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1

Development and implementation of robotized wire arc additive repair of a gas turbine diaphragm

Steckowicz Piotr, Pyrzanowski Paweł, Bulut Efe

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 2

art. no. e147920

EN

The current practice of reconstruction of oxidized turbine parts (due to hot corrosion) using arc welding methods facilitates restoration of the nominal shapes and dimensions, as well as other attributes and features. Intense development of 3D additive methods and techniques contributes to the repair/modification of different parts including gas turbine (GT) hardware. The article proves the viability of the concept of using a robotized additive arc welding metal active gas (MAG) process to repair and modify gas turbine diaphragms using different filler materials from the substrate. The industrialized robotic additive process (hybrid repair) shows that very good results were achieved if the diaphragm is cast of nickel-iron and the filler material for welding the passes is austenitic stainless steel (for instance 308 LSi). This is one of the novelties introduced to the repair process that was granted a patent (US11148235B2) and is already implemented in General Electric Service Centers.

2

Effect of the Electrode Extension on the Geometry of Parts Made of 316LSi Steel by Wire Arc Additive Manufacturing Method

Połaski Przemysław, Golański Dariusz, Kołodziejczak Paweł, Pakuła Anna

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

343--359

EN

Intensive research is currently being conducted on WAAM (Wire Arc Additive Manufacturing) processes. Previous studies have demonstrated the impact of current parameters on altering the structure and properties of 316L stainless steel. However, there is a lack of comprehensive information in the literature regarding the influence of electrode extension length (contact to tube distance) on changes in the structure and geometry of parts made of 316L steel using the CMT (Cold Metal Transfer) method. This parameter was often assumed to be constant in research experiments. The study aimed to determine how the length of the electrode extension affects the geometric properties of steel walls produced in the WAAM CMT additive manufacturing process. The experiment used 316LSi stainless steel to build 3D structures in the shape of straight walls. The chosen shape of the parts yielded the most benefits for preparing samples from the resulting structures for destructive testing. The research demonstrated that the length of the electrode extension is a crucial parameter in the additive manufacturing process of structures using the WAAM method. Modifying the electrode extension length in the WAAM process with a CMT machine impacts the bead geometry and, consequently, the overall model geometry. A 6 mm increase in the electrode extension length resulted in a model that was over 8 mm taller, despite using the same number of layers.

3

Fundamentals and advances of wire arc additive manufacturing: materials, process parameters, potential applications, and future trends

Saleh Bassiouny, Fathi Reham, Tian Yinbao, Radhika N., Jiang Jinghua, Ma Aibin

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no e96, 2023

EN

The advancement of the wire arc additive manufacturing (WAAM) process has been significant due to the cost-effectiveness in producing large metal components with high deposition rates. With the growth in the understanding of WAAM, researchers have found that the microstructure and mechanical properties of the fabricated components are greatly improved. As a result, a diverse range of materials have been linked to the process, leading to a wider application of WAAM in various industries. Thus, this review paper provides a comprehensive analysis of the recent advancements in WAAM, a technology that combines arc welding with additive manufacturing. The focus is on the microstructure, mechanical properties, materials used, process-related defects, and post-process treatments. The paper aims to offer guidance on producing high-quality and defect-free components by aligning the material characteristics with the capabilities of various WAAM techniques. The results of the paper highlight the strengths and limitations of WAAM and provide insights into its future prospects. This information is valuable for academics, designers, and manufacturers in the field, serving as a milestone for future WAAM research and application.

4

The effects of arc voltage and shielding gas type on the microstructure of wire arc additively manufactured 2209 duplex stainless steel

Kemény Dávid Miklós, Sándor Bence, Varbai Balázs, Katula Levente Tamás

Advances in Materials Science

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2023

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Vol. 23, nr 4(78)

62--82

EN

Duplex stainless steels (DSSs) are widely used due to their corrosion resistance. Austenite and ferrite determine the excellent properties. Ferrite provides strength and good corrosion resistance, while austenite provides toughness and weldability. During our research,samples were producedwith ER 2209 duplex steel wire using wirearc additive manufacturing (WAAM). Two different 17V and 19V arc voltages were used during the production. Two shielding gases were used for each voltage: M12-ArC-2.5 and M12-ArHeC-20/2. The research aimed to determine the ferrite ratio as a function of the welding parameters. The ferrite(or austenite)content must be between 30% and 70% for duplex stainless steel welds, according to the ISO 17781 standard.Based on our research, it can be stated that the austenite ratio increases as the voltage increases, thus failing to fulfill the standard's requirements. The helium content reduced the ferrite ratio even when the 17V voltage was used due to the gas's higher ionizationpotential. During the metallographicexamination, our welded samples met the standardrequirements for the austenite content for17V arc voltage and M12-ArC-2.5 shielding gas. The ferrite content in the entire sample cross-sectionfell between 30-42% duringferitscopeand image analysis measurements. These welding parameters can be recommended for industrial applications.

