Twin-Roll Casting Line Control for Abnormal Strip Rolling
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Solution Overview
Problem
Conventional rolling mill control systems fail to maintain stable rolling operations when materials with abnormalities such as hot bands or meandering are conveyed, leading to sudden fluctuations in motor torque, material slippage, and increased downtime for adjustments and replacements.
Innovation Solution
A control system for a twin roll-type continuous casting machine that includes a rolling mill control unit, conveyor control unit, and multiple control units to manage roll gap, tension, and speed, allowing for adaptive control strategies such as open control, tension control, and speed control to stabilize the process even with abnormal materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rolling roll is suddenly opened in a state where tension control is performed, then the abnormal material can be removed, but the motor torque suddenly fluctuates causing material slippage and pinch roll defects
Solution Approach 1:
The control method performs preliminary actions by detecting abnormalities in advance and proactively adjusting conveyor speed before the rolling mill opens. This preparatory speed adjustment prevents sudden torque fluctuations when the roll opens, eliminating material slippage and pinch roll defects while maintaining rolling stability.
Solution Approach 2:
The system implements feedback control by continuously monitoring material conditions and conveyor performance, then automatically adjusting conveyor speed in response to detected abnormalities. This closed-loop control ensures stable rolling by maintaining appropriate speed relationships between the conveyor and rolling mill throughout the abnormal material removal process.
2Reliability
If the rolling roll is opened to remove abnormal material, then the material defect can be addressed, but unsteady work such as adjustment and replacement of the pinch roll is required, increasing downtime
Solution Approach 1:
The control method performs preliminary speed adjustment of the conveyor before the rolling mill opens to remove abnormal material. This prevents material slippage and pinch roll defects in advance, eliminating the need for subsequent unsteady work such as pinch roll adjustment or replacement, thereby maintaining rolling continuity and reducing downtime.
Solution Approach 2:
The system achieves self-service by automatically detecting abnormalities and adjusting conveyor speed without operator intervention. This automated response prevents material defects and maintains stable rolling conditions, allowing continuous operation without manual adjustment or replacement work.
3Force
If tension control is maintained during roll opening, then the material tension is controlled, but the material slips against the pinch roll and cannot be rolled normally
Solution Approach 1:
The control method dynamically adjusts the conveyor speed based on the rolling mill's operational state and material conditions. When the rolling mill opens to remove abnormal material, the conveyor speed is automatically adjusted to maintain appropriate speed differential, preventing material slippage while allowing the rolling mill to open and close normally.
Solution Approach 2:
The system changes the conveyor speed parameter in response to rolling mill operations. When tension control is maintained during roll opening, the conveyor speed is adjusted to prevent material slippage, ensuring that material can be properly fed into the rolling mill after the abnormal material is removed.
Data Source
AI summary
A control system is a control system of casting and rolling equipment having a twin roll-type continuous casting machine, a rolling mill, and a conveyor. The control system includes a rolling mill control unit that controls the rolling mill by any one of controls including a rolling control and an open control, a conveyor control unit that controls the conveyor by any one of controls including a tension control and a speed control, a first control unit that controls to perform the rolling control and the tension control, a second control unit that controls to perform the open control and the speed control, and a third control unit that controls to resume the tension control and the rolling control.