the long side direction of the bottom surface of the slab when the slab is supported on a pedestal as shown in FIG. 8, and FIG. The temperature distribution in the long side direction of the bottom surface of the slab when the slab is supported is shown, but the temperature distribution on the bottom surface of the slab (on the pedestal side) is uneven in the long side direction, especially in the part that is not in contact with the pedestal. The distance to the floor is long and heat dissipation is large, resulting in a significant drop in temperature, which causes problems in terms of rolling and quality. <Problems to be solved by the invention> The invention reduces the heat dissipation from the bottom of the slab as described above, especially from the part not in contact with the pedestal,
This was done in order to provide an induction type slab heating device that can uniformly heat the long sides of the slab. <Means for solving the problem> As a result of intensive research into a method for uniformly heating a slab in a bottom-charging vertical induction heating furnace, the inventors of the present invention have developed a method to reduce the gap between the bottom of the slab and the hearth. We learned that heat dissipation from the slab could be reduced by doing so, and based on this knowledge, we came up with this idea. In the present invention, a pedestal 5 for locally supporting the end face of the long side of the slab is placed on a lifting hearth 6, and by lifting this lifting hearth, the slab is lifted from the lower part of the induction heating furnace 4. In a bottom-charging vertical induction heating furnace that is charged into the furnace, the length is shorter than the width of the induction heating furnace 4, and the distance between each pedestal 5 or the pedestal 5 is
A rotary heat insulator 7' having a width shorter than the distance between the inner wall of the induction heating furnace 4 and a slab in a space 16 formed near the lower end of the refractory heat insulator 7 and in which the rotary heat insulator 7' is accommodated. This is an induction type slab heating device, which comprises a shaft 8 disposed at a lower position close to the bottom surface, and the rotary heat insulating material 7' is fixed to the shaft 8 so as to be rotatable inside the furnace. <Operation> The present invention will be explained according to the drawings. First, in principle, as shown in FIGS. 1 and 2, after loading the slab 1 into the heating furnace 4, when heating the slab 1, a rotary heat insulator is placed in the part where the slab pedestal 5 is not located. 7' is placed close to the slab to reduce heat dissipation from the bottom of the slab, especially the portion that is not in contact with the pedestal. As shown in FIGS. 3 to 5, the structure is such that a space 16 is formed in a part near the lower end of the furnace wall refractory heat insulating material 7, and a rotary heat insulating material 7' (position and size is
Depends on the placement and size of the pedestal. ), which is rotatably supported by an internally water-cooled shaft 8, and is connected by a pin 11 to a rod 10 having an elongated guide piece 9 at its tip. The rod 10 is slidably supported by a bearing 15 provided outside the furnace wall. The other end of the rod 10 is connected to the tip metal fitting 13 of the cylinder 12 by a pin 14, and by pushing and pulling the cylinder, the rotary heat insulating material 7' is inserted through the rod 10.
is rotated 90 degrees, resulting in the state shown in Figure 3 or Figure 4. That is, after loading the slab 1 into the furnace, the cylinder 12 is operated and the rotary heat insulating material 7' is moved to cover both sides of the slab pedestal 5 or the gap between them, as shown in FIG. It rotates and heats while close to the bottom of the slab. When the slab reaches a predetermined temperature and heating is completed, the cylinder 12 is operated in reverse as shown in FIG. Transport the slab 1. As mentioned above, by using the shield plate of the rotary heat insulating material, which is easy to manufacture, to reduce the distance between the bottom of the slab where there is no pedestal and the hearth, heat dissipation from the bottom of the slab is reduced. This significantly reduced the temperature drop and enabled uniform heating of the bottom surface, resulting in improvements in rolling and quality. <Example> In the bottom-charging vertical induction heating furnace shown below, slabs with the following dimensions were heated to an average temperature of 1200°C with or without the rotary heat insulating material according to the present invention, and the difference in bottom surface temperature of the slabs was determined. (ΔT ₂ , see FIG. 11) was measured, and the results are summarized in the table below. 1 Induction heating furnace (Fig. 2 type) (1) Furnace dimensions Height: 2000mm, length: 3000mm, width: 500mm. (2) Slab pedestal height 850 x 3 pieces Slab 1000mm height x 2800mm length x 300mm thickness

[Table] As is clear from this example, according to the present invention, the temperature difference at the bottom of the slab was significantly reduced, and uniform heating was achieved. <Effects of the invention> According to the invention, when heating a slab in a bottom-charging vertical induction heating furnace, the long side end face (i.e., the bottom face) of the slab is heated more uniformly than before, resulting in improvements in the rolling and quality of the slab. It was hot.

[Brief explanation of the drawing]

Figures 1 and 2 are front sectional views of the heating furnace according to the present invention, Figure 3 is a sectional view along AA of Figure 2, Figure 4 is an explanatory view of Figure 3 when the rotary heat insulating material is not used, Figure 5 is a BB cross-sectional view in Figure 3, Figures 6 and 7 are cross-sectional side views of the bottom charging vertical heating furnace, Figures 8 and 9.
The figures are the cross-sectional front view of Fig. 6 and Fig. 7, and the sectional front view of Fig. 1.
0 and 11 are slab bottom surface temperature distribution diagrams in the cases of FIGS. 8 and 9, respectively. DESCRIPTION OF SYMBOLS 1... Slab, 2... Rotation lever, 3... Lifting device, 4... Bottom charging vertical heating furnace, 5... Slab pedestal, 5a, 5b, 5c... Slab pedestal, 6...
... Hearth, 7 ... Fireproof insulation material, 7' ... Rotary insulation material, 8 ... Shaft, 9 ... Guide piece, 10 ... Rod,
11... Pin, 12... Cylinder, 13... Tip hardware, 14... Pin, 15... Bearing, 16...
Space department.

Claims (1)

[Scope of utility model registration request] A pedestal 5 for locally supporting the long side end face of the slab 1 is placed on a lifting hearth 6, and the slab is loaded into the induction heating furnace 4 from the lower part by lifting the lifting hearth. In the bottom-charging vertical induction heating furnace, the length is shorter than the width of the induction heating furnace 4, and the width is shorter than the interval between each pedestal 5 or the interval between the pedestal 5 and the inner wall of the induction heating furnace 4. Rotating insulation material 7'
and a shaft 8 formed near the lower end of the fireproof heat insulating material 7 and disposed at a lower position close to the bottom surface of the slab within the space 16 in which the rotary heat insulating material 7' is housed. An induction type slab heating device characterized in that a type heat insulating material 7' is fixed to a shaft 8 so as to be rotatable inside the furnace.