Stepped Rolling Line Tension Control for Precise Thickness Transitions
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Solution Overview
Problem
Existing rolling technologies face challenges in achieving precise thickness transitions and efficient control during stepped rolling, particularly due to long response and control times, and require extensive empirical data for process parameter calculation.
Innovation Solution
A device and method that utilize a linear drive to measure and control tensile stress on rolling stock, maintaining constant tensile stress regardless of drive speed, and adjust torque and power consumption to optimize rolling and straightening processes, with force measuring bearings and servo motors enabling dynamic control and short transitions between thickness areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If control is based on strip speed and thickness measurements, then the rolling process can be controlled, but the response and control times are too long to achieve sufficiently good thickness transitions
Solution Approach 1:
The patent applies preliminary action by using a model-based feedforward control that calculates the required rolling forces and strip tensions in advance based on the desired thickness profile and process parameters. This allows the control system to anticipate and prepare for upcoming thickness transitions rather than reacting to them after they occur, significantly reducing control time and improving transition quality.
2Manufacturing precision
If strip tension is controlled by changing rotational speeds of decoiler and coiler devices, then strip tension forces can be controlled, but a large number of data must first be empirically recorded before sufficient basis is available for calculating process parameters
Solution Approach 1:
The patent replaces the empirical data recording and complex calculation system with a physics-based model that directly calculates strip tensions and rolling forces based on fundamental mechanical relationships. The model uses material properties, geometry, and process parameters to determine the required forces, eliminating the need for extensive empirical data collection and complex iterative calculations.
3Loss of time
If forces applied by work rolls are kept constant irrespective of roll gap change, then control time is reduced, but it requires controlling strip tension forces by changing rotational speeds of decoiler and coiler devices
Solution Approach 1:
The patent applies dynamics by making the rolling forces and strip tensions dynamic rather than constant. The model continuously calculates the required forces as functions of the instantaneous roll gap, strip thickness, and process parameters, allowing the system to adapt forces in real-time to maintain optimal rolling conditions throughout the thickness transition process.
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 allows for highly dynamic and precise control of tensile stress, optimizing the rolling process by directly influencing thickness reduction and microstructure flow, enabling shorter transitions and improved quality in stepped rolling.
Implementation Method 1
a linear drive arranged downstream of the pair of rolls in the rolling direction, which together with the pair of rolls can apply tensile stress to the rolling stock
Implementation Method 2
with means for detecting the tensile stress
Data Source
AI summary
The invention relates to a device for rolling, in particular for stepped rolling, of rolling stock with at least one pair of rolls and at least one linear drive arranged downstream of the pair of rolls in the rolling direction, which together with the pair of rolls can apply tensile stress to the rolling stock, and with means for detecting the tensile stress. In order to enable an improved method of flexibly rolling stock, the rolling device is characterized by means for detecting the tensile stress and by a control device for controlling the drive power of the linear drive as a function of the tensile stress detected, in order optionally to vary the tensile stress applied to the stock or to keep the tensile stress constant as the drive speeds behind the roll gap change. The invention also relates to a method of rolling the rolling stock using such a device.