Evaluation of post-treatments of novel hot-work tool steel manufactured by laser powder bed fusion for aluminum die casting applications

Vilardell, A.M.; Hosseini, Seyed; Åsberg, Mikael; Dahl-Jendelin, Anton; Krakhmalev, Pavel; Oikonomou, Christos; Hatami, Sepehr

doi:10.1016/j.msea.2020.140305

Cited by 16 publications

(9 citation statements)

References 18 publications

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“…The typical fracture appearance of tool steels, and in general metallic materials, failed under tensile loads in absence of large defects or embrittlement phenomena, does not show crack initiation and unstable propagation but only dimples and shear lip area, resulting from the failure mechanism described in ref. 48,49 However, previous literature works addressing the tensile behavior of tool steels manufactured by LPBF 37,38,40 reported fracture surfaces similar to those observed in the present work, suggesting that process-induced defects play a key role in the fracture mechanism of these steels when manufactured via LPBF, and thus on their tensile properties. To verify the hypothesis that tensile fractures occurred via an unstable crack propagation mechanism from pre-existing LPBF defects, linear-elastic fracture mechanics (LEFM) was applied by calculating the stress intensity factor K I at killer defects (i.e., observed at the crack initiation sites and thus accounted for tensile failures) using the formula…”

Section: Effect Of Lpbf Defects On the Tensile Behaviorsupporting

confidence: 75%

“…Moreover, the LPBF process generally results in the formation of peculiar defects, such as lack of fusion defects (hereafter indicated as LoF) and gas pores, which reduce density and, most importantly, severely affect the resulting mechanical properties. 34,35 Several authors 27,33,[36][37][38][39][40] reported the great effect of LPBF defects, in particular lack of fusion defects, on the mechanical properties of additively manufactured tool steels, especially on fatigue properties. Fonseca et al 31 reported that the choice of process parameters (such as laser power, scan speed, hatch distance, etc.)…”

Section: Introductionmentioning

confidence: 99%

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Effect of heat treatment and defects on the tensile behavior of a hot work tool steel manufactured by laser powder bed fusion

Zanni

Berto

Vullum

et al. 2023

Fatigue Fract Eng Mat Struct

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Microstructure and tensile properties of a hot work tool steel manufactured via laser powder bed fusion (LPBF) were investigated. Specimens were built under two different orientations and subjected to two quenching and tempering heat treatments, featuring different austenitizing and tempering temperatures and the eventual presence of a sub-zero step. Microstructural analyses revealed a homogeneous tempered martensite structure after both heat treatments, with the only distinction of a higher alloying segregation at a sub micrometric scale length in samples subjected to the highest tempering temperatures. Hardness and tensile tests indicated a negligible effect of building orientation on mechanical properties, but a significant influence of heat treatment parameters. The treatment featuring the lower tempering temperatures and the sub-zero step resulted in higher hardness, tensile strength, and elongation, attributed to a lower martensite tempering and alloying segregation. Tensile fracture occurred via crack initiation and unstable propagation from large LPBF defects in all the investigated conditions.defects, heat treatment, laser powder bed fusion, mechanical properties, tool steel Highlights• Microstructure and tensile properties of a tool steel produced via LPBF were studied.• Tensile failure was initiated from large defects due to the LPBF process.• No effect of building orientation on microstructure and tensile properties was observed.• The treatment with the lowest tempering temperatures induced the highest properties.

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Section: Effect Of Lpbf Defects On the Tensile Behaviorsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Effect of heat treatment and defects on the tensile behavior of a hot work tool steel manufactured by laser powder bed fusion

Zanni

Berto

Vullum

et al. 2023

Fatigue Fract Eng Mat Struct

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“…The LMDed specimens show a higher UTS but lower hardness. Except for the SLM+stress relieved (SR)+standard hardening and tempering (HT)+nitrided (N) specimens [51], the hardness of all other methods is much lower than that of laser remelting. Therefore, the laser remelted H13 steel in this work has a well mechanical performance and is mainly suited for high-strength applications that require wear resistance.…”

Section: Effect Of the Laser Remelting On The Mechanical Behaviourmentioning

confidence: 99%

Laser remelting of AISI H13 tool steel: influence of cooling rate on the surface properties

Xie

Raoelison²,

Di³

et al. 2022

Surf. Topogr.: Metrol. Prop.

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Laser surface remelting is an effective and suitable process to extend the longevity of components without additional materials. In this paper, a high energy density laser with a large size was used to improve the hardness of H13 tool steel. A predictive numerical multiphysics coupled model was established to investigate the temperature field and the profile of the molten pool. The effect of laser scanning speeds is investigated in terms of heat-affected depth, surface topography, and mechanical properties. In detail, the simulated temperature gradients with laser scanning speed in a range of 12 to 24 mm/s are ~8.4×105 K/m, involving a cooling rate less than 1×104 K/s can prevent cracking. The hardness of the remelted zone is in the range of 700-850 HV0.2, and the tensile performances are also recorded. The model in this work could not only link the mechanical properties with process parameters together, but also guide the actual experiment or processing bypassing the trial-and-error method, as well as extend to other materials and laser additive manufacturing.

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“…Quenching and tempering processes could help tailor a steel's microstructure and mechanical properties to specific applications [15]. HIP before quenching and tempering (Q&T) for hot-work tool steel manufactured by laser powder bed fusion significantly increased the impact toughness and ductility and slightly increased the yield and ultimate tensile strength values compared with the Q&T condition [16]. Besides, nitriding technology could help improve the surface hardness of steel [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

Trinh,

Nguyen,

Pham

et al. 2023

Acta Metall Slovaca

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AISI H13 steel samples were additively manufactured using a laser powder bed fusion (LPBF) system. The effect of annealing tem-perature, quenching & tempering, and nitriding were determined. The microstructure and properties of the samples were investigated using optical microscopy, scanning electron microscopy, electron backscattered diffraction, electron probe micro-analysis, X-ray diffraction, roughness measurement, and a hardness tester. The results show that the as-built AISI H13 steel sample had a roughness on the surface and pores inside. The microstructure consisted of martensite and retained austenite. The average hardness was 460 HV, and the porosity was 0.086 %. The annealing process helped homogenize the microstructure, increase the density, and reduce the porosity and hardness of the LPBF-manufactured sample. The quenching process helped increase the hardness of the steel to the maximum of 787 HV, then the tempering process reduced the hardness to 572 HV. Heat treatment and nitriding processes tended to increase the martensite block size, reduce the retained austenitic content, and precipitate the V-Mo-rich carbide in the LPBF-manufactured AISI H13 steel. After nitriding was conducted, the nitriding case depth was 87 um, and the surface hardness increased up to higher than 1020 HV due to the formation of CrN and Fe3-4N.

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Evaluation of post-treatments of novel hot-work tool steel manufactured by laser powder bed fusion for aluminum die casting applications

Cited by 16 publications

References 18 publications

Effect of heat treatment and defects on the tensile behavior of a hot work tool steel manufactured by laser powder bed fusion

Effect of heat treatment and defects on the tensile behavior of a hot work tool steel manufactured by laser powder bed fusion

Laser remelting of AISI H13 tool steel: influence of cooling rate on the surface properties

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

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