Induction Heater for Hot Strip Temperature Control
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Solution Overview
Problem
In the reverse rolling of a Steckel mill, despite having two coiler furnaces with heat retention functions forward and rearward, the hot strip temperatures decrease significantly at the width end portions and tail end portions, leading to poor hot strip quality due to uneven temperature distribution.
Innovation Solution
A novel method involving the placement of an induction heater between the mill stands, utilizing solenoid or transverse-type induction heaters, and implementing stable inter-mill stand tension control with vertically-movable rolls or pinch rolls to enhance temperature distribution and prevent hot strip damage, allowing for adjustable heating patterns and gap control to maintain optimal temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an induction heater is mounted between the coiler furnace and the rolling mill with the inductor gap approached as much as possible to increase heating efficiency, then the heating efficiency is improved, but the tension detection precision and tension control between the coiler furnace and the mill stand cannot be increased, and when hot strip tension loosens, the hot strip contacts the apparatus when forming a loop configuration, increasing the probability of damage
Solution Approach 1:
The patent introduces a mediator device (loop detector and tension control system) between the induction heater and the hot strip to detect loop formation and control tension. This intermediary system monitors the hot strip status and adjusts tension control rolls or pinch rolls to prevent contact between the hot strip and the induction heater, thereby maintaining high heating efficiency while preventing damage.
Solution Approach 2:
The patent implements a feedback mechanism where loop detectors continuously monitor the hot strip loop configuration between the coiler furnace and the rolling mill. When a loop is detected or tension loosens, the system provides feedback to the tension control system to adjust the position of control rolls or modify the inductor gap, ensuring the hot strip remains at an optimal distance from the induction heater without contact, thus preventing damage while maintaining heating efficiency.
2Reliability
If the inductor gap is opened in the safe direction to prevent hot strip contact, then the damage probability is reduced, but the heating efficiency degrades or heating cannot be performed
Solution Approach 1:
The patent applies dynamics by making the inductor gap adjustable rather than fixed. The gap between the induction heater coils and the hot strip can be dynamically modified based on real-time conditions. When the hot strip is properly tensioned and positioned, the gap is minimized for high heating efficiency. When loop formation is detected or tension loosens, the gap is automatically increased to prevent contact, thus balancing heating efficiency and safety dynamically.
Solution Approach 2:
The patent changes the parameter of the inductor gap distance based on operational conditions. The system monitors tension and loop formation, and when safe conditions are detected, the inductor gap is reduced to maximize heating efficiency. When potential contact risk is detected, the gap parameter is increased to prevent damage. This dynamic parameter adjustment resolves the contradiction between heating efficiency and safety.
3Temperature
If the hot strip is heated to maintain high temperature for quality improvement, then the metallurgical texture is improved, but the temperature distribution becomes uneven with significant temperature drops at width end portions and tail end portions
Solution Approach 1:
The patent applies local quality by positioning multiple induction heaters at different locations along the hot strip path - specifically between the coiler furnace and the rolling mill, and potentially at multiple points between mill stands. Each induction heater provides localized heating to specific sections of the hot strip, compensating for heat loss in different regions. This distributed localized heating approach maintains overall high temperature while improving temperature distribution uniformity across the width and length of the hot strip.
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
The method effectively increases and maintains hot strip temperatures in both the longitudinal and width directions, improving temperature distribution and reducing the risk of hot strip damage, thereby enhancing the quality and yield of the hot strip.
Implementation Method 1
a novel method involving the placement of an induction heater between the mill stands, utilizing solenoid or transverse-type induction heaters
Implementation Method 2
The induction heater according to claim 2 of the invention is an induction heater of the solenoid (the flux being perpendicular to the hot strip width cross section) type or the transverse (the flux being perpendicular to the hot strip longitudinal-direction cross section) type
Implementation Method 3
two coilers having heat retention called coiler furnaces are included frontward and rearward of rolling mills
Implementation Method 4
the temperatures decrease for the hot strip width end portions and front and tail end portions released from the coiler furnaces
Implementation Method 5
the temperatures decrease for the hot strip width end portions and front and tail end portions released from the coiler furnaces
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
According to an embodiment of the invention, a rolling equipment includes two coiler furnaces; a plurality of mill stands provided between the two coiler furnaces, the plurality of mill stands being for reverse rolling; and an induction heater provided between the plurality of mill stands, the induction heater implementing a heated temperature increase in a designated reverse rolling or in each reverse rolling, the heated temperature increase being in a hot strip longitudinal direction and width direction. Thus, the hot strip temperature distribution can be improved.