JPH10306313A - Apparatus for continuously heating steel slab and heating method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the surface temp. on a skid beam and to reduce the skid mark on a material to be heated by forming the combustion area near the skid beam, when a material to be heated is continuously fed and heated to a prescribed temperature. SOLUTION: In a continuous cast slab heating apparatus arranging plural skid beams for laying the material to be heated in the apparatus body provided with plural burners and arranging one or more of displacing positions in the width direction of the apparatus body to at least one piece of the skid beam in plural skid beams, fuel supplying tubes 31, 32 are arranged along the skid beam at the front side of the displacement and at the rear side of the displacement of the skid beam in the displacing position of the skid beam 1. The fuel supplying tube 31 at the front side of the displacement of the skid beam is opened toward the rear side of the displacement and fuel supplying tube 32 at the rear side of the displacement is opened toward the front side of the displacement. The neighborhood of the skid beam can effectively be heated with flame formed with the fuel spouted from the fuel supplying tube and oxygen in the apparatus body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous billet heating apparatus and a heating method, and more particularly to a continuous heating apparatus and a heating method for reducing skid marks on a material to be heated.

[0002]

2. Description of the Related Art A continuous steel slab in which a material to be heated is continuously charged and heated to a predetermined temperature as a heating furnace when a metal material such as a steel material such as a slab or a billet is hot-rolled or heat-treated. A heating device is used. Generally, a combustion flame by a burner is used as a heating source. The material to be heated is supported by a skid beam and transported by a walking beam from the loading side of the continuous heating device to the extraction side. It is desirable to heat the material to be heated as uniformly as possible, but it is difficult to heat the material to be heated uniformly since the temperature of the part supported by the skid beam is lower than that of the other parts. The low temperature portion of the material to be heated is called a skid mark.

In order to reduce the skid mark, for example, as disclosed in Japanese Utility Model Application Laid-Open No. 63-131747, in a heating furnace in which the skid beam is shifted in the width direction of the furnace, an extension of the skid beam before the shift is used. A plurality of ejection ports which are open upward and approach the lower position along the same, guide the combustion gas from the combustion burners provided on the side walls to the ejection ports, and eject the combustion gas from the ejection ports to provide a skid. A heating device for heating a mark has been proposed. However, since the temperature of the combustion gas is about the same as the temperature of the atmosphere in the furnace, a large heating capacity cannot be obtained.
Further, there is a problem that the piping is easily worn due to exposure to high temperatures.

[0004]

SUMMARY OF THE INVENTION According to the present invention, there is provided a continuous billet heating means for displacing at least one skid beam among a plurality of skid beams on which a billet is mounted, at one or more locations in the width direction of the heating device. In the displacement position of the skid beam, by forming a combustion region, the surface temperature of the skid beam is increased, the amount of heat applied to the surface of the material to be heated near the skid beam is increased, and the skid mark of the material to be heated is reduced. An object of the present invention is to reduce the wear of a fuel or oxygen supply pipe so that the effect can be enjoyed for a long period of time.

[0005]

According to one embodiment of the present invention, there is provided an apparatus having a plurality of burners, a plurality of skid beams on which a material to be heated is placed in a main body of the apparatus. A continuous billet heating method in which at least one of the plurality of skid beams is provided with one or more displacement portions in the width direction of the apparatus main body, and a material to be heated is continuously charged and heated to a predetermined temperature. In the apparatus, at the displacement point of the skid beam, the fuel supply pipes are arranged along the skid beam before and after the displacement of the skid beam, respectively. The fuel supply pipe which is opened and the fuel supply pipe on the rear side is opened toward the front side of the skid beam displacement to eject fuel, and the skid beam is formed by a flame formed by the fuel and oxygen in the apparatus body. Is a continuous steel strip heating apparatus characterized by heating the neighbor. Further, the present invention is a continuous slab heating device for guiding fuel along the cooling pipe of the skid beam when guiding the fuel supply pipe into the furnace from the connection with the fuel pipe outside the furnace. Further, a method of the present invention for achieving the above object is characterized in that, when heating using the continuous heating device of the present invention, a burner is burned with excess air and fuel is injected from a fuel supply pipe. It is.

