THE INFLUENCE OF PRIOR AGING ON MICROSTRUCTURE, TENSILE PROPERTIES AND HOT HARDNESS OF ALLOY 800HT

For high temperature applications espacially in the construction of eq uipment, carbide strengthened steels are widely used because of their good mechanical properties and relative low cost. These materials unde rgo microstructural changes under such service conditions which contri bute greatly to the strength properties and thus play an important rol e in equipment design considerations. The influence of a prior thermal ageing on the tensile strength values and the hot hardness of the aus tinitic iron bose alloy Alloy 800HT is examined in this work. It was t herefore necessary to carry out tensile and hot hardness tests with th e solution treated and overaged material at ranges between room temper ature and 900 degrees C. The microstructural changes are investigated using ligthmicroscopy SEM and TEM. The changes of the material propert ies with thermal pretreatment conditions is studied and discussed in t he context of the determined microstructural development.