JPS5974240A - Method for controlling temperature of steel sheet apparatus for measuring temperature of the same - Google Patents

Abstract

PURPOSE:To detect exactly the temp. of a hot-rolled steel sheet in a spray cooling zone and control precisely the cooling rate of the steel sheet in accordance with the detected temp. in the stage of water cooling the hot-rolled steel sheet by providing a radiation thermometer contained in a waterproof box to remove the influence of cooling water below the steel sheet. CONSTITUTION:A waterproof box 13 is installed below a steel sheet 4 in the intermediate positions of table rolls 12, 12 for conveying the sheet 4 and a temp. measuring device 11 having a radiation thermometer 14 disposed is provided therein the stage of cooling a hot-rolled steel sheet 4 by the spray of cooling water. The temp. of the sheet 4 is exactly measured from the rear by the thermometer 14 without receiving the influence of the cooling water flowing under the sheet 4 by a water shielding plate 20 and water shielding shutters 15, 17 provided to the box 13. The cooling rate of the hot-rolled steel sheet by the spray of the cooling water is adequately controlled by controlling the amt. of the spraying cooling water by the temp. measured with said thermometer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the temperature of a steel plate in a spray zone and a device for measuring the temperature of the steel plate.

Generally, when rolling a steel plate, knowing the temperature of the steel plate is important not only for operating the rolling mill but also for obtaining the desired mechanical properties of the plate. For this purpose, temperature measuring devices have conventionally been provided at various locations such as the descaling stand, the front and rear surfaces of the rolling mill, and the water cooling device.

However, in the spray zone, water was deposited on the upper surface of the steel plate, and cooling water entered the temperature measuring device below the p1 steel plate, so it was not possible to measure the temperature in the spray zone.

Therefore, as shown in FIG. 1, a steel plate 4 obtained by rolling a steel billet extracted from a heating furnace 1 by a rough rolling mill 2 and a finishing rolling mill 3 of several stands is placed in a first cooling spray zone 5 and a second cooling spray zone 5. In the line where the steel plate 4 is cooled in the cooling spray zone 6 and wound up by the winder 7, the temperature of the steel plate 4 in the spray zone 5.6 is determined at the entrance side of the spray zone 5, between the spray seats 75 and 6, and at the exit of the spray zone 6. Temperature measuring devices 8, 9.1 respectively above the sides
0, the upper surface temperature of the steel plate 4 was measured, and based on the temperature, prediction was made from a calculation formula such as a cooling model in the spray zone.

However, since this method does not detect the actual temperature of the steel plate 4 within the spray zone, it is not possible to accurately know the cooling pattern within the spray zone. Generally, it is not enough to simply cool the steel plate 4 to a predetermined temperature; the type of cooling pattern to be adopted in the cooling spray zone is an important factor in terms of quality. Particularly for thick plates, temperature control in the thickness direction may also be necessary. Therefore, it is not enough to simply install temperature measuring devices 8, 9, 10 on the inlet and outlet sides of the spray zone and make predictions. The steel weight invention was proposed in response to the above request, and its purpose is to detect the actual steel plate temperature in the spray zone and reliably control the cooling rate in the spray zone based on this, thereby achieving the desired temperature. To provide a steel plate temperature control method capable of producing high-quality steel plates, and to provide a steel plate temperature measuring device capable of measuring the temperature of the steel plate in a spray zone while avoiding the influence of cooling water when implementing the method.

Hereinafter, a specific example of the present invention will be described. In addition to the previously installed temperature rate regulators 8.9.10, the present invention also includes a temperature measuring device 11.11 installed below the steel plate 4 in each spray zone 5, 6.
' is provided. Here, when only the spray zone 5 is used and the winder 7' winds up a thin steel plate, the temperature measuring device 10 is not used.

As shown in FIGS. 2 and 3, the temperature measuring device 11 (
The same device 11'' is installed below the conveyance table rollers 12 and 12 (usually about 300 mm) of the steel plate 4. Cooling water drips down below the steel plate 4. A waterproof box 13 having 13a is provided.

Further, the lower surface of the waterproof box 13 is an inclined surface to drain the cooling water that has entered through the through hole 13a, and a drain port 13b is formed at the lower part. A radiation thermometer 14 is attached to the lower side of the waterproof box 13 at an elevation angle of, for example, 45 degrees, and looks at the center of the lower surface of the steel plate 1 through the through hole 13a. Further, a water-shielding shutter 15 is provided with a cylinder 16 so as to be openable and closable with respect to the through hole 13a. Furthermore, a water-shielding shutter 17 is disposed on the cylinder 18 so as to be openable and closable relative to the radiation thermometer 14. A viewing hole 20 is provided between the radiation thermometer 14 and the through hole 13a.
A water-shielding plate 20 having a diameter of 1.a is provided and hangs down from the swash plate of the waterproof box 13 to the vicinity of the lower plate. Reference numeral 21 denotes an air parsilo for cooling water and scale scattering, from which air can be freely injected toward the center of the lower surface of the steel plate 1 and the vicinity of the viewing hole 20a.

