Work Roll Preheating for Flatness Control Without Sensor Arrays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rolling processes for metallic strips, particularly in hot rolling of aluminum alloys, face challenges in achieving desired flatness and thickness profiles due to mechanical stress and heterogeneous thermal expansion of work rolls, leading to defects like edge waves and twist, and require complex thermal control systems with multiple sensors for stabilization.
Innovation Solution
A process for preheating work rolls using induction coils and a predefined thermal expansion profile, controlled by physical models to achieve a target thermal expansion profile without the need for surface temperature sensors, ensuring thermal stability and reducing material loss by stabilizing the thermal profile during rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple sensors and complex thermal control systems are used to stabilize work roll thermal profile, then manufacturing precision of metallic strip flatness is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by preheating the work rolls before the actual rolling operation begins. The method determines a target thermal expansion profile based on the metallic strip characteristics and preheats the work rolls to achieve this profile in advance, eliminating the need for complex real-time thermal control during rolling. This preliminary preparation stabilizes the thermal profile beforehand, improving flatness control while reducing system complexity.
Solution Approach 2:
The patent uses a predefined physical model to calculate the target thermal expansion profile, creating a theoretical copy or representation of the desired thermal state. This calculated profile is then used to guide the preheating process, allowing the system to achieve the correct thermal expansion pattern without requiring multiple sensors and complex feedback control systems during actual operation.
2Stability of the object's composition
If starting metallic strips are used to generate and stabilize thermal expansion profile, then thermal stability is improved, but loss of substance increases due to scrapping
Solution Approach 1:
The patent eliminates the need for starting metallic strips by performing preliminary preheating of the work rolls using induction heating coils before the actual rolling operation. This preliminary thermal preparation stabilizes the thermal expansion profile in advance, allowing the first production metallic strip to be rolled immediately without being sacrificed for thermal stabilization, thus preventing material waste.
Solution Approach 2:
The patent replaces the mechanical approach of using starting metallic strips (which physically pass through the rolls to generate heat) with an induction heating system that directly applies electromagnetic energy to heat the work rolls. This substitution eliminates the need for sacrificial starting material while achieving the same thermal stabilization objective.
3Manufacturing precision
If preheating process is implemented to stabilize thermal profile before rolling, then manufacturing precision is improved, but loss of time increases due to additional process step
Solution Approach 1:
The patent uses induction heating coils that generate electromagnetic fields to directly heat the work rolls, replacing slower conventional heating methods. This electromagnetic heating approach rapidly brings the work rolls to the target thermal expansion profile, minimizing the preheating time penalty while ensuring accurate thickness profile control during rolling.
Solution Approach 2:
The patent applies local quality by using induction heating coils positioned at specific locations around the work roll circumference to apply heat locally where needed. This targeted approach efficiently achieves the desired thermal expansion profile faster than uniform heating methods, reducing the overall preheating time while maintaining precision in the thermal distribution pattern.
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 process efficiently and quickly achieves the desired thermal expansion profile for work rolls, reducing defects in rolled metallic strips by stabilizing the thermal expansion, thus improving flatness and thickness profiles without the need for multiple sensors, enhancing the rolling process's efficiency and material utilization.
Implementation Method 1
the thermal control device includes Ni induction coils distributed along the longitudinal axis of the work roll
Implementation Method 2
activating the induction coils such that they supply the target thermal power profile
Implementation Method 3
determining a target thermal expansion profile (Δd(i)c)1≤i≤Ns at a calculation time tk
Data Source
AI summary
The invention relates to a method for preheating at least one working roll for rolling, involving phases of:determining a target thermal expansion profile,determining an effective mean temperature profile of longitudinal segments of the working roll and for determining a target mean temperature profile,activating a plurality of inductors distributed along the working roll in order to reduce a difference between the effective mean temperature and the target mean temperature.