The influence of pre-strain on the tensile and fatigue properties of a
dual phase DP600 was studied. The material was pre-strained by uni-axial
tension in rolling and transverse direction. Thereafter, specimens were
cut from the deformed plates in parallel or orthogonal to pre-strain
direction. It was found that pre-strain increases yield and tensile
strength. Results suggested that strain path change primarily affects
the elastic-plastic transition during early stage of reloading.
Pre-strained specimens showed an increase in high cycle regimes as a
consequence of yield strength increment, irrespective of imposed
pre-straining direction. A modified stress life equation which accounts
for pre-strain was proposed and showed good agreement with experimental
data. Bake hardening enhanced both tensile and high cycle fatigue
resistance. Walker equation was successfully fitted to account tensile
mean stress. In low cycle fatigue, negligible influence of pre-strain
was observed due to cyclic softening and residual stress relaxation.