JPS62142727A - Cooling apparatus for steel strip - Google Patents

Abstract

PURPOSE:To contrive water cooling at a middle temp. part and to improve cooling efficiency, by providing spray headers for water cooling and suction drum to the middle temp. part at a specified temp. range in a cooling zone, in a vertical heat treating furnace for a steel strip. CONSTITUTION:The suction drums 4a, 4b, 5 and the spray headers 6 are provided to the middle temp. part (b) of the cooling zone B. On both surfaces of the steel strip 10 cooled to 600-800 deg.C at a high temp. part (a) and passed through the part (b), the cooling water is injected from the headers 6 through a feed water pipe 34 by a pump 13 from a cooling water tank 11. In such a way, the strip 10 is water cooled to 300-450 deg.C, and cooling water flowing down or scattering on the surface of strip 10 is sucked by a blower 26 through a drainpipe 35 and completely sucked. In this way, since the flowing-down of cooling water to a low temp. part (c) can completely be interrupted and the part (c) can completely be air cooled, the deformation of steel strip due to transient boiling is not caused.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling device for a vertical continuous heat treatment furnace for heat treating steel strips such as austenitic stainless steel. [Prior Art] Continuous heat treatment of steel strips As an example of a furnace, as shown in the schematic vertical cross-sectional view of FIG. Air jet chamber 7
, lower air jet chamber 8, dipping tank 9
There is a vertical continuous heat treatment furnace consisting of a cooling zone (B) consisting of a cooling zone (B), etc. For example, a steel strip 10 such as austenitic stainless steel is heated to about 1100°C in a heating zone (A),
The cooling zone (B) is passed through the plate at a high speed of, for example, 10 to 150,771/cm to rapidly cool the plate to 100° C. or lower.

In the high temperature section (a) of this cooling zone (B), the temperature of the steel strip 10 passing through the sheet is controlled while being cooled by the combustion exhaust gas ejected from the gas curtain chamber 2 and the cooling air ejected from the upper air jet chamber 3. The cooling air flow is detected by a temperature detector 16a installed in the damper 14, and the opening degree of the damper 14 is adjusted by instructing the damper 14. By adjusting #, it is constantly cooled to a range of 600 to 800 tl. In the medium temperature section (b) and the low temperature section (C), temperature detectors i6 are installed at the respective outlets in the same way as described above.
b.

16c detects the temperature of the copper strip 10, adjusts the damper 14, and adjusts the Kt of each cooling air, thereby controlling the temperature between 300 and 450 degrees C and 150 and 2, respectively
Cool to a range of 50°C. Then, it is cooled to 100° C. or lower by immersing it in cooling water in a dipping tank 9, and sent to the next process via a zinc roll 19.

[Problem that the invention seeks to solve]

If the steel strip 10 in the high-temperature section (a), medium-temperature section (b), and low-temperature section (C1) is all cooled by air cooling, the cooling capacity is low, so a huge amount of air is required, and the power of the proar 12 becomes large. Therefore, the medium temperature part (b) 'e, which is the temperature range where water cooling is possible, is cooled by spraying cooling water, or
Alternatively, cooling by so-called laminar cooling, etc., which directly sprays water, has a higher cooling capacity than air cooling, resulting in significant energy savings; will also be water cooled.

However, when the copper strip 10 is water-cooled in the low temperature section (e), it enters the transition boiling region as shown in the graph of FIG.
Conventionally, it has been considered difficult to cool the middle temperature section (b) with water because the cooling curve is different from that of the middle temperature section (b) and deformation as shown in FIGS. 7 and 8 occurs.

[Failure to solve the problem]

In a vertical continuous heat treatment furnace, the cooling zone (600 to 800
A spray header and a suction drum for water cooling are provided in the medium temperature section, which is in the temperature range from 300 to 450 degrees Celsius.

