scholarly journals Hydrogen Embrittlement Behavior of 18Ni 300 Maraging Steel Produced by Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2360 ◽  
Author(s):  
Young Jin Kwon ◽  
Riccardo Casati ◽  
Mauro Coduri ◽  
Maurizio Vedani ◽  
Chong Soo Lee
Keyword(s):  
Hydrogen Embrittlement ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Constant Current ◽  
Hydrogen Atoms ◽  
Laser Melting ◽  
Constant Current Density ◽  
Hydrogen Charging

A study was performed to investigate the hydrogen embrittlement behavior of 18-Ni 300 maraging steel produced by selective laser melting and subjected to different heat treatment strategies. Hydrogen was pre-charged into the tensile samples by an electro-chemical method at the constant current density of 1 A m−2 and 50 A m−2 for 48 h at room temperature. Charged and uncharged specimens were subjected to tensile tests and the hydrogen concentration was eventually analysed using quadrupole mass spectroscopy. After tensile tests, uncharged maraging samples showed fracture surfaces with dimples. Conversely, in H-charged alloys, quasi-cleavage mode fractures occurred. A lower concentration of trapped hydrogen atoms and higher elongation at fracture were measured in the H-charged samples that were subjected to solution treatment prior to hydrogen charging, compared to the as-built counterparts. Isothermal aging treatment performed at 460 °C for 8 h before hydrogen charging increased the concentration of trapped hydrogen, giving rise to higher hydrogen embrittlement susceptibility.

scholarly journals Use of plasma nitriding to improve the wear and corrosion resistance of 18Ni-300 maraging steel manufactured by selective laser melting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Godec ◽  
B. Podgornik ◽  
A. Kocijan ◽  
Č. Donik ◽  
D. A. Skobir Balantič
Keyword(s):  
Corrosion Resistance ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Solution Treatment ◽  
Thermochemical Treatment ◽  
Laser Melting ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

Abstract18Ni-300 maraging steel manufactured by selective laser melting was plasma nitrided to improve its wear and corrosion resistance. The effects of a prior solution treatment, aging and the combination of both on the microstructure and the properties after nitriding were investigated. The results were compared with conventionally produced 18Ni-300 counterparts subjected to the same heat- and thermo-chemical treatments. The plasma nitriding was performed under the same conditions (temperature of 520 °C and time of 6 h) as the aging in order to investigate whether the nitriding and the aging could be carried out simultaneously in a single step. The aim of this work was to provide a better understanding of the morphology and chemical composition of the nitrided layer in the additive-manufactured maraging steel as a function of the prior heat treatments and to compare the wear and corrosion resistance with those of conventional maraging steel. The results show that nitriding without any prior aging leads to cracks in the compound layer, while nitriding of the prior-heat-treated additive-manufactured maraging steel leads to benefits from the thermochemical treatment in terms of wear and corrosion resistance. Some explanations for the origins of the cracks and pores in the nitride layers are provided.

Hydrogen Embrittlement in Inconel 718 Produced by Selective Laser Melting

2021 ◽  
Author(s):  
Giuseppe Macoretta ◽  
Marco Beghini ◽  
Bernardo Disma Monelli ◽  
Renzo Valentini ◽  
Francesco Aiello ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Hydrogen Diffusion ◽  
Mechanical Test ◽  
Tensile Tests ◽  
Material Strength ◽  
Hydrogen Effect ◽  
Laser Melting ◽  
Production Of Hydrogen

Abstract Inconel 718 is widely used to produce components subjected to relatively high temperatures and heavy loads. However, this alloy is also employed in aggressive environments promoting the production of hydrogen on the metal surface. Selective Laser Melting (SLM) is an emerging technology for the production of structural components, thanks to its ability to create complex geometries and reduce material consumption. Components produced by SLM are typically characterized by a peculiar microstructure and residual stresses that can affect hydrogen migration and accumulation. While the mechanical properties and fatigue endurance were deeply investigated in recent years, the resistance of SLMed Inconel 718 to the Hydrogen Embrittlement (HE) requires further investigation. The present paper deals with the effects of the SLM process on reducing the strength and ductility of Inconel 718. Standard tensile tests and slow strain rate tests were carried out for different hydrogen concentrations. Hydrogen content was measured in each specimen after the mechanical test. Fractographic analyses, along with hydrogen diffusion models, were carried out to preliminarily investigate the hydrogen effect on the material strength.

Use of Plasma Nitriding to Improve the Wear and Corrosion Resistance of 18Ni-300 Maraging Steel Manufactured by Selective Laser Melting

2020 ◽  
Author(s):  
Matjaž Godec ◽  
Bojan Podgornik ◽  
Aleksandra Kocijan ◽  
Črtomir Donik ◽  
Danijela Skobir Balantič
Keyword(s):  
Corrosion Resistance ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Solution Treatment ◽  
Thermochemical Treatment ◽  
Laser Melting ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

Abstract 18Ni-300 maraging steel manufactured by selective laser melting was plasma nitrided to improve its wear and corrosion resistance. The effects of a prior solution treatment, aging and the combination of both on the microstructure and the properties after nitriding were investigated. The results were compared with conventionally produced 18Ni-300 counterparts subjected to the same heat- and thermo-chemical treatments. The plasma nitriding was performed under the same conditions (temperature of 520 °C and time of 6 hours) as the aging in order to investigate whether the nitriding and the aging could be carried out simultaneously in a single step. The aim of this work was to provide a better understanding of the morphology and chemical composition of the nitrided layer in the additive-manufactured maraging steel as a function of the prior heat treatments and to compare the wear and corrosion resistance with those of conventional maraging steel. The results show that nitriding without any prior aging leads to cracks in the compound layer, while nitriding of the prior-heat-treated additive-manufactured maraging steel leads to benefits from the thermochemical treatment in terms of wear and corrosion resistance. Some explanations for the origins of the cracks and pores in the nitride layers are provided.

