This product is the lower bracket of automobile rear door, which is made of 5182 and 6063 aluminum, stamped and formed by cold-drawn profile and precision press, and assembled by argon arc welding, so as to achieve better assembly strength and lighter body without losing strength. Finally, the surface is coated by electrophoresis, which can meet the requirements of 1000 hours salt spray test at the highest, so that the product has good corrosion resistance and weather resistance, and better meets the requirements of outdoor use of automobiles.