Mechanisms of stick-slip vibration observed during ejection of warm compacted iron powder

Yukiko Ozaki, Tsuguyuki Takamiya, Tomoshige Ono

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The stress and friction coefficients on the die wall in warm compaction (W/C) were investigated during ejection of iron powder compacts by focusing on stick-slip phenomenon. Friction coefficients were measured during the ejection process by comparing W/C with cold compaction (C/C). In both cases, static friction coefficients were higher than kinetic friction coefficient that has been mentioned as the condition to generate the stick-slip, but the friction vibration was observed only in W/C not C/C. To confirm the mechanism of the stick-slip vibration generated specifically in W/C, static friction coefficients were measured in different ejecting velocities. The static friction coefficients in W/C increased prominently with decrease in ejecting velocity in comparison with C/C. This result indicates that local plastic flow of iron powder induced by heating results in broadening and producing stiffly adhesions between iron powder and the microscopic tips dispersed on the die surface during slower ejection, and the stick-slip might be attributed to such the adhesions. Consequently, it was proposed that blocking to forming the stiffly adhesions by modifying a microscopic morphology or materials of the die wall surface is an effective measure to suppress the stick-slip.

Original languageEnglish
Title of host publicationAdvances in Powder Metallurgy and Particulate Materials - Proceedings of the 2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015
PublisherMetal Powder Industries Federation
ISBN (Electronic)9781943694013
Publication statusPublished - Jan 1 2015
Externally publishedYes
Event2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015 - San Diego, United States
Duration: May 17 2015May 20 2015

Publication series

NameAdvances in Powder Metallurgy and Particulate Materials - Proceedings of the 2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015

Other

Other2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015
CountryUnited States
CitySan Diego
Period5/17/155/20/15

All Science Journal Classification (ASJC) codes

  • Metals and Alloys
  • Surfaces and Interfaces

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  • Cite this

    Ozaki, Y., Takamiya, T., & Ono, T. (2015). Mechanisms of stick-slip vibration observed during ejection of warm compacted iron powder. In Advances in Powder Metallurgy and Particulate Materials - Proceedings of the 2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015 (Advances in Powder Metallurgy and Particulate Materials - Proceedings of the 2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015). Metal Powder Industries Federation.