International audienceThe deformation and fracture of the high strength steel which is used to fabricate grade X100 steel pipe were investigated at room temperature, on plate and pipe. Anisotropic behaviour was characterized by using tensile tests conducted along different directions. The fracture toughness of plate and pipe materials are compared using compact tension (CT) and Charpy V-notched tests. In both cases, these materials give rise to good fracture properties. The aim of the present study is to establish unified constitutive equations able to describe the elastoplastic and damage behavior of one X100 linepipe steel. The model is then used to simulate three point bending and compact tension tests