Experimental investigation of the formability of heat treated AA6063 tubes using hydraulic rotary draw bending process

In this paper, the formability behavior of thin-walled aluminum tubes has been experimentally investigated using the hydraulic rotary draw bending process. At first, AA6063 tubes with a ratio of diameter to thickness of 13.88, outer diameter of 25 mm, and thickness of 1.8 mm were subjected to heat treatment operations; annealing and artificial aging. Then, bending experiments were carried out on as-received and heat-treated samples at fluid pressures of 0, 1, 1.8, 3.2, and 3.6 MPa. After performing the experiments, the amount of thinning and thickening of the bent tubes were measured. By examining the results, it was found that for all samples, the maximum thinning and thickening occur at an angle of 40 degrees to the pressure die. Also, the examination of the formability results of the tubes demonstrated that the heat treatment and the fluid pressure have interaction effects, so the effect of the heat treatment is not very noticeable at the fluid pressure of 0 MPa, but the effect of the heat treatment is remarkable at the maximum fluid pressure of 36 MPa. At maximum fluid pressure, aging heat treatment reduces thinning by 7% and annealing heat treatment increases thinning by 13% compared to the as-received sample. In addition, in comparison to the as-received sample, the thickening of aged tubes increases by 5% and decreases by 16%, respectively.