Microstructure quality control of steels using deep learning

In quality control, microstructures are investigated rigorously to ensure structural integrity, exclude the presence of critical volume defects, and validate the formation of the target microstructure. For quenched, hierarchically-structured steels, the morphology of the bainitic and martensitic mic...

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Main Authors: Ali Riza Durmaz, Sai Teja Potu, Daniel Romich, Johannes J. Möller, Ralf Nützel
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-08-01
Series:Frontiers in Materials
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmats.2023.1222456/full
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author Ali Riza Durmaz
Ali Riza Durmaz
Sai Teja Potu
Sai Teja Potu
Daniel Romich
Johannes J. Möller
Ralf Nützel
author_facet Ali Riza Durmaz
Ali Riza Durmaz
Sai Teja Potu
Sai Teja Potu
Daniel Romich
Johannes J. Möller
Ralf Nützel
author_sort Ali Riza Durmaz
collection DOAJ
description In quality control, microstructures are investigated rigorously to ensure structural integrity, exclude the presence of critical volume defects, and validate the formation of the target microstructure. For quenched, hierarchically-structured steels, the morphology of the bainitic and martensitic microstructures are of major concern to guarantee the reliability of the material under service conditions. Therefore, industries conduct small sample-size inspections of materials cross-sections through metallographers to validate the needle morphology of such microstructures. We demonstrate round-robin test results revealing that this visual grading is afflicted by pronounced subjectivity despite the thorough training of personnel. Instead, we propose a deep learning image classification approach that distinguishes steels based on their microstructure type and classifies their needle length alluding to the ISO 643 grain size assessment standard. This classification approach facilitates the reliable, objective, and automated classification of hierarchically structured steels. Specifically, an accuracy of 96% and roughly 91% is attained for the distinction of martensite/bainite subtypes and needle length, respectively. This is achieved on an image dataset that contains significant variance and labeling noise as it is acquired over more than 10 years from multiple plants, alloys, etchant applications, and light optical microscopes by many metallographers (raters). Interpretability analysis gives insights into the decision-making of these models and allows for estimating their generalization capability.
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spelling doaj.art-ca120744d3574262a21747e7fcade34a2023-08-11T01:11:36ZengFrontiers Media S.A.Frontiers in Materials2296-80162023-08-011010.3389/fmats.2023.12224561222456Microstructure quality control of steels using deep learningAli Riza Durmaz0Ali Riza Durmaz1Sai Teja Potu2Sai Teja Potu3Daniel Romich4Johannes J. Möller5Ralf Nützel6Group of Meso and Micromechanics, Fraunhofer Institute for Mechanics of Materials IWM, Freiburg im Breisgau, GermanyChair for Micro and Materials Mechanics, University of Freiburg, Freiburg im Breisgau, GermanyGroup of Meso and Micromechanics, Fraunhofer Institute for Mechanics of Materials IWM, Freiburg im Breisgau, GermanyInstitute of Mechanics and Computational Mechanics, Leibniz University Hannover, Hannover, GermanyMaterials Technology, Schaeffler Technologies AG & Co. KG, Schweinfurt, GermanyMaterials Technology, Schaeffler Technologies AG & Co. KG, Schweinfurt, GermanyMaterials Technology, Schaeffler Technologies AG & Co. KG, Schweinfurt, GermanyIn quality control, microstructures are investigated rigorously to ensure structural integrity, exclude the presence of critical volume defects, and validate the formation of the target microstructure. For quenched, hierarchically-structured steels, the morphology of the bainitic and martensitic microstructures are of major concern to guarantee the reliability of the material under service conditions. Therefore, industries conduct small sample-size inspections of materials cross-sections through metallographers to validate the needle morphology of such microstructures. We demonstrate round-robin test results revealing that this visual grading is afflicted by pronounced subjectivity despite the thorough training of personnel. Instead, we propose a deep learning image classification approach that distinguishes steels based on their microstructure type and classifies their needle length alluding to the ISO 643 grain size assessment standard. This classification approach facilitates the reliable, objective, and automated classification of hierarchically structured steels. Specifically, an accuracy of 96% and roughly 91% is attained for the distinction of martensite/bainite subtypes and needle length, respectively. This is achieved on an image dataset that contains significant variance and labeling noise as it is acquired over more than 10 years from multiple plants, alloys, etchant applications, and light optical microscopes by many metallographers (raters). Interpretability analysis gives insights into the decision-making of these models and allows for estimating their generalization capability.https://www.frontiersin.org/articles/10.3389/fmats.2023.1222456/fullquality controlmicrostructuregrain sizesteelmartensitebainite
spellingShingle Ali Riza Durmaz
Ali Riza Durmaz
Sai Teja Potu
Sai Teja Potu
Daniel Romich
Johannes J. Möller
Ralf Nützel
Microstructure quality control of steels using deep learning
Frontiers in Materials
quality control
microstructure
grain size
steel
martensite
bainite
title Microstructure quality control of steels using deep learning
title_full Microstructure quality control of steels using deep learning
title_fullStr Microstructure quality control of steels using deep learning
title_full_unstemmed Microstructure quality control of steels using deep learning
title_short Microstructure quality control of steels using deep learning
title_sort microstructure quality control of steels using deep learning
topic quality control
microstructure
grain size
steel
martensite
bainite
url https://www.frontiersin.org/articles/10.3389/fmats.2023.1222456/full
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