Roller Table Depression for Hot Strip Tension Control
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Solution Overview
Problem
In hot strip rolling processes, it is challenging to precisely control strip tension between successive rolling units, leading to excessive tension that can cause constrictions and cracks in the rolling stock, particularly in continuous production, where existing methods either result in high structural lengths or material losses due to inefficient decoupling and tension control.
Innovation Solution
A method and apparatus that form a rolling stock loop in a depression on the roller table, with the loop depth adjusted to match the free span of the rolling stock, supported by the roller table at an off-center portion, allowing the control device to minimize strip tension by calculating and maintaining the desired loop depth based on material, thickness, and temperature, and controlling the main drives to achieve a virtually tension-free rolling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a free-hanging rolling stock loop is formed in a depression on the roller table, then strip tension is reduced to a minimum, but the structural length of the installation increases
Solution Approach 1:
The patent introduces a vertical dimension by creating a depression in the roller table surface. This allows the rolling stock loop to be formed in three-dimensional space rather than requiring additional horizontal length, thereby reducing strip tension without proportionally increasing the installation's structural length.
Solution Approach 2:
The rolling stock loop is formed with a curved path following the depression contour. This curvature allows the material to naturally sag and form a loop that reduces tension through gravitational action, while the compact curved geometry minimizes the space required compared to a straight-line alternative.
2Object-affected harmful factors
If the loop depth is increased to reduce strip tension, then the yield point is not exceeded, but constrictions and cracks may form in the rolling stock
Solution Approach 1:
A measuring device continuously monitors the loop depth and provides feedback to the control device. The control device adjusts the roller table or rolling unit positions in real-time to maintain the loop depth within the optimal range, preventing both excessive tension and harmful constrictions or cracks in the rolling stock.
Solution Approach 2:
The system dynamically adjusts the loop depth based on real-time conditions rather than using a fixed geometry. This allows the loop depth to be optimized for each specific rolling operation, ensuring tension is reduced without creating constrictions or cracks that would compromise product quality.
3Object-affected harmful factors
If conventional decoupling methods are used between rolling relays, then strip tension control is achieved, but investment costs and thermal losses increase
Solution Approach 1:
The patent combines the decoupling function with the existing roller table structure by creating a depression in it. This eliminates the need for separate decoupling devices or coiling/uncoiling equipment, thereby reducing investment costs and minimizing thermal losses by keeping the rolling stock in a continuous flow without interruption or exposure to ambient air.
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 reduces strip tension to zero, preventing constrictions and cracks, improving the quality and output of the rolling process while maintaining a compact installation structure, thus enhancing the efficiency and quality of hot strip production.
Implementation Method 1
a rolling stock loop is formed in a depression arranged in a section of the roller table between the two rolling units
Data Source
AI summary
A method for reducing the strip tension of a rolling stock, may include: transporting the rolling stock using a roller table between two successive rolling units, wherein a rolling stock loop is formed in a depression in a section of the roller table between the two rolling units, the rolling stock loop being supported by the roller table at least in one off-center portion of the section, wherein the supporting line of the roller table in this portion corresponds to the catenary curve of the free span; measuring a loop depth of the rolling stock loop; calculating a desired value of the loop depth that corresponds substantially to the free span, e.g., depending on the material, thickness and temperature of the rolling stock; controlling the main drives and/or the gap adjustment of the rolling units based on the desired value and the measured loop depth, such that the loop depth substantially corresponds to the desired value.