Microstructure and Mechanical Properties of AA3003 Tube for Heat Exchanger Processed by Floating Plug Drawing

An AA3003 tube was severely deformed by cold floating plug drawing, and then annealed at temperatures from 210 to 460℃. The as drawn Al tube exhibited a typical deformation structure in which the grains were greatly elongated along the drawing direction. The hardness increased with increasing the reduction of cross-sectional area (RA), became 68Hv after RA= 99%. Up to 310℃, the Al tube still mainly exhibited a deformed structure. While complete recrystallization occurred at temperatures above 360℃. The hardness decreased with increasing the annealing temperature, and it became 33Hv after annealing at 410℃. Both the tensile and yield strengths also decreased with increasing the annealing temperature, but the decrease was larger in yield strength than in tensile strength. The elongation increased with increasing the annealing temperature. The changes in the strength and the elongation with the annealing temperature were the largest at 360℃, in which the complete recrystallization occurred.