Formability of Micro-Tubes in Hydroforming

Hartl, Christoph; Anyasodor, Gerald; Lungershausen, Joern

doi:10.1063/1.3589569

Title: Formability of Micro-Tubes in Hydroforming

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Abstract

Micro-hydroforming is a down-scaled metal forming process, based on the expansion of micro-tubes by internal pressurization within a die cavity. The objective of micro-hydroforming is to provide a technology for the economic mass production of complex shaped hollow micro-components. Influence of size effects in metal forming processes increases with scaling down of metal parts. Investigations into the change in formability of micro-tubes due to metal part scaling down constituted an important subject within the conducted fundamental research work. Experimental results are presented, concerning the analysis of the formability of micro-tubes made from stainless steel AISI 304 with an outer diameter of 800 {mu}m and a wall thickness of 40 {mu}m. An average ratio of tube wall thickness to grain size of 1.54 of up to 2.56 was analyzed. Miniaturised mechanical standard methods as well as bulge tests with internal hydrostatic pressurization of the tubular specimens were applied to analyze the influence of size-dependent effects. A test device was developed for the bulge experiments which enabled the pressurization of micro-tubes with internal pressures up to 4000 bar. To determine the attainable maximum achievable expansion ratio the tubes were pressurized in the bulge tests with increasing internal pressure until instability due tomore »« less

Authors:

Hartl, Christoph; Anyasodor, Gerald ^[1]; Lungershausen, Joern ^[2]

Institute of Production, Cologne University of Applied Sciences, Betzdorfer Str. 2, 50679 Cologne (Germany)
Institute of Product and Production Engineering, University of Northwestern Switzerland, Klosterzelgstr. 2, 5210 Windisch (Switzerland)

Publication Date:: Wed May 04 00:00:00 EDT 2011

OSTI Identifier:: 21516766

Resource Type:: Journal Article

Journal Name:: AIP Conference Proceedings

Additional Journal Information:: Journal Volume: 1353; Journal Issue: 1; Conference: ESAFORM 2011: 14. international ESAFORM conference on material forming, Belfast, Northern Ireland (United Kingdom), 27-29 Apr 2011; Other Information: DOI: 10.1063/1.3589569; (c) 2011 American Institute of Physics; Journal ID: ISSN 0094-243X

Country of Publication:: United States

Language:: English

Subject:: 42 ENGINEERING; ANNEALING; CAVITIES; COMPARATIVE EVALUATIONS; CORRELATIONS; DIES; EQUIPMENT; EXPANSION; GRAIN SIZE; INSTABILITY; MASS; METALS; PLASTICITY; PRESSURIZATION; SCALING; STAINLESS STEELS; THICKNESS; TUBES; ALLOYS; CARBON ADDITIONS; DIMENSIONS; ELEMENTS; EVALUATION; HEAT TREATMENTS; HIGH ALLOY STEELS; IRON ALLOYS; IRON BASE ALLOYS; MECHANICAL PROPERTIES; MICROSTRUCTURE; SIZE; STEELS; TRANSITION ELEMENT ALLOYS

Citation Formats


                    Hartl, Christoph, Anyasodor, Gerald, and Lungershausen, Joern. Formability of Micro-Tubes in Hydroforming.  United States: N. p., 2011. 
        Web.  doi:10.1063/1.3589569.

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                    Hartl, Christoph, Anyasodor, Gerald, & Lungershausen, Joern. Formability of Micro-Tubes in Hydroforming.  United States.  https://doi.org/10.1063/1.3589569

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                    Hartl, Christoph, Anyasodor, Gerald, and Lungershausen, Joern. 2011.  
        "Formability of Micro-Tubes in Hydroforming".  United States.  https://doi.org/10.1063/1.3589569.

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@article{osti_21516766,

  title        = {Formability of Micro-Tubes in Hydroforming},

  author       = {Hartl, Christoph and Anyasodor, Gerald and Lungershausen, Joern},

  abstractNote = {Micro-hydroforming is a down-scaled metal forming process, based on the expansion of micro-tubes by internal pressurization within a die cavity. The objective of micro-hydroforming is to provide a technology for the economic mass production of complex shaped hollow micro-components. Influence of size effects in metal forming processes increases with scaling down of metal parts. Investigations into the change in formability of micro-tubes due to metal part scaling down constituted an important subject within the conducted fundamental research work. Experimental results are presented, concerning the analysis of the formability of micro-tubes made from stainless steel AISI 304 with an outer diameter of 800 {mu}m and a wall thickness of 40 {mu}m. An average ratio of tube wall thickness to grain size of 1.54 of up to 2.56 was analyzed. Miniaturised mechanical standard methods as well as bulge tests with internal hydrostatic pressurization of the tubular specimens were applied to analyze the influence of size-dependent effects. A test device was developed for the bulge experiments which enabled the pressurization of micro-tubes with internal pressures up to 4000 bar. To determine the attainable maximum achievable expansion ratio the tubes were pressurized in the bulge tests with increasing internal pressure until instability due to necking and subsequent bursting occurred. Comparisons with corresponding tests of macro-tubes, made from the here investigated material, showed a change in formability of micro-tubes which was attributed to the scaling down of the hydroforming process. In addition, a restricted applicability of existing theoretical correlations for the determination of the maximum pressure at bursting was observed for down-scaled micro-hydroforming.},

  doi          = {10.1063/1.3589569},

  url          = {https://www.osti.gov/biblio/21516766},
  journal      = {AIP Conference Proceedings},

  issn         = {0094-243X},

  number       = 1,

  volume       = 1353,

  place        = {United States},

  year         = {Wed May 04 00:00:00 EDT 2011},

  month        = {Wed May 04 00:00:00 EDT 2011}

}

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