Special Issue "Recent Trends in Advanced High-strength Steels"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: 31 July 2019

Special Issue Editors

Guest Editor
Prof. Dr. Ricardo Branco

Department of Mechanical Engineering, University of Coimbra, Coimbra 3004-531, Portugal
E-Mail
Interests: mechanical behavior of materials; fatigue and fracture; multiaxial fatigue life prediction; low-cycle fatigue; fatigue crack initiation; numerical modelling of fatigue crack growth
Guest Editor
Prof. Dr. Filippo Berto

Department of Industrial and Mechanical Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
Website | E-Mail
Phone: +4748500574
Interests: fatigue of advanced and traditional materials; fracture mechanics; solid mechanics; structural integrity; additive materials
Guest Editor
Prof. Dr. Andrei Kotousov

School of Mechanical Engineering, University of Adelaide, South Australia 5005, Australia
Website | E-Mail
Interests: solid mechanics; fracture mechanics

Special Issue Information

Dear Colleagues,

Advanced high-strength steels play an important role in the modern automotive and rail industries because of their balanced properties in terms of strength, fatigue and fracture, wear, machinability, and production costs. In these industries, components are usually subjected to severe service conditions and, therefore, superior mechanical properties are of major engineering significance. Understanding the relationships between the mechanical properties and the chemical composition, microstructural features, and processing techniques is pivotal to develop safe and durable products.

The goal of this Special Issue is to foster the dissemination of the latest research in the field of advanced high-strength steels. Original contributions dealing with the structure characterisation and chemistry analysis; mechanisms involved in microstructure evolution and phase transformation during processing stages; influence of processing techniques and heat treatment routes on structural integrity; or examples of innovative industrial applications of advanced high-strength steels are encouraged. Both experimental and numerical approaches are welcome.

Prof. Dr. Ricardo Branco
Prof. Dr. Filippo Berto
Prof. Dr. Andrei Kotousov
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1500 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Advanced high-strength steels
  • Ultra high-strength steels
  • Dual-phase steels
  • Complex-phase steels
  • Transformation-induced plasticity steels
  • Bainitic steels

Published Papers (4 papers)