[Effect]

The copper strip, which has been cooled to 600 to s o o ℃ in the high temperature part of the cooling zone, is further cooled to 300 °C by water cooling using a spray header in the medium temperature part.
Cool to ~450°C and send to cold section. Each suction roll completely sucks the cooling water injected from the spray header and blocks it from flowing down to the low temperature section, while the upper and lower suction rolls absorb the cooling water that tries to enter the medium temperature section from the high temperature section and the low temperature section. suction air.

〔Example〕

One embodiment according to the present invention is shown in the schematic longitudinal sectional view in FIG.
This will be explained with reference to detailed longitudinal sections in FIGS. 3 and 3, and the same members as those described for the conventional device (FIG. 5) are given the same reference numerals, and redundant explanation will be omitted.

In Fig. 1, 4a and 4b are suction drums that are rotatably installed in pairs at the upper and lower parts of the medium temperature section (b), and 5 at the center, respectively. It is in contact with both sides of the steel strip 10 over its entire width. 6 is a spray header having a nozzle portion that sprays cooling water over the entire width of the copper strip 10, and each suction drum 4a, 4b.

It is fixedly installed between 5. Gas jet chamber 2, upper air jet chamber 3, suction drums 4a, 4
b+ 5% Main members such as the spray header 6, lower air jet chamber 8, and dipping tank 9 constitute a cooling zone (BI).

In FIGS. 2 to 4, 40 is a suction drum supported by a bearing 47a, and 16 rows of suction holes 4 in the circumferential direction are provided on the outer peripheral surface.
0a is bored over the entire width.

Reference numeral 42 denotes a fixedly supported cooling water suction pipe in which a circumferential row of suction holes 112 a are bored, and the left side thereof is connected to the drain pipe 35 . Reference numeral 43 denotes an air suction pipe fixed inside the cooling water suction pipe 42. Two rows of suction holes 43a are bored in the circumferential direction, and the left side thereof is connected to the exhaust pipe 33. It is a double pipe. The portion of the cooling water suction pipe 42 surrounded by the suction drum 40 is divided into two in the circumferential direction, and the portion between the cooling water suction pipe 42 and the air suction pipe 430 is sealed by a partition plate 46. A flange 48 is fixed to the left outer periphery of the cooling water suction pipe 42 and connects the cooling water suction pipe 42 and air suction'? The right end of 43 is sealed with a lid 49. 41 is a wiper made of heat-resistant resin or carbon, which connects the cooling water suction pipe 4 through a spring 44 and a guide.
They are arranged in two rows in the circumferential direction on the outer surface of No. 2. Cooling water suction pipe 42
A lit receiver 47b is provided between the center protrusion 49kl of the lid 49 and the 7th flange 40c of the suction drum 40, and a bearing 147C is provided between the center protrusion 49kl of the lid 49 and the 7th flange 40c of the suction drum 40. The flange 48, gaskets 48a and 49a on the outer periphery of the lid II9, and the wiper 41 come into contact with the inner surface of the suction 1/1 ram 40.

The above-mentioned members constitute the upper and lower conductor drums 4a and 4b.

Reference numeral 50 denotes a relatively small-diameter suction drum supported by a bearing 55a, and has twelve rows of suction holes 50a formed in the circumferential direction on its outer peripheral surface over its entire width. Reference numeral 52 denotes a fixedly supported cooling water suction pipe, in which a circumferential row of suction holes 52 a are bored, and the left side thereof is connected to the drain pipe 35 . A flange 56 is fixed to its left outer periphery, and its right end is sealed with a lid 57. 51 is Waino, spring 53
They are arranged in two rows in the circumferential direction on the outer surface of the cooling water suction pipe 52 via a guide 54. Cooling water suction 'W52 suction 1
- A bearing 551) is provided between the flange 50b of the ram 50 and the central protrusion 57b of the lid 57 and the suction drum 57.
A bearing 55c is provided between the seventh flange 50C and the seventh flange 50C. /ξ Mitsukin 56a, 5 on the outer periphery of the flange 56 and lid 57
A wiper 51 is installed in contact with the inner surface of the suction drum 50. The suction drum 5 in the central portion is constituted by the above members.

