Metal Strip Profile Control via Buckling Strain Correction

Solution Overview

Problem

Existing methods for predicting the profile of a metal strip after rolling do not accurately account for non-linear phenomena like buckling, leading to modeling errors and inadequate prediction precision.

Innovation Solution

A rolling control method that finds a critical buckling strain difference distribution and a true elongation strain difference distribution by correlating rolling load differences with elongation strain differences, allowing for precise control of the metal strip's profile by adjusting rolling conditions based on these distributions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional prediction methods are used that do not consider non-linear phenomena, then the prediction model is simple, but the prediction precision deteriorates due to modeling errors

Engineering Contradiction:

Improveprediction model complexityVSAvoidprofile prediction precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The prediction model is segmented into multiple components: a basic rolling model for linear behavior and a separate buckling model for non-linear phenomena. Each segment handles specific aspects of the deformation process, allowing the system to maintain simplicity where applicable while adding complexity only where necessary for accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The prediction system dynamically adapts its complexity based on the deformation conditions. When buckling is detected or anticipated, the model transitions from a simple linear prediction to a more complex non-linear prediction that incorporates buckling effects, optimizing the balance between model complexity and prediction precision.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If non-linear phenomena like buckling are considered in the prediction model, then the prediction precision improves, but the model complexity increases

Engineering Contradiction:

Improveprofile prediction precisionVSAvoidprediction model complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The prediction model is segmented into multiple components: a basic rolling model for linear behavior and a separate buckling model for non-linear phenomena. Each segment handles specific aspects of the deformation process, allowing the system to maintain simplicity where applicable while adding complexity only where necessary for accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The prediction system dynamically adapts its complexity based on the deformation conditions. When buckling is detected or anticipated, the model transitions from a simple linear prediction to a more complex non-linear prediction that incorporates buckling effects, optimizing the balance between model complexity and prediction precision.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the provisional elongation strain difference distribution is used directly for control, then the control process is simple, but the profile control precision deteriorates due to buckling effects

Engineering Contradiction:

Improvecontrol process simplicityVSAvoidprofile control precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

A correction term acts as an intermediary between the provisional elongation strain difference distribution and the final control parameters. This correction term accounts for buckling effects by calculating the difference between the provisional distribution and the critical buckling strain difference distribution, thereby improving control precision without significantly complicating the control process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The physical buckling phenomenon is replaced by a mathematical correction mechanism. Instead of directly simulating the complex non-linear buckling behavior, the system uses a correction term derived from the difference between provisional and critical strain distributions, substituting a simplified mathematical approach for the complex physical phenomenon.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3195945B1Rolling control method for metal plate, rolling control device, and method for manufacturing rolled metal plate

Publication Date: 2019.07.31 NIPPON STEEL CORPORATION

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AI summary

A provisional elongation strain difference distribution Δε(x) of a metal strip during rolling is found under conditions in which out-of-plane deformation of the metal strip is restrained. A critical buckling strain difference distribution Δεcr(x) is found based on the provisional elongation strain difference distribution Δε(x), a strip thickness and strip width of the metal strip, and tension acting on the metal strip at exit from a rolling mill. In cases in which the provisional elongation strain difference distribution Δε(x) exceeds the critical buckling strain difference distribution Δεcr(x), the difference between the provisional elongation strain difference distribution Δε(x) and the critical buckling strain difference distribution Δεcr(x) is found, and this difference is added to the provisional elongation strain difference distribution Δε(x) to find a true elongation strain difference distribution Δε'(x). Rolling conditions are set based on the true elongation strain difference distribution Δε'(x), and the metal strip is rolled, thereby controlling the profile of the metal strip.