Interstand Rolling Mill Sensing for Thermal Camber Compensation
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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, particularly in multi-stand rolling mills, which affects the consistency of the metal sheet or plate's thickness and flatness.
Innovation Solution
The implementation of sensors located between successive stands of a multi-stand hot rolling mill 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 can be 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 properties before it exits the rolling mill. This preliminary measurement allows the control system to detect thickness profile deviations earlier in the process, enabling faster adjustment of rolling mill mechanisms (such as work roll bending forces or roll speeds) to compensate for work roll thermal camber before the defective strip is produced, thereby reducing measurement delay and improving manufacturing precision
2Loss of information
If measurements are taken at the exit of the rolling mill, then thickness profile data can be obtained, but the data is too delayed to quickly adjust rolling mill control mechanisms
Solution Approach 1:
The patent implements a feedback control system that uses interstand thickness profile measurements to continuously monitor the rolling process and automatically adjusts rolling mill control mechanisms. The feedback loop operates in real-time by comparing measured thickness profile data against target values and dynamically modifying work roll bending forces, roll speeds, or other control parameters to maintain desired thickness profile, thereby eliminating the information loss and time delay associated with exit-only measurements
3Ease of operation
If standard rolling mill control mechanisms are used, then basic compensation can be achieved, but inadequate information is available to determine which stands require adjustment
Solution Approach 1:
The patent divides the rolling mill into individual rolling stands and places thickness profile measurement sensors at interstand locations between each stand. This segmentation allows the control system to attribute thickness profile deviations to specific rolling stands by analyzing the strip condition after each stand, providing stand-specific diagnostic information that enables targeted adjustments to individual stands rather than blanket adjustments across the entire mill, thereby improving ease of operation with precise control
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 allowing for immediate adjustments to the rolling mill control mechanisms, reducing waste and enhancing product quality by providing accurate, real-time data on roll gap geometry and material properties.
Implementation Method 1
the rolls of the mill and the metal sheet or plate passing through the rolls heat up due to the pressure and friction of rolling, metal deformation, and/or because the metal sheet or plate entering the rolling mill is hot. 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 2
Many rolling mills are also equipped with jacking mechanisms to apply pressure to work rolls chocks and/or backup rolls chocks to bend the rolls during processing
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.