Rolling Mill Zigzagging Control With Thrust-Compensated Leveling
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Solution Overview
Problem
Conventional zigzagging control methods for rolling mills fail to accurately account for the influence of inter-roll and material-roll thrust forces on differential loads, leading to inaccurate leveling corrections and potential damage to the rolling mill.
Innovation Solution
A method that estimates inter-roll and material-roll thrust forces based on measured cross angles and friction coefficients, and uses these parameters to correct rolling-load-difference information for precise reduction leveling control during the rolling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional differential-load type zigzagging control is used without considering thrust forces, then the control system is simple, but the leveling correction accuracy deteriorates due to unaccounted thrust forces causing differential load fluctuations
Solution Approach 1:
The patent calculates thrust forces (inter-roll thrust force and material-roll thrust force) before performing reduction leveling control. By preliminarily determining these thrust forces based on measured rolling loads and pre-stored coefficients, the system compensates for their influence on differential load, thereby improving leveling correction accuracy without requiring complex additional hardware
Solution Approach 2:
The patent introduces thrust force calculations as an intermediary step between rolling load measurement and leveling control. The thrust forces act as a mediating parameter that explains the relationship between rolling loads and differential load fluctuations, allowing the control system to distinguish between genuine leveling errors and those caused by thrust forces
2Measurement precision
If thrust forces are not considered in differential load measurement, then the measurement process is simple, but the differential load measurement becomes inaccurate due to unaccounted overturning moments
Solution Approach 1:
The patent pre-calculates and stores influence coefficients for thrust forces before the rolling operation. During actual measurement, these pre-stored coefficients are used to quickly determine thrust forces, avoiding complex real-time calculations and making the measurement process both accurate and efficient
Solution Approach 2:
The patent uses measured rolling loads as feedback to calculate thrust forces, which then feed back into the differential load measurement process. This closed-loop approach continuously refines the measurement by compensating for thrust force effects based on actual operating conditions
3Reliability
If accurate leveling correction is performed without considering thrust forces, then productivity is maintained, but the rolling mill may suffer damage due to inaccurate control
Solution Approach 1:
The patent performs thrust force calculations and differential load corrections before the tail portion of the workpiece passes through the rolling mill. This preliminary action ensures that accurate leveling control is in place before potential zigzagging occurs, preventing damage while maintaining continuous operation
Solution Approach 2:
The patent applies preliminary anti-action by calculating and compensating for thrust force effects before they can cause harmful differential load fluctuations. By anticipating and counteracting the influence of thrust forces in advance, the system prevents potential damage to the rolling mill
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 more accurate leveling corrections, reducing centerline deviations and preventing damage to the rolling mill by accurately accounting for thrust forces.
Implementation Method 1
work-side and drive-side rolling loads of at least any one of upper and lower roll assemblies are measured
Implementation Method 2
a roll-axis-direction thrust counterforce acting on a roll other than a backup roll is measured
Data Source
AI summary
There is provided a zigzagging control method for a workpiece including: an estimation step of, before rolling of a tail portion of the workpiece, acquiring at least any one of an inter-roll thrust force estimated based on an inter-roll cross angle and an inter-roll friction coefficient and a material-roll thrust force estimated based on a material-roll cross angle and a material-roll friction coefficient; and a tail control step of, during the rolling of the tail portion of the workpiece, measuring work-side and drive-side rolling loads, correcting a rolling load difference or a rolling load difference ratio based on any two of acquired parameters including a roll-axis-direction thrust counterforce at the measurement of the rolling loads, the inter-roll thrust force, and the material-roll thrust force, and performing reduction leveling control on a rolling mill based on the corrected rolling load difference or rolling load difference ratio.