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Heat-resistant Steels Containing 8 pct Cr.
MISSING :9 pages
The U.S. Bureau of Mines investigated fe-base alloys containing 8 pct cr with ni, al, and si additions as substitutes for standard aisi type 304 stainless steel (ss) in high-temperature oxidizing applications. The objective of this study was to reduce the amount of cr required to make an austenitic stainless steel while retaining satisfactory workability, mechanical properties, and oxidation resistance. Alloys prepared in this investigation had a composition of fe-8cr-1mn-0.07C with varying amounts of ni, al, and si. A minimum of 10 pct ni was required to achieve an austenitic composition. The microstructures of the austenitic alloys were very susceptible to room-temperature deformation-induced martensitic transformations. When the alloys were cold-worked or stressed, the materials had far greater tensile strengths than type 304 ss at room temperature. At higher temperatures, tensile strengths and workability of several of the alloys were comparable to that of type 304 ss. Although martensitic transformation caused the room- temperature properties of the experimental alloys to be quite different than those of type 304 ss, the superior oxidation reistance and similar hot workability of several alloys encourage their use as replacements for type 304 ss.
IH; Report of Investigations;
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division