Hot-Rolling Mill Temperature Control via Frequency-Component Segmentation
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Solution Overview
Problem
Conventional temperature control methods in hot-rolling mills face limitations due to differing response characteristics among various temperature adjusting means, leading to suboptimal temperature accuracy and potential operational constraints, such as slow response of rolling speed changes and rapid power fluctuations in induction heating, which can result in temperature fluctuations and operational limits.
Innovation Solution
A temperature control apparatus that calculates initial reference values for rolling speed, cooling water flow rate, and electric power based on manufacturing instructions, and uses frequency component extraction to correct these values dynamically, allowing for rapid temperature adjustments by induction heating for high-frequency fluctuations, slow rolling speed changes for low-frequency fluctuations, and medium-response cooling water flow rate adjustments for medium-frequency fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If rolling speed is changed for temperature adjustment, then temperature control is achieved, but response is slow due to control disturbance of the whole line
Solution Approach 1:
The temperature control system is segmented into multiple independent control loops: rolling speed control, cooling water flow rate control, and induction heating power control. Each loop operates independently to adjust temperature without causing whole-line control disturbance, enabling faster response while maintaining stability.
Solution Approach 2:
The system dynamically selects and adjusts the most appropriate temperature adjusting means based on real-time temperature deviations and operational constraints. The control strategy transitions from static rolling speed adjustment to dynamic multi-parameter adjustment, optimizing response speed while maintaining temperature accuracy.
2Temperature
If induction heating power is changed for temperature adjustment, then rapid temperature change is achieved, but operational constraints cause power fluctuations and limit continuous adjustment
Solution Approach 1:
The system implements feedback control by continuously monitoring material temperature and adjusting induction heating power accordingly. Temperature sensors provide real-time feedback to the control system, which modulates heating power to maintain temperature within target ranges, preventing excessive fluctuations and operational limits.
Solution Approach 2:
The system changes operational parameters (rolling speed, cooling water flow rate, induction heating power) based on temperature requirements and operational constraints. By dynamically adjusting multiple parameters rather than relying solely on induction heating power, the system achieves rapid temperature control while maintaining operational stability and avoiding power limit fluctuations.
3Temperature
If multiple temperature adjusting means are used, then temperature accuracy can be improved, but coordination of different response characteristics becomes complex
Solution Approach 1:
The control system introduces an intermediary coordination layer that manages the interaction between rolling speed control, cooling water flow rate control, and induction heating power control. This intermediary layer harmonizes the different response characteristics of each adjusting means, enabling accurate temperature control without overwhelming complexity in the control architecture.
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 effectively suppresses temperature fluctuations by utilizing the appropriate temperature adjusting means based on their response characteristics, preventing operational limits and improving temperature accuracy of rolled materials.
Implementation Method 1
an induction heating device that heats the rolled material
Implementation Method 2
a water cooling device that cools the rolled material
Data Source
AI summary
A temperature control apparatus of a hot-rolling mill according to the present invention extracts a high-frequency component, a medium-frequency component, and a low-frequency component from a deviation between a calculated value or a measured value of a material temperature in a temperature managing position set on an outlet side of the hot-rolling mill and a given temperature target value. The temperature control apparatus then corrects a reference value of electric power of an induction heating device set to an electric power changing device based on the high-frequency component, corrects a reference value of a cooling water flow rate set to a flow rate changing device based on the medium-frequency component, and corrects a reference value of a roll rotation speed set to a speed changing device based on the low-frequency component.