JPS589706A - Control method for tandem rolling mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling a tandem rolling mill when biting failure occurs.

In conventional tandem rolling mills, a failure in biting is detected visually by the operator, and a detector is placed between the stands, and when the material to be rolled is detected by this, it is judged as a failure in biting and the mill is stopped. Ta. The former method has the disadvantage that it takes time for the operator to determine that the biting has failed, resulting in greater damage, while the latter method detects that a loop □ has formed between the stands even if the injection is successful. It has the disadvantage of failing to understand and making incorrect decisions.

An object of the present invention is to provide a control method for quickly detecting biting failure in a tandem rolling mill and stopping the rolling mill.

If tandem mill 3 is properly engaged, the result will be as shown in Figure 1. However, if it doesn't work, as shown in Figure 2,
The material to be rolled 1 accumulates between the leading mill 2 and the tandem mill 3. In some cases, after this, the materials to be rolled may overlap and be caught in the tandem mill 2, as shown in FIG.

These conditions can be detected by the load current of the rolling mill. That is, the load current corresponding to the state shown in Fig. 1 is:
The load current of the front membrane mill is shown at 15 in FIG. 4, and the load current of the tandem mill is shown at 17 in FIG. Second
As for the load currents corresponding to the states shown in the figures, the load current of the front membrane mill is shown by 13 in FIG. 4, and the load current of the tandem mill is shown by 18 in FIG. 5. The load current corresponding to the state in FIG. 3 is shown by 13 in FIG. 4 for the front membrane mill, and 16 in FIG. 5 for the tandem mill.

If the biting is performed normally, the front membrane mill will be in a state where it is somewhat pulled by the tandem mill. For this reason, the load current decreases a little, as shown at 15 in FIG. On the other hand, if the biting is not normal, the mill will be slightly pushed. Therefore, as shown in FIG. 4, the load current increases slightly.

The main point of the present invention is to pay attention to the above relationship, detect the load current of each mill, and determine the state to determine whether or not the biting is going well.

The configuration of the present invention is shown in FIG. 2 is a recent mill, 3 is a tandem mill, 4 is each electric motor, 10 is a detector for detecting accumulated rolled material when the drawn material fails to bite, 5 is a load current detector, and 6 is a power supply device. , 7 is a current detection circuit that changes the level of the current detected by the load current detector 5 to a level that can be compared and judged. 8 is a mill current determination circuit.

The present invention will be explained in detail below.

Mill (1) Previous mill, RI/Dem determination function Determines whether the current is from the previous membrane mill or the tandem mill. The one detected first is determined to be the previous mill.

□□□) First mill current detection function Detects only the current of the recent mill.

-(3) Current value increase/decrease judgment function The time T shown in Fig. 4 is determined beforehand. It is. After the time T has elapsed, it is determined whether the load current should be increased or decreased. That is, 13 in Figure 4.
14 or 15.

(4) Preemptive Mill Current Determination Function As a result of the determination in item (3), if the current decreases or remains unchanged, it is determined to be normal, and if the current increases, it is determined that caution is required.

9 is a tandem mill current determination circuit. Its functions are: (a) Previous mill, tandem mill determination function Determines whether the current is the previous membrane mill or tandem mill. The one detected later is determined to be the tandem mill.

(b) Tandem mill current detection function Detects only the tandem mill current.

(C) Current value judgment function The time T shown in FIG. 5 is set in advance.

Also, all expected load current values (for example, 32 in FIG. 5) are set. After one hour, when a current value that is significantly different from what was predicted in advance is detected (for example, 16 or 18 in FIG. 5), it is determined that caution is required.

Recently, when the mill current determination circuit 8 and the tandem mill current determination circuit 9 each issued a "need for attention" signal, the rolling state was as shown in FIG. It can be judged as a failure. In this case, a signal is sent to the mill stop circuit 12 to immediately stop rolling. The abnormality detection circuit 11 is a circuit that 411 disconnects an abnormality when the detector 10 detects a material to be rolled, that is, when a failure in biting of the tandem mill is detected. Reference numeral 12 denotes a mill stop circuit, which determines that a biting failure has occurred and issues a mill stop signal when 8 and 9 issue a "need attention" signal i at the same time, or when the abnormality detection circuit 11 issues a signal.

Similarly, when the material to be rolled 1 comes from the opposite direction in Fig. 6, 8
．． 9's front membrane miter and tandem mill determination function allows you to detect failures in biting in exactly the same way by simply replacing the missing part and the tandem part.

According to the present invention, by quickly detecting a biting failure,
Damage can be reduced.

[Brief explanation of the drawing]

Figures 1' to 3 are diagrams showing the rolling conditions of the recent mill and tandem mill, Figure 4 is a state diagram of the load current of the recent mill, and Figure 5
The figure is a state diagram of the load current of the tandem mill, and FIG. 6 is a control system diagram of the present invention.

Claims (1)

[Claims] 1. A control method for a tandem rolling mill, characterized in that a failure in biting of the tandem rolling mill is detected by determining the load current of a tip film mill and determining the load current of the tandem rolling mill.