Effect of process variables on the formation of streak defects on anodized aluminum extrusions: An overview

Hanliang Zhu, Malcolm J. Couper, Arne K. Dahle

Research output: Contribution to journalReview ArticleResearchpeer-review

9 Citations (Scopus)


Streak defects are often present on anodized extrusions of 6xxx series aluminum alloys, increasing the fabrication cost of these products. Moreover, streaking often only becomes visible after etching and anodizing treatments, rather than in the as-extruded condition, making it difficult to identify the original causes and influencing factors of these defects. In this paper, various process variables that influence the formation of streak defects on anodized aluminium extrusions are reviewed on the basis of a literature review, industrial practice and experimental results. The influencing factors involved in various processing steps such as billet quality, extrusion process, die design and etching process are considered. Effective measures for preventing the formation of streak defects in industrial extrusion products are discussed.

Original languageEnglish
Pages (from-to)105-111
Number of pages7
JournalHigh Temperature Materials and Processes
Issue number2
Publication statusPublished - Apr 2012


  • Aluminum extrusion
  • Microstructure
  • Streak defect
  • Surface imperfection

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