INCOLOY? alloy MA956 (UNS S67956), first developed as an aerospace superalloy and now used in a range of industrial applications, combines excellent strength and fabricability with outstanding resistance to prolonged exposure up to 1300°C (2400°F). Its exceptional properties result from the mechanical alloying process by which it is made; a process which allows a fine distribution of yttrium oxide particles to be incorporated into a highly corrosion-resistant Fe-Cr-Al alloy. The alloy has excellent oxidation resistance up to 1300°C (2400°F) and significant creep strength up to its unusually high melting point of 1482°C (2700°F). Thicker sections may be used up to 1370°C (2500°F). Typical industrial applications include hearth rollers, radiant tubes, furnace muffles, fluidized bed retorts, heat treatment baskets, mesh belts, heat shields, burner nozzles, sensor tubes for thermowells and combustion chamber components for diesel engines. A full range of both hot and cold-worked mill products is available. The forming and machining characteristics are similar to those of conventional highchromium ferritic steels and Fe-Cr-Al alloys. Table 1. Limiting Chemical Composition, wt.% Publication Number SMC-008 Copyright ? Special Metals Corporation, 2004 (Sept 04) INCONEL, INCOLOY, and 800HT are trademarks of the Special Metals Corporation group of companies. The data contained in this publication is for informational purposes only and may be revised at any time without prior notice. The data is believed to be accurate and reliable, but Special Metals makes no representation or warranty of any kind (express or implied) and assumes no liability with respect to the accuracy or completeness of the information contained herein. Although the data is believed to be representative of the product, the actual characteristics or performance of the product may vary from what is shown in this publication. Nothing contained in this publication should be construed as guaranteeing the product for a particular use or application. Iron ...............................................................................Balance* Chromium ...................................................................18.5-21.5 Aluminum ....................................................................3.75-5.75 Titanium...........................................................................0.2-0.6 Carbon..........................................................................0.1 max. Yttrium oxide...................................................................0.3-0.7 Copper........................................................................0.15 max. Manganese .................................................................0.30 max. Cobalt ...........................................................................0.3 max. Nickel..........................................................................0.50 max. Phosphorus ................................................................0.02 max. Physical Properties Melting point 1480°C (2700°F) Density 7.25 g/cm3 (0.262 lb/in3) The unusually high solidus is 100-200°C higher than for most high-temperature nickel-base superalloys. Even at these extremely high temperatures the dispersion of yttrium oxide provides dimensional and structural stability and prevents embrittlement due to grain growth. The low density is only 70% that of molybdenum allowing INCOLOY alloy MA956 to be economically substituted for similar size fixtures in vacuum furnaces. The lower mass also reduces loading stresses. Unlike molybdenum, the alloy is completely immune to accidental exposure to air at elevated temperatures. *Reference to the ‘balance’ of an alloy’s composition does not guarantee this is exclusively of the element mentioned, but that it predominates and others are present only in minimal quantities.
