Grain Size Modification by Micro Rotary Swaging

Ishkina, Svetlana; Kuhfuß, Bernd; Schenck, Christian

doi:10.4028/www.scientific.net/kem.651-653.627

Cited by 9 publications

(5 citation statements)

References 4 publications

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“…The presented proceeding and the results are encouraging that the rotary swaging can be evolved as an alternative process for producing UFG wires with high dimensional accuracy. Next steps in the research will be the analysis of higher deformation degrees and the combination of the relative speed approach with the idea of non-rotation-symmetric strokes [5].…”

Section: Discussionmentioning

confidence: 99%

“…ECAS allows continuous production of bulk ultra fine grain (UFG) material with significant refinement of the microstructure due to shear deformation during swaging. Grain size modification of wires was also shown in [5]. An influence of new developed swaging tools and specific process with asymmetrical strokes of the forming dies on the material properties was studied.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the relative rotational speed on component features in micro rotary swaging

Ishkina

Kuhfuß

Schenck

2015

MATEC Web of Conferences

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Abstract.Micro rotary swaging is a cold forming process for production of micro components with determined geometry and surface. It is also possible to change the microstructure of wires and hence the material properties. Swaging dies revolve around the work piece with an overlaid radial oscillation. Newly developed tools (Flat Surface Dies, FSD) feature plain surfaces and do not represent the geometry of the formed part as in conventional swaging. Using these tools allows for producing wires with triangle geometry (cross section) as well as a circular shape. To test the influence of FSD on material properties by micro swaging a new method is investigated: the variation of the relative speed between the specimen and dies in infeed rotary swaging. During this specific process copper (C11000) and steel (304 Alloy) wires with diameter d 0 = 1 mm are formed. It is noticed that the mechanical characteristics such as ductility and strength differ from the characteristics after conventional swaging. Moreover this approach enables new possibilities to influence the geometry and the surface quality of wires. The impact of the relative speed on the processed wire features is described in this paper.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of the relative rotational speed on component features in micro rotary swaging

Ishkina

Kuhfuß

Schenck

2015

MATEC Web of Conferences

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“…Currently, RS technology is not only used for manufacturing hollow/solid cylindrical shafts, difficult to deform materials and less plastic metals (e.g., tungsten and magnesium alloys), but also for the fabrication of the hollow/solid shafts with variable diameter and of the workpieces with various cross-sections via proper die design [ 45 , 46 , 47 ]. In addition, because of the significant strengthening effect with low strain [ 40 ] and excellent grain refinement ability [ 48 ], RS is employed to fabricate the workpieces with ultrafine-grained (UFG) structure or even NG structure.…”

Section: Rotary Swagingmentioning

confidence: 99%

Nano-Gradient Materials Prepared by Rotary Swaging

Chen

Zhao

2021

Nanomaterials

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Gradient nanostructured metallic materials with a nanostructured surface layer show immense potential for various industrial applications because of their outstanding mechanical, fatigue, corrosion, tribological properties, etc. In the past several decades, various methods for fabricating gradient nanostructure have been developed. Nevertheless, the thickness of gradient microstructure is still in the micrometer scale due to the limitation of preparation techniques. As a traditional but potential technology, rotary swaging (RS) allows gradient stress and strain to be distributed across the radial direction of a bulk cylindrical workpiece. Therefore, in this review paper, we have systematically summarized gradient and even nano-gradient materials prepared by RS. We found that metals processed by RS usually possess inverse nano-gradient, i.e., nano-grains appear in the sample center, texture-gradient and dislocation density-gradient along the radial direction. Moreover, a broad gradient structure is distributed from center to edge of the whole processed rods. In addition, properties including micro-hardness, conductivity, corrosion, etc., of RS processed metals are also reviewed and discussed. Finally, we look forward to the future prospects and further research work for the RS processed materials.

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“…Moumi et al investigated the change of the microstructure after rotary swaging depending on the feed velocity as well as the increase or decrease of the martensite content with the variation of the forming temperature [Mou15a]. They deduced that rotary swaging could provide the opportunity to adjust the forming characteristics of the workpieces for further forming steps [Ish15a]. However, the process was to be enhanced in terms of tool geometry and process kinematics.…”

Section: Introductionmentioning

confidence: 99%

Micro Forming Processes

Kuhfuß¹,

Schattmann

Jahn

et al. 2019

Lecture Notes in Production Engineering

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The projects of this chapter describe micro forming processes that are studied as single processes but can also be combined as process chains. Proven examples are material accumulation and succeeding rotary swaging, or rotary swaging and extrusion.Micro forming differs from macro forming due to scaling effects, which can mean both challenges and benefits. Problems may arise from the handling of fragile parts or adhesive forces between the micro parts or friction effects.Benefits from scaling effects are made use of in the project "Generation of functional parts of a component by laser-based free-form heading". The aim is a material accumulation that is generated from short duration laser melting. This material accumulation gives the basis for succeeding cold forming operations. The first powerful application for the new technology was upsetting. In the macro range, upset ratios of about 2.3 are achievable, but this is reduced in the micro scale due to earlier buckling of the components. In the micro scale, where cohesive forces can exceed the gravitational force, the molten material forms a droplet that remains adhered to the rod. Thus, upset ratios of up to 500 were reached. The process development was accompanied by a mathematical model and allows for a deep insight into the thermodynamics of laser-induced material accumulation in the micro range.The laser molten material accumulation could, for example, be further processed by micro rotary swaging. Though rotary swaging has been known in the macro range for a long time and is nowadays an intensively used process in the automotive industry to produce lightweight components from tubular blanks, there are only a few scientific works that have addressed material characteristics like the work hardening or residual stress that are linked to the process and machine parameters and the resulting material flow. Due to micro scale specifics that follow from the kinematics, i.e. relatively smaller stiffness against part buckling and wider tool gaps in the opened state, the feed rates achievable cannot compete with high throughput technologies that produce 500 parts per minute and more. One major aim of the project "Rotary swaging of micro parts" was to increase the productivity for the main process variants, namely infeed and plunge rotary swaging. This demanded also process modeling to understand how parameter variations like friction between tools and the work in the different zones of the swaging tools affect the process.From the modeling and simulation, separate process variations were deduced and investigated. For infeed swaging, a special workpiece clamping allows for compensation of the pushback force, which results in a 10-fold increase of the maximum feed rate. For plunge rotary swaging, an approach was tested to close the tools gaps during opening using elastic intermediate elements that encapsule the workpiece against the forming dies and enable a 4-fold increase of the radial feed rate. 28 B. Kuhfuss et al.Micro rotary swaging could become a base technology ...

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Grain Size Modification by Micro Rotary Swaging

Cited by 9 publications

References 4 publications

Influence of the relative rotational speed on component features in micro rotary swaging

Influence of the relative rotational speed on component features in micro rotary swaging

Nano-Gradient Materials Prepared by Rotary Swaging

Micro Forming Processes

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