Cooling water is sprayed from the spray header 6 from the cooling water tank 11 through the water supply pipe 34 by the pump 13 to both sides of the copper strip 10 which is cooled to 600 to 800°C in the high temperature part and passed through the medium temperature part fb). Inject and cool with water to 300-450℃,
The cooling water flowing down or scattering on the surface of the copper strip 10 is completely sucked out from the suction holes 40a, 50a of each suction drum 40, 50 by suctioning it through the drain pipe 35 by the proa 26, and the air mixed in at this time is removed. It is separated by the lamist separator 24 and returned to the cooling water tank 11 by the drain pipe 37. The temperature of the steel strip 10 at the outlet of the medium temperature section (b) is always detected by the temperature detector 16b, and the amount of water to be injected is adjusted by adjusting the valve 15, and the temperature at the outlet is maintained at 300 to 450°C. ing. Further, the cooling air that is about to enter the medium temperature section (b) from the high temperature section ta+ and the low temperature section fc) is sucked by the blower 25 through the exhaust pipe 33 and sucked out from the suction hole 40a of the suction drum 40.

Each suction drum 40, 50 is pressed against the steel strip 10 with an appropriate pressure by a spring or the like (not shown), and is rotated in synchronization with the threading speed of the copper strip 100 by a drive device (not shown) on the right side.

While rotating, each of the rams 4a, 4b, and 5 of the sakshi mint 1 opens the suction holes 40a between each two rows of wipers 41 and 51.
, sucks cooling water from 50a, cooling water suction pipe 42.5
The water is sucked into the interior through the two suction holes 42a and 52a, and drained from the drain pipe. Wiper 41.51 is spring 4
4.53, the cooling water that is pressed against the inner surface of one suction drum 40.50 with an appropriate pressure and attached to the inner surface of the suction drum 40.50 is rotated by the two wipers 41.5.
Wipe off anything that tries to leak outside of 1.

The wiper 41 of each suction drum 4a, 4b cools the cooling air blown out from the high temperature part (a) above the wino<-41 of the upper suction drum 4a and the low temperature part (bl) below the lower suction drum 4b. It is sucked up through the upper and lower suction holes and discharged through the exhaust pipe 33.

〔Effect of the invention〕

The cooling device A according to the present invention has a medium-temperature section that is water-cooled and is equipped with a suction roll that completely sucks the cooling water, so that the cooling water can be completely blocked from flowing into the low-temperature section. Since it is completely air cooled, deformation of the copper strip due to transition boiling does not occur.

Therefore, water cooling in the medium-temperature section becomes more efficient, and with the improvement of cooling efficiency, it is possible to save a large amount of cooling energy.

[Brief explanation of drawings]

Fig. 1 is a schematic vertical cross-sectional view of an embodiment of the cooling device of the uninvented copper strip, Fig. 2 is a cross-sectional view of the intermediate temperature section of Fig. 1, and
The figure is a cross-sectional view taken along the line ■-■11 of No. 21J, FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 2, and FIG. A schematic longitudinal sectional view, and Figure 6 is a graph showing a cooling curve when the low temperature part is water-cooled.
FIGS. 7 and 8 show transition boiling during water cooling in the t-temperature zone. - A front view and a sectional view showing the deformation of the band. B...Cooling zone, b...Medium temperature section, 4a, 4b, 5...
・Suction drum, 6... Spray header, 10・
...He is Steel Emperor. Later Patent Attorney Shigefumi Okamoto and 2 others Figure 1 Figure 2 Figure 5 - Figure 8

Claims (1)

[Claims] In a vertical continuous heat treatment furnace for heat treating steel strips, a spray header and a suction drum for water cooling are installed in the medium temperature section of the cooling zone, which is in the temperature range from (600 to 800 degrees Celsius) to (300 to 450 degrees Celsius). Features a steel strip cooling device.