Microcracks in the aluminum spinning process (original) (raw)

The aluminum alloys spinning process is a very old process but very little studied, perhaps due to the low tonnage processed by this method, which makes it less relevant than other processes of plastic deformation. Nevertheless, it is an economically competitive method for the manufacture of light pressure vessels, consisting of a liner of aluminum alloy reinforced with fiber glass. This process presents the disadvantage of the formation of microcracks that serve as stress risers and cause the fracture of the container during the cyclical load. This happens with crack sizes much smaller than the ones predicted in the bibliography for the alloy AA6061. The formation and the characteristics of the microcracks were studied by analysing process variables such as heating temperature and plastic deformation velocity. The experiments showed that higher temperatures and smaller forming velocities reduced the formation of microcracks.