JPS60240307A - Outlet side device for hot finishing mill - Google Patents

Abstract

PURPOSE:To provide the titled device which measures the surface of a rolling material having no oxide films and residual moisture and subject exactly the non-defective material to controlled rolling by providing successively a nearest quick coller, dewatering device and measuring instrument for control between a hot finishing mill and zone cooler thereby forming the finer structure. CONSTITUTION:The rolling material 10 which is cooled 9 between the stands of the hot finishing mill and emitted from the final stand 1 is quickly cooled by the nearest cooler 4 without being exposed to the atm by which the structure thereof is made finer and better in quality. The surface moisture is removed by the high-pressure injection water or high-pressure gas of the dewatering device 5 so that the good surface condition having no oxidation and moisture is obtd. The material enters the measuring instrument 6 for feedback control in succession thereto where the material is measured. The material enters the final zone cooler. The material 10 is made to have the fine structure and is subjected to a measurement for control in the state of having no surface oxidation and moisture. The non-defective material is thus subjected exactly to the controlled rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an exit device of a hot finishing rolling mill, and particularly to an exit device provided between a hot finishing rolling mill and a zone cooling device. be.

(Prior art and its problems) Generally, in a hot rolling line for steel strips, for example,
1.2 after passing through the final stand of a 6-7 stage hot finishing mill
A hot-rolled steel plate finished rolled to a thickness of 800 to 1
7-10m after leaving the final stand at a temperature of 000℃
After passing through an air-cooling area where the wet quality, plate thickness, plate width, plate shape, etc. are measured, it is passed through a zone cooling device, water-cooled, and then monitored by a winder.

As mentioned above, in a conventional hot rolling line, a zone cooling device is used as an exit device between the final stand of a hot finishing mill and a zone cooling device to control the temperature and thickness of hot rolled steel sheets for feedback control of the rolling mill. , Feedback control sensors or measuring devices such as m-change gauges, xfiI thickness gauges, plate cap meters, pull-fill meters, and shape detectors are installed to measure plate width, plate shape, etc., and these measuring devices are used to measure steel plate An air cooling zone was necessary between the final stand of the hot finishing mill and the zone cooling system because the presence of water and steam on the surface degraded measurement precision.

However, as a result of providing an air-cooling zone on the exit side of the hot finishing mill, not only is there a problem of scale formation, but the internal strain caused by hot rolling is eliminated, causing the structure to become coarse. There was a problem.

As a method to solve the problem of scale caused by providing the above-mentioned air cooling area,
The publication describes a technology for blocking the atmosphere by placing a laminar water stream sprayed from a slit-shaped laminar nozzle over the entire front and back surfaces of the mh moving between the finishing rolling mill and the zone cooling device. There is. The purpose of this technology is to completely place the front and back surfaces of the steel plate in a stream of water to cut off contact with air, thereby reducing the occurrence of scale. It is necessary to cover the entire front and back surfaces of the steel plate in the entire area between the finish rolling mill and the zone cooling device. Therefore, it is necessary to measure the plate condition by measuring the thickness of the steel plate after finish rolling with an X-ray thickness gauge. There is a problem in that it cannot be carried out with a zone cooling device, and no consideration is given to the coarsening of the structure due to the disappearance of internal strain caused by hot rolling.

(Objective and Structure of the Invention 5!2.) The present invention has been made in view of the above-mentioned points.
The aim is to improve.

Improvement of the material quality of hot-rolled steel sheets is achieved by refining the structure.

Controlled rolling and controlled cooling are known as means for obtaining a fine structure. All of these methods reduce the grain size of r, γ-
The basic theory is rapid cooling during α transformation and suppression of α grain growth.

The present invention has a heat transfer coefficient of 1000 KOa//In''-hr'c or more within 0.5 seconds immediately after hot rolling.
It is possible to improve the material quality by α grain refinement by α transformation from a state where rolling strain remains by strongly water-cooling a hot rolled steel sheet at w (abbreviated as 1a near quenching in this specification). This is based on the recognition of the fact that a length of 1 to 5 m is sufficient for the quenching zone.

Therefore, the present invention is characterized in that, as the exit side/equipment of the hot finishing rolling mill, an immediate quenching device, a draining device, and a feedback control measuring device are sequentially provided on the exit side of the final stand of the finishing rolling mill. do.

(Example) Fig. 1 shows a part of a hot rolling line equipped with an exit device according to the present invention, and in the figure, 1 and 2 are the final stand and front stand of a hot finishing mill, and 8 is a A zone cooling device is shown.

As shown in the figure, between the final stand 1 and the zone cooling device 8, an immediate quenching device 4, a water draining device ^:, that is, a high-pressure water jetting device 5, and a sensor or measuring device 6 for feedback control are sequentially installed as outlet devices. It is being

The immediate quenching device 4 is installed within 6 m from the roll bite 7 of the final stand 1, and is located at the end near the final stand 1.
As shown in the enlarged view in Fig. 2, the water-cooled nozzle 8 located on the side of
It is preferable to use a variable high-pressure water nozzle with a variable injection pressure of 0 to 200 kg/cm2, and other nozzles may be constructed of conventionally known pipe laminars, slit laminars, guided jets, etc.

The water draining device 6 can use a gas jet jetting device among the above-mentioned high-pressure water jetting devices, and immediately after the immediate quenching device 4, high-pressure water or high-pressure gas is jetted toward the immediate quenching device to remove the surface of the steel plate. Measuring device 6 by excluding water and water vapor
This is to prevent deterioration in measurement accuracy due to

Also, as shown in Figure 1, 1 (17
An inter-stand cooling device 9 such as a water cooling jet can be provided between one or more stands, thereby increasing the amount of cooling control between the stands and further improving the immediate quenching effect at the exit side of the final stand. It is possible to suppress the generation of scale between stands.

With the above-described configuration, according to the apparatus of the present invention, the hot-rolled foil sheet 10 rolled in the final stand l of the hot finishing mill is exposed to the water injected from the latest quenching effect pool from the moment it comes out of the p-ruvite 7. It is rapidly cooled by
Through transformation, the α grain size is significantly refined, the material quality is improved, and scale formation is also suppressed.

In this way, after water and steam on the surface of the recently quenched hot rolled steel sheet 10 are removed by the draining device 6,
The measuring device 6 measures wet quality, plate thickness, plate width, plate shape, etc., and the rolling mill can be feedback-controlled using the measurement results.

(Effects of the Invention) According to the present invention, it is possible to improve the material quality of a hot-rolled steel sheet that has been hot finished rolled, to suppress the formation of scale, and to measure the temperature, plate thickness, plate width, plate shape, etc. This makes it possible to obtain highly controlled hot-rolled steel sheets.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the exit side portion of a hot finishing mill equipped with a device according to the present invention, and Fig. 2 is an enlarged partial view showing the arrangement of the frontmost water cooling nozzle with respect to roll-by F of the final stand of the finishing rolling mill. be. 1... Finishing mill final stand 2... Pre-stage stand 8... Zone cooling device 4...
- Immediate quenching device 6... Draining device 6... Measuring device for feedback control 7... Roll bite 8... Frontmost water cooling nozzle 9... Intermediate cooling device 10... Hot rolled steel plate. Patent applicant: Kawasaki Steel Corporation

Claims (1)

[Claims] L In the exit side device installed between the hot finishing rolling mill and the zone cooling device, a rapid cooling device, a draining device, and a measuring device for feedback control are sequentially installed on the exit side of the final stand of the finishing rolling mill. Output device of hot finishing rolling mill.