On the use of Charpy transition temperature as reference temperature for the choice of a pipe steel

•Transition temperature  depends on specimens and loading mode.•Here, the linear dependence of transition temperature with constraint is shown.•Constraint is evaluated by the effective T stress.•This approach gives the best choice of the reference transition temperature by reducing conservatism.

Transition temperature is not intrinsic to material but depends on specimens and mode of loading used for tests. Here, the linear dependence of transition temperature with constraint is shown. Constraint is evaluated by the effective T stress which is the value of the stress difference distribution for the effective distance provided by the Volumetric method.Application of this approach gives the best choice of the reference transition temperature by reducing conservatism when comparing with intrinsic transition temperature of the studied structure.