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Valiente Bermejo, María AsunciónORCID iD iconorcid.org/0000-0003-3374-6282
Publications (10 of 25) Show all publications
Baghdadchi, A., Cary, C., Sridhar, N., Valiente Bermejo, M. A., Fink, C. & Andersson, J. (2023). Corrosion resistance and microstructure analysis of additively manufactured 22% chromium duplex stainless steel by laser metal deposition with wire. Journal of Materials Research and Technology, 26, 6741-6756
Open this publication in new window or tab >>Corrosion resistance and microstructure analysis of additively manufactured 22% chromium duplex stainless steel by laser metal deposition with wire
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2023 (English)In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 26, p. 6741-6756Article in journal (Refereed) Published
Abstract [en]

Microstructure characteristics and pitting corrosion of a duplex stainless steel (DSS) manufactured by laser metal deposition with wire (LMDw) were studied. The layer-by-layer LMDw process resulted in a mixed microstructure of predominantly ferrite with 2% austenite and chromium-rich nitrides, and reheated regions with ~33% austenite. The high cooling rate of LMDw restricted the distribution of Cr, Mo, and Ni, in ferrite and austenite, while N diffuses from ferrite to austenite. Subsequent heat treatment at 1100 C for 1 h resulted in homogenized microstructure, dissolution of nitrides, and balanced ferrite/austenite ratio. It also led to the redistribution of Cr and Mo to ferrite, and Ni and N to austenite. At room temperature, cyclic potentiodynamic polarization measurements in 1.0 M NaCl solution showed no significant differences in corrosion resistance between the as-deposited and heat-treated samples, despite the differences in terms of ferrite to austenite ratio and elemental distribution. Critical pitting temperature (CPT) was the lowest (60 C) for the predominantly ferritic microstructure with finely dispersed chromium-rich nitrides; while reheated area with ~33% austenite in as-deposited condition achieved higher critical temperature comparable to what was obtained after heat treatment (73 and 68 C, respectively). At temperatures above the CPT, selective dissolution of the ferrite after deposition was observed due to depletion of N, while after heat treatment, austenite preferentially dissolved due to Cr and Mo concentrating in ferrite. In summary, results demonstrate how microstructural differences in terms of ferrite-to-austenite ratio, distribution of corrosion-resistant elements, and presence of nitrides affect corrosion resistance of LMDw DSS.

Keywords
Additive manufacturing, Duplex stainless steel, Laser metal deposition, Localized corrosion, Microstructure-property relation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-20883 (URN)10.1016/j.jmrt.2023.09.037 (DOI)2-s2.0-85171616425 (Scopus ID)
Note

CC BY 4.0

Available from: 2023-12-28 Created: 2023-12-28 Last updated: 2024-02-20
Aydin, G., Şelte, A., Andersson, J. & Valiente Bermejo, M. A. (2023). Towards Laser Metal Deposition of Modified PH 13-8Mo Powder. Key Engineering Materials, 964, 85-90
Open this publication in new window or tab >>Towards Laser Metal Deposition of Modified PH 13-8Mo Powder
2023 (English)In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 964, p. 85-90Article in journal (Refereed) Published
Abstract [en]

Modified PH 13-8Mo alloy exhibits a good combination of corrosion resistance and mechanical properties for demanding applications in aerospace, petrochemical, and tooling industries. Additive manufacturing, specifically the laser metal deposition process with powder as feedstock (LMDp), has the potential to be utilized in these industries. However, very limited knowledge on the LMDp of this alloy currently exists. The aim of this work was, therefore, to deposit a multi-track single layer of modified PH 13-8Mo alloy as a first step towards 3D geometries, and to analyze the resulting microstructure by using Optical Microscopy, Scanning Electron Microscopy, X-Ray Diffraction, Electron Backscatter Diffraction, and micro-hardness. It was found that the multitrack single layer was free from major defects. The microstructure was heterogeneous, and it consisted of a martensitic matrix and small amounts of δ ferrite, austenite, and AlN. The results of this research will be used to tailor the microstructure and properties of future 3D additively manufactured components.

Keywords
Additive manufacturing, Martensitic precipitation hardening stainless steels, Laser metal deposition, Modified PH 13-8Mo
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21099 (URN)10.4028/p-bhofw0 (DOI)
Funder
Knowledge Foundation, 20210094
Note

The Swedish Knowledge Foundation (KK-stiftelsen, Stiftelsen för kunskaps- ochkompetensutveckling) funded this research via DEDICATE: Directed Energy Deposition for Industrial Competitiveness in Additive Manufacturing Technologies project (Dnr.20210094). 

