Analysis of Friction Stir Welded Joint Properties of 2A12 Aluminum Alloy

2A12 hot-rolled aluminum alloy has high plasticity and toughness, and is widely used in the manufacturing of structural parts in aviation, aerospace, automobiles, and other fields. To explore the effect of friction stir welding process parameters on the welded joint properties of 2A12 hot-rolled aluminum alloy, experimental investigations were conducted. The surface appearance of the welded joints under different process parameters was observed, the microstructure, microhardness, tensile strength, yield strength, elongation and the fracture morphology of the welded joints were assessed. The findings suggested that when the rotation speed was 600 rpm and the forward speed was 250 mm/min, the tensile strength, yield strength and elongation of the welded joint were all maximum, which were 437.6 MPa, 381.6 MPa and 7.5 % respectively, reaching 85.5 %, 88.1 % and 35.7 % of the base material. Under the same forward speed, the tensile strength and elongation of the welded joint initially rose and subsequently declined with the increment of rotation speed. The microhardness distribution of the welded joint exhibited a W-shape pattern. The fracture morphology showed that the fracture type of the welded joint was a ductile fracture. Unlike the base material, the welded joints did not exhibit significant necking during the tensile testing. The research results can be utilized as a reference for the engineering application of friction stir welding of 2A12 hot-rolled aluminum alloy.