ANISOTROPIC CUTTING FORCE CHARACTERISTICS IN MILLING OF MARAGING STEEL PROCESSED THROUGH SELECTIVE LASER MELTING

2021 ◽  
pp. 1-16
Author(s):  
Shoichi Tamura ◽  
Takashi Matsumura ◽  
Atsushi Ezura ◽  
Kazuo Mori
Keyword(s):  
Additive Manufacturing ◽  
Cutting Force ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Cutting Forces ◽  
Manufacturing Process ◽  
Laser Scanning ◽  
Force Model ◽  
Laser Melting ◽  
Scanning Direction

Abstract Additive manufacturing process of maraging steel has been studied for high value parts in aerospace and automotive industries. The hybrid additive / subtractive manufacturing is effective to achieve tight tolerances and surface finishes. The additive process induces anisotropic mechanical properties of maraging steel, which depends on the laser scanning direction. Because anisotropy in the workpiece material has an influence on the cutting process, the surface finish and the dimension accuracy change according to the direction of the cutter feed with respect to the laser scanning direction. Therefore, the cutting parameters should be determined to control the cutting force considering material anisotropy. The paper discusses the cutting force in milling of maraging steel stacked with selective laser melting, as an additive manufacturing process. Anisotropic effect on the cutting forces is proved with the changing rate of the cutting force in milling of the workpieces stacked by repeating laser scanning at 0/90 degrees and 45/-45 degrees. The cutting forces, then, are analyzed in the chip flow models with piling up of orthogonal cuttings. The force model associates anisotropy with the shear stress on the shear plane. The changes in the cutting forces with the feed direction are discussed in the cutting tests and analysis.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Selective Laser Melted TiAl6V4 Alloy

2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Room Temperature ◽  
Base Alloy ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Treatment Procedures

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.

scholarly journals The Effect of Hydrogen-Charging on Mechanical Properties of Austenitic CrNi Steel Fabricated by Wire-Feed Electron Beam Additive Manufacturing

2021 ◽  
Vol 225 ◽  
pp. 01011
Author(s):  
Marina Panchenko ◽  
Eugeny Melnikov ◽  
Valentina Moskvina ◽  
Sergey Astafurov ◽  
Galina Maier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Hydrogen Embrittlement ◽  
Yield Strength ◽  
Cast Steel ◽  
Solution Treatment ◽  
Fracture Mechanisms ◽  
Hydrogen Charging ◽  
Wire Feed

A comparative study of the mechanical properties, fracture mechanisms and hydrogen embrittlement peculiarities was carried out using the specimens of austenitic CrNi steel produced by two different methods: wire-feed electron beam additive manufacturing and conventional casting followed by solid-solution treatment. Hydrogen-induced reduction of ductility and the increase in the yield strength are observed in steel specimens produced by both methods. Despite hydrogen embrittlement index is comparable in them, the increase in the yield strength after hydrogen-charging is different: 25 MPa for cast steel and 175 MPa for additively manufactured steel. This difference is associated with the peculiarities of phase composition and phase distribution in steels produced by different methods.

Anisotropic Cutting Force Characteristics in Milling of Maraging Steel Processed Through Selective Laser Melting

2021 ◽  
Author(s):  
Shoichi Tamura ◽  
Takashi Matsumura ◽  
Atsushi Ezura ◽  
Kazuo Mori
Keyword(s):  
Additive Manufacturing ◽  
Cutting Force ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Cutting Forces ◽  
Manufacturing Process ◽  
Laser Scanning ◽  
Force Model ◽  
Laser Melting ◽  
Scanning Direction

Abstract Additive manufacturing process of maraging steel has been studied for high value parts in aerospace and automotive industries. The hybrid additive / subtractive manufacturing is effective to achieve tight tolerances and surface finishes. The additive process induces anisotropic mechanical properties of maraging steel, which depends on the laser scanning direction. Because anisotropy in the workpiece material has an influence on the cutting process, the surface finish and the dimension accuracy change according to the direction of the cutter feed with respect to the laser scanning direction. Therefore, the cutting parameters should be determined to control the cutting force considering material anisotropy. The paper discusses the cutting force in milling of maraging steel stacked with selective laser melting, as an additive manufacturing process. Anisotropic effect on the cutting forces is proved with the changing rate of the cutting force in milling of the workpieces stacked by repeating laser scanning at 0/90 degrees and 45/−45 degrees. The cutting forces, then, are analyzed in the chip flow models with piling up of orthogonal cuttings. The force model associates anisotropy with the shear stress on the shear plane. The changes in the cutting forces with the feed direction are discussed in the cutting tests and analysis.

Changes of phase composition of maraging steel 1.2709 during selective laser melting

2019 ◽  
Vol 241 (1) ◽  
Author(s):  
Miroslav Mashlan ◽  
Fredericus Linderhof ◽  
Magdalena Davidova ◽  
Hana Kubickova ◽  
Elena Zemtsova
Keyword(s):  
Phase Composition ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Laser Melting
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