Description of a new concept for the development of adapted hot-work tool steels for laser-powder bed fusion

Röttger, Arne; Boes, J.; Großwendt, Felix; Weber, Sebastian

doi:10.1016/j.addma.2022.103292

Cited by 4 publications

(4 citation statements)

References 51 publications

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“…Depending on the application temperature, cold (up to 200 °C), hot (up to 550-650 °C), or highspeed steels (up to 650 °C) are used for the manufacturing of tools. If soft martensitic steels can be processed into dense samples using the PBF-LB/M process, the AM of carbon martensitic steels is only possible via the design of appropriate alloys [1][2][3][4] or additional measures, such as preheating. [5][6][7] The maximum application temperature of soft-martensitic or C-martensitic hardening tool steels is limited by Ostwald ripening of the corresponding precipitations and recovery and recrystallization of the metal matrix.…”

Section: Introductionmentioning

confidence: 99%

“…Depending on the application temperature, cold (up to 200 °C), hot (up to 550–650 °C), or high‐speed steels (up to 650 °C) are used for the manufacturing of tools. If soft martensitic steels can be processed into dense samples using the PBF‐LB/M process, the AM of carbon martensitic steels is only possible via the design of appropriate alloys [ 1–4 ] or additional measures, such as preheating. [ 5–7 ]…”

Section: Introductionmentioning

confidence: 99%

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Laser Powder Bed Fusion of Hard‐Phase Containing Co‐Base Alloy

Vehrs,

Röttger,

Roj

et al. 2024

Adv Eng Mater

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This work considers the processing of the hard‐phase containing CoCrW‐alloy Celsit F using powder bed fusion‐laser beam/metal (PBF‐LB/M), whereby a suitable process window for producing dense parts having a low‐defect density is determined. Several cuboid specimens are manufactured by varying the exposure parameters (laser power, hatch distance, scanning speed). With the help of quantitative image analysis, the samples are evaluated regarding crack density and porosity, and optimal exposure parameters are derived. Dense samples with a low defect density can be produced if the energy density is 60–70 J mm−3 and the base‐plate is preheated to 800 °C. Choosing lower energy densities leads to increased pore formation, whereas higher energy densities result in increased ablation and cracking. With a view to a later application in which additively manufactured hot work tools are made of Celsit F, the possibility of introducing internal cavities as potential cooling channels is considered. It can be shown that the hardness sideways is lower than above and below the cavity due to a changed microstructure and locally different heat dissipation. The results of this work give a first guideline for the PBF‐LB/M‐processing of wear‐resistant CoCrW alloys with a high hard phase volume content to tools for hot working.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laser Powder Bed Fusion of Hard‐Phase Containing Co‐Base Alloy

Vehrs,

Röttger,

Roj

et al. 2024

Adv Eng Mater

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“…Depending on the processing temperature and the required material properties, carbon-martensitic hardenable tool steels are commonly used. Due to the high tendency to cold cracking in Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) processing of carbon-martensitic hardening tool steels, these material classes can only be processed with special measures such as preheating [11][12][13][14][15] or with a correspondingly adapted alloy design [16]. As an alternative to carbon-martensitic hardening tool steels with a high tendency to cold cracking, the literature often refers to soft-martensitic (18Ni300) or precipitation-hardened grades (17-4PH, 15-5PH) being easy to process by AM.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of press-hardening tools or forming tools for cold work, in particular, carbon-martensitic hardenable steels with a higher hardness are mandatory. While the literature contains many works on the additive processing of maraging steels [17,[19][20][21][22][23][24] and carbon-martensitic hardenable hot-and high-speed tool steels [16,[25][26][27][28][29], only a few works on cold work steels, particularly on hard-phase-containing ledeburitic cold work steels, can be found in the literature. Botero et al [30] investigated the processing of a Cr-Mo-Valloyed ledeburitic cold work steel with a carbon content of 1.4 mass%, using Powder Bed Fusion/Electron Beam/ Metal (PBF-EB/M).…”

Section: Introductionmentioning

confidence: 99%

Additive manufacturing of carbon-martensitic hardening ledeburitic cold work tool steels using Fused Filament Fabrication and subsequent Supersolidus Liquid-Phase Sintering

Röttger,

Wieczorek,

Schmidtseifer

et al. 2024

Prog Addit Manuf

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In this work, the microstructure property relationship of D2 (X153CrMoV12; 1.2379) ledeburitic cold work steel processed by filament extrusion is investigated. Contrary to the conventional process, which involves a multi-step process of printing, debinding, and solid-state sintering, the specimens in this study were densified using Supersolidus Liquid-Phase Sintering (SLPS). SLPS occurs after thermal debinding in the interval between the solidus and liquidus temperatures. Optimized liquid-phase volume fraction was evaluated by means of thermodynamic calculations using the CALPHAD method and their experimental validation. The microstructure formation process during debinding, solid state, and SLPS sintering was investigated by X-ray diffraction and electron microscopy. Tomography studies confirm a relative density of 99.92% by volume during SLPS sintering at 1280 °C and provide a deep insight into local densification behavior during SLPS processing. In addition, surface roughness, as determined by confocal laser scanning microscopy, could be reduced. The reduction in porosity and surface roughness can be attributed to the presence of a liquid phase during SLPS. Using adapted heat treatment parameters determined by hardness-tempering curves, higher hardness values were achieved for SLPS-post-compacted specimens compared to conventionally processed specimens and the same material in the cast and heat-treated reference state.

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