The Annealing Effect on Microstructure and Texture Evolution of Spun Al-Mg Alloy Tubes with Cross Inner Ribs

Tubes with a cross inner rib exhibit significant internal residual stresses after spinning, which seriously affects their properties. The recrystallization and texture evolution of the tube at different annealing temperatures were investigated. The results showed that severe plastic deformation occurred during the spinning process, with an average grain size of 10.94 μm and a residual compressive stress of −75 MPa. The annealing treatment increased the yield strength and elongation but decreased the ultimate tensile strength. At 290 °C, the residual stress decreased to −50.1 MPa, the grain size was refined to 5.9 μm, the β-fiber structure was retained, and excellent mechanical properties were obtained, with a yield strength of 106.22 MPa, an elongation of 42.43%, and an ultimate tensile strength of 378.55 MPa. At 350 °C, the grain size increased to 7.2 μm, the β-fiber structure disappeared, the mechanical properties decreased, and the residual stress was further reduced to −24.01 MPa. The fracture mode after annealing was a ductile fracture.