May 13 - 16, 2008
Gaylord Palms
Orlando, Florida USA

Value-Added Processes

068 VA 
Thursday, May 15 - 9:30am

Mechanisms of Streaking on Anodized 6xxx-Series Exrusions

Xinquan Zhang and Malcolm J. Couper -- Rio Tinto Aluminium Technology, Australia;
Hanliang Zhu and Arne K. Dahle -- Materials Engineering, University of Queensland, Australia

Streaking surface defects common to anodized 6xxx-series soft alloy extrusions become apparent only after anodizing, making cause identification difficult. Eight types of streaking defects are presented focusing on the two most common – streaking near changes in cross-section, and in hollow profile welding zones. Effects of alloy composition, die design, die correction, and extrusion conditions on streaking intensity are discussed.