The influence of the rare earth metals modification on the fracture toughness of G17CrMo5-5 cast steel at low temperature

This paper presents the influence of the rare earth metals (REM) modification on mechanical properties and fracture toughness of G17CrMo5-5 cast steel at low temperatures. The REM was in the form of mishmetal. The research has been performed on serial (several) industrial melts. The fracture toughness values of unmodified and modified cast steel at the temperature range from -80 degrees C to 20 degrees C were tested. The reference temperatures of the brittle-to-ductile transition, T-Q, for both unmodified and modified cast steel were determined. The positive influence of the modification by REM on the fracture toughness and the reference temperature T-Q are shown.