Another device of the present invention that achieves the above object is to dispose a plurality of skid beams on which a material to be heated is placed in an apparatus body having a plurality of burners, At least one skid beam among the skid beams is provided with one displacement portion in the width direction of the apparatus main body.
In the continuous billet heating apparatus provided above and continuously heating the material to be heated to a predetermined temperature, the oxygen supply pipes are respectively provided before and after the displacement of the skid beam at the displacement position of the skid beam. Is placed along the skid beam,
The oxygen supply pipe on the front side of the displacement of the skid beam opens toward the rear side of the displacement, and the oxygen supply pipe on the rear side of the displacement opens toward the front side of the displacement of the skid beam to eject oxygen, and the oxygen and the inside of the apparatus main body. A continuous billet heating apparatus characterized in that a vicinity of a skid beam is heated by a flame formed by fuel. Further, it is a continuous billet heating apparatus for guiding oxygen along the cooling pipe of the skid beam when guiding the oxygen supply pipe into the furnace from the connection with the oxygen pipe outside the furnace. Further, the method of the present invention for achieving the above object is a continuous heating method characterized in that, when heating using the continuous heating device of the present invention, a burner is over-burned and fuel is injected from an oxygen supply pipe. is there.

[0007] Still another object of the present invention to achieve the above object is to dispose a plurality of skid beams on which a material to be heated is placed in an apparatus main body having a plurality of burners. In a continuous billet heating apparatus in which at least one of the skid beams is provided with two or more displacement portions in the width direction of the apparatus main body in the at least one skid beam, and the material to be heated is continuously charged and heated to a predetermined temperature, At the displacement point, a fuel supply pipe for injecting fuel and an oxygen supply pipe for injecting oxygen are arranged on the side before and after the displacement of the skid beam, and the injection direction of the fuel supply pipe and the oxygen supply pipe. A continuous billet heating apparatus characterized in that the injection direction is opposed to the vicinity of the skid beam and the vicinity of the skid beam is heated by a flame formed by fuel and oxygen ejected from each supply pipe. Further, the displacement widths of all the displacement points coincide with each other, and the displacement direction of the odd-numbered displacement points and the displacement direction of the even-numbered displacement points are opposite to each other. is there. Furthermore, when guiding the fuel supply pipe and the oxygen supply pipe from the connection portion with the fuel pipe and the oxygen pipe outside the furnace, the fuel and oxygen are guided into the furnace along the cooling pipe of the skid beam. It is a continuous billet heating device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus of the present invention will be described with reference to the illustrated example. FIG. 1 shows a part of a longitudinal section of the continuous heating device, in which a material S to be heated is conveyed on a skid beam 1 along a passing line L. A plurality of burners B1 to B8 are provided as side burners above and below the passage line L in the heating device main body. In this example, a total of eight burners B1 to B8, each of four upper and lower units, are disposed on a line of the same height parallel to the passing line L in a zone divided by the partition wall 4. I have. Such a zone continues in the direction of the passing line L.

FIG. 2 is a cross-sectional view taken along line AA 'of FIG. 1 showing the entire furnace length in a horizontal cross section in the longitudinal direction of the continuous heating apparatus. The skid beams 11 to 14 and the walking beam in the continuous heating apparatus are shown. An example of the arrangement of 21 to 24 is shown. The left side of the figure is the charging side of the material to be heated, and the right side of the figure is the extraction side. The skid beams 11 to 14 form displacement locations C1 to C8 which are displaced in the furnace width direction (direction intersecting the beam length direction) at one or more arbitrary positions in the longitudinal direction. I have. The displacement direction of the displacement portion of the skid beam may be any direction, and in the figure, the displacement portions C1, C2, C7, and C8 are upward, and the displacement portions C3 to C
6 is displaced downward.

