Hot-Rolled Strip Temperature Modeling Across Cooling Regimes

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Solution Overview

Problem

Existing methods for determining the temperature of hot-rolled steel strips in hot rolling installations are not sufficiently accurate, leading to variations in cooling and degradation of steel strip mechanical properties due to disturbances from upstream equipment.

Innovation Solution

A method that incorporates a thermal model configured to account for impingement cooling and parallel flow cooling, allowing for more precise temperature determination by discretizing the metal strip into portions and estimating heat flux using specific cooling regimes, including impingement, parallel flow, remaining coolant, and air cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple thermal model is used for temperature determination, then the device complexity is reduced, but the measurement precision deteriorates

Engineering Contradiction:
Improvethermal model complexityVSAvoidtemperature determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the cooling process into distinct zones (impingement cooling zone and parallel flow cooling zone) based on the coolant header geometry and strip position. This segmentation allows the thermal model to apply different heat transfer correlations to different zones, improving temperature prediction accuracy without requiring a single overly complex model. The run-out table is divided into multiple sections, each with its own cooling characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different heat transfer coefficients and cooling mechanisms for different locations on the strip surface. Specifically, it distinguishes between impingement cooling (where coolant jets directly strike the strip) and parallel flow cooling (where coolant flows parallel to the strip surface). Each zone uses appropriate local thermal parameters and correlations tailored to its specific cooling mechanism.

Inventive Principle:
Principle #3Local quality

2Device complexity

If upstream equipment disturbances are not compensated, then the control system complexity is reduced, but the manufacturing precision deteriorates

Engineering Contradiction:
Improvecontrol system complexityVSAvoidsteel strip mechanical properties
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements feedback control by continuously measuring the actual strip temperature using pyrometers and comparing it with the target temperature profile. The thermal model uses this temperature feedback to adjust cooling predictions and compensate for upstream disturbances. The system dynamically adjusts cooling water flow rates based on real-time temperature measurements, creating a closed-loop control system that maintains manufacturing precision despite disturbances from the finishing mill.

Inventive Principle:
Principle #23Feedback

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 method provides a more accurate and robust temperature determination, reducing temperature errors and improving the mechanical properties of the steel strips by effectively controlling the cooling process across various industrial configurations.

Implementation Method 1

a thermal model which is configured for modeling both an impingement cooling corresponding to the cooling of the strip portion by coolant falling under the at least one coolant header and a parallel flow cooling corresponding to the cooling of the strip portion by coolant falling at a given distance from the at least one coolant header

Methodology Applied
Scientific EffectImpingement cooling: Convection

Implementation Method 2

a thermal model which is configured for modeling both an impingement cooling corresponding to the cooling of the strip portion by coolant falling under the at least one coolant header and a parallel flow cooling corresponding to the cooling of the strip portion by coolant falling at a given distance from the at least one coolant header

Methodology Applied
Scientific EffectParallel flow cooling: Convection

Implementation Method 3

In order to properly compute the strip thermal path, heat transfer equation has to be solved with account for various phenomena occurring at the strip surfaces

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3645182B1Method and electronic device for determining the temperature of a metal strip, related control method, computer program, control apparatus and hot rolling installation
Publication Date: 2021.08.04 ARCELORMITTAL SA
  • EP3645182B1 patent drawingFigure 1~2
  • EP3645182B1 patent drawingFigure 3
  • EP3645182B1 patent drawingFigure 4

AI summary

This method for determining the temperature of a metal strip (1 ) inside a cooling apparatus (4) of a hot rolling installation is implemented by an electronic device (12). This method includes acquiring a temperature measure of a strip portion at a current time instant; estimating, at the current time instant, a heat flux extracted from the strip portion inside the cooling apparatus according to a thermal model, and computing a strip portion temperature at a next time instant from the acquired temperature measure and the estimated extracted heat flux. The thermal model models an air cooling of the strip portion, a coolant header cooling of the strip portion by a coolant header and a remaining coolant cooling of the strip portion, wherein for the coolant header cooling the model models both an impingement cooling of the strip portion and a parallel flow cooling of the strip portion.