Hot rolling facility of steel plate and hot rolling method

Abstract

Hot rolling facility and method of steel plate excellent in facility cost and maintainability of facility and having good cooling capacity which can produce a steel plate having excellent characteristics efficiently by controlling the temperature of a rolling material properly. At a position where the inlet side and the outlet side of a mill (12) are close to each other, a cooling facility (20), for supplying cooling water to the upper and lower surfaces of the steel plate (10) that is being passed, is arranged. The cooling facility (20) is provided with an upper header (21) having an upper nozzle (22) for ejecting rod-shaped cooling water (23) toward the upper surface of the steel plate (10) at an inclination angle [TheTa] U = 30 DEG - 60 DEG at such a position that the stagnant cooling water (24) supplied to the upper surface of the steel plate (10) is dammed by a work roll (12a), and provided with a lower header (31) having a lower nozzle (32) for ejecting rod-shaped cooling water (33) toward the lower surface of the steel plate (10) at an angle of elevation [TheTa] L = 45 DEG - 90 DEG between the work roll (12a) and a table roller (13a) adjacent thereto.

Description

technical field [0001] The present invention relates to a hot rolling mill and a hot rolling method for steel plates and steel sheets. Background technique [0002] In recent years, in the process of manufacturing a steel sheet by hot rolling, the temperature of a rolling material (rolling material) is controlled to manufacture a steel sheet having excellent properties. [0003] For example, by performing controlled rolling (CR) in which finish rolling is performed with the temperature of the rolled material in the non-recrystallization temperature range (non-recrystallization temperature range), steel sheets with excellent properties can be produced . [0004] In addition, it is being studied to reduce the surface temperature of the steel plate by supplying cooling water to the steel plate immediately after leaving the roll bite of the hot rolling mill, thereby suppressing the scale formation. Thin scale steel sheet. [0005] As a technique used for controlling the tempe...

AI Technical Summary

Problems solved by technology

[0008] However, the technologies described in the above-mentioned Japanese Patent Application Publication No. 2002-361315 and Japanese Patent Application Publication No. 62-260022 have relatively large problems in terms of equipment cost, equipment maintenance, and cooling performance.

[0009] First, in the technology described in Japanese Patent Application Laid-Open No. 2002-361315, there is a problem that although the cooling water supplied to the upper surface of the steel plate temporarily stagnates on the steel plate, the cooling area of ​​the steel plate changes due to the change of the stagnant state, and thus High temperature control accuracy cannot be obtained

For example, as shown in FIG. 6 , when the discharge port of the slit nozzle 52 is clogged due to adhesion of a foreign substance 60 , the cooling water film 53 is destroyed.

In addition, in order to intercept the cooling water in the injection area (in the cooling area), it is necessary to spray at a high pressure, but when the film cooling water 53 is sprayed at a high pressure, the balance of the injection pressure becomes poor, and there is a problem that the cooling water film 53 is easily broken.

If the cooling water film 53 is not formed, the cooling water leaks to the upstream and downstream directions of the injection area, and it stays on the steel plate 10 to partially cool the steel plate 10, and there is a problem of uneven temperature.

There is also a technique to remove the cooling water remaining on the upper surface of the steel plate 10 with a side sprayer, etc., but it cannot be completely removed when the amount of cooling water is large, and there is still a problem of temperature deviation.

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