JPS6045964B2 - Heat retention method for transported high temperature steel materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of insulating high-temperature steel materials in hot rolling, thick plates, and the like.

Most conventional line heat insulation methods for high-temperature steel materials concern the upper surface of the steel material, and there are almost no examples in which effective heat insulation is achieved for the lower surface of the steel material.

This is due to the following problem regarding the heat retention device on the bottom side. (1) Steel scale falls and accumulates on the heat insulation device, increasing heat storage loss and impeding the heat retention effect, and at the same time, the high-temperature scale causes reaction and deterioration of the heat insulation material.

(2) Cooling water for roll cooling (including vaporized water)
Due to this, rapid heating and cooling are repeated, and the insulation material is damaged due to thermal shock, and water vapor permeates or adheres to the insulation material, reducing the heat retention effect.

Conventional examples of heat insulation on the lower side of steel materials include those using general castables, heat-resistant bricks, etc.
Due to the two problems mentioned above, almost no heat retention effect could be expected.

Another method is to use a metal plate with low emissivity (high reflectance), but even with this method, the surface deteriorates due to scale and cooling water coming into contact with the low emissivity metal plate, and the initial low emissivity is lost. The desired heat retention effect could not be obtained.

In order to solve the above problems, the heat insulating device on the bottom of the steel must not only have a heat retaining effect, but must also have a structure that prevents steel scale from accumulating, and must be made of a material that will not be affected by contact with steel scale. This also requires the use of structures and materials that are unaffected by roll cooling water.

The present invention has been made to solve the above problems,
The aim is to effectively insulate the lower surface of the transported high-temperature steel material. In order to achieve the above object, the present invention disposes a large number of copper tubes (vibs) between the rollers that convey the high-temperature steel material and at intervals that allow the scale to fall in the vertical direction below the conveyance level. The present invention provides a method for keeping high-temperature steel materials warm by absorbing radiant heat from the steel material with the steel pipe and then radiating it to the high-temperature steel material as radiant heat.

This will be explained below using the drawings. The method for insulating the lower surface of a high-temperature steel material according to the present invention is carried out to the extent that the scale detached from the high-temperature steel material 1 (arrows indicate the direction of movement) does not accumulate, for example, as shown in FIG. The vibrators 3 are arranged almost parallel to the roller 2 at intervals of It is something. In this case, it is desirable to arrange as many vibrators as possible in multiple stages, taking into consideration the equipment space and the ease with which the scale will fall. High temperature steel material 1 shown in Figure 1
The transport table of 2 is not equipped with a fluorocarbon to prevent the steel material 1 from protruding downward between each roller 2, but
Another embodiment of the present invention is shown in FIGS. 2a and 2b.
1 shows a method of keeping the bottom surface of the high-temperature steel material 1 warm when equipped with the following.

In this method, the vibrator 3 is placed on the front 4, which is protected at several locations on the apron support angle 5. By welding only one side, expansion and contraction due to thermal expansion in the longitudinal direction of the vibrator 3 is released and deformation thereof is prevented. FIG. 3 shows an embodiment of the arrangement of the vibrator 3 according to the present invention.

p is the distance between the centers of J Vibes 3 arranged in the horizontal direction, h
is the distance between the centers of the vibrators 3 arranged in the vertical direction, d is the outer diameter of the vibrators 3, and the vibrators 3 are arranged so that the relationships p≦2d and h≦2d hold. The outer diameter of the vibrator used in the experiment was 25.47T0f1 (1 inch).
It was so hot. In the embodiment shown in FIG. 1 or 2, the vibrator 3 uses stainless steel as its material,
Even if the scale comes into contact with the vibrator 3 or is exposed to roll cooling water, it is hardly affected.

Furthermore, in order to cut radiation heat conduction between the high-temperature inner surface and the low-temperature inner surface of the vibrator 3 in the inner space of the vibrator 3, it is also possible to improve the heat insulation properties by filling the vibrator 3 with a substance having low thermal conductivity. Furthermore, if the surface temperature of the vibrator 3 closest to the high-temperature steel material 1 approaches the temperature of the high-temperature steel material 1 instantaneously when the high-temperature steel material 1 passes through, strong insulation can be achieved. It is necessary to reduce the thickness of the vibrator 3 and reduce its heat capacity. However, it is not possible to make the vibrator extremely thin due to its strength and lifespan, so instead of reducing the thickness of the vibrator 3, a very thin foil-like material is used around the outer periphery of the vibrator 3, as shown in Figure 4. A similar effect can be achieved by using several layers of material 6. This is because the foil wrapped in several layers provides a multilayer insulation effect, and the outermost portion of the foil heats up almost instantaneously.

Figure 5 shows a stainless steel vibrator (SU) with a wall thickness of 1.5 TWL.
S3O4) The condition when it is as it is is the hail line (a) and the same vibrator with SUS3lOS (25Cr-20Ni)
The state when the foil (thickness 0.01?) is wrapped around the hail line (opening) and the line (c) showing the same high temperature heat flake (heat flake temperature 1000℃), It shows temperature increase characteristics.

As is clear from the figure, the outer surface temperature of the vibrator 3 wrapped with metal foil rapidly rises. An actual line test according to the present invention was conducted using a method in which a stainless steel vibrator was installed between a rough rolling mill and a finishing mill as shown in FIG. 2, and its durability and heat retention effect were investigated. As for durability, after about a month had passed since installation, there was no scale build-up, and although some parts of the vibrator surface on the high-temperature steel side had become dull due to heat, no deformation or damage was observed. It has been confirmed that this is not possible. Next, the heat retention effect was examined by actually measuring the temperature of the bottom surface of the slab at the entrance and exit of the heat insulation cover.

The results are shown in Table 1. Table 1 shows that the method of the present invention, which uses two stages of stainless steel vibrators, is more than twice as effective at retaining heat as the conventional method using insulating bricks. In addition, in this actual line test, as a side effect of the method of the present invention, radiation heat transfer between the slab and the roller other than the contact heat transfer between the conveyor roller and the high-temperature slab was blocked by the stainless steel vibrator. The roller temperature does not rise much,
It has become clear that they are thermally protected.

As is clear from the above description, according to the method of the present invention, the lower surface of the steel material can be extremely effectively insulated, and its implementation is highly effective.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIGS. 2a and 2b are longitudinal sectional views and plan views of other embodiments of the invention, and FIGS.
The figure is a side view of an embodiment of the main part of the present invention, and FIG. 5 is a diagram showing the relationship between time and surface temperature. 1... Steel material, 2... Roller, 3... Vibrator, 6...
...Foil-like substance.

Claims (1)

[Scope of Claims] 1. A large number of steel pipes are arranged between rollers that transport high-temperature steel materials and at intervals that allow scales to fall in the vertical direction below the transport level, and the radiant heat from the high-temperature steel materials is absorbed by the steel pipes. A method for keeping heat of conveyed high-temperature steel materials, which is characterized by absorbing heat and then radiating it to the high-temperature steel materials as radiant heat. 2. The heat retention method according to claim 1, characterized in that the inside of the steel pipe is filled with a substance having low thermal conductivity. 3. The heat retention method according to claim 1, characterized in that metal foil is wrapped around the outer periphery of the steel pipe.