JPS59232215A - Skid pipe for billet heating furnace - Google Patents

Abstract

PURPOSE:To enable gaseous cooling of a skid pipe without posing any problem in strength by providing the 1st heat insulating member on the outside circumference of the pipe then providing the 2nd heat insulating member layer via a heat resistant protector. CONSTITUTION:The 1st heat insulating member 3 consisting of ceramic fibers, etc. is wound on the outside circumference of a pipe body 1 of a skid pipe for a billet heating furnace. Studs 6 are circumferentially provided at some intervals to the body 1 in the longitudinal direction thereof to reinforce the attaching condition of the member 3. A heat resistant protector 4 of a metal or ceramics holding the member 3 to the body 1 is provided on the outside circumference of the member 3. The 2nd heat insulating member 5 is further wound on the outside circumference. the skid buttons 2 provided to the body 1 are projected from the member 5 to support the heated billet. The heat loss from the skid is suppressed by such pipe.

Description

[Detailed description of the invention] The present invention relates to improvements in skid pipes for steel billet heating furnaces.

The skid pipe that supports the steel billets in the billet heating furnace is
Generally, cooling water flows inside the structure to prevent a decrease in strength due to thermal effects. However, with this water-cooled skid, the heat lost through the cooling water is approximately 109 seconds after the heating furnace heat input.
However, the fundamental problem is that effective heat recovery cannot be performed due to the low temperature potential. Therefore, in order to save energy in the heating furnace, it is important to cool the skid pipe with a medium other than water, such as gas, to reduce the heat generated by the skid and to recover the heat effectively. Whether it can be done is a major technical challenge. However, when skid cooling is performed using a gas (for example, air), there are the following major problems. That is, a heat insulating material is wrapped around the outer circumference of the skin pipe to reduce heat loss due to cooling and protect the pipe metal.
It is exposed to a high temperature atmosphere of 0 to 1,300 degrees Celsius, and conversely, during shutdown or heat retention, the temperature drops to room temperature to several hundred degrees, making it susceptible to thermal deformation and the like, resulting in the problem of the insulation material falling off. In order to prevent such falling of the insulation material, in Figure 1 (AI
In the case of water cooling as shown in , the temperature of the thin metal pipe body with large cooling capacity itself is the permissible limit temperature (350 ~
However, in the case of gas cooling shown in the figure), the cooling capacity is inferior to water cooling, so the temperature of the metal pipe body exceeds the allowable limit temperature, and the skid pipe It becomes difficult to maintain strength.

The present invention was devised in view of these conventional drawbacks, and it is an object of the present invention to provide a skid pipe structure that can be cooled with gas.

Therefore, the present invention provides a first heat insulating member on the outer periphery of the pipe body, a heat resistant protector for holding the heat insulating member on the outer periphery of the first heat insulating member, and a second heat insulating member on the outer periphery of the heat resistant protector. Its basic feature is that it is equipped with a heat insulating member.

An embodiment of the present invention will be described below.

Figures 2 to 4 show the present invention as a skid long beam (
(1)
is the pipe body, (2) is the skid button, and the heated steel piece is connected to the pipe body (1) through this skid button (2).
).

A first heat insulating member (3) is wrapped around the outer periphery of the pipe body (1). Studs (6) are provided at predetermined intervals in the longitudinal direction of the pipe body (1) at intervals in the circumferential direction, reinforcing the mounting state of the Ml heat insulating member (3). As this heat insulating member (3), for example, ceramic fibers, castable refractories, etc. are used.

Moreover, this heat insulating member (3) can be constructed of one or more layers of heat insulating material.

Note that the stud (6) is preferably made of a highly heat-resistant material (metal or ceramic);
A fixed bottle or the like can be used instead.

On the outer periphery of the first heat insulating member (3), the first heat insulating member (3)
) is provided with a heat-resistant protector (4) for holding it against the pipe body. This heat resistant protector (4
The ring is made of metal or ceramic that has a heat resistance temperature of about 1250°C or higher.For example, in the case of metal, it is made of 28% carbon, -21%Fe, 0.1%C, 0.9%Mn, and 1%5i.
Cobalt alloy having a composition of -7A part Co or TH
OO4 (C: 0.08 inch or less, cr: 48.0~
52.0%, Ni: 1.0-1.5% as the main component, including Co, W, Nb'i), TAH-39 (C
: O, i%, Cr: 35%, Ni: 5(1+, W:
15chi] etc. are used. Further, in addition to a metal mesh or plate body, the heat-resistant protector (4) may also be made of a wire mesh, a mesh belt, or the like.

