Investigation of surface cracking of hot-extruded AA7075 billet

Sukunthakan Ngernbamrung*, Yudai Suzuki, Norio Takatsuji, Kuniaki Dohda

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Extrudability of AA7075 is determined by tearing occurring through extrusion conditions by extrusion limit diagram relating to temperatures and speeds. Extruded parts were observed for tearing appearance and analyzed elements. As results, localization of melting by local heat generated by friction coupled with tension stress and zinc-segregated concentration stimulates tearing sensitivity. Furthermore, at small grain region, zinc-segregated concentration is well scattered without tearing. Therefore, an attempt to control microstructure in die by a newly-developed twist-groove porthole die is proposed to induce large severe deformation in die leading to grain refinement reducing tearing sensitivity to accelerate speed in hot extrusion.

Original languageEnglish (US)
Pages (from-to)217-224
Number of pages8
JournalProcedia Manufacturing
StatePublished - Jan 1 2018
Event17th International Conference on Metal Forming, METAL FORMING 2018 - Toyohashi, Japan
Duration: Sep 16 2018Sep 19 2018


  • Aluminum alloy 7075
  • Hot extrusion
  • Porthole die
  • Surface cracking
  • Tearing

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Artificial Intelligence

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