Rates ranged from near zero to almost 30,000 mdd at 30°C depending on the type of steel used. No cracking or pitting was observed. This variation did not correlate effectively with grain size or roughness factor, but may be related either to the amount or distribution of minor constituents in the steel. Both mechanical stress and quenching from 1000°C increased the dissolution rate. The reduction reaction was in part, if not wholly, nitrate to nitrite. The corrosion product was nonprotective and often nonadherent and appeared to be a hydrated or ammoniated iron (11) hydroxide.
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Goodrich et al. (1961) studied this question.