Abstract
Cr-Mo-V cast steel was subjected to high temperature tensile tests, creep rupture tests and thermal fatigue tests to investigate the effect of aluminium deoxidation, cast block size and heat treatment on its high temperature properties (Its tensile strength, rupture strength and thermal fatigue resistance).
The tensile test data show that the austenitizing temperature and the cooling rate are primary factors for the tensile strength of Cr-Mo-V cast steel. They show also that the strong deoxidation (Al 0.9kg/ton) reduces not only variation of the tensile test data owing to elimination of microporosities, but slightly decreases the ultimate strength and the 0.2% proof stress.
Strong deoxidation impairs the rupture strength and ductility of Cr-Mo-V cast steel, normalized and tempered. Its double step heat treatment, however, improves its rupture ductility, although it reduces its rupture strength.
The result of the thermal-fatigue tests of Cr-Mo-V cast steel shows its superior thermal-fatigue resistance to that of Cr-Mo cast steel.
