JPS58141321A - Lighting method of skid pipe of heating furnace - Google Patents

Abstract

PURPOSE:To decrease the quantity of heat transfer to the cooling water in a skid pipe, by applying heat insulating refractory linings wherein an inside layer consists of heat insulating materials, an intermediate layer of refractories contg. metallic fibers and an outside layers of heat insulating materials on the skid pipe. CONSTITUTION:Ceramic fibers 3' impregnated with colloidal silica as heat insulating materials are wound around a skid pipe 1 of a heating furnace as an inside layer of the linings thereof. Refractory castables 5' contg. >=0.1wt% fibers 7 of stainless steel or the like are lined thickly thereon. Ceramic fibers 4' as an outside layer are wound on the outside of the castables 5' with adhesive agents. Then, there is no need for studding to the pipe 1; therefore, the quantity of the heat to be flowed out through the studs is eliminated and the heat losses by the cooling water in the pipe 1 are decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for refractory, thermally insulating lining of skid pipes in heating furnaces, such as continuous heating furnaces for billets.

For example, a walking-beam continuous slab reheating furnace has a fixed beam and a movable beam, which are heated by a water-cooled hollow metal elongate body called a skid pipe.
The outer periphery of the skid pipe is coated with a refractory material to maintain the physical strength of the skid pipe at high temperatures and to suppress the transfer of heat from the inside of the furnace to the cooling water. is being measured.

Conventionally, as a typical lining for this skid pipe, as shown in FIG.
6 to 8 studs 2 of the same shape or a similar shape are implanted in the circumferential direction of the pipe by a method such as welding at intervals of 50 to 120 m in the length direction, a heat insulating material 3 is provided in the inner layer, and an intermediate layer; There is a method in which the second refractory material 5 is made to hold the heat insulating material 4 in its outer layer. In addition to this, the above-mentioned heat insulating layer 3 and fireproof layer 5 2.
Some have a layered structure.

These conventional skid pipe two-inning methods have the following drawbacks.

In the case of the three-layer lining shown in FIG. 1, a large amount of heat transfers from the inside of the furnace to the cooling water in the pipe l via the studs 2 installed in the pipe l.

Furthermore, in the case of a lining with a two-layer structure, since there is no heat insulating layer 4 compared to a lining with a three-layer structure, the amount of heat lost is even greater.

This invention solves the above-mentioned drawbacks of the conventional heating furnace skid pipe lining method, and is characterized by: When constructing a refractory heat-insulating lining for a skid pipe, a heat insulating material is added to the inner layer. O in the middle layer,
Fireproof materials containing 1% (wt%) or more of metal fibers,
This is a method of lining a heating furnace skid pipe by building a heat insulating material on the outer layer.

The two-inning method for a heating furnace skid pipe according to the present invention will be explained in detail below based on one embodiment thereof.

FIG. 2 shows a cross section of a skid pipe lining when the method of lining a heating furnace skid pipe according to the present invention is carried out. In this figure, 1 is a pipe, and a carbon steel pipe for ordinary piping is used.

3' is ceramic fiber as a heat insulating material,
It is wrapped as the first layer of Pai Goo's lining and acts as an insulating layer. In this example, the seven ramic fiber strips are rolled to a thickness of 30 m. Further, the material used for the ceramic fiber 3' is one impregnated with colloidal silica.

5' is a fireproof castable, and 1.0 inch (weight %) of stainless steel copper (8U8304) fiber 7 having a diameter of 0.5fi and a length of 50m is mixed uniformly into the fireproof castable 5'. be. In this example, a refractory castable 5' mixed with stainless steel fibers 7 is lined to a thickness of 70 m without any slids planted in the pipe l. The amount of metal fibers such as stainless steel fibers mixed into the refractory castable is preferably 0.1% or more (% by weight of the refractory castable when dry). If the content is less than 0.1%, there is no reinforcing effect on the castable refractory material. In addition, the material of the metal fiber should be one that has high oxidation resistance at high temperatures, maintains a certain level of strength without easily deteriorating, and has a coefficient of linear expansion that is not extremely different from that of refractories, for example, 13% Or steel.

18% Or steel, o-stenitic stainless steel, etc. are preferred. Although SUS 304 was used in this example,
They are selectively used according to their usage conditions. In addition, the shape should be such that it can be easily mixed with the monolithic refractory.

4' is a ceramic fiber which is wound around the outside of the refractory castable 5' and comes into direct contact with the atmosphere of the furnace. Ceramic fiber 4' is wrapped around the outside of refractory castable 5' via an adhesive. The ceramic fiber 4' is made of ceramic fiber for veneering.

In this example, ceramic fibers for veneering were used, but various types such as those processed into a donut shape can be used.

In this example, the stud 2 is not installed in the pipe 1, but when the stud 2 is installed, the
If it is about 150 to 300 pieces/m' (conventionally, 150 to 300 pieces/m'), the amount of heat transferred from the inside of the furnace to the cooling water in pipe 1 through the studs can be suppressed to a minimum, and the castable refractory material lined with Since it does not restrict thermal expansion and contraction, the occurrence of cracks can be greatly reduced.

Since the heating furnace skid pipe lining method according to the present invention is configured as described above, ■ Since there are very few or no studs installed in the pipe, the amount of heat flowing out through the studs is extremely small; Alternatively, it can be eliminated, and water cooling heat loss can be reduced.

■The temperature of the metal fibers mixed in the refractory castable is lowered by the outer layer of ceramic fibers, which is lower than the furnace atmosphere temperature, so there is no deterioration of the metal fibers.

Since the reinforcing effect can be maintained, the number of planted studs can be reduced or eliminated.

It produces the following effects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of skid pipe lining showing an example of a conventional heating furnace skid pipe lining method. FIG. 2 is a sectional view of a skid pipe lining showing an embodiment of the heating skid pipe lining method according to the present invention. 1...Pipe 2...Stud 3...
Insulation material 3'... Ceramic phi 4...
・Insulation bar

Claims (1)

[Claims] When constructing fireproof and insulating lining for skid pipes, it is recommended to construct a heat insulating material in the inner layer, a refractory mixed with 0.1% (weight 1%) or more of metal fibers in the middle layer, and a heat insulating material in the outer layer. Features a two-inning method for heating furnace skid pipes.