Investigation to Self-Piercing Riveting of Wrought Magnesium AZ31 Sheets

Abstract

In this study, the fabrication of the desired SPR joints was investigated as a function of the preheat temperature and strain rate. To determine the optimum preheat temperature, Gleeble thermal analogue testing of 2mm thick magnesium AZ31 was used to assess the combined influence of preheat temperature and strain rate on the strength and total elongation of magnesium AZ31. Magnesium alloy AZ31 with a thickness of 2mm was preheated with various temperatures prior to self-piercing riveting. The appearances, cross-sections and mechanical tests of the SPR magnesium AZ31 joints were investigated. It was found that a preheat temperature of 180 to 200oC largely eliminated the cracking in magnesium AZ31 joints. The joint strength increases with increasing preheat temperature from ambient to 200oC. The strength increase is attributed to the reduction in joint cracking and an increase in mechanical interlock between the rivet and work pieces.

Review on joining processes of magnesium alloy sheets

“…A suitable preheating temperature range of 180-200°C for AZ31 magnesium alloy was obtained, and in preheating a 2-mm-thick AZ31 sheet to 200°C when performing the SPR process, the joint strength was increased by 17%. The increase in strength is attributed to the reduction in joint cracking and the increase in the value of joint interlock [67].…”