The Effect of the Stress State on the Ultimate Plasticity of Steel X80

摘要

The dependence of ultimate plasticity on the triaxiality parameter and the Lode-Nadai coefficient is obtained for steel X80. The fracture locus allows the plasticity of the investigated materials to be evaluated for the whole range of the Lode-Nadai coefficient. Cylindrical specimen tension, bell-type specimen tension and compression and membrane extrusion are used for fracture locus calibration. The results can be used for plasticity resource estimation for steels under a complex stress-strain state in main pipelines subject to extreme loads.