Investigation Of The Mechanical Properties Of Magnesium Alloy Tubes By Ring Hoop Tension Test

The Magnesium alloy tubes manufacting process by extruding have significant anisotropy, which leads to great difference between the transverse direction and the axial direction. To evaluate the anisotropy behavior resulting form the tube-making process, tube transverse tensile properties must be obtained. There is no convenient standard test method to measure transverse tube tensile properties without flattening the material.The ring hoop tension test was established to obtain the transverse tensile properties. Under the positive pressure linear transform assumed condition and the boundary condition, the relational expression of the positive pressure and the hoop tension about the angle and the friction coefficient were derived.The ring hoop tension test process of magnesium alloy tubes was simulated to proof the relational expression of the hoop tension obtained above. The influence of friction coefficient, the angle of gage section and temperature on the location of deformation zone, the distribution of deformation and the total deformation rate were researched.The ring hoop tension tests at different temperatures were carried out. The equal wide sample was adopted to prove the relational expression of the hoop tension. The influence of friction coefficient, the angle of gage section and temperature on the location of deformation zone, the distribution of deformation and the total deformation rate were researched. The influence of the welded seam, which was existed on the divergent die extruding tubes, was researched according to the test with divergent die extruding tubes samples. The distribution of deformation and the total deformation rate were considered comparing the three kind of samples.Warm hydroforming experiments of magnesium alloy tubes at different temperatures were carried out to study the trend curve of bulging rate, whose results were compared with that of the ring hoop tension test.