Plane stress fractur toughness evaluation of removable radial shield assembly materials

The principal objective of this program was to determine the suitability of small surveillance specimens, such as precracked Charpys and small compact specimens to detect and accurately represent toughness changes in 316 stainless steel from irradiation damage. The materials were 316 stainless cold rolled 20% as baseline and cold rolled 50% to simulate the irradiation damaged condition. Specimens were: standard compacts 3.2 mm (0.125 inch) thick but of 1/2T, 1T and 4T plan view sizes. Jsub(R)-Curves were developed and these were compared to results from subsize Charpys, both precracked and machine notched, and single edge tension, SE(T) specimens. All were constant thickness at (0.125-inch) 3.2 mm. Loading was both static and dynamic. Whenever possible, thoughness evaluation was by J and the Jsub(R)-Curve behaviors. The Jsub(R)-Curve behavior was found to be specimen size and geometry independent. Increased cold reduction from 20% to 50% increased strength and reduced toughness. These effects were observed in all specimen types and sizes from Charpy size to SE(T) size. Dynamic strain rates increased strength and lowered Jsub(R)-Curve toughness. Trends established by Jsub(R)-Curve were always evident in the Charpy results. (orig.)