Numerical study on the X80 UOE pipe forming process

The UOE process is an effective approach for manufacturing large-diameter submerged-arc welding pipes used in oil and gas pipelines. A UOE process comprises the successive procedures of crimping, U-forming, O-forming, joining, welding, and expanding. In this study, a two-dimensional finite element model of UOE forming process is established and all the forming stages of an X80 high strength steel pipe are numerically studied. A kinematic hardening model is incorporated in FEM to describe the Bauschinger effect of X80 steel. The formation mechanism of O-forming open-seam is unveiled based on analysis of the complex deformation and springback behaviors of plate under loading-unloading-reverse loading condition. The validity of the model established is demonstrated by comparing the calculated result and practical measurement. Furthermore, the influence of processing parameters, friction coefficient and material properties on open-seam and ovality are numerically investigated.