JPH0564220B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling cooling in a cooling zone of a continuous heat treatment furnace for metal strips, for example a continuous annealing furnace for steel strips.

(Prior Art) It has been known that a high-quality steel strip can be obtained with compact maintenance by winding the steel strip around a cooling roll and cooling it in the cooling zone of a continuous annealing furnace.

However, this method has a problem in that shape defects are likely to occur due to non-uniform cooling in the width direction, and this is often caused by the shape of the steel plate on the entrance side of the cooling roll. That is, if there is a shape-defective part (mainly a middle roll with an elongated center part) in the steel plate on the entrance side of the cooling roll, that part will not be cooled and the shape-defectiveness will be amplified.

In order to solve this problem, we focused on the fact that the distribution of the shape of the steel plate matches the distribution of the plate temperature, that is, the shape of the steel plate deteriorates due to thermal expansion in areas where the plate temperature is high. The inlet side plate temperature distribution is measured and used as a feed forward signal for the plate width direction temperature control means, or the outlet side plate temperature distribution is measured and used as a feedback signal for the plate width direction temperature control means to ensure uniformity. We proposed a cooling method.

However, as shown in Figure 2, generally the temperature distribution in the width direction and the plate shape match, but in a continuous annealing furnace, heating is performed while being bent at the position of a crowned hearth roll installed in the furnace. ,
As cooling takes place, the temperature distribution in the width direction and the shape of the plate do not necessarily match, as shown in Figure 3. Therefore, even with the above proposal, the temperature distribution in the width direction does not always match the shape of the plate. The problem of occurrence of shape defects is not completely solved.

(Problems to be Solved by the Invention) The purpose of the present invention is to completely solve the above-mentioned problems,
An object of the present invention is to provide a cooling control method for a metal strip that can stably perform uniform cooling in the width direction of the strip.

(Means for Solving the Problems) The above-mentioned object of the present invention is to cool a metal strip in a cooling zone of a continuous heat treatment furnace, which is provided with means for controlling the plate temperature in the width direction on the inlet side of the cooling roll. A strip widthwise shape detector is provided on the inlet or outlet side of the control means, and the control pattern of the control means is adjusted according to the strip widthwise shape detected by the detector, thereby achieving uniform cooling in the strip width direction. This is achieved by doing the following.

That is, in the present invention, the shape of the steel sheet on the entrance side of the cooling zone is directly detected by a shape detector, and if the central part of the steel strip is swollen, for example, the shape of the steel sheet on the entrance side of the cooling zone is detected in the sheet width direction. By cooling only that part using temperature control means and keeping it flat in the width direction, the contact of the steel strip with the cooling roll is made uniform. As the shape detector, for example, an eddy current shape detector is used.

The present invention will be explained based on FIG. FIG. 1 shows an array of equipment for implementing the invention. In the figure, 1 is a steel strip, 3 is a means for controlling the width direction plate provided on the inlet side of the cooling roll groups 7a to 7e, for example, a jet cooler, 4 is a means for adjusting the flow rate of cooling gas supplied to the jet cooler 3, and 5 is a Jet cooler 3
5' is a plate widthwise shape detector installed before the jet cooler 3, 6 and 9 are non-cooling rolls, and 10 is a widthwise plate thermometer on the entry side. , 11 is a width direction plate thermometer on the outlet side, 1
2 is a calculator, 13 is a cooling roll moving device 8a,
This is the control device for 8c and 8e.

The heated and soaked steel strip 1 is cooled to a predetermined strip temperature by the widthwise strip temperature control means 3, and the strip widthwise shape detector 5 provided on the outlet side of the control means 3 determines its temperature. A shape is detected. Detected steel strip 1
The shape of is introduced into the computer 12. For example, if the detected shape of the steel strip 1 is bulged in the center,
A control signal is sent from the computer 12 to the control means so that the widthwise plate temperature control means 3 cools only the swollen portion of the steel strip before that portion contacts the cooling roll. . The steel strip 1, which has been flattened in the width direction, is passed through the non-cooling roll 6, the cooling roll groups 7a to 7e, and the non-cooling roll 9, and is cooled uniformly in the width direction of the steel sheet, resulting in a columnar shape. Excellent steel strip can be manufactured.

In the above-mentioned embodiment, the plate width direction shape detector 5 is provided on the outlet side of the width direction plate temperature control means 3, but as shown by 5' in the figure, the plate width direction shape detector 5 is provided on the input side of the control means 3. A width direction shape detector may be provided to detect the width direction shape of the metal strip introduced into the control means and adjust the control pattern of the control means in accordance with the detected shape.

(Effects of the Invention) According to the present invention, when the metal strip is cooled by the cooling roll, the occurrence of shape defects due to non-uniform cooling in the width direction due to the shape of the metal strip on the entrance side of the cooling roll can be avoided. The effect is that uniform cooling in the width direction can always be stably performed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a row of equipment for implementing the present invention, and FIGS. 2 and 3 are diagrams showing the relationship between the temperature distribution in the width direction of the board and the board shape. DESCRIPTION OF SYMBOLS 1... Steel strip, 3... Width direction board temperature control means, 4...
...Cooling gas flow rate adjustment means, 5, 5'... Board width direction shape detector, 6, 9... Non-cooling roll, 7a~
e... Cooling roll group, 8a, 8c, 8e... Cooling roll moving device, 10, 11... Width direction plate thermometer, 12... Computer, 13... Control device for the cooling roll moving device.

Claims (1)

[Claims] 1. When cooling a metal strip in the cooling zone of a continuous heat treatment furnace, which is equipped with means for controlling the sheet temperature in the width direction on the inlet side of the cooling roll, a shape detector in the width direction of the strip is provided on the inlet side or the outlet side of the control means. . A method for controlling the cooling of a metal strip, characterized in that the control pattern of the control means is adjusted in accordance with the form of the metal strip in the width direction detected by the detector, thereby performing uniform cooling in the width direction of the metal strip.