JPH0587460A - Continuous slab heating furnace - Google Patents

Abstract

PURPOSE:To provide a heating furnace in which the thickness of partition walls is reduced and the furnace capacity is small by providing the heating furnace with at least two rows of transporting and heating means and a refractory partition wall between respective rows of transporting means which buries longitudinally a water- cooling pipe that is surrounded with fiber. CONSTITUTION:Objects 3a, 3b (slabs) to be heated that are transported from the process of continuous casting are pushed by pushers 4 into respective heating chambers 6a, 6b in a heating furnace that are divided by a refractory partition wall 2. After the steel slabs are heated to specified temperature, they are sent to the process of rolling. In this case a lower partition wall 2a formed by a material that contains 80-90% of sintered light chamotte that contains 10-20% of coarse particles of grain diameter in 3-5mm and-7% of small particles of grain diameter smaller than 5mm with 1-2% of alumina cement added to cover the outer faces of the chamotte and an upper partition wall 2b that is a little thinner than the lower partition wall 2a constitute the refractory partition wall 2, and both upper and lower partition walls have respectively a water cooling pipe P covered with fiber that is buried in the partition walls and runs longitudinally by snaking. And on both sides of each of the partition walls 2a, 2b ceramic fiber is provided.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a continuous billet heating furnace,
For example, the present invention relates to a suitable continuous billet heating furnace capable of coping with changes in the operating rates of the continuous casting process and rolling process installed before and after that.

[0002]

2. Description of the Related Art The capacity required for a billet heating furnace is roughly classified into hot steel billet charged at high temperature and cold steel billet charged after cooling, and further, simply during hot rolling. There is a case where heating is performed for the purpose of reducing the deformation resistance, and a case where heat treatment at a high temperature for a long time is required due to treatment such as solid solution of alloy elements and diffusion of impurity elements. For this reason, the heating capacity required for the heating furnace greatly differs depending on the cast (steel) piece, and the processing capacity is inconsistent with the rolling process in which the processing time is relatively stable.

In order to solve the above-mentioned drawbacks, for example, as disclosed in Japanese Patent Publication No. 56-49970, the transfer space in the furnace is divided by a finishing wall in the left-right direction in the heating process, and heating is performed. When the processing capacity of the rolling process following the process can be covered by one row of the heating furnace, the heating furnace is operated in one row, and the rolling line capacity is high, and the heating capacity is insufficient in one row operation of the heating furnace. There is a method in which the heating furnace is operated in two rows. Therefore, the heating furnace is required to have means capable of independent operation of each row, such as one-row operation and two-row operation.

[0004]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 56-4997
In the method of stacking bricks according to Japanese Patent No. 0, the height from the floor to the ceiling of the furnace body is usually 4 to 6 m, and the wall thickness of a brick self-supporting wall has a wall thickness of two or more bricks (about 460 m). ~ 1000 mm), the wall thickness of the pass line part is thick, and the heat loss due to brick heat storage becomes large.

In addition, when a partition wall is installed in an existing furnace, there is a drawback that the length that can be charged into the object to be heated must be shortened, and when the partition wall is installed in the new furnace, it is equivalent to the partition wall thickness. There is a drawback that the furnace width becomes larger and the equipment cost increases.

Such a drawback lies in the fact that the partition wall cannot be made thin originally. In other words, if the conventional partition wall brick is made thin, there is no case where it is actually industrialized due to the problems of thermal shock resistance, airtightness, and thermal conductivity, especially when the two-row operation is one side hot side charging and the other side cold side charging. ..

The present invention has been made in order to solve the above problems, and realizes a continuous billet heating furnace capable of coping with changes in the operating rates of both the continuous casting process and the rolling process. ..

[0008]

Means for Solving the Problems A feature of the present invention is to provide a billet heating furnace having at least two rows of transport heating means in the bill transport direction, wherein a fire-resistant partition wall is provided between each row of the transport means. The refractory partition wall is made up of vertically embedded water-cooled pipes surrounded by fibers.
0 to 20%, 5 mm <5 to 7% containing 5 to 7% calcined lightweight chamotte and alumina cement as the main component, and the ceramic fiber is attached to the wall surface, continuous billet heating furnace and billet conveying direction In a billet heating furnace having at least two rows of conveying and heating means, a refractory partition wall is provided between each row of the conveying means, and the refractory partition wall is vertically embedded with a water-cooled pipe surrounded by fibers to form grains. The main component is calcined lightweight chamotte containing 3 to 5% diameter of coarse particles 10 to 20%, 5 mm <5 to 7% and alumina cement, ceramic fiber is attached to the wall surface, and further to the joint with the furnace ceiling. It is a continuous billet heating furnace characterized by having a cushioning material interposed.

