Dissimilar spot welding of aluminium alloy and hot dip galvanised steel by metal flow: application of friction anchor welding to aluminium alloy and Zn-coated steel

摘要

Lap joints of an upper Al alloy (1.0 mm-thick A5052) and lower hot dip galvanized steel (1.2 mm-thick Gl steel) were welded by a novel spot welding process for dissimilar metal lap joints using a new tool with the tip made of spherical ceramics, i.e. 'Friction Anchor Welding'. As a result, the rotating tool was plunged only to 1.3-1.4 mm from the Al alloy surface, and accordingly, a steelprojection was not formed in the Al alloy sheet. Further, the Al alloy near the rotating tool wasremoved. However, near this removed area, the Zn layer on the Gl steel melted and was removedby friction heat, and consequently, the Gl steel and the Al alloy were welded. Thus, the tensileshear strength reached about 2.6 kN/point.