Rolling Mill Interstand Sensing for Thickness and Flatness Control
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Solution Overview
Problem
Current hot rolling mill control systems face challenges in achieving real-time compensation for work roll thermal camber due to inaccurate thermal models and delayed measurements of metal sheet or plate flatness and thickness profile, leading to inconsistencies in the thickness and flatness of the processed metal sheet or plate.
Innovation Solution
Implementing sensors between rolling mill stands to measure thermal camber, flatness, and thickness profile, allowing for real-time feedback loop control to adjust rolling mill mechanisms such as deformable backup rolls, bending jacks, and coolant sprays to maintain target tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal models and exit measurements are used to control rolling mill mechanisms, then some compensation for work roll thermal camber is achieved, but the compensation is inadequate due to model inaccuracies and measurement delays
Solution Approach 1:
The patent places thickness profile measurement sensors at interstand locations (between rolling stands) to measure the metal strip thickness profile before it exits the rolling mill. This preliminary measurement allows the control system to detect thickness variations early in the rolling process, enabling timely adjustments to rolling mill mechanisms (such as work roll bending, roll cooling, or roll gap control) to compensate for work roll thermal camber and maintain consistent thickness profile throughout production.
Solution Approach 2:
The patent implements a feedback control system where interstand thickness profile measurements are continuously fed back to the control system, which automatically adjusts rolling mill mechanisms to compensate for detected thickness variations. This closed-loop feedback enables real-time correction of work roll thermal camber effects, improving thickness profile consistency without relying on inaccurate thermal models or delayed exit measurements.
2Manufacturing precision
If exit measurements are used to adjust rolling mill control mechanisms, then some flatness and thickness profile control is achieved, but the adjustments are too delayed to effectively respond to changing process conditions
Solution Approach 1:
The patent positions thickness profile and flatness measurement sensors at interstand locations to perform preliminary measurements of the metal strip while it is still within the rolling mill processing sequence. This early detection of flatness and thickness variations enables the control system to initiate corrective actions (such as adjusting work roll bending forces, modifying roll cooling rates, or changing roll gap settings) before the strip exits the rolling mill, significantly reducing control response time and improving flatness consistency.
3Loss of information
If traditional sensors at mill entry and exit are used, then basic thickness monitoring is achieved, but inadequate information is obtained to determine which specific rolling stands require adjustment
Solution Approach 1:
The patent divides the rolling mill into multiple measurement zones by placing thickness profile sensors at interstand locations between individual rolling stands. This segmentation allows the control system to measure and identify which specific rolling stands are producing thickness variations, enabling targeted adjustments to only the problematic stands rather than requiring blanket adjustments across all stands, thus providing detailed process condition information without excessive overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables improved consistency and quality of the metal sheet or plate by providing immediate adjustments to rolling mill control mechanisms, reducing waste and enhancing product quality by ensuring precise control over thickness and flatness profiles.
Implementation Method 1
measuring a thickness profile of a metal strip with a thickness profile measurement sensor
Implementation Method 2
measuring a flatness of the metal strip with a flatness measurement sensor
Implementation Method 3
measuring a camber of a roll of the rolling mill with a roll camber sensor
Implementation Method 4
The resulting heat causes expansion of the rolling mill rolls, which affects the thickness profile, flatness and quality of the processed metal sheet or plate
Implementation Method 5
adjusting, by the controller, a rolling mill control mechanism such that the roll gap geometry provides a desired thickness profile and a desired flatness
Data Source
AI summary
A rolling mill control system and method includes use of sensors located between rolling mill stands to directly measure metal sheet or plate flatness, thickness profile, position, and the camber of the rolls in the mill. A feedback loop control system adjusts or adapts rolling mill control mechanisms to control the rolling process.