JP2849186B2 - Roll abnormality detection method in continuous casting equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality of a roll such as a bent or eccentric roll in a continuous casting facility.

Conventional technology Continuous casting is performed by continuously drawing the molten metal poured into the mold as a slab from below the mold, and a roller for guiding the slab, a pinch roll for drawing the slab, etc. Different large and small rolls are arranged.

Problems to be Solved by the Invention In terms of slab quality control, roll alignment management is one of the most important things in continuous casting equipment, and the misalignment amount that is the difference from the reference line for each roll is within the set value. The roll is likely to be bent or eccentric due to heat or load,
The misalignment amount may exceed the set value, which may degrade the slab quality.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its first object to provide a method for detecting an abnormality such as bending loss or eccentricity of a roll when the abnormality occurs. It is a second object to provide a method capable of estimating whether a roll has occurred.

In order to achieve the first object, the roll abnormality detecting method includes a step of detecting a driving torque of a pinch roll, a step of performing a power spectrum analysis of the detected driving torque waveform by Fourier transform, Detecting a power abnormality by analysis. The method for achieving the second object is as described above, wherein the roll diameter is calculated from the frequency at which the abnormality appears, and the abnormality location is estimated. It is characterized by the following.

When the rolls have different diameters, the time required for one rotation, that is, the frequency is different. The frequency H ₂ is the roll diameter D, when the casting speed is V _s, is determined as H _z = V _s / πD.

When the roll is bent or eccentric, the torque fluctuates, which appears as an abnormality in the frequency of the roll obtained from the casting speed. That is, if the frequency of each roll is calculated based on the casting speed and the frequency components are extracted by power spectrum analysis using Fourier transform, the abnormality of the roll is detected.

Further, the roll diameter is obtained from the frequency at which the abnormality appears, and the abnormal location is estimated from this.

Embodiment A motor 4 for driving a pinch roll 3 that is disposed below a casting mold 1 and pulls out a slab 2 is provided with a VVVF (variable voltage frequency) control panel 6 according to the rotation speed measured by a rotation speed detector 5.
Is controlled by a strand process computer (PC) 7 via a computer, and a torque signal obtained from the rotation speed is converted to an FFT (Fast Fourier Transfer) analyzer 8
Is subjected to a frequency analysis, that is, a Fourier transform into a fundamental wave and a harmonic corresponding to the fundamental wave (see FIG. 2), and the analysis value is obtained.
The data is input to the CPU 10 via an IF (interface) 9.

The CPU 10 detects a frequency band in which the frequency-analyzed spectrum greatly fluctuates as compared with the steady state, and calculates the frequency of each roll from the casting speed and the roll diameter obtained via the strands PC7 to IF9 (first). Table shows the frequency H _z of the roll diameter of 420φ from 120φ when the casting speed is 0 · 7m / min), obtaining a roll diameter of the detected abnormal frequency. Then, an alarm is output to the alarm device 11 to issue an alarm, and the roll corresponding to the roll diameter of the abnormal frequency is displayed on the CRT 12
To be displayed.

Effects of the Invention The present invention is configured as described above and has the following effects.

According to the method of the first aspect, an abnormality of the roll such as a bending loss or eccentricity of the roll is detected.

According to the method of the second aspect, it is possible to further estimate the abnormal portion, and it is possible to perform quick and accurate treatment, thereby shortening the time required for repairing the roll.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a continuous casting facility used in the method of the present invention, and FIG. 2 is a diagram obtained by frequency analysis. 1 ... mold, 2 ... slab, 3 ... pinch roll, 4 ...
Motor, 5 Rotation detector, 6 Control panel, 7 Strand PC, 8 FFT analyzer, 9 Interface, 10 CPU, 11 Alarm device, 12 CRT

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-168946 (JP, A) JP-A-57-209761 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B22D 11/16 104

Claims (2)

(57) [Claims] 1. A method comprising: detecting a driving torque of a pinch roll; analyzing a power spectrum of the detected driving torque waveform by Fourier transform; and detecting an abnormal power by analyzing the power spectrum. For detecting roll abnormalities in continuous casting equipment. 2. The method for detecting a roll abnormality in a continuous casting facility according to claim 1, wherein the roll diameter is calculated from the frequency at which the abnormality appears, and the abnormal location is estimated.