Creep resistant Ni-based superalloy casting and method of manufacture for advanced high-temperature applications

A method of casting a creep-resistant Ni-based superalloy, the method comprising:

• forming a feed stock comprising Nickel (Ni) and at least one of Chromium (Cr), Cobalt (Co), Aluminum (Al), Titanium (Ti), Niobium (Nb), Iron (Fe), Carbon (C), Manganese (Mn), Molybdenum (Mo), Silicon (Si), Copper (Cu), Phosphorus (P), Sulfur (S) and Boron (B);
• and
• fabricating an as-cast article comprising creep-resistant Ni-based superalloy in a predetermined shape using the feed stock and at least one process comprising vacuum induction melting (VIM), electroslag remelting (ESR) and/or vacuum arc remelting (VAR), wherein fabricating the creep-resistant Ni-based superalloy comprises:
• melting the feed stock in a furnace, forming a liquid metal;
• pouring the liquid metal into a preheated mold, forming a molten metal;
• solidifying the molten metal in the preheated mold, forming the as-cast article;
• and
• homogenizing the as-cast article, wherein homogenizing the as-cast article comprises a heating sequence of one hour at about 1075° C., three hours at about 1125° C., eight hours at about 1200° C. and eight hours at about 1250° C., wherein the homogenizing the as-cast article forms a specific element segregation below ±1% variation from the nominal chemistry of these elements throughout the as-cast article.

A method of casting a creep-resistant Ni-based superalloy, the method comprising:

• forming a feed stock comprising Nickel (Ni) and at least one of Chromium (Cr), Cobalt (Co), Aluminum (Al), Titanium (Ti), Niobium (Nb), Iron (Fe), Carbon (C), Manganese (Mn), Molybdenum (Mo), Silicon (Si), Copper (Cu), Phosphorus (P), Sulfur (S) and Boron (B);
• and
• fabricating an as-cast article comprising creep-resistant Ni-based superalloy in a predetermined shape using the feed stock and at least one process comprising vacuum induction melting (VIM), electroslag remelting (ESR) and/or vacuum arc remelting (VAR), wherein fabricating the creep-resistant Ni-based superalloy comprises:
• melting the feed stock in a furnace, forming a liquid metal;
• pouring the liquid metal into a preheated mold, forming a molten metal, wherein preheating the mold comprises heating the mold to about 300° C. to about 700° C. from about 10 minutes to about 5 hours;
• solidifying the molten metal in the preheated mold, forming the as-cast article;
• and
• homogenizing the as-cast article, at least two of the sequential steps of treating the cast alloy:
• 0.5 to 5 hours at 1075±25° C.;
• 1.5 to 3 hours at 1125±25° C.;
• 3 to 15 hours at 1200±25° C.;
• 3 to 24 hours at 1250±25° C., wherein the homogenizing the as-cast article forms a specific element segregation below ±1% variation from the nominal chemistry of these elements throughout the as-cast article.