Rolling Mill Cross-Angle Identification from Vertical Roll Load Difference
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Solution Overview
Problem
Existing methods for identifying the inter-roll cross angle in rolling mills face challenges such as inaccurate measurement of thrust forces due to roll skew angles, changes in frictional coefficients, and asymmetric errors, particularly when measuring differential loads between the driving and working sides, which can lead to errors in calculating the thrust coefficient and skew amount.
Innovation Solution
A cross angle identification method that applies a roll bending force between work and backup rolls with a gap open, detects vertical roll loads during normal and reverse rotations or stop states, and calculates load differences to identify the inter-roll cross angle, allowing for precise identification of the frictional coefficient and thrust counterforce position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a distance sensor is used to measure roll skew angle, then the inter-roll cross angle can be obtained, but measurement accuracy deteriorates due to roll vibration and chock position fluctuation
Solution Approach 1:
The patent replaces the mechanical distance sensor measurement system with a load-based measurement system. Instead of measuring physical displacement of the roll, the invention measures the load difference between driving and working sides, which is then used to calculate the thrust coefficient and skew amount. This substitution eliminates the direct mechanical contact and vibration issues associated with distance sensors.
Solution Approach 2:
The patent introduces load detection devices as an intermediary to indirectly measure the thrust force effects. Rather than directly measuring the difficult-to-obtain thrust force or roll position, the system measures vertical roll loads and uses the load difference as an intermediary parameter to derive the skew angle and thrust coefficient through calculation.
2Measurement precision
If thrust force is measured directly, then accurate thrust coefficient can be obtained, but measurement becomes complex requiring additional devices
Solution Approach 1:
The patent replaces direct thrust force measurement with a load-based indirect measurement system. Instead of using complex thrust force sensors, the invention uses vertical load detection devices to measure the weight of rolls and the load difference between sides, then calculates thrust parameters through mathematical relationships.
Solution Approach 2:
The patent extracts the measurement of vertical roll loads as a separate, simpler function. By measuring only the vertical loads on the driving and working sides and calculating the difference, the system extracts the necessary information to determine thrust coefficient without needing to directly measure the horizontal thrust force.
3Reliability
If load difference measurement is performed during rolling, then thrust effects can be detected, but measurement accuracy deteriorates due to asymmetric errors and friction variations
Solution Approach 1:
The patent performs preliminary measurements of vertical roll loads before rolling operations. By measuring the loads when the mill is not rolling, the system establishes baseline values that eliminate the influence of rolling-induced asymmetric errors and friction variations, allowing for more accurate thrust coefficient calculation.
Solution Approach 2:
The patent changes the measurement parameters from horizontal thrust force to vertical roll load. This parameter change allows the system to measure quantities that are more stable and less affected by rolling conditions, friction variations, and asymmetric errors, while still being able to calculate thrust-related parameters through established relationships.
Data Source
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AI summary
The present invention provides a method for identifying an inter-roll cross angle in a rolling mill of four-high or more including at least a pair of work rolls and a pair of backup rolls by, when rolling is not performed, applying a roll bending force to apply a load between rolls of an upper roll assembly including the work roll on the upper side and between rolls of a lower roll assembly including the work roll on the lower side, in a state where a roll gap between the work rolls is put into an open state, detecting vertical roll loads that act in the vertical direction on the rolling support positions on the working side and the driving side of at least one of the backup roll on the upper side or the backup roll on the lower side, and calculating a load difference between the vertical roll loads on the working side and the driving side.