MODELING OF THE ELASTO-PLASTIC BEHAVIOR OF HSLA X140 STEEL: EFFECT OF PRE-STRAIN AND TRIAXIALITY

In this work, a comprehensive experimental campaign is conducted to investigate the effect of pre-strain on the mechanical properties of X140 steel used in high performance threaded connections. Mechanical tests are used to characterize the plastic and fracture behavior of the material. Smooth tensile (ST), notched tensile (NT), plane strain (PE) and shear tests (STC) were performed. Cyclic tension-compression tests are used to characterize kinematic hardening. Initially qualified as isotropic, this material showed an anisotropic behavior after undergoing a pre-strain expansion as its plastic flow becomes loading direction dependent. This pre-strain effect is well reproduced using a phenomenological modeling combining isotropic and kinematic hardening contributions with a Hosford’s criterion.
EXTENDED ABSTRACT