Accession Number : AD0437105


Title :   EVALUATION OF 18NI-9CO-5MO (300 KSI) MARAGING STEEL SHEET; PART II: METALLOGRAPHIC PROPERTIES AND METALLURGICAL CONSIDERATIONS,


Corporate Author : DOUGLAS AIRCRAFT CO INC SANTA MONICA CALIF


Personal Author(s) : Corn,D L


Report Date : 06 Feb 1964


Pagination or Media Count : 62


Abstract : An investigation of 18Ni-9Co-4Mo maraging steel revealed the grain size of the as-received material to be less than ASTM 8. Annealing at 1800 F for 6 hours increased this size to approximately ASTM 4. Annealing in the range 1200 F to 1250 F verified that austenite is formed and retained in significant amounts upon cooling to room temperature. It is suggested the stabilized austenite is surrounded by a ferrite envelope. Mechanical properties of annealed material are discussed. Material containing stabilized austenite displays annealed tensile properties which are a function of annealing temperature and time at annealing temperature. All microstructures representing the effects of aging alone were very similar. However, areas containing reverted austenite were observed in a specimen that had been aged at 950 F. Annealing had an observable influence on aged microstructure. Photomicrographs of annealed-and-aged specimens are presented which permit the approximation of the prior annealing temperature. (Author)


Descriptors :   *MARAGING STEELS , *SHEETS , HEAT TREATMENT , NICKEL ALLOYS , COBALT ALLOYS , MOLYBDENUM ALLOYS , AUSTENITE , MARTENSITE , PHASE STUDIES , FERRITES , MICROSTRUCTURE , MECHANICAL PROPERTIES , PHOTOMICROGRAPHY


Distribution Statement : APPROVED FOR PUBLIC RELEASE