Friction Stir Welding of thin Sheets of Magnesium Alloy AZ31B

Friction stir welding developed in early 90’s is a refreshing approach to the joining of different kinds of metals. FSW has become increasingly popular and provides excellent alternative to conventional welding or riveting sheets of various metals. The paper present the results of research work on linear FSW joining magnesium alloys AZ31B of 0.5 mm in thickness. The study was conducted on properly adapted numerical controlled 3 axis milling machine using a own made tools and fastening device. The tool dimensions have been estimated in accordance with the algorithm shown in the literature [2]. All joints were made of end-to end (butt) configuration under different process parameters. The effect of selected technological parameters on the quality of the joint was analyzed. Produced butt joint have been subjected to a static tensile testing to identify mechanical features of the materials of joints compared to parent materials. Measurements of micro hardness HV in the plastically formed stir zone of joint and in the parent material have been carried out. Axial and radial welding forces in the joining region were recorded during the tests and their dependency from the welding parameters was studied . Based on results of strength tests the efficiency of joints for sheets of 0.5 mm in thicknesses oscillated up to 90% compared to the parent material. It has been found that for given parameters the correct, free of defects joints were obtained. The results suggests that FSW can be potentially applied to magnesium alloys.