Effects of process time and thread on tensile shear strength of al alloy lap joint produced by friction stir spot welding

Mitsuo Fujimoto, Daisuke Watanabe, Natsumi Abe, Yutaka Sato, Hiroyuki Kokawa

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

In automotive applications, friction stir spot welding (FSSW) has been practically used in the construction of aluminium car bodies. In this study, the weld strength and factors governing the weld strength in the friction stir spot welded aluminium alloy 6061-T6 were examined. The weld strength increased with the process time during FSSW up to 3 s, beyond which it decreased. The fracture path changed from the lapped interface into the shoulder edge as the process time increased, and the maximum strength was obtained at the process time when the transition of the fracture path occurred. The cross-sectional microstructure depended on the threads on the probe surface, i.e. the elliptical zone was formed in the stir zone by the threads, but an effect of the thread on the weld strength was hardly found. The present study suggests that the weld strength was strongly related to the size of the well-consolidated region, which was larger than the elliptical zone observed in the vicinity of the exit hole.

Original languageEnglish
Pages (from-to)169-175
Number of pages7
JournalWelding International
Volume24
Issue number3
DOIs
Publication statusPublished - 2010 Mar 1

Keywords

  • Aluminium alloy
  • Friction stir spot welding
  • Process time
  • Stir zone
  • Tensile shear strength
  • Thread

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

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