FIG. 3 is a diagram showing an example of the installation position of the fuel supply pipe, for example, an enlarged view of a displacement point C3 in FIG. At a displacement point C3 of the skid beam 13, fuel supply pipes 31, 32 are provided along a cooling pipe P indicated by a dotted line in the beam main body. One fuel supply pipe 31 is provided along the cooling pipe on the front side of the displacement point, and opens rearward at the position where the skid beam is displaced, and the other fuel supply pipe 32 is located on the rear side of the displacement point. The cooling pipe is provided along the cooling pipe, and is opened in a forward direction of the displaced portion at a position where the skid beam is displaced. Therefore, the fuel injected from the fuel supply pipes 31 and 32 is ejected in the direction of the arrow in the figure. Since oxygen is provided for combustion in the furnace by overburning the air with the burner, the oxygen and the fuel ejected from the fuel supply pipes 31 and 32 are burned, and the combustion flame F schematically shown in FIG. Is formed. Heat is generated by the flame F, the surface temperature of the skid beam rises, and the material to be heated near the skid beam is heated.

The fuel supply pipes 31 and 32 shown in FIG.
May be an oxygen supply pipe. In such a case, the fuel for combustion is present in the furnace by overburning the fuel with the burner, and the fuel and oxygen ejected from the oxygen supply pipes 31 and 32 are burned, and the combustion schematically shown in the figure is performed. A flame F is formed. Heat is generated by this flame, and the surface temperature of the skid beam 1 rises.

FIG. 4 is a view showing an example in which both a fuel supply pipe and an oxygen supply pipe are installed. 2 shows two adjacent displacement points in the skid beam 1. Fuel supply pipes 31, 32 and oxygen supply pipes 33, 34 are provided along a cooling pipe P indicated by a dotted line in the beam main body. A fuel supply pipe 31 opened toward the rear of the displacement point at the left displacement point in the drawing, and an oxygen supply pipe 3 opened toward the front of the displacement point at the right displacement point in the drawing.
3 is opposed. Although not shown, the fuel supply pipe 32 and the oxygen supply pipe 34 are opposed to the oxygen supply pipe and the fuel supply pipe which are opened at another adjacent displacement point. The fuel injected from the fuel supply pipes 31 and 32 is ejected in the direction of the black arrow in the figure. Similarly, the oxygen injected from the oxygen supply pipes 33 and 34 is emitted in the direction of the white arrow in the drawing. The fuel ejected from the fuel supply pipes 31 and 32 and the oxygen ejected from the oxygen supply pipes 33 and 34 burn, and a combustion flame F schematically shown in the figure is formed.
Heat is generated by this flame, and the surface temperature of the skid beam 1 rises.

By the way, on the surface of the material to be heated near the skid beam, transfer of radiant heat transfer with the surface of the skid beam is dominant. However, since the skid beam is cooled, its surface temperature is generally lower than the ambient temperature in the furnace. Therefore, the surface of the material to be heated in the vicinity of the skid beam is less likely to be heated than other portions.

Since the surface temperature of the skid beam 1 is increased by the combustion flame F shown as an example in FIGS.
The heating capability of the surface of the material to be heated in the vicinity of the skid beam is improved, and skid marks on the material to be heated can be reduced. Moreover, since the fuel supply pipe and the oxygen supply pipe are provided along the cooling pipe, the fuel supply pipe and the oxygen supply pipe are not exposed to the high temperature in the furnace and are not damaged.

[0015]

【Example】

[Example 1 of the present invention] A continuous heating apparatus as shown in FIG.
The billet was continuously heated. Furnace size is 4
0 m, furnace width 10 m, upper zone 7 height 2.2 m,
The height of the lower zone 8 is 2 m. The entire furnace length is divided into four upper and lower zones by partition walls. The preheating zone, the heating zone and the soaking zone each have four burners on the left and right side walls in both the upper zone and the lower zone. The fuel used was coke oven gas.

