Hot Rolling Thickness Control Using Pyrometer Skid Mark Tracking
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Solution Overview
Problem
Conventional hot-rolled finishing plate thickness control techniques face challenges in suppressing plate thickness deviations due to skid marks, with existing meters being prone to wear, costly, and unstable load feedback, leading to unreliable and inefficient skid mark thickness variation control.
Innovation Solution
A plate thickness control device and method utilizing a pyrometer to detect temperature differences and calculate screw-down amounts based on plate speed, enabling feedforward control to accurately adjust rolling stand forces and reduce skid mark-induced thickness variations without relying on load cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plate thickness meter is installed between a controlled rolling stand and a preceding rolling stand to perform feedforward AGC, then plate thickness deviation due to skid mark can be suppressed, but the plate thickness meter is exposed to severe environment causing wear and abrupt failure, reducing reliability
Solution Approach 1:
The patent uses a pyrometer to measure temperature as a substitute for directly measuring plate thickness with a meter in the severe environment. The temperature distribution pattern serves as a copy or indicator of the plate surface condition, allowing indirect detection of skid marks without exposing a thickness meter to the harsh rolling environment
Solution Approach 2:
The patent replaces the mechanical plate thickness meter with a non-contact pyrometer that measures temperature distribution. This substitution eliminates the need for physical contact between the measurement device and the plate, avoiding wear and failure while still enabling detection of skid mark conditions
2Manufacturing precision
If gauge meter AGC is used to adjust screw-down amount based on force change detection, then plate thickness control can be performed, but if load feedback is unstable (due to noise in load cell or oil pressure type PT), the gain cannot be increased and plate thickness variation cannot be reduced
Solution Approach 1:
The patent uses temperature distribution measured by pyrometer as an alternative indicator to force measurement. The temperature pattern serves as a copy of the plate surface condition that correlates with skid marks, providing a more stable feedback signal than load cell or oil pressure measurements
Solution Approach 2:
The patent introduces temperature measurement as an intermediary parameter between the skid mark condition and the control action. Instead of directly measuring force with unstable load feedback, the system uses temperature distribution as an intermediate indicator that can be reliably measured and used for control
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
The solution effectively suppresses plate thickness variations by performing feedforward control based on temperature deviations, improving control accuracy and reliability, even in environments with unstable load feedback, and reducing the need for expensive load cells.
Implementation Method 1
a pyrometer disposed on an entry side of the rolling stand... a difference calculation part for outputting a difference temperature between a lock-on temperature of a plate-to-be-rolled measured by the pyrometer and a measurement value other than a head end portion of the plate-to-be-rolled measured by the pyrometer
Data Source
AI summary
A plate thickness control device controlling plate thickness of a hot rolling mill that includes a rolling stand. The plate thickness control device includes: a pyrometer disposed on an entry side of the rolling stand; a difference calculation part that outputs a difference temperature between a lock-on temperature of the plate-to-be-rolled measured by the pyrometer and a measurement value of a portion other than a tip portion of the plate-to-be-rolled measured by the pyrometer; a tracking part that transfers the difference temperature from the position of the pyrometer to immediately below the rolling stand based on plate speed of the plate-to-be-rolled; and a computation part that calculates a screw-down amount of the rolling stand based on the difference temperature transmitted from the tracking part.