Forsterite Evaluation on Grain-Oriented Steel Sheets

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Solution Overview

Problem

Current methods for evaluating forsterite on grain-oriented electrical steel sheets are destructive and time-consuming, lacking a non-destructive means to check for the presence, location, and distribution of forsterite without damaging the measurement object.

Innovation Solution

Employing cathodoluminescence (CL) imaging using a SEM equipped with a light-evaluation device, where an electron beam excites light from the forsterite layer, allowing for the visualization and quantitative assessment of forsterite presence, location, and distribution without sample destruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If destructive analysis methods (oxygen analysis, SEM observation) are used to evaluate forsterite, then measurement precision can be achieved, but the measurement object is damaged and evaluation time increases

Engineering Contradiction:

Improveforsterite evaluation precisionVSAvoidnon-destructive evaluation

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces destructive mechanical/chemical analysis methods (oxygen analysis requiring steel dissolution, SEM requiring sample preparation) with optical detection using a charge-coupled device camera that captures light reflected from or transmitted through the forsterite layer, enabling non-destructive evaluation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary substance to evaluate forsterite properties. By measuring light absorption, reflection, or transmission characteristics, the system obtains forsterite evaluation data without direct contact or damage to the measurement object

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If destructive sample preparation (steel dissolution, cross-section polishing) is performed, then forsterite amount can be determined, but evaluation time increases significantly

Engineering Contradiction:

Improveforsterite amountVSAvoidevaluation time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent performs preliminary action by establishing a correlation between light characteristics and forsterite amount in advance. Once this correlation is established, rapid non-destructive measurements can be performed without repeating time-consuming sample preparation and chemical analysis

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent substitutes time-consuming mechanical sample preparation (polishing, sectioning) and chemical analysis (oxygen analysis requiring steel dissolution) with rapid optical measurement using light detection and image processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Difficulty of detecting and measuring

If conventional evaluation methods are used, then forsterite presence can be detected, but the field of view is limited and quantitative assessment is difficult

Engineering Contradiction:

Improveforsterite detectionVSAvoiddistribution information

Core Design Contradiction:

Difficulty of detecting and measuringVSLoss of information

Solution Approach 1:

The patent transitions from point-based or limited-area measurements to two-dimensional or three-dimensional optical field measurement. By capturing light characteristics across the entire visible area with a charge-coupled device camera, the system obtains comprehensive spatial distribution information of forsterite

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent creates a multi-functional evaluation system that simultaneously provides forsterite presence detection, quantitative amount assessment, and spatial distribution mapping through a single optical measurement approach, eliminating the need for multiple separate analysis methods

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables easy, non-destructive evaluation of forsterite presence, location, and distribution, providing a wide field of view and quantitative data, thus improving the assessment of forsterite uniformity and adhesion properties on steel sheets.

Implementation Method 1

employing cathodoluminescence (CL) imaging using a SEM equipped with a light-evaluation device, where an electron beam excites light from the forsterite layer

Methodology Applied

Scientific EffectCathodoluminescence: Cathodoluminescence

Data Source

PatentEP2980566B1Forsterite confirmation method, forsterite evaluation device, and steel sheet production line

Publication Date: 2018.10.10 JFE STEEL CORP

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AI summary

Provided is a technique for easily checking the presence of forsterite without destroying a measurement object. The location where forsterite is present is checked in a region from which light excited by an electron beam is emitted when a material containing forsterite is irradiated with an electron beam. The present invention is preferably applied to the case where the material is a grain oriented electrical steel sheet having a forsterite layer. In addition, it is preferable that the accelerating voltage be 30 kV or more when an electron beam is radiated in the case where the material is a grain oriented electrical steel sheet having a tension coating layer on the forsterite layer.