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The effects of nitrogen content on the susceptibility of AISI Type 304 stainless steel to stress corrosion cracking have been studied by exposing U-bend specimens of the alloy containing various amounts of nitrogen to boiling magnesium chloride solutions. It was found that nitrogen in solid solution in Type 304 stainless steel reduces the resistance of the alloy to stress corrosion. Increasing amounts of nitrogen cause shorter times to crack initiation and more rapid failures by increasing the rate of propagation. The susceptibility of Type 304 is further increased by thermally aging the stressed U-bend specimens at 154 C before exposing them to the corrosive medium. The observations from this investigation seem to support those past theories which suggested that the increased susceptibility of austenitic stainless steels with higher nitrogen contents was due to the formation of nitrogen-rich areas within the austenitic matrix.

Internal-friction studies were made on 304 austenitic stainless steel to determine if this is a valid method for measuring interstitial diffusion in face-centered metals and alloys. Both unnitrided and nitrided 304 stainless steel wires were tested in a torsional pendulum at frequencies from 0.33 to 1.1 cps. Internal-friction spectra were recorded and analyzed. The conclusions reached were that interstitial atoms can cause relaxation peaks to appear on the internal-friction spectra and that the observed peaks were much broader than nitrogen-induced peaks in body-centered cubic materials.