Effects of loading rate and temperature on J-R fracture resistance of an SA516-Gr.70 steel for nuclear piping

The effects of loading rate and temperature on the fracture resistance of a n ASME SA516-Gr.70 steel for nuclear piping were investigated through J-R t ests conducted in the wide ranges of temperatures, including reactor operat ing temperature, and loading rates, including quasi dynamic rate. Tensile p roperties were also investigated in the temperature range of 100-316 degree s C over a range of strain rates. The test results indicated that the SA516 -Gr.70 steel was very susceptible to dynamic strain aging (DSA). The fractu re resistance showed a minimum in the temperature range between 200 and 400 degrees C, depending on loading rate. The temperature for minimum was move d to higher temperature as the loading rates were increased. The minimum wa s discussed in the viewpoints of DSA that is manifested by elevated tempera ture tensile tests. The crack tip strain rates of fracture specimens were a lso correlated with the strain rates of tensile tests to interpret the DSA effect. (C) 1999 Elsevier Science Ltd. All nights reserved.