LAUSR

The phase transformations of the X38CrMoV5-1 (AISI H11-1) steel are studied in the present work. Parts are usually manufactured by die-casting followed by a heat treatment, and the resulting microstructure as well as the mechanical properties are highly sensitive to the heat treatment conditions. The heat treatment consists on a quenching and tempering and it is not able to remove the casting dendritic microstructure or porosity but anyway, it is carried out to achieve an acceptable ductility, good hardness, and/or tensile strength in order to avoid catastrophic failures in service. These manufactured parts are used as safety braking parts. The authors use differential thermal analysis (DTA) and dilatometry techniques to obtain the phase transformation temperatures AC1 and AC3 and, therefore achieve an optimized heat treatment for this steel application. The microstructure obtained with this optimized heat treatment is totally martensitic providing the desired mechanical properties for this application.