Cooling Stretch Enthalpy Control for Strip Width Flatness

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Solution Overview

Problem

Existing methods for controlling the cooling of metal strips or plates in hot-strip and heavy-plate mills fail to ensure homogeneous temperature distribution and mechanical properties, leading to defects and increased scrap due to non-uniform cooling and reliance on surface temperature measurements.

Innovation Solution

Determining the initial enthalpy distribution across the material width and calculating a target enthalpy distribution using a microstructure model to optimize flatness and mechanical properties, allowing for dynamic adjustment of coolant amounts and curves during the cooling process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single fixed coolant amount is used for cooling the rolling material, then the cooling process is simple to control, but the temperature distribution becomes non-uniform leading to flatness defects and increased scrap

Engineering Contradiction:

Improveflatness and evenness of rolling materialVSAvoidcooling control system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cooling stretch is divided into multiple cooling zones along the rolling material width, with each zone having independent coolant amount control. This segmentation enables different cooling rates to be applied to different width ranges, achieving uniform temperature distribution and flatness while maintaining manageable system complexity through modular control

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different coolant amounts are applied to different width ranges of the rolling material based on local temperature requirements. The control device calculates and sets specific coolant amounts for each cooling zone, allowing local optimization of temperature distribution and flatness without requiring complex global control

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If surface temperature measurements are used to control cooling, then the control method is simple, but the actual energy content and homogeneous temperature distribution cannot be ensured

Engineering Contradiction:

Improvehomogeneous temperature distributionVSAvoidtemperature measurement accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

A control device acts as an intermediary between temperature measurement and cooling control. It calculates the required coolant amount based on measured temperatures and desired target temperatures, then applies the calculated cooling. This intermediary calculation layer ensures homogeneous temperature distribution by compensating for surface measurement limitations

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Direct physical temperature measurement of the bulk material is replaced by mathematical calculation of required coolant amounts based on surface measurements and heat transfer models. This substitution enables accurate control of internal energy content without requiring intrusive internal sensors

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If different cooling rates are applied to different width ranges, then flatness is improved, but the system complexity and control difficulty increase

Engineering Contradiction:

Improveflatness of strip or plateVSAvoidcooling control operation

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The cooling control system dynamically adjusts coolant amounts for different width ranges based on real-time temperature measurements and calculations. The control device automatically determines optimal cooling rates for each zone, making the complex multi-zone control as easy to operate as single-zone control while achieving superior flatness

Inventive Principle:

Principle #15Dynamics

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 approach ensures improved flatness and mechanical properties by achieving a homogeneous enthalpy distribution, reducing defects and scrap by allowing real-time correction of deviations through targeted cooling adjustments.

Implementation Method 1

a control device for the rolling material determines and sets the optimum coolant amount and coolant amount curve for passage through a cooling stretch

Methodology Applied

Scientific EffectHeat removal: Cooling

Data Source

PatentUS11779977B2Method for setting different cooling curves of rolling material over the strip width of a cooling stretch in a hot-strip mill or heavy-plate mill

Publication Date: 2023.10.10 SMS GROUP GMBH

AI summary

A method for setting different cooling rates of metal strips or metal plates (rolling material) over the strip width of a cooling stretch in a hot-strip mill or heavy-plate mill is presented. According to the method, for the calculation of the cooling rate, the initial enthalpy distribution over the material width of the rolling material before the cooling is determined. Proceeding therefrom, a target enthalpy distribution is determined in the width direction and length direction of the rolling material while taking into account a calculation of the flatness and the mechanical properties by means of a microstructure model. Subsequently, the coolant amount and the coolant curve of the cooling stretch are set.