Evolution of stress and strain in 2219 aluminum alloy ring during roll-bending process

Abstract

The residual stress of large aluminum alloy ring after heat treatment will cause serious deformation in subsequent processing. The conventional methods for reduction of residual stress (such as stepwise cold pressing and bulging) have little effect in the residual stress reduction for large-scale ring component and will induce inhomogeneous stress distribution. In this paper, roll bending process is adopted to reduce the quenched residual stress of 2219 aluminum alloy super-large ring. The numerical model of roll bending process was established, and the evolution and distribution of stress and strain after roll bending were studied. The influence of roll winding number on the uniformity of stress and strain was analyzed. The results show that the arch-shaped quenched residual stress of the ring changes to N-shaped distribution from inside to outside after roll bending process. The value of the residual stress reduces from ± 180 MPa in quenched state to the value within ± 50 MPa in roll bended state. With the increase of roll winding number, the stress uniformity is improved, but the stress reduction amplitude is basically the same. By analyzing the elastic–plastic strain distribution characteristics and strain springback law of the ring after roll bending, the formation mechanism of N-shaped residual stress distribution after roll bending is revealed.