Optimized density profiles for powder metallurgical gears

Gräser, Eva; Hajeck, Marko; Bezold, Alexander; Broeckmann, Christoph; Brumm, Markus; Klocke, Fritz

doi:10.1007/s11740-014-0543-1

Cited by 6 publications

(7 citation statements)

References 6 publications

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“…The heat treatment simulation describes the microstructure evolution, hardness and residual stresses. The density profile after cold rolling is determined by image analysis based on experimental results in (Gräser et al, 2014) and (Hajeck, 2017). Density, hardness and residual stresses are input data for the analytical calculation of the tooth root load bearing capacity.…”

Section: The Icme Approachmentioning

confidence: 99%

“…Furthermore, higher flexibility in shape optimization and better performance in noise vibration harshness are other potential advantages of the PM route (Leupold et al, 2017). However, sintered gears generally show lower strengths due to the remaining porosity from the process, which severely hinders their applications in automotive transmissions (Gräser et al, 2014). To improve the load bearing capacity, several techniques were suggested to densify highly loaded sintered gears at the functional surface (Kotthoff, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Surface densified and heat-treated sintered gears can achieve a tooth flank load bearing capacity that is comparable to that of conventional gears at the flank. However, the tooth root bearing capacity still needs to be improved (Frech et al, 2018;Gräser et al, 2014). Computer simulations were used in this study to understand the correlation between the process parameters and the tooth root load bearing capacity of the sintered gears.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Digital Twin of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

Rajaei¹,

Deng²,

Schenk³

et al. 2020

Preprint

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This paper presents a digital twin of the powder metallurgical (PM) production chain of high-performance sintered gears based on an integrated computational materials engineering (ICME) platform. Discrete and finite element methods (DEM and FEM) were combined to describe the macroscopic material response to the thermomechanical loads and process conditions during the entire production process. The microstructural evolution during the sintering process was predicted on then meso-scale using a Monte-Carlo Model. The effective elastic properties were determined by a homogenization method based on modelling a representative volume element (RVE). The results were subsequently used for the FE modelling of the heat treatment process. Through the development of multi-scale models, it was possible on the one hand to obtain characteristics of the microstructural features and on the other hand the predicted hardness and residual stress distributions allow the calculation of the tooth root load bearing capacity of the heat-treated sintered gears.

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Section: The Icme Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Digital Twin of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

Rajaei¹,

Deng²,

Schenk³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…Furthermore, higher flexibility in shape optimization and a better noise-vibration-harshness behaviour are other potential advantages of the PM route [3]. However, sintered gears generally show lower strengths due to the remaining porosity after sintering, which severely hinders their applications in automotive transmissions [5]. To improve the load bearing capacity, several techniques were suggested to densify highly loaded sintered gears at the functional surface [6].…”

Section: Introductionmentioning

confidence: 99%

Numerical Modelling of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

Rajaei

Deng

Schenk

et al. 2021

Chin. J. Mech. Eng.

View full text Add to dashboard Cite

This paper presents a digital model for the powder metallurgical (PM) production chain of high-performance sintered gears based on an integrated computational materials engineering (ICME) platform. Discrete and finite element methods (DEM and FEM) were combined to describe the macroscopic material response to the thermomechanical loads and process conditions during the entire production process. The microstructural evolution during the sintering process was predicted on the meso-scale using a Monte-Carlo Model. The effective elastic properties were determined by a homogenization method based on modelling a representative volume element (RVE). The results were subsequently used for the FE modelling of the heat treatment process. Through the development of multi-scale models, it was possible obtain characteristics of the microstructural features. The predicted hardness and residual stress distributions allowed the calculation of the tooth root load bearing capacity of the heat-treated sintered gears.

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“…The densification in the FEM simulations agreed with the experimental results, no deformation results were included. Gräser (Gräser et al, 2014) conducted FEM calculations for the root tooth stress of a PM densified gear. Cho (Cho et al, 2015) and co-workers developed a program for the gear rolling process of PM gears that predicts densification and deformation behavior of rolled gears with Shima and Oyane (Shima and Oyane, 1976) porous plasticity material model.…”

Section: Introductionmentioning

confidence: 99%

Improved PM gear rolling simulations using advanced material modelling

Angelopoulos

2017

JAMDSM

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The gear rolling densification of Powder Metal (PM) gears leads to better mechanical properties due to the selectively closed porosity of some hundreds of a micrometer under the surface of the tooth. The optimization of this process is critical in order to reduce the overall design time of the process and to increase the quality of the rolled gear. One way to optimize the process, tool design and gear with stock is to conduct Finite Element (FE) simulations with a plasticity material model for porous metals. The simulations should be able to predict the resulted geometry and densification, after that the opposite procedure can be conducted and by using simulations as a design tool to predict the process parameters. In this paper, FE simulations are being performed for the gear rolling densification process. The aim is to investigate how such simulations can be used to improve the quality of the rolled gear. Moreover, to identify how more advanced plasticity material models such as the anisotropic model of Ponte-Castaneda Kailasam and coworkers can help and increase the accuracy of the calculations, compared to more commonly used models such as the one suggested by Gurson-TveergardNeedleman (GTN). Furthermore, the results from the simulations in densification and involute profile are also correlated with experimental results to validate the accuracy of the simulations. Finally, the accuracy of the simulations in densification and involute profile will define if the target of optimizing the gear rolling densification process through FE simulations is realistic.Keywords : Gears, Powder etal m , FEM, Plasticity, Densification, Gear olling, r Simulations IntroductionPowder Metallurgy (PM) is an established technology for manufacturing components in many applications. The reason is the high productivity of highly complex parts with good mechanical properties and tolerances. At the same time it is an environmentally friendly process. The stages for manufacturing a component from powder metal are three, first iron powder is mixed with carbon and other alloying elements that are chosen depended on the application. The mixed powder is then filled into a mold and pressed by the tool. At this stage the pressed component possesses a low strength due to the fact that the grains are stacked together from plasticization during compaction. The final process is the sintering process, the components undergo a heat treatment under certain atmosphere conditions and in a temperature bellow the melting temperature of the alloy in order to bond by means of atomic diffusion between adjacent powder particles and attain the required strength. The product that is taken after sintering is a ferrous porous steel component with lower mechanical properties than the full dense part due to the presence of porosity.One of the component that is increasingly becoming very interesting to the PM industry are highly loaded gears. Highly loaded PM gears can be produced by pressing sintering and then treated with post sintering operations which ...

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Optimized density profiles for powder metallurgical gears

Cited by 6 publications

References 6 publications

A Digital Twin of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

A Digital Twin of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

Numerical Modelling of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

Improved PM gear rolling simulations using advanced material modelling

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