Abstract
The local tube cladding utilizes mechanics of deformation at the interface of the punch and the tube. More specifically, the punch shape influences the material flow and the pressure at the interface. This study investigates the cladding of AA6060/SS304 bimetallic tubes using a spherical tipped punch of varying diameter at a constant rate of 5 mm/min. Different from previous studies, where axial feed rate seemed to take precedence, in this study the punch diameter was isolated as the primary variable, and the effects on deformation stability, bonding mechanics, and surface finish, were documented.Two sets of experiments were performed using a spherical tipped punch of 65 mm and 69 mm diameter. Under the studied conditions, cladding was successfully completed using the 65 mm diameter punch with a maximum forming load of 44 kN. The 69 mm diameter punch, however, achieved a maximum forming load of 88 kN, showing unstable deformation with flange rupture, material back flow, and thinning. Although forming was not successful, the larger diameter punch increased the maximum interfacial shear load from 5.35 kN to 21.46 kN and decreased the surface roughness from 0.7133 µm to 0.6325 µm. The 65 mm punch produced cladded tubes with a greater average hardness value of 52.06 HV compared to 51.89 HV of the 69 mm punch. Overall, under the investigated forming conditions, changing the punch diameter from 65 mm to 69 mm resulted in clear differences in forming load, deformation stability, maximum interfacial shear load, and surface roughness.