The skid beam and the walking beam were arranged as shown in FIG. In the heating zone and the soaking zone, 10 skid beam displacement locations were provided for each skid beam every 2 m in the longitudinal direction of the furnace. At the displacement point, the furnace was shifted by 400 mm in the width direction of the furnace. In the two skid beams 11 and 12 at the upper side in the figure, the displacement was performed upward at odd-numbered displacement points, and was performed downward at even-numbered displacement points. In the two skid beams 13 and 14 on the lower side in the figure, the displacement was performed in the downward direction at the odd-numbered displacement points, and was performed in the upward direction at the even-numbered displacement points. The fuel supply pipe of the present invention was provided at the position where the skid beam was displaced as shown in FIG.

The burners in the preheating zone, upper heating zone and upper soaking zone burned at an air ratio of 1.05. The burner in the lower heating zone and the lower soaking zone has an air ratio of 1.5
Burned in. In the lower heating zone and the lower soaking zone, 30% of the total fuel supplied to each zone was supplied from the fuel supply pipe. Thereby, the air ratio of the entire zone in the lower heating zone and the lower soaking zone is 1.0.
It becomes 5.

The material to be heated has a length of 8 m, a width of 1.2 m and a thickness of 2
A 50 mm steel slab, heated for 160 minutes. The installation positions of the material to be heated with respect to the skid beam 1 and the walking beam 2 are as shown in FIG. Further, in order to measure the heating temperature of the material to be heated, a thermocouple was embedded in the material to be heated, and the embedding position is shown in FIG.

FIG. 7 shows the temperature distribution of the material to be heated at the time of extracting the material to be heated, which is measured by embedding a thermocouple in the material to be heated immediately after the continuous heating device of the present invention is operated. In the present invention, the temperature deviation of the mark “○” is 26 ° C., which indicates that the heating of the material to be heated is more uniform than that of 43 ° C. in the mark “△” of the following conventional example. 30 days after operating the continuous heating device of the present invention and 9 days after
FIG. 8 shows the temperature distribution of the heated material at the time of extracting the heated material measured after embedding the thermocouple in the heated material 0 days later. 3
The temperature deviation after 0 days is 25 ° C, and the temperature deviation after 90 days is 26
° C, which shows that a skid mark reduction effect equivalent to that immediately after operation is obtained.

Inventive Example 2 In the heating apparatus used in Inventive Example 1, the material to be heated was heated in the same manner as in Inventive Example 1, except that the fuel supply pipe was changed to an oxygen supply pipe. The burners in the preheating zone, upper heating zone and upper soaking zone burned at an air ratio of 1.05. The burners in the lower heating zone and lower soaking zone burned at an air ratio of 0.735. In the lower heating zone and the lower soaking zone, 30% of the total oxygen supplied to each zone was supplied from the oxygen supply pipe. Thereby, the air ratio of the entire zone in the lower heating zone and the lower soaking zone is 1.05. The method of measuring the size and the heating time of the material to be heated and the heating temperature of the material to be heated are the same as those in Example 1 of the present invention.

FIG. 9 shows the temperature distribution of the material to be heated at the time of extracting the material to be heated, which is measured by embedding a thermocouple in the material to be heated immediately after the continuous heating device of the present invention is operated. In the present invention, the temperature deviation of the mark “○” is 28 ° C., which indicates that the heating of the material to be heated is more uniform than that of 43 ° C. of the mark “従 来” of the following conventional example. 30 days after operating the continuous heating device of the present invention and 9 days after
FIG. 10 shows the temperature distribution of the material to be heated at the time of extraction of the material to be heated, which was measured by embedding the thermocouple in the material to be heated after 0 day.
The temperature deviation after 30 days is 28 ° C, and the temperature deviation after 90 days is 3
At 0 ° C., it can be seen that a skid mark reduction effect equivalent to that immediately after the operation was obtained.

