Steckel Mill Reversing Unit Cold Head Control
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Solution Overview
Problem
In Steckel mills, the head and foot ends of rolled products become excessively cooled during the reversing process, leading to increased rolling forces and reduced quality due to uneven temperature distribution, resulting in potential faults and material wastage.
Innovation Solution
A method is implemented where the target thickness is ignored at the head end during rolling, and measured variables such as thickness and hardness are monitored to adapt the reversing unit's control, allowing for elastic deformation and minimizing the impact of cold sections, thereby preventing faults and maximizing usable product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heating devices are provided between the reversing unit and the winding furnaces to maintain temperature, then the temperature distribution becomes more uniform, but energy consumption increases significantly and additional space is required
Solution Approach 1:
The patent applies preliminary action by adjusting the rolling parameters (ignoring target thickness, using measured variables for control) before the material enters the critical cooling zone. This preventive approach avoids the need for subsequent heating interventions, thereby eliminating the energy consumption and space requirements associated with heating devices while still achieving uniform temperature distribution through controlled rolling processes
2Force
If the reversing unit is designed for high rolling forces to handle cold head and foot ends, then the rolling forces are sufficient, but changes in thickness and flatness occur reducing product quality
Solution Approach 1:
The patent implements dynamics by dynamically adjusting the rolling control strategy based on the material's thermal state. The system transitions from standard target thickness control to measured variable-based control when cold sections are detected, allowing the rolling forces to adapt to the varying material conditions. This dynamic adjustment maintains sufficient rolling force for cold sections while preventing excessive force application that would cause thickness and flatness defects
Solution Approach 2:
The patent applies feedback by continuously monitoring measured variables (thickness, hardness) during the rolling process and using this information to adjust the rolling unit operation. When the measured variables indicate cold section conditions, the feedback loop modifies the control parameters to ignore target thickness temporarily, allowing the system to respond to actual material conditions rather than following a fixed target, thereby maintaining both sufficient force and manufacturing precision
3Manufacturing precision
If target thickness control is applied during rolling of cold sections, then thickness precision is maintained, but rolling faults occur due to excessive rolling forces on cold material
Solution Approach 1:
The patent applies self-service by enabling the rolling control system to automatically detect cold section conditions through measured variables and autonomously adjust its operation. The system serves itself by switching from target thickness control to a mode that prioritizes rolling force management when cold material is detected, eliminating the need for external intervention or complex additional heating equipment while maintaining process reliability
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 ensures that the majority of the rolled product is rolled to a high quality by minimizing the influence of cold sections, allowing for reliable feeding and maintaining acceptable flatness, while the thicker ends can be cut off to achieve the desired target thickness, thus reducing material wastage.
Implementation Method 1
an elastic deformation and/or a plastic forming of the material takes place
Implementation Method 2
an elastic deformation and/or a plastic forming of the material takes place
Implementation Method 3
winding furnaces for the rolled product arranged on the entry side and the exit side with respect to the reversing unit
Data Source
AI summary
A Steckel mill has a reversing unit for rolling a rolled product and winding furnaces arranged on the entrance side and exit side of the reversing unit. When rolling the rolled product in a region of a head of the rolled product, a target thickness of the rolled product is ignored, while measuring a current thickness and/or a hardness of the rolled product and comparing this with a setpoint value. One the measured variable reaches or is below the setpoint value, the reversing unit is operated with a view to achieving the target thickness of the rolled product. The Steckel mill is operated to allow for rolling of a cold, non-rollable piece of the rolled product, so that malfunctions are avoided and the usable part of the rolled product is as large as possible.