Temperature control device for hot rolling mill

Abstract

A temperature control unit of hot rolling machine that avoids any sharp temperature change of rolling material at a place near the outlet of the rolling machine to thereby realize a high-precision control of sheet thickness. Accordingly, in a hot rolling machine equipped with multiple rolling stands continually disposed and further with multiple cooling units for cooling of rolling material, first, the cooling water pressure of each of the cooling units is computed using up to the upper limit pressure preferentially from one of the multiple cooling units disposed on the inlet side of the rolling machine on the basis of the target temperature and inlet actual temperature of the rolling material. Subsequently, on the basis of the target temperature and outlet actual temperature of the rolling material, so as to reduce any deviation between the target temperature and the outlet actual temperature, there is computed the cooling water pressure of one of the cooling units in operation disposed nearest the outlet of the rolling machine. At that stage, when the cooling water pressure of the cooling unit under control reaches the upper limit pressure, the control object is changed to the cooling unit disposed adjacent to the outlet of the rolling machine. On the other hand, when the cooling water pressure reaches the lower limit pressure, the control object is changed to the cooling unit disposed adjacent to the inlet of the rolling machine.

Description

technical field [0001] The present invention relates to a temperature control device for a hot rolling mill that sequentially arranges a plurality of rolling mill stands and sequentially rolls heated steel plates, etc., by using these rolling mill stands. Background technique [0002] In a hot rolling mill for rolling a rolled material such as a heated steel plate, it is very important to control the temperature of the rolled material at the exit side of the rolling mill to a target temperature in order to improve the quality of the rolled product. Therefore, various temperature control devices for controlling the temperature of the rolled material at the exit side of the hot rolling mill to a target temperature have been known for a long time. [0003] For example, as a technology of an existing hot-rolling mill temperature control device, it has been proposed to arrange a plurality of cooling devices for cooling rolled materials between a plurality of continuously arranged...

AI Technical Summary

Problems solved by technology

Therefore, due to the operation and stop of the entire cooling device, the temperature of the rolled material changes greatly, and the high-precision control of the temperature is limited.

In addition, the large temperature change of the rolled material also has a negative impact on the thickness accuracy

[0007] On the other hand, in the description of Patent Document 2, there is also the following problem, that is, since the cooling water flow rate is sequentially changed from the cooling device near the exit side of the rolling mill, the temperature of the rolled material is sharply increased near the exit side of the hot rolling finishing mill. Variety

Therefore, interference with the plate thickness control (AGC: AUTO GAUGE CONTROL) also has a great influence on the plate thickness accuracy

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