Available from: 2023-12-20 Created: 2023-12-20 Last updated: 2024-01-15Bibliographically approved
Valiente Bermejo, M. A., Maumeviciene, D., Petroniené, S., Sukacké, V., Vaiciuniené, J., Namrata, S. & Rakhshanda, K. (2022). Community of Practice: Supporting Teachers Towards Innovations. In: Intermediality in communication: Translation Media Discourse. Paper presented at International conference 17-18 November, 2022, Kaunas, Lituania (pp. 20-20).
Open this publication in new window or tab >>Community of Practice: Supporting Teachers Towards Innovations
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2022 (English)In: Intermediality in communication: Translation Media Discourse, 2022, p. 20-20Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

See page 20 in conferensce abstract book.

Keywords
Support, teacher
National Category
Pedagogical Work
Identifiers
urn:nbn:se:hv:diva-19376 (URN)
Conference
International conference 17-18 November, 2022, Kaunas, Lituania
Projects
HACK-IT project ERASMUS project number 2021-1-PT01-KA220-HED-000023406
Available from: 2022-11-23 Created: 2022-11-23 Last updated: 2023-03-20Bibliographically approved
Valiente Bermejo, M. A., Magniez, L., Jonasson, A., Selin, S., Frodigh, M., Hurtig, K., . . . Karlsson, L. (2022). Exposure of FeCrAl Overlay Welds on Superheater Tubes: Influence of Local Environment on Degradation. Journal of Failure Analysis and Prevention, 22(1), 400-408
Open this publication in new window or tab >>Exposure of FeCrAl Overlay Welds on Superheater Tubes: Influence of Local Environment on Degradation
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2022 (English)In: Journal of Failure Analysis and Prevention, ISSN 1547-7029, E-ISSN 1864-1245, Vol. 22, no 1, p. 400-408Article in journal (Refereed) Published
Abstract [en]

Two experimental FeCrAl alloy overlay welds on tube shields were exposed in the superheater of a full-size waste fired boiler for 6 months. The tube shields were in different tube lines and positions within the superheater chamber to investigate possible heterogeneities in the exposure environment. The visual inspection of the exposed tube shields and the corrosion-erosion rates calculated from the analysis of cross-sections showed that the mid-length roof location experienced the most aggressive environment. The compositional differences between the two experimental alloys were not found to be determinant in their performance under these specific exposure conditions. It was concluded that erosion had a decisive influence on the results. The identification of local differences within the superheater chamber is important when deciding on the material selection for the different areas and locations to be protected. The output of this study is therefore interesting for further design consideration of superheaters as well as for future planning of exposures.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Boiler, Superheater, Overlay welding, FeCrAl alloys
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-18080 (URN)10.1007/s11668-022-01337-5 (DOI)
Available from: 2022-01-25 Created: 2022-01-25 Last updated: 2023-03-09Bibliographically approved
Johansson, M., Stenwall, P., Valiente Bermejo, M. A. & Andersson, J. (2022). Varestraint weldability testing of Sanicro 25 and 310S stainless steel. In: Stan A. David,Zhili Feng, Thoams J. Lienert (Ed.), Advances in Welding & Additive Manufacturing Research: . Paper presented at Advances in Welding & Additive Manufacturing Research Virtual Conference 2022, June 13,2 2022 - June 16, 2022. American Welding Society
Open this publication in new window or tab >>Varestraint weldability testing of Sanicro 25 and 310S stainless steel
2022 (English)In: Advances in Welding & Additive Manufacturing Research / [ed] Stan A. David,Zhili Feng, Thoams J. Lienert, American Welding Society , 2022Conference paper, Oral presentation only (Refereed)
Place, publisher, year, edition, pages
American Welding Society, 2022
Keywords
varestraint weldability, stainless steel.
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-19967 (URN)
Conference
Advances in Welding & Additive Manufacturing Research Virtual Conference 2022, June 13,2 2022 - June 16, 2022
Available from: 2023-05-11 Created: 2023-05-11 Last updated: 2023-12-19
Baghdadchi, A., Hosseini, V., Valiente Bermejo, M. A., Axelsson, B., Harati, E., Högström, M. & Karlsson, L. (2022). Wire laser metal deposition of 22% Cr duplex stainless steel: as-deposited and heat-treated microstructure and mechanical properties. Journal of Materials Science, 57(21), 9556-9575
Open this publication in new window or tab >>Wire laser metal deposition of 22% Cr duplex stainless steel: as-deposited and heat-treated microstructure and mechanical properties
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2022 (English)In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 57, no 21, p. 9556-9575Article in journal (Refereed) Published
Abstract [en]