In addition to the main component of the refractory partition wall, it is also possible to mix hollow alumina particles and fibers made of metal or ceramic to further improve strength and heat insulation.

[0010]

In the present invention, when installing the partition wall that divides the furnace width direction of the existing heating furnace, the furnace volume reduction due to the thinning of the partition wall is minimized as shown in FIGS. In order to minimize heat transfer between adjacent furnaces, a water-cooled pipe with fibers installed around the outer peripheral surface is buried to improve fire resistance (15
00 ℃ or above) and heat insulation (0.5 cal / mh ℃ or below),
A partition wall is constructed using a refractory material that has peeling resistance, spalling resistance, and that suppresses the occurrence of cracks. Ceramic fibers are attached to both sides of this partition wall to provide airtightness and thermal shock resistance. A buffer material is provided at the joint between the partition wall itself and the furnace ceiling in order to prevent the partition wall itself and the partition wall from being damaged by absorbing a slight amount of thermal expansion and contraction of the partition wall.

The use of calcined lightweight chamotte and alumina cement as the material of the partition wall maintains a heat conductivity of at least 1500 ° C. and a thermal conductivity of 0.4 to 0.5 cal / mh ° C., and minimizes shrinkage during operation. Therefore, by firing in advance, it became possible to completely independently heat each row. In addition, as a grain size composition, 3 to 5 mm of coarse grains is 7 to 10%, 5 mm <is 5 to 7
%, The generation of cracks during operation is completely eliminated.

FIG. 1 is a block diagram showing a heating process of a steel slab. A heating furnace 1 is arranged between a continuous casting process and a rolling process, and is placed on a conveying roller from the continuous casting process and conveyed. Heated object (hereinafter referred to as steel slab) 3a, 3b
Is charged by the pusher 4 into the heating chambers 6a and 6b partitioned by the fireproof partition wall 2. The heating chambers 6a and 6b are individually provided with charging ports 5a and 5b and extraction ports 7a and 7b.

FIG. 2 shows a vertical cross section of the refractory partition wall 2 of the heating furnace 1. The installation range of the refractory partition wall 2 is shown by diagonal lines, and an independent furnace pressure control device is shown for each row (see FIG. Only one column is listed in.) This control device has a furnace pressure detecting end 11
a (b), furnace pressure damper 10a (b), and control unit 12a
It is composed of (b).

FIG. 3 shows a cross section taken along the line AA in FIG. 2 and is a cross section of the heating furnace 1. A refractory partition wall 2 is provided at the center of the furnace width so as to extend from the furnace charging side to the furnace extracting side, and a walking beam 16 and a fixed beam are respectively provided in the two heating chambers 6a, 6b in the furnace length direction of the heating furnace 1. 14 is provided. Drive device (not shown) provided independently for each heating chamber
The walking beam 16 is moved up-forward-down-
A rectangular operation of retreating is performed so that the steel pieces 3a and 3b are alternately placed on the walking beam 16 and the fixed beam 14 to be conveyed in the furnace. Further, axial flow burners 19a, 19b, 20a, 20b are provided above and below the billet conveying surface so that the front and back of the billets 3a, 3b can be heated, and the temperature of the heating chambers 6a, 6b can be individually adjusted in the furnace length direction. It has a device (not shown). 21 is a refractory brick, 2
2 is a steel frame, 23 is a support bar, and 24 is a support metal.

The detailed construction of the fireproof partition wall 2 in the heating chambers 6a and 6b will be described with reference to FIGS.

The refractory partition wall 2 comprises coarse particles 10 having a particle size of 3 to 5 mm.
〜20%, 80% to 90% of light weight chamotte containing 5 to 7% of 5mm <, and 1 to 2% of alumina cement on the outside.
It is composed of a lower partition wall 2a added and molded and an upper partition wall 2b (FIG. 7-1) which is slightly thinner than this. These are joined at a level directly below the slab transfer path line in the furnace by a castable (K) for joining as shown in FIG. 7-1. Further, each partition wall 2a, 2b is provided with ceramic fibers a (heat insulating material) on both side surfaces thereof to facilitate thinning and repair of the wall itself, and a partition wall structure such as a wall support metal or a support for a furnace. Enables weight reduction of hardware.

Further, water cooling pipes (steel pipes) P1 and P2 are vertically embedded over the respective partition walls 2a and 2b, and this is also at the level immediately below the slab transfer path line in FIG. 7-1 (P1 diameter> P2 diameter). ), As shown in FIG. 7-2 (when P1 diameter = P2 diameter), they are joined by a sleeve (short steel pipe) SR for joining.

