Hot-Strip Flatness Measurement With Active Lateral Drift Correction
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Solution Overview
Problem
In hot rolling mills, the lateral movement of hot strips during flatness measurement is a significant challenge, especially with thin strips, leading to unstable strip paths, increased wear on side guides, and disruptions in the rolling process, making it difficult to measure linear flatness errors and potentially causing band breaks.
Innovation Solution
A flatness measuring device with an inlet-side and outlet-side deflection roller, along with a middle deflection roller that can be adjusted to correct the strip's position, utilizing a detection device and adjusting mechanism to vary the angle between the deflection rollers' longitudinal axis and the flatness measuring device's axis based on the strip's actual position, ensuring accurate centering and preventing lateral movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measuring roller is used to measure flatness by wrapping around the metal strip, then flatness measurement is enabled, but lateral strip drift increases significantly
Solution Approach 1:
The patent introduces an intermediary control system that uses detection devices to monitor strip position and adjustment devices to actively correct lateral drift. This intermediary control mechanism mediates between the measuring roller's need to contact the strip and the requirement for stable strip path, allowing the measuring roller to function while preventing harmful lateral movements through real-time position correction.
2Measurement precision
If the measuring roll is immersed in the metal strip to perform flatness measurement, then measurement function is achieved, but wear on lateral guides increases significantly
Solution Approach 1:
The patent implements a feedback control system where detection devices continuously monitor the strip's actual position and provide this information to a control device. The control device then activates adjustment devices to correct any lateral deviations. This closed-loop feedback mechanism prevents excessive lateral movements that would otherwise cause wear on lateral guides, while still allowing the measuring roller to be immersed in the strip for accurate flatness measurement.
3Device complexity
If conventional control methods are used with long clamping lengths between rolling stand and flatness measuring roll, then system simplicity is maintained, but measurement accuracy is disrupted due to tension distortion
Solution Approach 1:
The patent replaces conventional mechanical control methods with an active control system that uses detection devices (such as optical sensors) to monitor strip position and employs adjustment devices to actively compensate for lateral drift. This substitution of mechanical control with sensor-based active control enables accurate flatness measurement even with long clamping lengths, as the system can detect and correct tension-induced distortions in real-time rather than relying solely on mechanical constraints.
Data Source
Figure 1A~1B
Figure 2
AI summary
The invention relates to a flatness-measuring device (1) for measuring the flatness of a hot-rolled strip (2) within a hot-rolling mill, comprising: - at least one entry-side deflection roller (3) for contacting a first large side of the hot-rolled strip (2); - at least one exit-side deflection roller (5) for contacting the first large side of the hot-rolled strip (2); and - at least one central deflection roller (7), which is disposed between the entry-side deflection roller (3) and the exit-side deflection roller (5) with respect to a strip running direction (6) of the hot-rolled strip (2), can be placed against a second large side of the hot-rolled strip (2) opposite from the first large side of the hot-rolled strip (2), and is used as a flatness-measuring roller. In order to prevent the hot-rolled strip (2) from running laterally in a hot-rolling mill during a flatness measurement on the hot-rolled strip (2), the flatness-measuring device (1) has at least one sensing apparatus (8) for sensing an actual position (LIst) of the hot-rolled strip (2) and at least one adjusting apparatus (9), which is connected to the sensing apparatus (8) and to at least one of the deflection rollers (3, 5, 7) and is designed to vary an angle (α) between a longitudinal central axis (10) of the deflection roller (3, 5, 7) connected to the adjusting apparatus (9) and a longitudinal axis (11) of the flatness-measuring device (1) running transversely to the deflection rollers (3, 5, 7) in accordance with the deviation of the actual position (LIst) of the hot-rolled strip (2) from a predefined target position (LSoll) of the hot-rolled strip (2).