Rolling Mill Cross-Angle Detection from Backup Roll Load Imbalance
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Solution Overview
Problem
Existing rolling mill technologies face challenges in accurately measuring inter-roll cross angles due to issues like roll vibration, fluctuating chock positions, and changing frictional coefficients, leading to errors in thrust force calculation and zigzagging control.
Innovation Solution
A method and device for identifying inter-roll cross angles by applying a roll bending force, detecting vertical roll loads during normal and reverse rotations or rotations and stops, and calculating load differences to determine the cross angle and frictional coefficients, allowing for precise adjustment of roll positions to eliminate thrust forces.
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 roll vibration and chock position fluctuation cause measurement errors
Solution Approach 1:
The patent introduces a load detection device as an intermediary to measure vertical roll loads, which indirectly reflects the inter-roll cross angle through load difference calculations. This mediator approach avoids direct measurement of the unstable roll position while still obtaining the required angular information through force measurements.
Solution Approach 2:
The patent replaces the mechanical distance sensor measurement system with a load-based detection system. Instead of mechanically measuring the horizontal displacement of rolls, the system uses vertical load measurements and mathematical calculations to determine the inter-roll cross angle, thereby eliminating the problems caused by roll vibration and chock position fluctuation.
2Device complexity
If thrust force is calculated from roll skew angle alone, then calculation is simplified, but frictional coefficient changes cause inaccurate thrust force calculation
Solution Approach 1:
The patent implements a feedback mechanism where vertical roll loads are continuously measured and used to calculate the inter-roll cross angle and frictional coefficient. The system dynamically adjusts the frictional coefficient based on actual load conditions, ensuring accurate thrust force calculation even as operating conditions change during rolling operations.
3Measurement precision
If load difference measurement is performed during rolling, then thrust force can be estimated, but left-right asymmetric errors and frictional resistance cause measurement errors
Solution Approach 1:
The patent performs preliminary measurement of vertical roll loads before rolling begins, when the material is not yet in the rolling mill. This preliminary action allows the system to establish baseline load values and calculate the inter-roll cross angle without the interference of rolling forces, frictional resistance, and asymmetric errors that occur during actual rolling operations.
Data Source
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.