The effects of nitrogen concentration between 0.27 per cent and 1.30 per cent on internal friction peaks in 304L stainless steel

Abstract

An investigation was conducted to determine the effect of nitrogen concentration between 0.27 percent and 1.30 percent on the internal friction peaks in 304L stainless steel. The amplitude of the internal friction peak associated with the stress-induced diffusion of interstitial nitrogen increased as a linear function of the nitrogen content. The activation energy of diffusion was found to decrease with an increase in nitrogen content.

The presence of another internal friction peak was observed in the spectrum of the sar.iple containing 1.30 percent nitrogen. A metallographic investigation and a change in the magnetic properties of the specimens after testing along with the disappearance of the internal friction peak caused by nitrogen diffusion when the specimen was rerun indicated that the second peak probably resulted form a chromium-nitrogen interaction.