Inventive Example 3 In the heating apparatus used in Inventive Example 1, half of the fuel supply pipes were changed to oxygen supply pipes, and the material to be heated was heated in the same manner as in Inventive Example 1. When changing the fuel supply pipe to the oxygen supply pipe, the fuel supply pipe and the oxygen supply pipe were changed so as to face each other. The burners in the preheating, heating and soaking zones burned at an air ratio of 1.05. However, the burner in the lower heating zone and the lower soaking zone reduced the combustion load to 70%. In the lower heating zone and the lower soaking zone, 30% of the total fuel supplied to each zone was supplied from the fuel supply pipe, and 30% of the total oxygen was supplied from the oxygen supply pipe. Thereby, the air ratio of the entire zone in the lower heating zone and the lower soaking zone is 1.05. The method of measuring the size and the heating time of the material to be heated and the heating temperature of the material to be heated are the same as those in Example 1 of the present invention.

FIG. 11 shows the temperature distribution of the material to be heated at the time of extracting the material to be heated, which is measured by embedding a thermocouple in the material to be heated immediately after the continuous heating device of the present invention is operated. Example of the present invention ○
The temperature deviation of the mark is 23 ° C, and the following conventional example 43 ° C of the mark
It can be seen that the heating of the material to be heated is more uniform than in FIG. 30 days after operating the continuous heating device of the present invention and 9 days after
FIG. 12 shows the temperature distribution of the material to be heated at the time of extracting the material to be heated, which was measured by embedding the thermocouple in the material to be heated after 0 day.
The temperature deviation after 30 days is 23 ° C, and the temperature deviation after 90 days is 2
At 4 ° C., it can be seen that a skid mark reduction effect equivalent to that immediately after the operation was obtained.

[Conventional Example] Combustion gas guide tube 9 shown in FIG.
And the combustion gas ejection pipe 10 were set in the lower heating zone and the lower soaking zone. The air ratio of each burner B and the material S to be heated
The material to be heated was heated under the same conditions as in Example of the present invention except for the size, heating time and the like. The temperature distribution of the material to be heated at the time of extracting the material to be heated was as indicated by the triangle in FIG. 7 immediately after the operation of the heating device.

[0025]

According to the heating apparatus and method of the present invention,
By forming a combustion zone near the skid beam,
Raises the surface temperature of the skid beam, increases the amount of heat applied to the surface of the material to be heated near the skid beam, reduces skid marks on the material to be heated, and reduces the wear on the fuel supply tube and oxygen supply tube. Can be enjoyed.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of an example of a continuous heating apparatus according to the present invention in a furnace length direction.

FIG. 2 is a horizontal cross-sectional view in the furnace length direction showing the arrangement of a skid beam and a walking beam of the continuous heating apparatus of the present invention, and is a view taken along the line AA ′ in FIG.

FIG. 3 is a diagram showing an example of an installation position of a fuel supply pipe or an oxygen supply pipe of the continuous heating device of the present invention.

FIG. 4 is a diagram showing an example of the installation positions of a fuel supply pipe and an oxygen supply pipe of the continuous heating device of the present invention.

FIG. 5 is a horizontal cross-sectional view in the furnace length direction showing the arrangement of a skid beam and a walking beam of the present invention example and the conventional example.

FIG. 6 is a diagram showing a thermocouple embedment position for measuring a heating temperature of a material to be heated according to an example of the present invention and a conventional example.

FIG. 7 is a diagram showing the temperature distribution of the material to be heated at the time of extracting the material to be heated immediately after the operation of the facility of Example 1 of the present invention and the conventional example.

FIG. 8 is a diagram showing the temperature distribution of the material to be heated at the time of extracting the material to be heated 30 days after and 90 days after the operation of the facility of Example 1 of the present invention.

FIG. 9 is a diagram showing the temperature distribution of the material to be heated at the time of extracting the material to be heated immediately after the operation of the facility of Example 2 of the present invention and the conventional example.

FIG. 10 is a diagram showing a temperature distribution of a material to be heated at the time of extracting the material to be heated 30 days and 90 days after the operation of the facility of Example 2 of the present invention.

