ON THE CORROSION OF SINGLE CRYSTALS, BICRYSTALS AND POLYCRYSTALS OF AN AUSTENITIC STAINLESS STEEL IN BOILING NITRIC ACID
Abstract
Single crystals, bicrystals and polycrystals of 20%Cr-20%Ni austenitic stainless steel were corroded in boiling nitric acid. The weight loss was independent of crystallographic orientation, grain size, and heat treatment. Metallographic observations showed no correlation between weight loss and microstructure. Adding 5 g/liter of Cr(6+), which is known to accelerate rates by one to two orders of magnitude, did not change the above conclusions. No significant change in the corrosion rates and morphologies occurred for single and bicrystals, even for those of high carbon (0.06%) and high nitrogen (0.24%) content, after aging under conditions which normally produce marked sensitization in polycrystalline samples. The morphology of attack was a complex combination of pitting and grain boundary attack dependent on thermal history and grain misorientation, but these effects were not reflected in the over-all corrosion rate unless grain dropping occurred.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 23, 1962
- Accession Number
- AD0273777
Entities
People
- H.w. Paxton
- R.d. Leggett
Organizations
- Carnegie Institute of Technology