Influence of Baseplate Heating and Shielding Gas on Distortion, Mechanical and Case hardening Properties of 16MnCr5 fabricated by Laser Powder Bed Fusion

Schmitt, Matthias; Kempter, Bernhard; Inayathulla, Syed; Gottwalt, Albin; Horn, Max; Binder, Maximilian; Winkler, Jakob; Schlick, Georg; Tobie, Thomas; Stahl, Karsten; Reinhart, Gunther

doi:10.1016/j.procir.2020.03.089

Cited by 9 publications

(3 citation statements)

References 14 publications

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“…Hence, the diffusivity of carbon into additively manufactured 16MnCr5 guarantees the development of an adequate case-hardened layer. This was also observed for the case hardening steels 16MnCr5 and 20MnCr5 in other research (Bartels et al , 2020; Schmitt et al , 2020a; Schmitt et al , 2020b; Yang and Sisson, 2020).…”

Section: Discussionsupporting

confidence: 86%

Static load-carrying behavior and material properties of additively manufactured gears (PBF-LB/M, 16MnCr5)

Brummer,

Raddatz,

Schmitt

et al. 2023

RPJ

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Purpose Numerous metals can be processed using the additive manufacturing process laser-based powder bed fusion of metals (PBF-LB/M, ISO/ASTM 52900). The main advantages of additive manufacturing technologies are the high degree of design freedom and the cost-effective implementation of lightweight structures. This could be profitable for gears with increased power density, combining reduced mass with considerable material strength. Current research on additively manufactured gears is focused on developing lightweight structures but is seldom accompanied by simulations and even less by mechanical testing. There has been very little research into the mechanical and material properties of additively manufactured gears. The purpose of this study is to investigate the behavior of lightweight structures in additively manufactured gears under static loads. Design/methodology/approach This research identifies the static load-carrying capacity of helical gears with different lightweight structures produced by PBF-LB/M with the case hardening steel 16MnCr5. A static gear loading test rig with a maximum torque at the pinion of T1 = 1200 Nm is used. Further focus is set on analyzing material properties such as the relative density, microstructure, hardness depth profile and chemical composition. Findings All additively manufactured gear variants show no failure or plastic deformation at the maximum test load. The shaft hub connection, the lightweight hub designs and the gearing itself are stable and intact regarding their form and function. The identified material characteristics are comparable to conventionally manufactured gears (wrought and machined), but also some particularities were observed. Originality/value This research demonstrates the mechanical strength of lightweight structures in gears. Future research needs to consider the dynamic load-carrying capacity of additively manufactured gears.

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Section: Discussionsupporting

confidence: 86%

Static load-carrying behavior and material properties of additively manufactured gears (PBF-LB/M, 16MnCr5)

Brummer,

Raddatz,

Schmitt

et al. 2023

RPJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…The as‐built tensile strength was almost as high as the one of the quenched and tempered reference specimens. In their work, Schmitt et al [ 8 ] investigated the influence of different platform preheating temperatures on the material properties of 16MnCr5. For the lowest temperatures, a mostly ferritic structure was observed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Volumetric Energy Density and Part Height on the Material Properties of Low‐Alloyed Steels Manufactured by Laser‐Based Powder Bed Fusion of Metals

Bartels,

Novotny,

Albert

et al. 2023

Adv Eng Mater

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The layer‐by‐layer manufacturing approach in laser powder bed fusion of metals (PBF‐LB/M) leads to heat accumulation in the workpiece with increasing part heights. The effect of this heat accumulation on the resulting material properties has, however, only barely been studied for low‐alloyed steels. The goal of this work is to analyze the influence of different PBF‐LB/M‐specific boundary conditions like varying part heights and volumetric energy densities (VED) on the resulting material properties. It isfound that lower part regions possess similar hardness (380–410 HV1) and retained austenite values (7%–8%), independent of the applied VED. Higher energy inputs lead to higher retained austenite contents of up to 20% due to an incomplete transformation upon cooling. This rise in retained austenite content is also linked to a decreased material hardness down to 320 HV1. In higher part regions, this effect is reversed as the retained austenite content starts to decrease for the highest investigated VED. This is caused by the in situ preheating temperatures caused by heat accumulation, which favor a bainitic transformation. The part height‐specific properties indicate that the microstructure formation forms through a continuous transformation in lower part regions and through an isothermal transformation in higher regions.

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“…The works by Schmitt et al [10,11] show that this class of material can be processed without larger defects. Further investigations focused on the case-hardenability of additively manufactured casehardening steels [12,13]. Comparable hardness values could be obtained after hardening even though the process-specific fine microstructure might negatively affect the carbon diffusion.…”

Section: Introductionmentioning

confidence: 99%

On the Influence of Volumetric Energy Density and Inter-Layer Time on the Material Properties of Case-Hardening Steels

Bartels,

Albert,

Nahr

et al. 2023

Alloys

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Case-hardening steels are gaining increasing interest in the field of laser powder bed fusion (PBF-LB/M) due to their excellent weldability. In combination with post-process carburization heat treatment, the surface properties can be improved to generate high-strength products. When manufacturing larger products by means of PBF-LB/M, the in situ heat accumulation and the altered cooling rates affect the resulting material properties. Therefore, the fabrication of larger products requires an understanding on the influencing factors that affect the material properties. This work investigates the effect of different volumetric energy densities (VED) on the resulting microstructural and mechanical properties. It is found that the hardness decreases continuously along the build direction. The gradient depends on the applied energy and is stronger for higher energy inputs due to heat accumulation and lowered cooling rates. Furthermore, countering strategies are investigated to avoid process-specific hardness reduction along the build direction. This includes a reduced number of parts within the build job as well as a modified inter-layer time (ILT) between consecutive layers of the specimen. Applying a moderate inter-layer time helps to counter process-specific overheating, which is indicated by an almost homogeneous material hardness and melt pool size along the build direction.

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Influence of Baseplate Heating and Shielding Gas on Distortion, Mechanical and Case hardening Properties of 16MnCr5 fabricated by Laser Powder Bed Fusion

Cited by 9 publications

References 14 publications

Static load-carrying behavior and material properties of additively manufactured gears (PBF-LB/M, 16MnCr5)

Static load-carrying behavior and material properties of additively manufactured gears (PBF-LB/M, 16MnCr5)

Effect of Volumetric Energy Density and Part Height on the Material Properties of Low‐Alloyed Steels Manufactured by Laser‐Based Powder Bed Fusion of Metals

On the Influence of Volumetric Energy Density and Inter-Layer Time on the Material Properties of Case-Hardening Steels

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