JPS58207331A - Heating furnace for rolling - Google Patents

Abstract

PURPOSE:To make the temp. of a steel material in the transverse direction of a heating furnace for rolling uniform without decreasing productivity, by providing partition walls which suspend down to the prescribed height above the steel material and are longitudinal in the transfer direction of the steel material near both side walls of said furnace. CONSTITUTION:Partition plates 7 are provided respectively near side walls 1a in the furnace chamber 6 of a heating furnace 1 for rolling. The longitudinal direction of the plates 7 is made identical with the conveying direction of a slab 3 and the top end parts of the plates 7 are stuck to the ceiling part 1b of the wall 1. The bottom end parts thereof are suspended down to the prescribed height from the surface of the slab 3. The plates 7 are provided in the position within about 1.2m from the wall 1a. Burners 4b provided in the small furnace chamber segmented in both end parts of the slab 3 are usually held extinguished in order to maintain the low furnace temp. in said segments or a small amt. of fuel to the extent of maintaining the temp. is charged thereto. The deviation in the temp. of the slab 3 in the transverse direction thereof is thus decreased to about 15 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a rolling heating furnace that heats steel materials such as slab blooms to a predetermined temperature required for rolling.

Recently, the demand for pipe materials with high toughness even at low temperatures has been increasing, and for this reason, the demand for chondral rolling materials is increasing. When rolling this chondral rolling material, titanium, niobium, etc. are used. With the usual component system to be added, the slab temperature at the time of heating furnace extraction is 90
The temperature is as low as 0 to 1,100°C, and the temperature deviation between the grain size value and the minimum pupil temperature in the slab needs to be thermalized (uniformed) to 20 to 40°C or less. Moreover, since the slab of the above-mentioned composition system needs to have a fine structure at the start of rolling, there is a restriction that the above-mentioned additives must not form a solid solution during heating. 11u It is usually necessary to keep the temperature below 0 to 20°C. As shown in Fig. 1, the temperature deviation within the slab that occurs in commonly used rolling heating furnaces such as walking beam furnaces and pusher furnaces has the following three elements (in Fig. 1, the slab 6 is ).

(1), Temperature deviation within the slab 6 in the thickness direction (for example, temperature deviation between B and F, usually B>C>F) (2), Slab temperature at the part that contacts the skit 2 that supports the slab 6 However, the so-called skid marks (for example, the flat fE of the X section and the
J temperature difference C>D) (3), furnace width direction furnace temperature distribution, furnace 1i
j! Slab temperature deviation in the furnace width direction caused by the shape relationship between the slab and the furnace mold including l'4W1a (for example, temperature g difference between A-B straddle E-F, A>B straddle E>F) The temperature deviation in (2) is approximately 15 to 20°C in the above (1) in normal heating that uniformly heats in the width direction of the furnace during the furnace time that ensures a predetermined productivity.
In θζ, it is about 20 to 50°C, and in (3) above, it is about 50 to 40°C.

That is, the difference between the highest temperature point within the slab and the lowest temperature point within the slab is approximately 50°C. Among these, the present invention relates to the temperature deviation shown in (3) above, and the present invention relates to the temperature deviation shown in (1) and (3) above.
Assuming that the temperature deviation that occurs in 2) is unavoidable,
It is necessary to reduce the temperature deviation according to (3) above to about 10°C or less.

For example, when the slab 3 is heated in a conventional rolling heating furnace equipped with all axial flow burners 4 as shown in FIG. 2, the furnace temperature in the width direction of the furnace is as shown in FIG. 6.

By the way, the longitudinal side of the slab 6, that is, the vicinity of the furnace side wall 1a, is easily heated due to its shape with the furnace shape.
Therefore, the temperature deviation within the slab in the furnace width direction becomes as shown in FIG. In Figure 4, the temperature deviation inside the slab in the furnace width direction seems to be shown by the line (A) or (B) ((A) is the slab surface temperature, (B) is the center of the slab in the thickness direction - opposite), about 30 degrees.
At the longitudinal ends of the slab, the amount of overshoot relative to the average extraction temperature (c) is approximately 65°.
C, which does not meet the requirements of the Chondral rolling material mentioned above. In this case, conventional measures have been taken such as cutting off the entire slab for the portion that exceeds the requirements, resulting in a decrease in yield. On the other hand, the temperature deviation in the longitudinal direction of the slab 6 also affects the amount of width expansion of the plate material during rolling, so if the temperature deviation becomes large, the width of the plate at the end of rolling will vary, resulting in truncation loss. This resulted in a significant decrease in yield, as the material increased and was scrapped as defective material.

