Use of the small punch test to determine the ductile-to-brittle transition temperature of structural steels

ABSTRACT The small punch test (SPT) consists in punching very small square specimens, measuring 10 × 10 mm2 and 0.5‐mm thickness, until fracture using a 2.5‐mm‐diameter hemispherical punch. Different specimens of a structural steel were tested from room temperature to cryogenic temperatures in order to determine its ductile‐to‐brittle transition temperature (DBTT). The DBTT obtained in SPT (DBTTSTP) is much lower than the DBTT obtained by means of Charpy specimens (DBTTCVN). The variation of the mechanical parameters calculated from the SPTs with temperature was also calculated and the operative fracture micromechanisms defined using a scanning electron microscope.