In such a temperature measuring device, the through hole 13a is closed by the shutter 15 while the steel plate 4 is not being transported, and the front surface of the radiation thermometer 14 is also closed by the shutter 17 if necessary. This particularly prevents the radiation thermometer 14 from being adversely affected by the cooling water. When the steel plate 4 is transported and the temperature is to be measured, the shutters 15, 17 are opened, and the radiation thermometer 14 measures the temperature at the center of the lower surface of the steel plate 4 through the viewing hole 20a and the through hole 13a. At this time, since air purge is performed from each air parsilo 21, the cooling water and scale pressing against the center of the lower surface of the steel plate 4 are blown away, and the cooling water that is about to pass through the viewing hole 20a is scattered. Also, some of the cooling water flows through the through hole 13a into the waterproof box 1.
3, but since the water shielding plate 20 is hanging down,
It does not reach the radiation thermometer 14 and goes directly to the drain port 13b.
is discharged from.

The temperature of the lower surface of the round steel plate 4 within the spray zone 5°6 detected in this way is used for the following control.

That is, the temperature signals from the temperature measuring devices 11, 11' are taken into the main processing unit (CPU) 21 together with the temperature signals from the temperature measuring devices 8, 9, and 10. CPU21 with Mata
Other element information 22 such as plate thickness, plate width, steel plate conveyance speed, steel plate material, or cooling pattern model is also taken in.

Then, the CPU obtains these signals and information, determines the amount of cooling water injection from each spray of the preset zone and control bank in the spray zones 5 and 6, and the distribution of the amount of injection at each position, and adjusts the amount of injection.
It mainly controls the cooling rate of the steel plate 4. As a result, since the cooling rate of the steel plate 4 is conventionally controlled based on the steel plate temperature measured outside the spray zone, the desired cooling rate and cooling pattern can be reliably obtained, and the quality of the steel plate 4 can be improved. By the way, the above temperature measuring device 10.10
', the radiation thermometer 14 is not placed directly under the steel plate 4,
The reason for slanting with an appropriate angle of elevation and placing it on the side is not only to avoid falling cooling water and scale, but also to
This was done in consideration of ease of maintenance, installation space, etc.

As described above, according to the method of the present invention, since the steel plate temperature measuring device is provided below the steel plate, it is possible to measure the temperature of the steel plate with special measures, and based on this, it is possible to spray accurately. The cooling rate of the steel plate within the zone can be controlled. Therefore, it is possible to reliably improve the quality of the obtained steel plate.

Furthermore, the apparatus of the present invention is not only suitable for the above-mentioned method, but also has a waterproof box and a temperature measuring device inside, so that it can prevent the effects of cooling water, scale, etc. Moreover, since a water-shielding means such as a shutter or a water-shielding plate is provided between the through hole and the temperature measuring device, the water-shielding effect is further enhanced.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of the control method of the present invention method together with a cooling pattern of the steel plate, Fig. 2 is a plan view showing the arrangement of the steel plate temperature measuring device according to the present invention, and Fig. 3 is the −
■It is a detailed sectional view taken along the line. 2.3...Rolling mill 4...Steel plate 5,6...Spray zone 7,7'...Rewinder 8,9.10...Temperature measuring device 11.11'...Temperature measuring device 12...Transportation Table roller 13...Waterproof box 13a...Through hole 1
4. Radiation thermometer 15°17. Waterproof shutter 2
0...Water shield plate 21...Main processing unit

Claims (2)

[Claims] (1) In the cooling water spray zone on the upper surface of the steel plate, a steel plate temperature measuring device facing the back side of the steel plate is installed below the steel plate and between the conveyor table rollers, and the temperature of the steel plate from the steel plate temperature measuring device in the spray zone is A method for controlling the temperature of a steel plate, comprising controlling the cooling rate within a spray zone of the steel plate by adjusting the amount of cooling water sprayed from each spray based on a steel plate temperature signal. (2) In the cooling water spray zone on the upper surface of the steel plate, a waterproof bogges with a through hole on the upper surface is installed below the steel plate and between the transfer tables, and the position below the through hole is avoided in the waterproof box. 1. A steel plate temperature measuring device for temperature control of a steel plate, characterized in that a temperature measuring device is provided which looks at the back side of the steel plate from the side through a through hole, and a water shielding means is provided between the temperature measuring device and the through hole.