JPS6138760A - Cooling method of casting plate - Google Patents

Abstract

PURPOSE:To grow a solidified shell to a uniform thickness and to prevent the generation of internal defects by measuring the thickness of the solidified shell in the transverse direction of a casting plate and changing the cooling condition in the transverse direction in accordance with the thickness thereof. CONSTITUTION:A temp. measuring unit 1 provided successively with many temp. sensors 5 is provided in the transverse direction of the casting plate 3 and the measuring signals from the sensors 5 are inputted to a control unit 4 which operates the temp. distribution in the transverse direction of the plate 3. The temp. in the thin part of the solidified shell where much of the unsolidified shell of the plate 3 is contained is high and the thickness distribution of the solidified shell is detected from the above-mentioned temp. distribution. A cooling unit 2 disposed with many cooling nozzles 6 in the transverse direction of the plate 3 in such a manner that the flow rates thereof can be discretely controlled is controlled in accordance with the thickness distribution, i.e., temp. distribution of the solidified shell to change the cooling condition in the transverse direction. The solidified shell is thus grown in the uniform condition and the generation of internal defects such as the internal segregation of impurities and hollows is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cooling a cast plate spun by a continuous casting machine.

[Prior Art] The inside of a cast plate immediately after being spun from a continuous casting machine is in an unsolidified state, and the thickness of the solidified shell of the cast plate is not necessarily uniform.

Conventionally, a cast plate spun from a continuous casting machine is cooled by a cooling device regardless of its solidification state. In such conventional cooling methods, a solidified shell grows with a non-uniform thickness, and the molten metal may be partially trapped. When the molten metal is partially confined, that part solidifies with a local delay, and as a result, impurities segregate in the part or the part becomes hollow, causing internal defects. This hastened problems such as cracking in post-processes such as rolling.

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned deficiencies of the prior art. The object of the present invention is to provide a method for cooling a cast plate in which the cast plate is not trapped.

[Means for Solving the Problems] The present invention subsides the solidified shell thickness in the width direction of a cast plate, and changes the cooling state in the width direction in accordance with the solidified shell thickness, The solidified shell is grown with a uniform thickness to prevent internal defects from occurring.

[Example] The present invention will be described in detail below with reference to the drawings.

The figure is a schematic diagram showing an example of an apparatus for carrying out the present invention, in which 1 is a temperature measurement unit, 2 is a cooling unit, and 3 is a temperature measurement unit.
4 indicates a cast plate, and 4 indicates a control unit.

The temperature measurement unit 1 has a large number of temperature sensors 5 arranged in series in the width direction of the cast plate 3, and detection signals from the temperature sensors 5 are inputted to the control unit 4. The cooling unit 2 also has a nozzle 6 connected to a cooling water source (not shown).
Each nozzle 6 is provided with a cutoff valve (not shown) that can be opened and closed independently, and the cutoff valve is electrically connected to the control unit 4. It can be opened and closed by a control signal from the control unit 4.

The control unit 4 converts the signal from the temperature sensor 5 into an A/D converter.
The detection results from each temperature sensor 5 and the position of each temperature sensor 5 are stored in correspondence with each other, and the temperature distribution of the cast plate 3 is calculated, and based on the calculation result, the downstream side is The cooling state in the cooling unit 2 is determined. Furthermore,
- The speed of the cast plate 3 is input in advance to the control unit 4 or the speed signal from the speed detector is input, and when the position of the cast plate 3 measured by the temperature measurement unit 1 reaches the cooling unit 2, The shutoff valve of each nozzle 6 is opened and closed based on the determined cooling state.

The temperature of the thin part of the solidified shell of the cast plate 3 containing unsolidified metal, that is, the part containing a large amount of unsolidified metal, is high, and by measuring the surface temperature distribution of the cast plate 3 h1, the thickness distribution of the solidified shell can be determined. be able to. Therefore, it is only necessary to control the outflow state of the cooling water from the cooling unit 2 so as to correspond to the temperature distribution measured by the temperature measurement unit 1 and to cool the high temperature portions more than other portions. For example, the cooling state of the cast plate 3 in the width direction can be partially controlled by opening every other nozzle cutoff valve in a low temperature area and all the corresponding nozzle cutoff valves in a high temperature area. to ensure uniform growth of the solidified shell.

Incidentally, examples of the temperature sensor include an infrared temperature sensor, and it is also possible to measure the temperature distribution by imaging the cast plate with a television camera and analyzing the image with a computer.

Furthermore, if an ultrasonic sensor is used instead of a temperature sensor, it is also possible to directly measure the thickness of the solidified shell.

Furthermore, in the illustrated example, cooling unit 1 is provided for measuring unit 1, but cooling units may be provided as required, or combinations of measuring units and cooling units may be provided as required.

Furthermore, the flow rate may be adjusted in addition to blocking the cooling water from flowing out from the nozzle.

[Effects of the Invention] As described above, according to the present invention, a cast plate is cooled so that its solidified shell can grow uniformly, so it is possible to prevent molten metal from being partially trapped, and to prevent internal defects. Occurrence can be prevented.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an example of an apparatus for carrying out the present invention. 1 is a temperature measurement unit, 2 is a cooling unit, 3 is a casting plate, 4 is a control unit, 5 is a temperature sensor, and 6 is a nozzle. Patent application: Hitoshi Kawajima Harima Heavy Industries Co., Ltd. Patent application: Nippon Steel Tube Co., Ltd.

Claims (1)

[Scope of Claims] 1) A method for cooling a cast plate, comprising: measuring the thickness of the solidified shell in the width direction of the cast plate, and changing the cooling state in the width direction in accordance with the thickness of the solidified shell. 2) The method for cooling a cast plate according to claim 1, wherein a plurality of cooling nozzles are arranged in the width direction, and the flow rate of the cooling nozzles is individually controlled.