Duplex stainless steel (DSS) blocks with dimensions of 150 × 70x30 mm3 were fabricated by Laser Metal Deposition with Wire (LMDw). Implementation of a programmable logic control system and the hot-wire technology provided a stable and consistent process producing high-quality and virtually defect-free deposits. Microstructure and mechanical properties were studied for as-deposited (AD) material and when heat-treated (HT) for 1 h at 1100 °C. The AD microstructure was inhomogeneous with highly ferritic areas with nitrides and austenitic regions with fine secondary austenite occurring in a periodic manner. Heat treatment produced a homogenized microstructure, free from nitrides and fine secondary austenite, with balanced ferrite and austenite fractions. Although some nitrogen was lost during LMDw, heat treatment or reheating by subsequent passes in AD allowed the formation of about 50% austenite. Mechanical properties fulfilled common requirements on strength and toughness in both as-deposited and heat-treated conditions achieving the highest strength in AD condition and best toughness and ductility in HT condition. Epitaxial ferrite growth, giving elongated grains along the build direction, resulted in somewhat higher toughness in both AD and HT conditions when cracks propagated perpendicular to the build direction. It was concluded that high-quality components can be produced by LMDw and that deposits can be used in either AD or HT conditions. The findings of this research provide valuable input for the fabrication of high-performance DSS AM components

National Category
Manufacturing, Surface and Joining Technology Metallurgy and Metallic Materials
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-18106 (URN)10.1007/s10853-022-06878-6 (DOI)
Available from: 2022-02-07 Created: 2022-02-07 Last updated: 2024-02-20Bibliographically approved
Kisielewicz, A., Thalavai Pandian, K., Sthen, D., Hagqvist, P., Valiente Bermejo, M. A., Sikström, F. & Ancona, A. (2021). Hot-Wire Laser-Directed Energy Deposition: Process Characteristics and Benefits of Resistive Pre-Heating of the Feedstock Wire. Metals, 11(4), 1-25
Open this publication in new window or tab >>Hot-Wire Laser-Directed Energy Deposition: Process Characteristics and Benefits of Resistive Pre-Heating of the Feedstock Wire
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2021 (English)In: Metals, ISSN 2075-4701, Vol. 11, no 4, p. 1-25Article in journal (Refereed) Published
Abstract [en]

This study investigates the influence of resistive pre-heating of the feedstock wire (here called hot-wire) on the stability of laser-directed energy deposition of Duplex stainless steel. Data acquired online during depositions as well as metallographic investigations revealed the process characteristic and its stability window. The online data, such as electrical signals in the pre-heating circuit and images captured from side-view of the process interaction zone gave insight on the metal transfer between the molten wire and the melt pool. The results show that the characteristics of the process, like laser-wire and wire-melt pool interaction, vary depending on the level of the wire pre-heating. In addition, application of two independent energy sources, laser beam and electrical power, allows fine-tuning of the heat input and increases penetration depth, with little influence on the height and width of the beads. This allows for better process stability as well as elimination of lack of fusion defects. Electrical signals measured in the hot-wire circuit indicate the process stability such that the resistive pre-heating can be used for in-process monitoring. The conclusion is that the resistive pre-heating gives additional means for controlling the stability and the heat input of the laser-directed energy deposition.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
laser-directed energy deposition with wire, laser–metal deposition with wire, hot-wire, resistive pre-heating, in-process monitoring
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-16428 (URN)10.3390/met11040634 (DOI)000643283500001 ()2-s2.0-85104042477 (Scopus ID)
Funder
Vinnova, 2019-02752
Note

Finansiärer:Stiftelsen för Kunskaps- och KompetensutvecklingProjektnummer: 20160281, 20170060

Available from: 2021-04-14 Created: 2021-04-14 Last updated: 2023-10-26
Valiente Bermejo, M. A., Thalavai Pandian, K., Axelsson, B., Harati, E., Kisielewicz, A. & Karlsson, L. (2021). Microstructure of laser metal deposited duplex stainless steel: Influence of shielding gas and heat treatment. Welding in the World, 65, 525-541
Open this publication in new window or tab >>Microstructure of laser metal deposited duplex stainless steel: Influence of shielding gas and heat treatment
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2021 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 65, p. 525-541Article in journal (Refereed) Published
Abstract [en]

This research work is the first step in evaluating the feasibility of producing industrial components by using Laser Metal Deposition with duplex stainless steel Wire (LMDw). The influence of Ar and N2 shielding gases was investigated in terms of nitrogen loss and in the microstructure and austenite content of different deposited geometries. The evolution of the microstructure in the build-up direction of the Ar and N2-shielded blocks was compared in the heat-treated and as-deposited conditions. The susceptibility for oxygen pick-up in the LMDw deposits was also analyzed, and oxygen was found to be in the range of conventional gas-shielded weldments. Nitrogen loss occurred when Ar-shielding was used; however, the use of N2-shielding prevented nitrogen loss. Austenite content was nearly doubled by using N2-shielding instead of Ar-shielding. The heat treatment resulted in an increase of the austenite content and of the homogeneity in the microstructure regardless of the shielding gas used. The similarity in microstructure and the low spread in the phase balance for the as-deposited geometries is a sign of having achieved a stable and consistent LMDw process in order to proceed with the build-up of more complex geometries closer to industrial full-size components.