This vertical arrangement allows the thermal expansion of the pipe itself in the vertical direction to escape and restrains in the width direction of the furnace, so that the wall itself can be surely maintained in its self-supporting property and shape. Further, the furnace ceiling side and the furnace floor side of the water cooling pipe are of a penetrating type outside the furnace and a U-turn type as shown in FIG.

The penetration type on the furnace ceiling side is shown in FIG. 5, and the U-turn type on the hearth side is shown in FIG. 6, and the details will be described later. Moreover, ceramic fibers b (heat insulating material) are provided around the outer peripheral surface of each water cooling pipe to reduce the temperature difference between the water cooling pipe itself and the wall body, prevent cracks in the wall body, and prevent water cracking between the water cooling pipe and the wall body. Maintains close contact with the main body, absorbs the difference in thermal expansion, reliably prevents the wall body from falling off, and reduces heat loss due to water cooling.

As shown in FIG. 4, connecting bars c are provided at appropriate intervals between the vertical portions of the water-cooled pipe P to form a reinforcing skeleton for the partition wall, and in addition to this radiator cooling effect, it is advantageous to make the partition wall thinner. It is possible if possible.

In FIG. 5, the water cooling pipe P2 is the furnace ceiling 1
It penetrates through the refractory heat insulating material 3 of 3 and is supported so as to be vertically slidable by thermal expansion and contraction.

The upper end surface and the upper end side surface of the upper partition wall 2b are respectively brought into contact with the refractory heat insulating material d via the expansion absorbing material e.

In FIG. 6, the U-turn part PU of the water-cooled pipe P1 is set on the saddle part of the pillow-shaped supporting metal f to prevent lateral rolling and to enable a thin self-supporting wall. In the figure,
g is a refractory castable inside the hearth, and h is an adiabatic castable outside the hearth.

[0024]

According to the present invention, by providing a fireproof partition wall in the heating chamber, independent heating operation corresponding to the combustion load of each row of the heating furnace can be advantageously performed.

Further, the wall thickness of the refractory partition wall can be made thin so that the heating efficiency is not lowered when it is installed in an existing furnace, and the furnace width is increased when it is installed in a new furnace. Moreover, it is possible to install heating equipment having excellent economical efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of the present invention and showing an entire heating process of a steel slab.

FIG. 2 is a vertical cross-sectional view of the fireproof partition wall of the heating furnace according to the embodiment of the present invention, and is an explanatory view showing an installation range of the fireproof partition wall and a furnace pressure control device.

3 is an embodiment of the present invention, AA in FIG.
FIG.

FIG. 4 is a cross-sectional view showing a detailed configuration of the refractory partition wall of FIG. 2, which is an embodiment of the present invention.

5 is an illustration of an upper structure of the partition wall in FIG. 3, which is an embodiment of the present invention.

6 is an explanatory view of the furnace bottom support structure of FIG. 3. FIG.

7 is an explanatory diagram of an example of the intermediate connection structure of FIG. 3, and 2 is an explanatory diagram of another example of the intermediate connection structure.

[Explanation of symbols]

 1 Heating Furnace 2 Fireproof Partition Walls 3a, 3b Steel Pieces 6a, 6b Heating Chambers 8a, 8b Flue 10a, 10b Furnace Pressure Dampers 11a, 11b Furnace Pressure Detecting Ends 12a, 12b Furnace Pressure Control Section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiri Ueshima 2-4-7 Korimachi, Nishi-ku, Osaka City Chugai Furnace Industry Co., Ltd. (72) Hideki Takaguchi 2-4-7, Kyomachibori, Nishi-ku, Osaka Chugai Furnace Industry Co., Ltd.

Claims (2)

[Claims] 1. A billet heating furnace having at least two rows of conveying and heating means in a billet conveying direction, wherein a refractory partition wall is provided between each row of the conveying means, and the refractory partition wall is surrounded by fibers. Water-cooled pipe is embedded vertically, and the particle size is 3-5.
A continuous billet heating furnace, characterized in that the main components are calcined lightweight chamotte containing 10 to 20% of coarse particles of 5 mm and 5 mm <5 to 7% and alumina cement, and ceramic fibers are attached to the wall surface. 2. A billet heating furnace having at least two rows of conveying and heating means in the billet conveying direction, wherein a refractory partition wall is provided between each row of the conveying means, and the refractory partition wall is surrounded by fibers. Water-cooled pipe is embedded vertically, and the particle size is 3-5.
mm coarse particles of 10 to 20%, 5 mm <5 to 7% containing a light weight chamotte and alumina cement as the main components, ceramic fibers are attached to the wall surface, and a cushioning material is further added to the joint with the ceiling of the furnace. A continuous billet heating furnace characterized by being interposed.