ABSTRACT
Few of the non-ferrous metals are suitable for high temperature service and non-metalIics should generally be avoided. Consequently, first consideration should be given to ferrous materials, ranging from the medium carbon steels through the super alloys. For service temperatures up to 450°F (230°C) the commercial grades of medium carbon and alloy steels, frequently used in fastener manufacture, will perform satisfactorily. From 450°F to about 900°F (480°C) stainless steels and the chrome-moly steels in the AISI 4100, 8600 and 8700 series (covered by ASTM A193) are adequate. For higher temperature service one of the specialIy developed heat resistant super alloys must be used. For instance A-286 and Inco 718 exhibit reasonably good strength properties to about 1200°F (650°C) while the nickelcobalt alloys such as M252, Waspalloy, Udimet, and Rene 41 are good up to 1600°F (870°C). Beyond this temperature the designer must turn to refrac-
tory metals with their high alloy content of columbium, molybdenum, tantalum, or tungsten. Some of the tungsten alloys have performance capability in temperatures exceeding 3000°F (l650°C).