A second heat-insulating material (5) is wrapped around the outer periphery of the heat-resistant protector (4). The material of this heat insulating member (5) is similar to the first O heat insulating material, such as ceramic fiber or castable refractory rT;3.

Note that the tip of the skid button (2) is connected to the second heat insulating member (5)'l! The heated steel billet is designed to be removed from the 1 liter.

In addition, Figure 15 shows the case where the invention is applied to a skid bost beam (vertical member), but the structure is similar to that shown in Figures 2 to 4 except that there is no skid button. have.

In addition, what is shown in Articles 71(a) to ci shows the cross-sectional structure of the skid pipe used in the abbreviated form as the second heat insulating member, and such a structure may be adopted depending on the case. . Among these, the one shown in (a) is provided with ceramic fibers (7) on the outer periphery of the pipe body (1), and is further provided with a castable refractory (8) on the outer periphery, which is a heat insulating member (
9). A heat resistant protector (4) is provided around the outer periphery of this heat insulating member (9). Anchor studs 4 are provided in the circumferential direction of the pipe body (1). The hole shown in (b) is the pipe body (
1) A lath αυ is wrapped around the outer circumference of t′1. , a heat insulating member (9) is wrapped around the outer periphery of the ceramic fiber,
Furthermore, a heat-resistant protector (4) is provided around the outer periphery.

A bottle Q4 is provided for reinforcing the attached state of the heat insulating member (9). The one shown in (c) is basically the same as the one shown in (b), but a stud a3 and a bottle (6) are provided for reinforcing the heat insulating material.

If the skid pipe has a structure as shown in Figures 2 to 5, even if the second heat insulating member (5) falls off for some reason when the gas cooling method is applied, the first heat insulating member (5) Since the member (3) is securely held against the pipe body by the heat-resistant protector (4), the temperature of the heat-resistant protector (4) increases due to the falling off, but the temperature of the skid pipe body (1) does not increase. is small and therefore does not pose any serious problem. Furthermore, since gas cooling is possible in this way, heat recovery can be effectively performed by using cooling air as part of the combustion air.

Figures 6 (a) and (b) show an example of the temperature of each part when the skid pipe of the present invention is used for air cooling, where the cooling air flow rate is 90 rIL/S and the ambient temperature is 1300°C. Under these conditions, (a) shows the temperature distribution under normal conditions, and (b) shows the temperature distribution after the second heat insulating member falls off. According to this, in the normal state shown in (a), the surface temperature of the second heat insulating member (5) T: 1296°C, the surface temperature of the heat-resistant protector (4) T2 near 00°C, and the pipe body temperature T3: 135℃, gas temperature inside the pipe T: 10
It is 0°C. On the other hand, in the case shown in (b) after the heat insulating member falls off, the heat resistant protector (4
) surface temperature! Although T2 rises to 1280°C, the pipe body temperature T3 is 200°C, and as can be seen from FIG. 1, the temperature is kept well below the allowable limit temperature of the pipe body.

According to the skid pipe of the present invention as described above, it is possible to perform gas cooling without causing any strength problems to the pipe, thereby suppressing heat loss from the skid and effectively recovering that heat. This has the elegant effect of allowing the heating furnace to be operated while

[Brief explanation of drawings]

Figure 1 shows the relationship between the furnace atmosphere temperature and the temperature of the main body of a conventional skid pipe when the insulation member falls off. Figures 2 to 4 show an embodiment in which the present invention is applied to a skid long beam.
The figure is a longitudinal sectional view, FIG. 3 is a cross-sectional view, and FIG. 4 is a cutaway perspective view. FIG. 5 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a skid post beat. Figure 6 (a
) and (b) show an example of the temperature of each part when the skid pipe of the present invention is used for air cooling. FIGS. 7(a) to 7(c) are cross-sectional views each showing a skid pipe having a structure in which the second heat insulating member is omitted. In the figure, (1) shows the pipe body, (3) the first heat insulating member, (4) the heat resistant protector, and (5) the second heat insulating member. Patent applicant Nippon Kokan Co., Ltd. Inventor Sa 1) Tetsu Reuma
1) Kendo Shun Akiyama - 4th
Figure-78- Figure 5

Claims (1)

[Claims] In addition to installing a gx insulation member around the outer circumference of the pipe body,
A skid pipe for a steel billet heating furnace, comprising a heat-resistant protector for holding the heat-insulating member provided on the outer periphery of the heat-insulating member of the px, and a second heat-insulating member provided on the outer periphery of the heat-resistant protector.