Grain-refined extruded aluminum alloy tubular product with large wall thickness and preparation method thereof

The invention discloses a grain-refined extruded aluminum alloy tubular product with large wall thickness and a preparation method thereof. The tubular product comprises the following metallic substances in percentage by weight: 1.0-1.15% of Mg, 0.60-0.75% of Si, 0.20-0.35% of Cu, 0.35% of Fe, 0.10% of Mn, 0.05-0.08% of Cr, 0.15% of Zn, 0.10% of Ti and the balance of aluminum. The invention further discloses a preparation method of the grain-refined extruded aluminum alloy tubular product with large wall thickness. The grain-refined extruded aluminum alloy tubular product with large wall thickness provided by the invention solves the problem that the grains of the base and surface of a 6061 alloy extruded aluminum alloy tubular product with great wall thickness are thick and big, the deficiency of bulky crystal spots generated after anodic oxidation can be eliminated and indexes of the final product, such as inner welding quality and mechanical performance, can satisfy the GB/T6892-2006 standard requirement.