An assessment of tensile, irradiation creep, creep rupture, and fatigue behavior in austenitic stainless steels with emphasis on spectral effects

Weldability of neutron irradiated austenitic stainless steels

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/52690/1/JNM-D-12-00519-2.pdf

Surface cracking on Σ3, Σ9 CSL and random grain boundaries in helium implanted 316L austenitic stainless steel

Re-weldability tests of irradiated austenitic stainless steel by a TIG welding method

The effect of an applied stress on the welding of irradiated steels

Helium was implanted in type 316 stainless steel, through tritium decay, to levels of 0. 18, 2. 5, 27, 105, and 256 atomic parts per million (appm). Bead-on-sheet welds were then made using the gas tungsten arc (GTA) process. Intergranular cracking occurred in the heat-affected zones (HAZs) of specimens with helium concentrations equal to or greater than 2.5 appm. No such cracking was observed in helium-free control specimens or in specimens containing the lowest helium concentration. In addition to the HAZ cracking, brittle, centerline cracking occurred in the fusion zone of specimens containing 105 and 256 appm helium. Transmission and scanning electron microscopy results indicated that both the HAZ cracking and centerline cracking in the fusion zone resulted from the stress-induced growth and coalescence of cavities initiated at helium bubbles on interfaces. For the HAZ case, the cavity growth rate is modeled and shown to predict the experimentally measured 1-second time lag between peak weld temperature and the onset of cracking.

H. T. Lin

Papers

Cavity microstructure and kinetics during gas tungsten arc welding of helium-containing stainless steel