Rolling Mill Chock Position Measurement for Wear-Induced Strip Wedge
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Solution Overview
Problem
Current rolling mill technologies face challenges in accurately adjusting roll chock positions due to wear, leading to axis misalignment and asymmetry in rolled material thickness, which increases maintenance time and costs, and existing methods suffer from measurement inaccuracies and errors in thrust force measurements.
Innovation Solution
A rolling mill system with position measurement devices that measure roll chock positions independently of liner wear, and a method to control strip wedge by adjusting the positions of work-side and drive-side roll chocks, ensuring accurate alignment and minimizing axial deviations between working and backup rolls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position measurement devices are used to measure roll chock positions, then measurement can be performed, but measurement accuracy deteriorates due to liner wear and long stroke
Solution Approach 1:
The patent introduces a laser displacement sensor as an intermediary measurement device that measures the position of the roll chock relative to a fixed reference point on the housing, rather than measuring the full stroke distance. This intermediary measurement approach eliminates the accumulation of errors over long measurement distances and avoids the influence of liner wear on measurement accuracy.
2Measurement precision
If thrust force measurement is used to detect skew amount between working rolls and backup rolls, then skew detection can be performed, but measurement accuracy deteriorates due to hysteresis errors
Solution Approach 1:
The patent replaces the mechanical thrust force measurement system with a laser-based optical measurement system. The laser displacement sensor directly measures the positional deviation of the roll chock, eliminating the need for mechanical force sensors and the complex signal processing required to separate hysteresis effects from actual skew measurements.
3Productivity
If roll chock positions are not adjusted for liner wear, then operation continues without interruption, but manufacturing precision deteriorates due to axis misalignment and strip wedge
Solution Approach 1:
The patent implements a feedback control system where the laser displacement sensor continuously monitors the roll chock position, and the control unit automatically calculates and applies correction values to maintain accurate roll alignment. This feedback mechanism enables continuous operation while preserving manufacturing precision by compensating for liner wear in real-time.
Solution Approach 2:
The patent performs preliminary measurement of the roll chock position relative to the housing using the laser displacement sensor, and pre-calculates the correction values needed to compensate for liner wear before the wear affects rolling precision. This preliminary action allows the system to maintain accuracy proactively rather than reactively.
Data Source
AI summary
There are provided a work-side position measurement device and a drive-side position measurement device for directly measuring positions of roll chocks in a rolling direction, and positions of upper and lower working rolls and upper and lower backup rolls in the rolling direction are adjusted to zero point or predetermined positions. Alternatively, a change caused in the strip wedge due to a minute crossing of the axes of working rolls and backup rolls is calculated, and the quantities of leveling of a work-side rolling reduction cylinder device and a drive-side rolling reduction cylinder device are adjusted to make the strip edge equal to or smaller than a predetermined value. Accordingly, the bilateral asymmetry (strip wedge) of the thickness distribution of a rolled material is easily adjusted even in the event that the positions of the roll chocks in the rolling direction are changed due to wear on various components.