Width-Dependent Belt Cooling for Metal Strip Homogeneity

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Solution Overview

Problem

In hot strip mills, poor strip tracking due to uneven heating and material properties across the strip width leads to non-uniform rolling, which interferes with subsequent process steps and results in unsatisfactory temperature homogenization and rolling forces.

Innovation Solution

A manufacturing method where spatially resolved initial values of a metal strip's properties are recorded and used to determine expected values, with control values for the cooling device being calculated and adjusted to achieve uniform properties across the strip width, allowing for precise control of temperature and material strength during rolling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the slab is heated unevenly in the furnace, then the heating of the slab is uneven across the strip width, but this leads to non-uniform material properties and poor strip tracking

Engineering Contradiction:
Improvetemperature uniformityVSAvoidstrip tracking
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The cooling device applies width-dependent cooling rates to different regions of the slab. The control computer calculates target cooling rates for first, second, and third regions across the width, allowing each region to be cooled according to its specific thermal state and material properties, thereby achieving uniform temperature distribution and homogeneous material properties across the strip width

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts the cooling rate parameter across different width regions. By varying the cooling rate according to position (first, second, and third regions), the system compensates for initial heating non-uniformity and achieves homogeneous material properties throughout the slab width

Inventive Principle:
Principle #35Parameter changes

2Temperature

If width-dependent preliminary cooling is applied to equalize temperature, then temperature uniformity improves, but device complexity increases

Engineering Contradiction:
Improvetemperature uniformityVSAvoidcooling control system
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The control computer receives actual values from detectors and compares them with target values, then adjusts the cooling device operations accordingly. This closed-loop feedback system automatically compensates for initial non-uniformities without requiring complex manual intervention or overly sophisticated hardware

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces complex mechanical adjustment mechanisms with a computational approach. The control computer calculates width-dependent target cooling rates based on detector inputs and controls the cooling device through electronic signals, substituting mechanical complexity with software-based control logic

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical 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 method enables the production of metal strips with homogeneous properties across the width, improving strip tracking and reducing non-uniform rolling forces, thereby enhancing the quality and reliability of the rolling process.

Implementation Method 1

the slab is thicker on one side than the other... attempts are made in the prior art to homogenize the temperature of the pre-strip by means of a cooling device downstream of the roughing mill

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2841215B1Equalisation of belt properties by means of width-dependent preliminary belt cooling
Publication Date: 2016.05.18 PRIMETALS TECH GERMANY GMBH
  • EP2841215B1 patent drawingFigure 1
  • EP2841215B1 patent drawingFigure 2~3
  • EP2841215B1 patent drawingFigure 4

AI summary

A metal strip (1) is roughed in a roughing mill (2), then cooled in a cooling device (3) and finally finish-rolled in a finishing train (8) with multiple rolling stands (9). At the latest when the metal strip (1) runs into the cooling device (3), initial values of a first property of the metal strip (1) are recorded in a spatially resolved form in the direction of the width of the strip and are fed to a rolling model (20). By means of the rolling model (20), expected values of a second property of the metal strip (1) are determined for a location that lies at or behind the first rolling stand (9) of the finishing train (8), in a spatially resolved form in the direction of the width of the strip. The expected values depend on the respective initial values and on the respective activation values (S) of the cooling device (3). The activation values (S) of the cooling device (3) are determined by means of the rolling model (20) in a spatially resolved form in the direction of the width of the strip in such a way that the expected values are made to approximate desired values of the second property in a spatially resolved form in the direction of the width of the strip. The cooling device (3) is activated in a way corresponding to the determined activation values (S).