Prediction of cleavage fracture in ferritic steels by small punch tests with a modified Weibull stress model

• The modified Weibull stress model is recommended for a blunt notched specimen.
• The Weibull scale parameter is a power function of temperature.
• It is the pre-investigation work to estimate T0 of the master curve by small punch tests.

In this paper, conventional small punch (SP) tests are carried out to determine the SP ductile-to-brittle transition temperature, TSP. The center holed small punch (CHSP) specimens are tested at TSP to determine the Weibull parameters with two different Weibull stress model. The relationship between temperature and the Weibull stress scale parameter, σu, is investigated. The result showed that a unique set of Weibull parameters for CHSP specimens and 0.4T SENB specimens is available by using the modified model not the original model. And the Weibull stress scale parameter, σu, is a power function of temperature.