Rolling Mill Feedback Control for Flat Steel Property Tuning
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Solution Overview
Problem
Existing rolling mills face challenges in precisely adjusting material properties of flat rolled products, such as yield strength and magnetizability, which can lead to discrepancies between actual and desired values, particularly in advanced high-strength steels and martensitic/bainitic grades, requiring additional heat treatment steps.
Innovation Solution
A control device in the rolling mill adjusts the ratio of upper to lower peripheral speeds of the working rolls based on real-time measured variables, allowing direct control over material properties without complex model calculations, and incorporates temperature modifications and rolling force adjustments to set desired properties accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional rolling control methods are used, then the rolling process is simple, but the material properties (yield strength, magnetizability) cannot be precisely adjusted
Solution Approach 1:
The control device receives measured variables from sensor devices arranged upstream and/or downstream of the rolling stand, uses these measurements to determine control values that adjust rolling parameters, and implements closed-loop feedback control to precisely achieve target material properties
Solution Approach 2:
The control device determines control values based on measured variables before the material property deviation occurs, allowing preventive adjustment of rolling parameters to ensure target properties are achieved without requiring complex post-processing
2Productivity
If conventional rolling control is used, then the process is straightforward, but additional heat treatment steps are required
Solution Approach 1:
The invention extracts and eliminates the need for additional heat treatment steps by implementing precise control of material properties during the rolling process itself, removing unnecessary subsequent processing operations
Solution Approach 2:
The invention merges the material property control function into the rolling process itself by using feedback control to adjust rolling parameters, combining what were previously separate operations (rolling + heat treatment) into a single integrated process
3Manufacturing precision
If asymmetric rolling with different peripheral speeds is applied, then material properties can be adjusted, but the control complexity increases
Solution Approach 1:
The control device dynamically adjusts the ratio of peripheral speeds of upper and lower working rolls based on measured variables and feedback control, allowing the system to adapt rolling conditions in real-time rather than using fixed asymmetric speed ratios
Solution Approach 2:
The invention changes the control parameter from fixed asymmetric speed ratios to dynamically adjusted speed ratios determined by the control device based on measured variables, enabling precise material property control while simplifying operation through automated parameter optimization
Data Source
AI summary
A rolling mill has a rolling stand (1) in which a flat rolled product (2) composed of metal is rolled. A sensor device (6), which detects at least one measured variable (M) characteristic of a material property of the flat rolled product (2), is arranged upstream and/or downstream of the rolling stand (1). The material property can be, in particular, an electromagnetic property or a mechanical property of the rolled product (2). The sensor device (6) transfers the detected measured variable (M) to a control device (9) for the rolling mill. Taking into account the measured variable (M), the control device (9) determines a control value (A) for the rolling stand (1). The control of the rolling stand (1) influences the material property of the flat rolled product (2). The control value (A) is a ratio of the peripheral speeds (vO, vU) at which the upper and the lower working rolls (3, 4) of the rolling stand (1) rotate.