Work Roll Shift Control for Edge Drop Reduction
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Solution Overview
Problem
Conventional rolling mills face challenges in reducing edge drop and achieving stable rolling due to strip meandering, which complicates the precise alignment of taper shoulder positions of work rolls, leading to increased edge trimming and reduced yield.
Innovation Solution
A rolling mill equipped with work roll shift devices and a strip widthwise end position detector that adjusts the taper start positions of work and intermediate rolls to coincide with the actual strip widthwise ends, reducing edge drop and improving shape stability through precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If taper shoulder positions of work rolls are shifted to coincide with strip widthwise end positions, then edge drop is reduced and yield is improved, but strip meandering causes deviation in positioning leading to insufficient improvement
Solution Approach 1:
The patent employs a feedback mechanism where the actual position of the strip widthwise ends is detected and used to adjust the taper shoulder positions of the work rolls. This closed-loop control ensures that despite strip meandering, the taper shoulders are always correctly positioned relative to the actual strip ends, resolving the positioning accuracy issue while maintaining edge drop control.
2Manufacturing precision
If taper shoulder positions are precisely aligned with strip widthwise ends, then edge drop is reduced, but control operation becomes complicated and costs increase
Solution Approach 1:
The patent uses a feedback-based automatic control system that detects the actual strip widthwise end positions and automatically adjusts the work roll taper shoulder positions accordingly. This eliminates the need for complex manual control operations while achieving precise edge drop control, thus reducing both operational complexity and costs.
3Loss of substance
If work rolls with tapered portions are used to reduce edge drop, then yield is improved, but strip shape stability during acceleration and deceleration is compromised
Solution Approach 1:
The patent implements a dynamic control system that can adjust the taper shoulder positions of the work rolls in real-time based on rolling conditions. During acceleration and deceleration, the system dynamically adjusts the positioning to maintain optimal contact between the tapered portions and the strip, thereby maintaining both edge drop control and strip shape stability under varying operational conditions.
Data Source
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AI summary
A rolling mill equipped with a work roll shift function is provided that can improve yield and realize stable rolling with a simple means. In a six-high rolling mill or a four-high rolling mill, a pair of upper and lower work rolls (2) are provided with tapered portions (2b) in upper and lower positions in point symmetry, shift cylinders (13) are provided for shifting the pair of upper and lower work rolls (2) in roll axial directions and a strip widthwise end position detector (32) is provided for detecting strip widthwise ends of a metal strip (1), and a controller (35) is further provided for performing shift control of the shift cylinders (13) so as to cause taper start positions (2a) of the tapered portions (2b) of the pair of upper and lower work rolls (2) to coincide with the vicinities of the insides of the strip widthwise ends or the vicinities of the outsides of the strip widthwise ends detected by the strip widthwise end position detector (32).