Alloy Additions for Improved Creep-Rupture Properties of a Cast Austenitic Alloy

摘要

A new cast austenitic alloy, CF8C-Plus, has been developed by Oak Ridge National Laboratory (ORNL) and Caterpillar for a wide range of high temperature applications including diesel exhaust components and turbine casings. The creep strength of CF8C-Plus is much greater than that of the standard cast CF8C and comparable to the highest strength wrought commercial stainless steel alloys. Further alloy modifications typical in some commercial wrought stainless steel alloys are being pursued for increased creep strength, high-temperature stability, and corrosion resistance. The effect of these alloy additions, namely B, W, Cu, and Al, on tensile and creep strength are discussed in terms of the observed microstructural changes. The addition of Cu was found to be beneficial to the creep strength of the alloy while the addition of W had little effect on either tensile and creep properties. The addition of Al, and to a lesser degree B, decreased the tensile and creep strength of the alloy.