JPS6348604B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a set speed required for each stand when changing the thickness of the running plate when a tandem rolling mill continuously rolls coils having different original plate thicknesses and/or different finished plate thicknesses between the runs. The ratio is
This invention relates to a method for changing plate thickness during running to avoid exceeding the speed cone of each stand and to minimize the range of change when setting the speed ratio. Recently, cold rolling mills have begun to continuously roll large strip coils to improve yield.
Along with this, there has been a demand for rolling in which a plurality of original sheets and/or strips of finished sheet thickness are rolled into one coil. Conventionally, in order to change the plate thickness in the middle of one coil, it was necessary to stop the rolling mill midway and change the set speed ratio of the roll gap and each stand. By the way, such a change method not only causes a large time loss but also causes a long off-gauge, which in turn has the problem of lowering the yield. On the other hand, with the realization of complete continuity of tandem rolling mills, the roll gap and speed ratio are changed for each stand in sequence as the point at which the plate thickness is to be changed passes through each stand of the rolling mill. A method of changing the plate thickness during running is known (Japanese Patent Publication No. 48-17146 and others). In this method, the speed ratio and roll gap are changed sequentially from the first stand using the speed setting method shown in Table 1 below, so if the speed ratio change range is large, the first stand As shown in the figure, there is a possibility that the set speed ratio of the first stand or the last stand exceeds the maximum speed (speed cone) unique to each stand. Also, the amount of change in speed ratio is large,
In rolling mills that use MG sets with poor speed control responsiveness, the length of off-gauge occurrence becomes longer.
Therefore, application of this method is difficult.

【table】

Claims (1)

[Claims] 1. In a tandem rolling mill consisting of n stands that continuously rolls coils with different original plate thicknesses and/or points with different finished plate thicknesses between runs,
It is used to roll the preceding plate thickness when changing the rolled plate thickness during rolling by appropriately changing the roll gap and the speed ratio of each stand as the plate thickness change points pass sequentially from the entrance stand. The speed ratio used for rolling the following plate thickness is compared in advance with the speed ratio to be used for rolling the subsequent plate thickness, the stand with the least amount of change is found, this stand is set as the pivot, and the plate thickness change point is the i-th stand. (i = 2 to n), the speed ratio from the first stand to the i-th stand is set to the trailing thickness, and the speed ratio including the i-th stand to the last stand is set to the speed ratio of the preceding board thickness. A running plate thickness changing method characterized by sequentially changing the roll gap to a predetermined value in accordance with the change.