To deal with such an open chain, conventionally, as shown in No. 51Δ, in order to lower the furnace temperature around the furnace side wall 1a, the furnace Ji1
Extinguish the axial flow burner 4a on the I51!1 side of a, or set the furnace temperature lower to extend the furnace time a.
hv, a method was adopted to reduce the temperature deviation within the slab in the furnace width direction. However, by using the fourth method, the furnace temperature on the furnace side 1a decreased, and the temperature unevenness inside the slab was improved by 20°C6 as a practical result, but the target 1a
Achieving temperatures below 0°C was difficult. Also, in the latter method, as shown in Fig. 6, the temperature deviation in the slab in the furnace width direction (TE-T8) became smaller if the furnace time was increased (however, the furnace temperature in both the furnace length direction and furnace width direction decreased). (Assuming that the temperature is constant at 1020°C and the slab extraction temperature is 950°C), this direction greatly reduces production efficiency and requires long heating times, so it is difficult to guarantee productivity. (to the extent possible)
However, there were disadvantages such as the fact that the energy consumption was limited and the fuel consumption was also poor (in terms of fuel consumption), which was contrary to the purpose of energy conservation. Furthermore, there is a strong correlation between the temperature deviation within the slab during heating and the amount of alloys such as titanium and niobium added. The amount of alloys such as titanium and niobium that need to be processed has increased, increasing production costs. In conventional methods, it is not possible to reduce the temperature deviation within the slab in the width direction of the furnace, so this was dealt with by increasing the amount of alloys such as titanium and niobium added, but this increased production costs.

The present invention has been made in order to solve the above-mentioned drawbacks, and it is possible to reduce
The objective is to obtain a rolling heating furnace that uniformly heats steel materials such as slabs and blooms.

Is the present invention intended for the above purpose? It was done to achieve
A partition plate is provided near both side walls of the rolling heating furnace, the partition plate hanging down from the ceiling of the rolling heating furnace to a predetermined height above the steel material, and whose longitudinal direction is the direction in which the steel material is transferred. The present invention provides a rolling heating furnace.

7 shows an embodiment of the present invention, and is a vertical sectional view of a rolling heating furnace in which the door 6 is surrounded by the furnace wall 1, with respect to the direction in which the slab 60 is drawn. The rolling heating furnace 1 is provided with a partition wall 7 on the side G of the furnace side wall 1aIt of the furnace chamber 6. The longitudinal direction of the partition wall 7 is set in the same direction as the conveying direction of the slab 6, and the upper end of the partition plate 7 is connected to the furnace side wall 1aIt. 1 on the ceiling 16 of wall 1! 4
L, the upper end is ηζ so that it hangs down from the surface of the slab 6 with a weave 11 in places. Note that the partition wall 7 is the furnace 171a.
It is located within approximately 1.2 m from the

Therefore, the single-heating furnace chamber 6 is substantially divided into three furnace chambers by the partition wall 7. Both sides of the slab 3 are each divided into relatively small furnace chambers, and the burners 4b in each of these compartments are used to lower the furnace temperature in this compartment compared to the furnace temperature in the central compartment. , it is usually desirable to input a small amount of fuel to extinguish or retain heat. Due to the radiation of the partition wall 7, the furnace temperature in the sections on both sides of the slab 6 becomes lower than that in the center section, and the swallow radiation from the ceiling of the furnace wall in the center of the furnace to both sides of the slab is becomes smaller. This suppresses the temperature rise on both sides of the slab, and
The temperature in the longitudinal direction is equalized.

When the present invention was carried out based on the above (four compositions), the extraction temperature was 950°C, the furnace temperature was approximately 1020°C, and the heating time was approximately 230°C.
Under heating conditions of 10 minutes, when the difference in temperature between the central part of the furnace chamber 6 and the furnace wall 1a is approximately 70°C, the temperature deviation in the longitudinal direction of the slab 6 becomes minimum, which is approximately 10°. It was C. Note that if the distance between the lower end of the partition wall 7 and the top surface of the slab 6 in the lower zone 6 of the partition wall 7 and the distance between the top of the partition wall 7 and the bottom surface of the slab 3 in the lower zone change, The effect provided by the partition wall 7 varies. Therefore, in order to reduce the temperature deviation in the longitudinal direction of the slab 3 as much as possible, it is desirable that the height of the partition wall 7 is variable so that it can always be set to an appropriate value.

The relationship between the furnace width direction and the furnace temperature of the rolling heating furnace (FIG. 7) according to the present invention is shown in FIG. 8, and the relationship between the slab longitudinal direction and the slab surface temperature is shown in FIG. ) is the target average extraction temperature.

Note that a four-piece axial flow burner provided in the heating furnace or a roof burner may be used instead. In the case of a side burner, the partition wall may be completely opened only in the area that is exposed to the flame of the side burner.

FIG. 10 shows another practical example of the present invention, in which a movable partition wall 7a that partitions the upper part of the furnace chamber 6 is suspended and supported by a chain 8 connected to a winding mechanism installed outside the furnace. shows.

