Zonal Heating Steel Strip Thermal Expansion Control

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Solution Overview

Problem

Continuous annealing systems face challenges in achieving uniform mechanical properties across the width of steel strips due to temperature variations, leading to band fluttering and potential system damage from uneven thermal expansion.

Innovation Solution

A method for zonal heating of steel strips with high selectivity, using tailored guide rollers and localized heating/cooling techniques to manage thermal expansion, ensuring that heated zones are guided and cooled to achieve uniform mechanical properties across the strip width.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the steel strip is heated unevenly across the width to achieve different mechanical properties, then the mechanical property differentiation is improved, but the band fluttering increases due to uneven thermal expansion

Engineering Contradiction:
Improvemechanical property differentiationVSAvoidband stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The heating system is divided into multiple independent heating zones across the strip width, each可控 to provide different temperature levels. This segmentation allows precise control of thermal expansion in each zone while maintaining overall band stability, resolving the contradiction between mechanical property differentiation and band stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the strip receive customized heating treatments tailored to their specific mechanical property requirements. The heating parameters (temperature, duration, intensity) are locally optimized for each zone, enabling precise mechanical property control without causing excessive thermal expansion differences that would lead to band fluttering.

Inventive Principle:
Principle #3Local quality

2Reliability

If cooling gas flows are used to compensate for temperature differences across the strip width, then the thermal expansion uniformity is improved, but the ability to create different mechanical properties is reduced

Engineering Contradiction:
Improvethermal expansion uniformityVSAvoidmechanical property differentiation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The cooling process is implemented in two distinct stages: first, uniform cooling to establish thermal expansion uniformity and stabilize the band; second, selective localized cooling in specific zones to create the desired mechanical property differences. This periodic action sequence resolves the contradiction by first ensuring stability, then enabling precision differentiation.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If the strip is cooled in two stages with different temperatures, then the mechanical property control is improved, but the process complexity increases

Engineering Contradiction:
Improvemechanical property controlVSAvoidcooling process structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cooling system is segmented into multiple independently controllable cooling zones, each capable of operating at different temperature levels and cooling rates. This segmentation allows the complex two-stage cooling process to be managed through modular zone control, reducing operational complexity while maintaining precise mechanical property control.

Inventive Principle:
Principle #1Segmentation

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 effectively controls thermal expansion, reducing band fluttering and enabling the production of steel strips with significant differences in tensile strength across their width, enhancing the reliability and efficiency of continuous annealing systems.

Implementation Method 1

a) to be heated differently zonally with the heating device (2)

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

and in front of a cooling device (3) to be cooled zonally

Methodology Applied
Scientific EffectThermal cooling: Cooling

Implementation Method 3

the task is to heat up the strip differently and/or cool it down differently... fundamentally different temperatures in the strip lead to the steel strip assuming different thermal expansions or thermal expansion states. This leads to the band fluttering

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3201369B1Method for the manufacture of steel strip material having different mechanical properties across the width of the strip
Publication Date: 2018.08.29 VOESTALPINE STAHL GMBH
  • EP3201369B1 patent drawingFigure 1
  • EP3201369B1 patent drawingFigure 2
  • EP3201369B1 patent drawingFigure 3

AI summary

The invention relates to a method for forming metal strip material with different mechanical characteristics across the width of the strip, wherein the strip is heated in zones with respect to the width, so that temporary zones with different heat states are created, and the strip is subsequently cooled in order to create regions with different metal structures and thus mechanical characteristics, wherein a heating device is applied to one or more zones to be heated while the other zones are delimited from the heating, are free of the heating or are actively cooled, or a heat flow, which is registered in the zones which are not to be heated, is deflected into contact masses abutting the zones which are not to be heated.