This EU RONORM specifies a method for the spectrophoto-metric determination of nitrogen in steels.
The method is primarily intended for the determination of total nitrogen in very low nitrogen non-alloy steels. It may be used, however, for any low nitrogen ferrous alloy that is soluble in hydrochloric acid provided that the acid-resistant form of silicon nitride is not present. This highly resistant nitride has been found only in samples of silicon steels manu-
factured without aluminium addition and then only in sheet material.
The method is applicable to nitrogen contents from 0.0005 to 0.005% (m/m).
NOTE - The method has also been successfully applied to a pure iron with a nitrogen content of 0.0038% (m/m) — see Annex.