Rolling Mill Feedback Control for Material Property Tuning
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Solution Overview
Problem
Existing rolling mills face challenges in precisely adjusting material properties of flat rolling stock, such as achieving desired geometric and material properties like yield point, hardness, and magnetizability, which can lead to deviations from target values, particularly when producing advanced high-strength steels and other grades, requiring additional thermal treatments.
Innovation Solution
A rolling mill design where the control device calculates a control value as the ratio of upper to lower peripheral speeds of the work rolls, allowing direct adjustment of material properties without complex model calculations, and incorporating a sensor device to measure variables that influence the rolling process, enabling precise control over material properties through asymmetrical rolling and temperature adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional rolling methods are used to set geometric properties, then width and thickness can be controlled, but material properties such as yield point, hardness, and magnetizability deviate from target values
Solution Approach 1:
The invention changes the rolling parameters by introducing asymmetrical rolling where the upper and lower work rolls rotate at different peripheral speeds. This parameter change (speed ratio) directly influences the material properties during rolling, enabling precise control of yield point, hardness, and magnetizability without requiring post-rolling thermal treatments
Solution Approach 2:
The invention implements a feedback control system where a sensor device measures a variable characteristic of the material property, transmits the measured value to a control device, and the control device adjusts the speed ratio of the work rolls based on this feedback to maintain material properties within target ranges
2Manufacturing precision
If thermal treatment is applied after hot rolling to set material properties, then desired yield point and hardness can be achieved, but production time and process complexity increase
Solution Approach 1:
The invention performs the material property setting action during the rolling process itself rather than as a subsequent step. By applying asymmetrical rolling with controlled speed ratios, the desired material properties are established preliminarily during hot rolling, eliminating the need for post-rolling thermal treatment operations
Solution Approach 2:
The invention extracts the material property control function from the subsequent thermal treatment process and integrates it into the rolling process itself. The asymmetrical rolling mechanism directly controls material properties during deformation, removing the separate thermal treatment step from the production flow
3Adaptability or versatility
If asymmetrical rolling is used to adjust material properties, then targeted control of magnetizability and strength is possible, but control system complexity increases
Solution Approach 1:
The invention applies asymmetry by making the peripheral speeds of the upper and lower work rolls different from each other. This asymmetrical rolling creates specific stress states and deformation patterns that enable targeted control of material properties such as magnetizability and strength, which cannot be achieved with symmetrical rolling
Solution Approach 2:
The control device is designed to be multi-functional, handling both the measurement of material properties via sensor integration and the adjustment of rolling parameters (speed ratio) based on measured values. This universal control approach manages complexity by consolidating multiple functions into a single integrated system
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 targeted and reliable adjustment of material properties, reducing the need for post-processing thermal treatments and improving the precision of material properties in flat rolling stock, particularly for advanced high-strength steels and other challenging materials.
Implementation Method 1
a sensor device (6) which is designed to detect a measured variable (M) which is characteristic of a material property (28) of the flat rolling stock (2)
Implementation Method 2
In asymmetric rolling, the peripheral speeds of an upper and a lower work roll of a rolling mill differ from each other. During rolling, shear forces act on the flat rolling stock in the transport direction. Due to the shear forces, a rearrangement of the crystal orientation is brought about.
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
A rolling mill has a first rolling stand (1) in which a flat metal stock (2) is rolled. A sensor device (6) is arranged upstream and/or downstream of the first rolling stand (1), by means of which at least one measured variable (M) characteristic of a material property of the flat metal stock (2) is detected. The material property can be, in particular, an electromagnetic property or a mechanical property of the metal stock (2). The sensor device (6) transmits the detected measured variable (M) to a control unit (9) for the rolling mill. The control unit (9) takes the transmitted measured variable (M) into account when determining a control value (A) for the first rolling stand (1). Controlling the first rolling stand (1) with the control value (A) influences the material property of the flat metal stock (2).