This study aims to evaluate the relevance of the active plasticity hypothesis in predicting the risk of cleavage fracture during a WPS loading cycle. We define a critical loading path, along which the active plasticity hypothesis might fail. On this critical loading path, Beremin local model is compared to a stress-based criterion model. The chosen critical loading path is a LTF (Load-Transient-Fracture) cycle, including an isothermal preloading up to F1WPS = 42 kN at TWPS = −25°C followed by a cooling down to TFRAC = −150°C with a progressive loading up to F2WPS = 45 kN before an isothermal reloading up to fracture at −150°C. The final loading level (F2WPS = 45 kN) is chosen so that the plasticity is not active during the cooling phase while the stress-based criterion is. Two sets of experiments, performed on normalized compact tensile specimens made of 16MND5 steel, have demonstrated that the active plasticity was a necessary condition for cleavage fracture.

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