Plastic deformation history in infeed rotary swaging process

Liu, Yang; Herrmann, Marius; Schenck, Christian; Kuhfuß, Bernd

doi:10.1063/1.5008093

Cited by 11 publications

(7 citation statements)

References 9 publications

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“…Simulations are used to investigate the process and the material behavior during rotary swaging. For example, the material flow [4], plastic strain [11] and strain rates [12] have been investigated. The von Mises equivalent stress was examined by Ameli et al, who found it to be directly related to the residual stresses [13].…”

Section: Introductionmentioning

confidence: 99%

Influence of Process Fluctuations on Residual Stress Evolution in Rotary Swaging of Steel Tubes

et al. 2019

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Infeed rotary swaging is a cold forming production technique to reduce the diameter of axisymmetric components. The forming is achieved discontinuously by a series of radial strokes that are spread over the shell of the part. Due to tolerances within the rotary swaging machine, these strokes perform individually and the resulting stroke pattern is not homogeneous with regards to circumferential and longitudinal distribution. Nevertheless, in combination with the high number of performed strokes and the large contact area between the dies and the part, the external part properties, such as diameter, roundness and surface roughness, show even values along the finished part. In contrast, strength-defining internal part properties, like microstructure and residual stress components, are more sensitive to the actual pattern and temporal sequence of the individual strokes, which is investigated in this study. The impact of process fluctuations during the conventional process, which are induced by the tolerances of machine tool components, was verified by numerical simulations, physical tests and measurements of residual stress distributions at the surface and at depth. Furthermore, a method is introduced to maintain the stroke following angle ∆φ at zero by flat dies, and thus the actual pattern and temporal sequence of the strokes was homogenized. The results show that the residual stress fluctuations at the surface could be controlled and reduced. Furthermore, it is demonstrated that the depth profile of the residual stresses at a distance of 300 µm from the surface developed independently from the process fluctuations.

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Section: Introductionmentioning

confidence: 99%

Influence of Process Fluctuations on Residual Stress Evolution in Rotary Swaging of Steel Tubes

et al. 2019

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“…This finally leads to the failure of the surface near material layer and with that the detachment of abrasive particles from the work piece's surface. The explained mechanism of particle generation is supported by the findings from finite element method (FEM) simulations, investigating stress states in the work piece material emerging while rotary swaging with sine wave structured rotary swaging dies [9]. The abrasive particles generated in the experiments can be characterized as fine tinsels, except the case of machining of aluminum work pieces with uncoated forming dies.…”

Section: Discussionmentioning

confidence: 75%

Reducing Abrasive Particle Generation in Dry Rotary Swaging by Utilizing DLC Hard Coated Dies

et al. 2018

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The emphasis of this paper is the investigation of the impact of the diamond like carbon (DLC) hard coating system on the amount of abrasive particles being generated during dry rotary swaging. Rotary swaging experiments applying coated and uncoated macro structured forming dies were carried out against aluminum and steel work pieces varying the process parameter feed velocity. It was found that DLC coatings effectively reduce the generation of abrasive particles from the work piece. For dry machining of aluminum the amount was reduced to a tenth of the original quantity achieved with uncoated dies. The results are discussed with regard to the mechanics of interfacing surfaces. Additionally, forming dies exhibiting macro structures surfaces of improved design were introduced and applied in dry rotary swaging experiments, which allowed minimizing the abrasive particle generation.

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“…The second peak was more sensitive to the friction condition than the first peak. Wear and adhesion were found on the locations of both peaks on the die [ 20 ].…”

Section: Results Of Simulationmentioning

confidence: 99%

“…ΔPE z contributes to the overall elongation whereas ΔPE y contributes to the final wall thickness. As the former research showed, there are local positions where the material flow is the most active [ 15 , 20 ], but the features of the active areas and the influence of the friction condition were not thoroughly investigated, which could further affect the die life. Local peaks were defined to describe the feature of the ΔPE z ( Figure 4 ).…”

Section: Methodsmentioning

confidence: 99%

Material Flow in Infeed Rotary Swaging of Tubes

Liu

Herrmann

et al. 2020

Materials

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Rotary swaging is an incremental metal forming process widely used to reduce the cross–section of parts. For tubular parts, the final wall thickness also changes during the process. The lubricant condition is a factor, which affects these geometry changes. Beneath the change of the geometry, the complex material flow during the process determines the final geometry and the mechanical properties. Therefore, with a thorough insight into the material flow, it could be understood how to control it in order to achieve desired properties. Producing tubes with uniform outer diameter and changing inner profiles is an application of this method. Furthermore, applying this method, different local cold hardening could be achieved by different total strain. In this study, the dependency of the material flow on the lubrication conditions was investigated. Simulations with combined hardening material models were verified by the change of the wall thickness of tubes. It was found that friction condition significantly influences the back shifting of the workpiece and the elongation caused by each stroke. Results from simulations and experiments showed that a certain lubricant condition leads to the highest axial elongation of the workpiece.

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Plastic deformation history in infeed rotary swaging process

Cited by 11 publications

References 9 publications

Influence of Process Fluctuations on Residual Stress Evolution in Rotary Swaging of Steel Tubes

Influence of Process Fluctuations on Residual Stress Evolution in Rotary Swaging of Steel Tubes

Reducing Abrasive Particle Generation in Dry Rotary Swaging by Utilizing DLC Hard Coated Dies

Material Flow in Infeed Rotary Swaging of Tubes

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