Place, publisher, year, edition, pages
Springer, 2021
Keywords
Duplex stainless steels, Additive manufacturing, Laser metal deposition, Directed energy deposition, Laser beam additive manufacturing
National Category
Manufacturing, Surface and Joining Technology Metallurgy and Metallic Materials
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-16106 (URN)10.1007/s40194-020-01036-5 (DOI)000598987700002 ()2-s2.0-85097168175 (Scopus ID)
Funder
Knowledge Foundation, 20170060
Available from: 2020-12-10 Created: 2020-12-10 Last updated: 2021-03-10Bibliographically approved
Valiente Bermejo, M. A., Eynian, M., Malmsköld, L. & Scotti, A. (2021). University-industry collaboration in curriculum design and delivery: A model and its application in manufacturing engineering courses. Industry & higher education, 36(5)
Open this publication in new window or tab >>University-industry collaboration in curriculum design and delivery: A model and its application in manufacturing engineering courses
2021 (English)In: Industry & higher education, ISSN 0950-4222, E-ISSN 2043-6858, Vol. 36, no 5Article in journal (Refereed) Published
Abstract [en]

The advantages and importance of university-industry collaboration, particularly in curriculum design and delivery, are well-known. However, although curriculum development models are available in the literature, very few are sufficiently concrete to be applicable in practice or are generalizable beyond their discipline of origin. In this paper, a co-operative model based on the Plan-Do-Study-Act cycle is presented and described. An example of its application in the curriculum design of two courses in welding within a Manufacturing Engineering Master's program is detailed. The model was found successful based on the evaluation of the courses by students, teachers, and the industrial representatives involved. Therefore, it proved to be an effective tool for bridging the gap between industrial needs and academia in the field of Manufacturing Engineering education. At the same time, the methodology is generalizable and is applicable to any field of education.

Keywords
university–industry collaboration, curriculum design, higher education, co-production, manufacturing engineering education, welding courses
National Category
Production Engineering, Human Work Science and Ergonomics Learning Pedagogy
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-17974 (URN)10.1177/09504222211064204 (DOI)000737889800001 ()2-s2.0-85121783972 (Scopus ID)
Funder
Knowledge Foundation, 20180019
Available from: 2021-12-30 Created: 2021-12-30 Last updated: 2023-06-04
Valiente Bermejo, M. A., Eyzop, D., Hurtig, K. & Karlsson, L. (2021). Welding of Large Thickness Super Duplex Stainless Steel: Microstructure and Properties. METALS, 11(8), Article ID 1184.
Open this publication in new window or tab >>Welding of Large Thickness Super Duplex Stainless Steel: Microstructure and Properties
2021 (English)In: METALS, E-ISSN 2075-4701, Vol. 11, no 8, article id 1184Article in journal (Refereed) Published
Abstract [en]

In this study, Submerged Arc Welding (SAW) and Gas Metal Arc Welding (GMAW) processes were used in multi-pass welding of 33 mm thickness super duplex stainless steel plates. Recommended and higher than recommended arc energy and interpass temperatures were used. Both GMAW and SAW processes were able to produce large thickness weldments meeting the microstructural, mechanical, and corrosion resistance requirements, and also when using higher than recommended arc energy and interpass temperature. It was possible to reduce the number of welding passes by half when using higher than recommended arc energy and interpass temperature. The SAW process needed only half of the welding time required for the GMAW process to produce a weldment with nearly the same number of weld passes, when using recommended arc energy and interpass temperature. Based on the results of this investigation, the practical recommendations for welding large thicknesses should be revised and updated.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
multi-pass welding; large thickness; super duplex stainless steel; SAW; GMAW; microstructure; properties
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-17447 (URN)10.3390/met11081184 (DOI)000689406800001 ()2-s2.0-85111059453 (Scopus ID)
Funder
Knowledge Foundation, 20140046
Available from: 2021-10-18 Created: 2021-10-18 Last updated: 2022-04-04
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3374-6282

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