This document specifies a spectrophotometric method for the determination of nitrogen in steels.
The method is primarily intended for the determination of total nitrogen in very low contents in non-alloy steels.
It can 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. These highly resistant nitrides have been found only in samples of silicon steels manufactured without aluminium addition and then only in sheet material.
The method is applicable to nitrogen contents from 0,000 5 % (by mass) to 0,005 % (by mass).
The precision data of the present method are given in Annex A.