The movable partition wall 7a is suspended in the furnace chamber 6 by a chain 8 via a hook 9. The chain is wrapped around an 8-piece sprocket 10b, and the rotating shaft 11 of the sprocket 10b
It is connected to a motor 16 via a motor sprocket 12. Therefore, by driving the motor 13 to rotate the sprocket 10b and letting out or winding the chain 8, the movable partition wall 7a can be raised and lowered. A guide 14 is provided to completely prevent or reduce leakage of the furnace atmosphere gas from the sliding portion of the partition wall 7a, and to guide the movable partition wall 7a in the vertical direction.

It can be detected by detecting the rotation angle of the partition wall 7a (for example, the sprocket) 10b, and its value is determined by checking the furnace temperature distribution in the furnace width direction and the temperature distribution in the furnace or in the longitudinal direction of the slab at the time of extraction. However, the temperature deviation inside the slab is adjusted to be small. If the distance between the furnace gl wall'') a and the end of the slab 6 changes, the effect of the partition wall 7a will change; If the partition 7a is provided so that the distance from the side wall 1a), the effect remains the same and uniform heating is possible.In order to further increase the effect of the partition wall, it is possible to As another embodiment of the present invention, a method of providing a plurality of partition walls and sliding them vertically or in the oven width direction depending on the length of the slab is also possible in order to achieve more uniform heating.

Further, the partition wall does not necessarily need to be provided over the entire length of the furnace, and may be installed only in the leveling zone or the soaking zone and heating zone where it is highly effective. The thickness of the partition wall is not particularly limited, but the thinner the better.

Further, in this embodiment, the case where the partition wall is provided in the upper part of the furnace has been described, but it is also possible to provide it in the lower part of the furnace. The main purpose of the partition wall is to raise and lower the furnace temperature near both ends of the slab and to completely block heat radiation from the center of the furnace to both ends of the slab. It is also possible to perform Flm with gold and ceramics.

As is clear from the above explanation, according to the invention, the temperature in the longitudinal direction of steel materials such as slab blooms can be uniformized without reducing productivity by providing all partition walls that partition the inside of the furnace. This makes it possible to heat the area in a fraction of the time, and since it reduces the portion that is heated in vain, it contributes to the ray energy, which is highly effective.

[Brief explanation of the drawing]

Figures 1, 2, and 5 are cross-sectional views of an example of a conventional heating furnace, and Figures 3, 4, and 6 show the temperature in the width direction of the conventional heating furnace, and the temperature in the longitudinal direction of the slab. A diagram showing the relationship between temperature, heating time, and temperature deviation, FIG. 7 is a cross-sectional view of the embodiment of the present invention, and FIGS. 8 and 9 are diagrams showing the temperature in the oven width direction and the longitudinal direction of the slab according to the embodiment of the present invention. FIG. 10, a diagram showing the temperature, is a cross-sectional view of another conventional example of the present invention. 1a...Side wall, 1b...Furnace ceiling, 6...Slab, 7.7a...Partition plate ◇ Agent Patent attorney Sanro Kimura Fig. 5 Fig. 6 Fig. 6 1σ藝I! 1'Dark Bon Figure 7 Figure 8 Figure 9 T h''77'8 Suzakuta Figure 10 Procedural Amendment (Voluntary) Director of the Japan Patent Office '8゛ June 3, 1982
81゜2, Relation to the case of the person amending the name of the invention for rolling heating furnace (,,;; Patent applicant name (
412+ 3 Main Steel Pipe Co., Ltd. Contents of supplementary IF subject to agent amendment =)・1) Erroneous parts in this specification will be corrected as follows. Page lines, errors, corrections,
2.1 to 4 mm and the above component system: In addition, in the varnish slab, the structure at the beginning of rolling must be fine and fine, so there is a restriction that the above additives must not be mixed together during heating. , 3. 10-11' under 10℃5fDu't 10
The temperature needs to be about ~15°C. It is necessary to keep the above-mentioned condolence below 46-4.
5112 Titanium, niobium, etc. □ Alloy Quantity of alloy storage is ゛6° 7・lE1ka. ,. +si*o. - Earthquake ~, 1-1 ship car 2/)------,',
−−−−−−−−. 6; 9 Rolling heating furnace) Rolling heating furnace 7'
20. It was 10c. The temperature was 15°C. 12) In this specification, from page 9, line 16 to page 10, line 9, "It is acceptable to use only the furnace side wall 1a and the slab 6."
Delete that part. 6) The claims of this specification are amended as shown in the attached sheet. 4) Correct Figure 9 in the separate sheet. :1:: Attachment "Claims Claims: A partition plate that hangs down at a predetermined height above the steel material [2 and whose longitudinal direction is the direction in which the steel material is transported] is provided near both side walls of the rolling heating furnace." Features of rolling heating furnace.” Revised drawing

Claims (1)

[Claims] A rolling heating device characterized in that a partition plate is provided near both side walls of the rolling heating furnace, the partition plate hanging down to a predetermined height above the steel material from the ceiling of the rolling heating furnace and having its longitudinal direction in the direction of conveyance of the steel material. Furnace.