2017 Volume 58 Issue 679 Pages 692-698
In-plane tension/compression tests of an annealed steel sheet were carried out to investigate the work-hardening behavior under two-stage loading paths. The two-stage loading paths consist of plane-strain tension/compression for the 90° direction from the rolling direction followed by unloading and subsequent uniaxial tension/compression in the 0° and 90° directions from the first loading direction. It was found that the work-hardening behaviors were significantly affected by the inner product of the strain rate mode tensors for the first and second loadings and that the effect of the deformation mode （tension/compression） was small. A new work-hardening equation that can reproduce the work-hardening behavior in the second loading was proposed. Experiments and finite element analyses of pipes with bending deformation history under internal-pressure and axial compression were performed. As work-hardening behaviors for those analyses, compression in the axial direction of the pipe or tension in the circumferential direction of the pipe was applied in accordance with the proposed equation. The calculated result for tension applied in the circumferential direction was in the closest agreement with the experimental result.