FIG. 11 is a diagram showing the temperature distribution of the material to be heated at the time of extracting the material to be heated immediately after the operation of the facility of Example 3 of the present invention and the conventional example.

FIG. 12 is a diagram showing the temperature distribution of the material to be heated at the time of extracting the material to be heated 30 days and 90 days after the operation of the facility of Example 3 of the present invention.

FIG. 13 is a view showing installation positions of a combustion gas guide pipe and a combustion gas ejection pipe of a conventional example.

[Explanation of symbols]

 1, 11 to 14 Skid beam 2, 21 to 24 Walking beam 3, 31 to 34 Fuel supply pipe or oxygen supply pipe 4, Partition wall 5, Ceiling wall 6, Furnace floor wall 7, Upper zone 8, Lower zone 9: Combustion gas guide pipe 10: Combustion gas ejection pipe C1 to C8 Displacement point of skid beam B, B1 to B8 ... Burner D ... Insulation material L ... Passing line P ... Cooling pipe S ... Material to be heated

Claims (8)

[Claims] 1. An apparatus body having a plurality of burners,
A plurality of skid beams on which a material to be heated is placed are arranged, and at least one of the plurality of skid beams is placed.
In a continuous billet heating apparatus in which one or more displacement parts in the width direction of the apparatus main body are provided in the book skid beam and the material to be heated is continuously charged and heated to a predetermined temperature, The fuel supply pipes are arranged along the skid beam before and after the displacement of the skid beam, respectively.The fuel supply pipe before the displacement of the skid beam opens toward the rear side of the displacement, and the fuel supply pipe on the side after the displacement is disposed. A continuous steel billet heating apparatus characterized in that a supply pipe is opened toward the front side of the displacement of the skid beam to eject fuel, and the vicinity of the skid beam is heated by a flame formed by the fuel and oxygen in the apparatus body. 2. The fuel supply system according to claim 1, wherein the fuel supply pipe is replaced with an oxygen supply pipe, and the vicinity of the skid beam is heated by a flame formed by oxygen ejected from the oxygen supply pipe and fuel in the apparatus main body. Continuous billet heating device. 3. An apparatus main body having a plurality of burners,
A plurality of skid beams on which a material to be heated is placed are arranged, and at least one of the plurality of skid beams is placed.
In a continuous steel billet heating apparatus in which two or more displacement points in the width direction of the apparatus main body are provided in the book skid beam and the material to be heated is continuously charged and heated to a predetermined temperature, at the displacement points,
A fuel supply pipe for injecting fuel and an oxygen supply pipe for injecting oxygen are arranged before and after the displacement of the skid beam, and the injection direction of the fuel supply pipe and the injection direction of the oxygen supply pipe are opposed to each other. A continuous billet heating apparatus characterized in that the vicinity of a skid beam is heated by a flame formed by fuel and oxygen ejected from each supply pipe. 4. The displacement width of all the displaced portions coincides, and the displacement directions of the odd-numbered displaced portions and the even-numbered displaced portions are opposite to each other. Continuous billet heating equipment. 5. When the fuel supply pipe is introduced into the furnace from a connection with the fuel pipe outside the furnace, the fuel is guided into the furnace along the cooling pipe of the skid beam. Item 4. A continuous billet heating apparatus according to item 1 or 3. 6. When the oxygen supply pipe is introduced into the furnace from the connection portion with the oxygen pipe outside the furnace, oxygen is guided into the furnace along the cooling pipe of the skid beam. Item 4. A continuous billet heating apparatus according to item 2 or 3. 7. A continuous heating method using the continuous heating device according to claim 1 or the continuous heating device according to claim 5, wherein burner is burned with excess air and fuel is injected from a fuel supply pipe. Continuous heating method. 8. A continuous heating apparatus using the continuous heating apparatus according to claim 2 or the continuous heating apparatus according to claim 6, wherein the burner burns fuel excessively and oxygen is injected from an oxygen supply pipe. Continuous heating method.