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Research

Open AccessArticle Numerical Study of the Effect of Inclusions on the Residual Stress Distribution in High-Strength Martensitic Steels During Cooling
Appl. Sci. 2019, 9(3), 455; https://doi.org/10.3390/app9030455
Received: 31 December 2018 / Revised: 24 January 2019 / Accepted: 26 January 2019 / Published: 29 January 2019
Cited by 1 | PDF Full-text (12049 KB) | HTML Full-text | XML Full-text
Abstract
In high-strength martensitic steels, the inclusions significantly affect the material performance especially in terms of fatigue properties. In this study, a numerical procedure to investigate the effect of the inclusions types and shapes on the residual stresses during the cooling process of the [...] Read more.
In high-strength martensitic steels, the inclusions significantly affect the material performance especially in terms of fatigue properties. In this study, a numerical procedure to investigate the effect of the inclusions types and shapes on the residual stresses during the cooling process of the martensitic steels is applied systematically based on the scanning electronic microscopy (SEM) and energy dispersive spectrometer (EDS) results of different types of inclusions. The results show that the maximum residual stress around the interface between Mg-Al-O inclusion and the matrix is the largest, followed by TiN, Al-Ca-O-S, and MnS when the inclusions are assumed as perfect spheres for simplicity. However, these results are proved to be 28.0 to 48.0% inaccurate compared to the results considering actual shapes of inclusions. Furthermore, the convex shape of inclusion will lead to stress concentration in the matrix while the concave shape of inclusion will lead to stress concentration in the inclusion. The residual stress increases with the increase of inclusion edge angle. The increase rate is the largest for TiN inclusions on the concave angle, which leads to extreme stress concentration inside TiN inclusion. Full article
(This article belongs to the Special Issue Recent Trends in Advanced High-strength Steels)
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Open AccessArticle Integrating the Shape Constants of a Novel Material Stress-Strain Characterization Model for Parametric Numerical Analysis of the Deformational Capacity of High-Strength X80-Grade Steel Pipelines
Appl. Sci. 2019, 9(2), 322; https://doi.org/10.3390/app9020322
Received: 11 December 2018 / Revised: 11 January 2019 / Accepted: 11 January 2019 / Published: 17 January 2019
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Abstract
Pipelines typically exhibit significant inelastic deformation under various loading conditions, making it imperative for limit state design to include considerations for the deformational capacity of pipelines. The methods employed to achieve higher strength of API X80 line pipe steels during the plate manufacturing [...] Read more.
Pipelines typically exhibit significant inelastic deformation under various loading conditions, making it imperative for limit state design to include considerations for the deformational capacity of pipelines. The methods employed to achieve higher strength of API X80 line pipe steels during the plate manufacturing process tend to increase the hardness of the pipe material, albeit at the cost of ductility and strain hardenability. This study features a simple and robust material stress-strain characterization model, which is able to mathematically characterize the shape of a diverse range of stress-strain curves, even for materials with a distinct yield point and an extended yield plateau. Extensive parametric finite element analysis is performed to study the relationship between relevant parameters and the deformational capacity of API X80 pipelines subjected to uniform axial compression, uniform bending, and combined axial compression and bending. Nonlinear regression analysis is employed to develop six nonlinear semi-empirical equations for the critical limit strain, wherein the shape constants of the material model are adapted as dimensionless parameters. The goodness-of-fit of the developed equations was graphically and statistically evaluated, and excellent predictive accuracy was obtained for all six developed equations. Full article
(This article belongs to the Special Issue Recent Trends in Advanced High-strength Steels)
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Open AccessArticle Effects of Temperature and Time of Isothermal Holding on Retained Austenite Stability in Medium-Mn Steels
Appl. Sci. 2018, 8(11), 2156; https://doi.org/10.3390/app8112156
Received: 25 September 2018 / Revised: 31 October 2018 / Accepted: 1 November 2018 / Published: 4 November 2018
Cited by 2 | PDF Full-text (16359 KB) | HTML Full-text | XML Full-text
Abstract
Effects of isothermal holding time and temperature on the stability of retained austenite in medium manganese bainitic steels with and without Nb microaddition were investigated. The amount of retained austenite for various variants of thermomechanical processing was determined by X-ray diffraction. Relationships between [...] Read more.
Effects of isothermal holding time and temperature on the stability of retained austenite in medium manganese bainitic steels with and without Nb microaddition were investigated. The amount of retained austenite for various variants of thermomechanical processing was determined by X-ray diffraction. Relationships between processing conditions and microstructure were revealed using light microscopy and scanning electron microscopy techniques. The isothermal holding temperatures changed from 500 to 300 °C and the time was from 60 to 1800 s. The optimal time and temperature of isothermal holding for all the investigated steels were 400 °C and 300 s, respectively. The relationships between the Mn content, amount of retained austenite, and carbon enrichment of the retained austenite (RA) were observed. The noticeable effect of Nb microaddition on the amount of retained austenite was not observed. In general, the carbon content in RA was slightly lower for the steels containing Nb. The optimum gamma phase amount was up to 18% for the 3% Mn steels, whereas it was c.a. 13% for the steels with 5% Mn. It was found that the morphology of blocky/interlath retained austenite depends substantially on the isothermal holding temperature. Full article
(This article belongs to the Special Issue Recent Trends in Advanced High-strength Steels)
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Open AccessArticle Fracture Toughness of Hybrid Components with Selective Laser Melting 18Ni300 Steel Parts
Appl. Sci. 2018, 8(10), 1879; https://doi.org/10.3390/app8101879
Received: 27 July 2018 / Revised: 1 October 2018 / Accepted: 2 October 2018 / Published: 11 October 2018
Cited by 1 | PDF Full-text (7294 KB) | HTML Full-text | XML Full-text
Abstract
Selective Laser Melting (SLM) is currently one of the more advanced manufacturing and prototyping processes, allowing the 3D-printing of complex parts through the layer-by-layer deposition of powder materials melted by laser. This work concerns the study of the fracture toughness of maraging AISI [...] Read more.
Selective Laser Melting (SLM) is currently one of the more advanced manufacturing and prototyping processes, allowing the 3D-printing of complex parts through the layer-by-layer deposition of powder materials melted by laser. This work concerns the study of the fracture toughness of maraging AISI 18Ni300 steel implants by SLM built over two different conventional steels, AISI H13 and AISI 420, ranging the scan rate between 200 mm/s and 400 mm/s. The SLM process creates an interface zone between the conventional steel and the laser melted implant in the final form of compact tension (CT) samples, where the hardness is higher than the 3D-printed material but lower than the conventional steel. Both fully 3D-printed series and 3D-printed implants series produced at 200 mm/s of scan rate showed higher fracture toughness than the other series built at 400 mm/s of scan rate due to a lower level of internal defects. An inexpressive variation of fracture toughness was observed between the implanted series with the same parameters. The crack growth path for all samples occurred in the limit of interface/3D-printed material zone and occurred between laser melted layers. Full article
(This article belongs to the Special Issue Recent Trends in Advanced High-strength Steels)
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