Tensile Properties of AISI Types 304 and 347 Stainless Steels at Moderate Temperatures for Section Sizes Ranging From Bars to Extremely Large Forgings

The tensile properties of AISI types 304 and 347 annealed stainless steels were investigated for the temperature range from 75 to 800 F. Several lots of materials were studied in each of several section sizes ranging from bar stock to extremely large forgings. A considerable variation in properties, particularly yield strength and elongation, were observed between different lots of a given type of steel of a given size category. These variations correlated with variations in the annealed hardness and are attributed to the use of different annealing treatments by the suppliers. At equivalent hardness levels the properties obtained from the various section sizes were comparable. Within any given lot or forging the properties were quite uniform for equivalent specimen orientations. The transverse ductility of the large forgings was considerably less than the longitudinal ductility. However, this relatively poor ductility did not lead to notch sensitivity or embrittlement problems.