5

Optimal design of Wire-and-Arc Additively Manufactured I-beams for prescribed deflection

Bruggi Matteo, Laghi Vittoria, Trombetti Tomaso

Computer Assisted Methods in Engineering and Science

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2022

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Vol. 29, no. 4

357--378

EN

Alloys fabricated by wire-and-arc additive manufacturing (WAAM) exhibit a peculiar anisotropy in their elastic response. As shown by recent numerical investigations concerning the optimal design of WAAM-produced structural components, the printing direction remarkably affects the stiffness of the optimal layouts, as well as their shape. So far, single-plate specimens have been investigated. In this contribution, the optimal design of WAAM-produced I-beams is addressed assuming that a web plate and two flat flanges are printed and subsequently welded to assemble the structural component. A formulation of displacement-constrained topology optimization is implemented to design minimum weight specimens resorting to a simplified two-dimensional model of the I-beam. Comparisons are provided addressing solutions achieved by performing topology optimization with (i) conventional isotropic stainless steel and with (ii) WAAM-produced orthotropic stainless steel at prescribed printing orientations. Lightweight solutions arise whose specific shape depends on the selected material and the adopted printing direction.

6

The chemical composition of the weld deposit in metallic products made using wire arc additive manufacturing methods

Pańcikiewicz Krzysztof

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2022

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Vol. 66, No. 4

53--59

EN

The article presents an analysis concerning the obtainment of weld deposit properties (declared by the manufacturer of the filler metal) in the finished products made using additive manufacturing processes involving the application of arc welding methods. The use of an incompatible base material during the initial stage of the additive manufacturing process led to significanchanges in the chemical composition of the obtained layer (when compared with the chemical composition of the weld deposit declared by the producer of the filler metal). The dilution of the partly melted incompatible base material with the weld deposit resulted in the obtainment of a layer characterised by different properties (i.e. microstructure, hardness, corrosion resistance) than those declared by the manufacturer of the filler metal. The results obtained in the tests described in the article were compared with the requirements related to the making of the weld deposit subsequently subjected to the analysis of chemical composition (in accordance with the PN-EN ISO 6847 standard). The requirements specified in the aforesaid standard are used during tests related to, among other things, the conformity assessment procedure applied when qualifying filler metals.

PL

W artykule przedstawiono analizę problemu związanego z otrzymywaniem, deklarowanych przez producenta materiału dodatkowego, cech stopiwa w gotowych wyrobach kształtowanych przyrostowo z użyciem łukowych metod spawalniczych. Zastosowanie niedopasowanego materiału podstawowego do kształtowanego przyrostowo wyrobu na początkowym etapie wytwarzania prowadzi do istotnych zmian składu chemicznego pomiędzy uzyskaną warstwą a deklarowanym składem chemicznym stopiwa. Na skutek wymieszania nadtopionego niedopasowanego materiału podstawowego ze stopiwem uzyskiwana jest warstwa, która charakteryzuje się innymi cechami (tj. mikrostruktura, twardość, odporność na korozję) niż deklarowane przez producenta spoiwa. Wyniki te odniesiono do wymagań dotyczących wykonania stopiwa do analizy składu chemicznego, zgodnie z PN-EN ISO 6847, stosowanych do badania stopiwa, m.in. w ramach procedury oceny zgodności podczas kwalifikowania typu materiału dodatkowego do spawania.

7

Thermal monitoring for Metallic Additive Manufacturing multi-beads multi-layers parts

Rauch Matthieu, Hascoet Jean-Yves, Rousseau Clement, Ruckert Guillaume

Journal of Machine Engineering

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2021

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Vol. 21, No. 3

92--100

EN

Among Metallic Additive Manufacturing processes, Directed Energy Deposition (DED) processes are very promising for the Industry. An issue that prevents a larger development of DED is the reliability of the process, since its complexity makes the result of the manufacturing variable. Thermal behavior is a critical aspect for which uncontrolled phenomena can lead to part failure. Some thermal monitoring and closed-loop control methods have been developed, that enables to observe and regulate the heating of the processed part. However, these methods rely on local measures from a region or a single external surface of a part, and thus provide partial information of thermal fields in the whole part volume. This paper proposes a method that combines diverse data to compute online a process indicator that is meaningful for the thermal state of the whole part, and hence for the control of the manufacturing of multi-beads multi-layer parts. A simulation-based model using thermal partial data is proposed. An online monitoring experiment is proposed for validation of the model. Relevance of the control method to ensure mechanical properties of the part is then tested.