Defect-dominated fatigue behavior in type 630 stainless steel fabricated by selective laser melting

Akita, Masayuki; Uematsu, Yoshihiko; Kakiuchi, Toshifumi; Nakajima, Masaki; Kawaguchi, Ryosei

doi:10.1016/j.msea.2016.04.042

Cited by 72 publications

(50 citation statements)

References 31 publications

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“…PH stainless-steel AM samples exhibit columnar bcc grains with strong overall [118] texture and small equi-axed fcc grains at molten pool boundaries, as shown in Figure 4. Previous work on as-built PH SS AM components revealed a non-equilibrium microstructure, as well as strong differences in texture parallel and perpendicular to the build direction, due to the very high cooling rates [17,99,[104][105][106][107]115]. Some of the literature claimed that the as-built microstructure via L-PBF contains martensite and retained austenite (metastable phase at room temperature) [26,27,95,98,[119][120][121][122], completely different from that of a wrought 17-4 PH stainless steel, which is fully martensitic.…”

Section: Microstructure In As L-pbfed Statementioning

confidence: 99%

“…Most of these parts are important load-bearing components of heavy machinery in a demanding service environment. However, PH stainless steels have poor workability and machinability due to their high strength and high hardness, which result in a long production cycle and difficulties in obtaining desired shapes through conventional machining and forming processes [17].Due to the high strength and high hardness of PH steels, they are difficult to be manufactured via conventional machining processes. Additive manufacturing (AM) processes [18][19][20][21][22][23][24]] offer great new opportunities for producing high-strength PH steel parts with high geometric complexity [25].…”

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confidence: 99%

“…Additive manufacturing (AM) processes [18][19][20][21][22][23][24]] offer great new opportunities for producing high-strength PH steel parts with high geometric complexity [25]. Some metal AM processes are used for printing PH steel parts, including laser powder bed fusion (L-PBF) [17,26,27], wire arc additive manufacturing (WAAM) [28][29][30][31], and direct metal laser deposition (DMLD) [2]. Compared with L-PBF, the printing accuracy of DMLD is limited by the convergence size of the powder flow, and the forming accuracy of DLMD is lower than that of L-PBF.…”

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Laser Powder Bed Fusion of Precipitation-Hardened Martensitic Stainless Steels: A Review

Zai

Zhang

Wang

et al. 2020

Metals

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Martensitic stainless steels are widely used in industries due to their high strength and good corrosion resistance performance. Precipitation-hardened (PH) martensitic stainless steels feature very high strength compared with other stainless steels, around 3-4 times the strength of austenitic stainless steels such as 304 and 316. However, the poor workability due to the high strength and hardness induced by precipitation hardening limits the extensive utilization of PH stainless steels as structural components of complex shapes. Laser powder bed fusion (L-PBF) is an attractive additive manufacturing technology, which not only exhibits the advantages of producing complex and precise parts with a short lead time, but also avoids or reduces the subsequent machining process. In this review, the microstructures of martensitic stainless steels in the as-built state, as well as the effects of process parameters, building atmosphere, and heat treatments on the microstructures, are reviewed. Then, the characteristics of defects in the as-built state and the causes are specifically analyzed. Afterward, the effect of process parameters and heat treatment conditions on mechanical properties are summarized and reviewed. Finally, the remaining issues and suggestions on future research on L-PBF of martensitic precipitation-hardened stainless steels are put forward.Metals 2020, 10, 255 2 of 25 types of microstructures can be obtained with different heat treatment processes [9]. The typical temperature range for aging heat treatment for this alloy is 480-620 • C [1]. Under the H900 condition (aging temperature: 482 • C, time: 1 h), the precipitation in 17-4 PH stainless steel begins with Cu-rich precipitates (bcc, body center cubic) that maintain a coherent relationship with the matrix, which would lead to an increase in tensile strength and toughness [4]. These precipitates can transform into non-coherent Cu-rich particles (fcc, face center cubic) after extended aging at 400 • C [5]. After experiencing over-aging, the precipitates are coarsened. The number of precipitates is reduced, and the coherence relationship is also destroyed [6,10]. These changes together lead to a decrease in mechanical strength, but an increase in ductility and impact toughness.PH stainless steels are widely used in the aerospace industry [11,12], the marine industry [13], nuclear reactor components [14], chemical process equipment [15], and medical apparatus due to their high tensile strength, impact strength, fracture toughness, and corrosion resistance at typical service temperatures below 300 • C [15,16]. Most of these parts are important load-bearing components of heavy machinery in a demanding service environment. However, PH stainless steels have poor workability and machinability due to their high strength and high hardness, which result in a long production cycle and difficulties in obtaining desired shapes through conventional machining and forming processes [17].Due to the high strength and high hardness of PH steels, they are difficult to b...

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Section: Microstructure In As L-pbfed Statementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Laser Powder Bed Fusion of Precipitation-Hardened Martensitic Stainless Steels: A Review

Zai

Zhang

Wang

et al. 2020

Metals

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“…In recent years, the austenitic stainless steel [7], precipitation hardening stainless steel [8], martensitic stainless steel [9], high manganese steel [10], super-duplex stainless steel (SDSS) [11][12][13][14] 2 of 12 prepared using SLM were studied. Although SLM technology has a certain basis for the preparation of SDSS, SLM of HDSS with higher nitrogen content has rarely been reported.…”

Section: Introductionmentioning

confidence: 99%

The Microstructure, Mechanical Properties, and Corrosion Resistance of UNS S32707 Hyper-Duplex Stainless Steel Processed by Selective Laser Melting

Feng

Chen

Wang

et al. 2019

Metals

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UNS S32707 hyper-duplex stainless steel (HDSS) parts with complex shapes for ocean engineering were prepared by selective laser melting (SLM) process. In the process of SLM, the balance between austenite and ferrite was undermined due to the high melting temperature and rapid cooling rate, resulting in poor ductility and toughness. The solution annealing was carried out with various temperatures (1050-1200 • C) for one hour at a time. The evolution of microstructures, mechanical properties, and corrosion resistance of UNS S32707 samples prepared by SLM was comprehensively investigated. The results indicate that a decrease in nitrogen content during the SLM process reduced the content of austenite, and a nearly balanced microstructure was obtained after appropriate solution annealing. The ratio between ferrite and austenite was approximately 59.5:40.5. The samples with solution treated at 1150 • C and 1100 • C exhibited better comprehensive mechanical properties and pitting resistance, respectively.

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Quasi-static analysis of mechanical properties of Ti6Al4V lattice structures manufactured using selective laser melting

Feng

Tang

Liu

et al. 2017

Int J Adv Manuf Technol

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Defect-dominated fatigue behavior in type 630 stainless steel fabricated by selective laser melting

Cited by 72 publications

References 31 publications

Laser Powder Bed Fusion of Precipitation-Hardened Martensitic Stainless Steels: A Review

Laser Powder Bed Fusion of Precipitation-Hardened Martensitic Stainless Steels: A Review

The Microstructure, Mechanical Properties, and Corrosion Resistance of UNS S32707 Hyper-Duplex Stainless Steel Processed by Selective Laser Melting

Quasi-static analysis of mechanical properties of Ti6Al4V lattice structures manufactured using selective laser melting

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